Extraction of phthalate esters from water and beverages using a graphene
红薯叶多糖提取工艺流程
红薯叶多糖提取工艺流程英文回答:The extraction process of polysaccharides from sweet potato leaves can be divided into several steps. Here is a general outline of the process:1. Preparation of sweet potato leaves: The first step is to collect fresh sweet potato leaves and wash them thoroughly to remove any dirt or impurities. The leaves are then dried and ground into a fine powder.2. Extraction: The powdered sweet potato leaves are mixed with a suitable solvent, such as water or ethanol, in a specific ratio. The mixture is then heated and stirredfor a certain period of time to allow the polysaccharides to dissolve in the solvent.3. Filtration: After the extraction process, the mixture is filtered to remove any insoluble impurities.This can be done using filter paper or other filtration methods.4. Concentration: The filtrate containing the dissolved polysaccharides is then concentrated to remove the solvent and obtain a concentrated polysaccharide solution. This can be achieved through methods like evaporation or freeze-drying.5. Purification: To further purify the polysaccharides, various techniques can be employed, such as precipitation with ethanol or acetone, dialysis, or chromatography. These methods help remove any remaining impurities and isolate the polysaccharides.6. Drying: The purified polysaccharides are then dried to obtain a solid form. This can be done through methods like spray drying or vacuum drying.7. Characterization: Finally, the extracted polysaccharides can be characterized using various analytical techniques, such as infrared spectroscopy ornuclear magnetic resonance spectroscopy, to determine their chemical composition and structural properties.中文回答:红薯叶多糖的提取工艺流程可以分为几个步骤。
固相萃取-气相色谱法测定水环境中邻苯二甲酸酯
固相萃取-气相色谱法测定水环境中邻苯二甲酸酯沈斐;苏晓燕;李睿;朱培瑜;许燕娟;陈静【摘要】采用固相萃取法对水样进行提取富集,气相色谱法测定水中6种邻苯二甲酸酯类有机污染物,并对方法进行了探索、优化和验证。
对水体pH在固相萃取过程中对邻苯二甲酸酯萃取回收率的影响进行了研究,解决了邻苯二甲酸2-乙基己基酯和邻苯二甲酸二正辛酯回收率不高的问题。
在空白水加标实验中,邻苯二甲酸酯的回收率能达到93.2%~116.3%。
除此之外,还对工业废水和地表水进行了加标回收实验,获得了较高的回收率及测定精度。
%The development, optimisation and validation of a method for the determination of trace levels of phthalate esters in aqueous media is described. Extraction is by solid phase extraction followed by GC analysis. By adjusting the pH to the sample before the SPE, the recovery may be improved when di-(2-ethylhexyl) phthalate ( DEHP) and di-n-octylphthalate ( DnOP) determination is required. The accuracy determined as recovery was93.2%-116.3% for both compounds in distilled water. In addition, recoveries and method precision of phthalates were measured in wastewater and surface water.【期刊名称】《中国环境监测》【年(卷),期】2014(000)001【总页数】4页(P150-153)【关键词】邻苯二甲酸酯;固相萃取;pH;气相色谱【作者】沈斐;苏晓燕;李睿;朱培瑜;许燕娟;陈静【作者单位】无锡市环境监测中心站,江苏无锡214000;无锡市环境监测中心站,江苏无锡 214000;无锡市环境监测中心站,江苏无锡 214000;无锡市环境监测中心站,江苏无锡 214000;无锡市环境监测中心站,江苏无锡 214000;无锡市环境监测中心站,江苏无锡 214000【正文语种】中文【中图分类】X830.2邻苯二甲酸酯是环境中常见的有机污染物,特别是作为塑料增塑剂,由于未聚合到塑料基质中,随着使用时间的推移,逐渐转移到环境中,造成对大气、水体和土壤等的污染。
食用植物油中邻苯二甲酸酯类塑化剂的分析
食用植物油中邻苯二甲酸酯类塑化剂的分析白羽;杨丹;惠菊【摘要】本文采用随机抽样的方法,抽取120份市售食用植物油样品,采用气相色谱-质谱法检测了3种邻苯二甲酸酯类塑化剂的浓度,并进行危害性评估.结果表明,120份样品中,邻苯二甲酸二丁酯(DBP)的检出率为10.8%,最高检出浓度为33.12%.邻苯二甲酸二(2-乙基)己酯(DEHP)和邻苯二甲酸二异壬酯(DINP)未检出.对当前市售食用植物油中邻苯二甲酸酯类(PAEs)塑化剂的含量进行监测,有助于了解市售食用植物油中塑化剂的污染状况,为食用植物油的安全监管提供理论依据.【期刊名称】《粮食与食品工业》【年(卷),期】2019(026)001【总页数】4页(P1-4)【关键词】食用植物油;邻苯二甲酸酯;塑化剂【作者】白羽;杨丹;惠菊【作者单位】北京城市学院北京 100083;国贸食品科技(北京)有限公司北京102209;中粮营养健康研究院有限公司,营养健康与食品安全北京市重点实验室北京 102209;中粮营养健康研究院有限公司,营养健康与食品安全北京市重点实验室北京 102209【正文语种】中文【中图分类】TS221邻苯二甲酸酯类(phthalic acid esters,PAEs)塑化剂是被广泛应用在食物包装材料中的高分子材料助剂[1],广泛存在于空气、土壤、水体及生物体内的污染物[2]。
国内外有研究表明,邻苯二甲酸酯类塑化剂是一类类雌性激素,具有不同程度的肾毒性、生殖毒性、发育毒性和其他毒性,如邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基)己酯(DEHP)和邻苯二甲酸二异壬酯(DINP)[3]。
美国国家癌症研究所对PAEs进行了动物实验,结果表明DEHP对动物具有致癌作用,对人类还无法证实。
Saillenfait等发现DBP对胚胎有致畸的作用,而我国也进行了相关的毒理性研究,研究表明DINP对生殖、发育和癌症有一定的影响[4-6]。
邻苯二甲酸酯类塑化剂疑似环境荷尔蒙,对健康危害相当大,一旦通过呼吸道、消化道和皮肤等途径进入人体,由于其性质溶于脂肪不溶于水,便会积蓄在脂肪中不易排出,从而导致人体内残留高浓度的邻苯二甲酸酯[7-8]。
缺陷UiO-66对水中塑化剂的吸附
CHEMICAL INDUSTRY AND ENGINEERING PROGRESS 2018年第37卷第3期·1062·化 工 进展缺陷UiO-66对水中塑化剂的吸附白杨,张尔攀,赵红挺(杭州电子科技大学材料与环境工程学院,浙江 杭州 310018)摘要:金属有机骨架材料(metal-organic frameworks ,MOFs )是一种具有骨架结构的新型多孔材料。
本研究合成了金属有机框架化合物UiO-66和有缺陷的UiO-66(UiO-66-1),并研究了其作为吸附剂吸附塑化剂邻苯二甲酸二甲酯(DMP )的性能及其吸附动力学,最后通过拟合吸附等温线和吸附动力学模型拟合了吸附剂的最大吸附量和最快吸附时间。
实验结果表明,UiO-66-1对DMP 有更好的吸附性能,在5~10min 内快速达到吸附平衡,pH 在3~10吸附率仍可保持稳定;分析测试结果表明,引入缺陷的UiO-66-1的比表面积比UiO-66大,达到了1438m 2/g ,孔容为0.58cm 3/g ,晶体的尺寸也明显增大,吸附量增大了近一倍,最大吸附量可达到404mg/g ,且循环利用率高;通过吸附等温线模型和吸附动力学模型的拟合研究表明,UiO-66-1的吸附过程比较符合Langmuir 模型和拟二级动力学模型。
关键词:聚合物;污染;吸附(作用)中图分类号:O625;O627 文献标志码:A 文章编号:1000–6613(2018)03–1062–08 DOI :10.16085/j.issn.1000-6613.2017-0637Defected UiO-66 for adsorption of plasticizer in aqueous phaseBAI Yang ,ZHANG Erpan ,ZHAO Hongting(College of Materials and Environmental Engineering ,Hangzhou Dianzi University ,Hangzhou 310018,Zhejiang ,China )Abstract: Metal-organic frameworks (MOFs) are a new type of porous materials with skeletal structure.In this study ,two metal organic framework compounds (MOFs),namely ,UiO-66 and defective UiO-66 (UiO-66-1)were synthesized and evaluated for their adsorption for plasticizer dimethyl phthalate (DMP )from aqueous solution. Results showed that UiO-66-1 had better DMP adsorption performance than that of UiO-66. For UiO-66-1,the adsorption kinetics results showed that 5—10min was sufficient to reach equilibrium. The adsorption rate remained stable at b pH between 3—10. The adsorption kinetics could be well described by using a quasi-second-order kinetics model. Analysis results showed that defective UiO-66-1 had much higher specific surface area and pore volume compared to UiO-66,reaching as high as 1438m 2/g and 0.58cm 3/g ,respectively ,thereby enabling a better adsorption performance for DMP. The maximum adsorption capacity of UiO-66-1,as fitted by using Langmuir model ,could reach as high as 404mg/g ,twice as much as that of UiO-66. Moreover ,the MOFs could also be recycled for adsorption. Key words: polymers ;pollution ;adsorption邻苯二甲酸酯类物质(phthalate esters ,PAEs )是一类常用的塑化剂,可以改善材料的灵活性和耐久性[1-2],普遍存于人们日常生活的各个方面,空气、土壤、水、酒、方便面甚至药品中都检测到了塑化收稿日期:2017-04-11;修改稿日期:2017-11-15。
食品中邻苯二甲酸酯类增塑剂含量的测定(经正己烷溶解、超声波辅助提取、固相萃取浓缩)
食品中邻苯二甲酸酯类增塑剂含量的测定柴丽月1,辛志宏1,蔡 晶2,俞美香3,胡秋辉1,*(1.南京农业大学食品科技学院,江苏 南京 210095;2.江苏省产品质量监督检验中心所,江苏 南京 210029;3.江苏省环境检测中心,江苏 南京 210036)摘 要:采用气相色谱法测定14种食品中5种邻苯二甲酸酯[邻苯二甲酸二甲酯( DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二乙酯(DBP)、邻苯二甲酸二(2-乙基己基)酯(DEHP)、邻苯二甲酸二正辛酯(DnOP)]的含量。
样品经正己烷溶解、超声波辅助提取、固相萃取浓缩富集等预处理,以保留时间定性,外标法定量。
结果表明,该分析条件下样品的回收率为72.3%~101.5%,相对标准偏差为2.69%~5.84%,说明本方法准确可靠。
14种食品中检出的邻苯二甲酸酯类约69%的含量高于欧洲规定的每天0.3 mg/kg 体重的标准,表明邻苯二甲酸酯类污染物在被检食品中有较大的的迁移。
关键词:邻苯二甲酸酯;检测;气相色谱Determination of Phthalate Plasticizers in FoodsCHAI Li-yue 1,XIN Zhi-hong 1,CAI Jing 2,YU Mei-xiang 3,HU Qiu-hui 1,*(1.College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China ;2.Jiangsu Provincial Supervising and Testing Center for Products Quality, Nanjing 210029, China ;3.Jiangsu Environmental Monitoring Center, Nanjing 210036, China)Abstract :A capillary gas chromatographic method with flame ionization detector (GC-FID) for the detection of five phthalates dimethyl phthalate (DMP), di-ethyl phthalate (DEP), di-butyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP) and dioctyl phthalate (DnOP) in 14 kinds of foods was developed. The samples were extracted with hexane by ultrasonically assisted procedure. The extracts were cleaned up with SPE and determined by GC. Retention time of the peaks was applied for qualitative analysis, and external standard method was used for quantitative analysis. Results showed that the recoveries of the five phthalates are between 72.3% and 101.5% with relative standard deviations of 2.69%~5.84%. Consequently, this method is accurate and credible. In Europe, the total tolerable daily intake (TTDI) of total phthalate esters per person has been estimated to be 0.3 mg/kg body weight. The contents of about 69% of the phthalates detected in foods are more than 0.3 mg/kg, over the Europe standard. This indicates that there is quite high concentration of the phthalates migrating into foods.Key words :phthalates ;determine ;GC中图分类号:TS207.5 文献标识码:A 文章编号:1002-6630(2008)07-0362-04收稿日期:2008-04-20基金项目:江苏省自然科学基金项目(BK2007576)作者简介:柴丽月(1981-),女,硕士研究生,研究方向为食品安全。
气相色谱法测定冷加工糕点中反式脂肪酸的含量
142立的方法能够满足PAEs的检测需要。
参考文献:[1]孙树萍, 阮文举. 食品塑料包装中有害物质[J]. 化学教育,2007,28(6):3-5.[2]JOSEF, JIMENEZL, RUBIOS, et al. Determination of phthalate esters in sewage by hemimieues-based soild-phase extraction and liquid chromatography-mass spectrometry[J]. Analytica Chimica Acta, 2005, 551(1-3):142-149.[3] Li XJ, Zeng Z R, Chen Y, et al. Determination of phthalate a c i d e s t e r s p l a s t i c i z e r s i n p l a s t i c b y u l t r a s o n i c s o l v e n t e x t r a c t i o n combined with solid-phase microextraction using calyxarene fiber[J]. Talanta, 2004, 63:(10)1013-1019.[4] Gomez-Hens A., Aguilat-Caballos M R. Social an d economic interest in the control of phthalic acid esters[J]. Trends in Analytical Chemistry, 2003, 22(11):847-857.[5] Xue, Kunzhao, Gu, Pengyang, Yu, Juewang. Adsorption of Dimethyl Phthalate on Marine Sediments[J]. Water, air and soil pollution, 2004, 157:(1-4)179-192.[6] Loff PD, Subotic U., Oulmi-Kagerman J., et al. Diethylhexylphthalate (DEHP) extracted by typical newborn lipid emulsions from polyvinylchloride in fusion systerns causes significant changes in histology of rabbit liver[J]. JPEN J PARENTER ENTERAL NUTR, 2007, 31:(3)188-193.[7] Pogribny IP, Tryndyak VP, Boureiko A., et al. Mechanismsof peroxisome proliferator induced DNA hypomethylation in rat Liver[J]. Mutat Res, 2008, 644:(1-2)17-23.[8] 孙利, 陈志峰, 雍伟, 等. 与食品接触的塑料成型品中邻苯二甲酸酯类增塑剂迁移量的测定[J]. 中国为啥检验杂志, 2008, 18(3):93-428.[9] 赵文红. 酞酸酯类增塑剂毒理研究进展[J]. 环节与职业医学, 2003, 20(2):135-138.[10] Api AM. Toxicological profile of diethyl phthalate: a vehicle for fragrance and cosmetic ingredients [J]. Food Chem Toxicol, 2001, 39(2)97-108.[11]Eve M, Russell CC, Paul MD. Male reproductive tractmalformations in rats following gestational and lactational exposure to di(n2butyl ) phthalate: an antiandrogenic mechanism [J]. Toxicol Sci, 1998, 43(1):47-48.[12] 吴刚. 虞慧芳. 傅科杰, 等. 食品塑料包装材料中邻苯二甲酸酯类化合物的GC -MS分析方法[J]. 检验检疫科学, 2006, 16(5):33-35.[13] 张双灵, 徐仰丽, 王世清. 食品塑料包装袋中DEHP气相色谱检测方法的建立[J].食品科学,2007,8(28):341-344.[14] 赵俊虹. 气质联用法检测塑料包装西式火腿肠中邻苯二甲酸酯类增塑剂[J].粮油加工,2010,(5)131-133.[15]中华人民共和国国家标准. 中华人民共和国卫生部, 中国国家标准化管理委员会ICS67.040, C53. 食品容器、包装材料用添加剂使用卫生标准[s].气相色谱法测定冷加工糕点中反式脂肪酸的含量彭亚锋*,符昌雨,杨保刚上海市质量监督检验技术研究院/国家食品质量监督检验中心(上海 200233)摘要用气相色谱法分析了我国广大消费者所喜欢的的23批次冷加工糕点。
邻苯二甲酸酯的毒性及相关限制法规
邻苯二甲酸酯的毒性及相关限制法规郭永梅【摘要】With the "Taiwan Clounding Agent Event", phthalate esters are concerned. As plastic additives, phthalate esters are widely used in various fields, especially in the field of packaging. The study found that phthalate esters have mutagenicity, carcinogenicity and teratogenicity and other toxic. They are harmful to human and animal's liver and kidney. Due to weaker interaction between phthalate esters and plastic molecules, phthalate esters could easily migrate to food from food packaging materials. Now every country around the world has formulated relevant policies to restrict the use of phthalate esters. Our country has also developed a series of policies and regulations to control the use of phthalate esters. The research of new detection methods and alternatives will be the main way out to solve the problems of our current phthalate esters in the future.%自台湾“起云剂事件”爆发以来,邻苯二甲酸酯开始为人们所知。
邻苯二甲酸酯的分析方法研究进展
邻苯二甲酸酯的分析方法研究进展作者:陈朝琼严平李茂全魏敏陈卫中【摘要】本文介绍了环境中邻苯二甲酸酯类化合物分析方法的研究进展,对大气、水体、土壤、植物、食品和塑料产品中的邻苯二甲酸酯的样品的预处理方法和检测技术作了综述,并提出了检测中存在的问题和研究前景。
【关键词】邻苯二甲酸酯;样品前处理;气相色谱法;液相色谱法Abstract:The analysis methods of phthalate esters in environment were reviewed.The pretreatment technology and determination methods of different samples in water,soil,air and so on were compared in this paper.Furthermore,the problems in determination and research prospect were mentioned in this paper.Key words:phthalate esters;sample pretreatment;gas chromatography;high performance liquid chromatography1 前言邻苯二甲酸酯(Phthalic Acid Esters,简称PAEs,别名酞酸酯)是一类重要的有机化合物质,常见的有邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二正丁酯(DBP)、邻苯二甲酸二正辛酯(DOP)、邻苯二甲酸二异辛酯(DEHP)和邻苯二甲酸丁基苄酯(BBP)。
PAEs主要用作塑料的增塑剂,增大产品的可塑性和提高产品的强度,也可用作农药载体,驱虫剂、化妆品、香味品、润滑剂和去泡剂的生产原料。
近年来,随着工业生产和塑料制品的使用,邻苯二甲酸酯不断进入环境,普遍存在于土壤、底泥、水体、生物、空气及大气降尘物等环境样品中,成为环境中无所不在的污染物。
EPA 3510C-1996 分液漏斗的液体提取
METHOD 3510CSEPARATORY FUNNEL LIQUID-LIQUID EXTRACTION1.0SCOPE AND APPLICATION1.1This method describes a procedure for isolating organic compounds from aqueous samples. The method also describes concentration techniques suitable for preparing the extract for the appropriate determinative methods described in Section 4.3 of Chapter Four.1.2This method is applicable to the isolation and concentration of water-insoluble and slightly water-soluble organics in preparation for a variety of chromatographic procedures.1.3This method is restricted to use by or under the supervision of trained analysts. Each analyst must demonstrate the ability to generate acceptable results with this method.2.0SUMMARY OF METHOD2.1 A measured volume of sample, usually 1 liter, at a specified pH (see Table 1), is serially extracted with methylene chloride using a separatory funnel.2.2The extract is dried, concentrated (if necessary), and, as necessary, exchanged into a solvent compatible with the cleanup or determinative method to be used (see Table 1 for appropriate exchange solvents).3.0INTERFERENCES3.1Refer to Method 3500.3.2The decomposition of some analytes has been demonstrated under basic extraction conditions. Organochlorine pesticides may dechlorinate, phthalate esters may exchange, and phenols may react to form tannates. These reactions increase with increasing pH, and are decreased by the shorter reaction times available in Method 3510. Method 3510 is preferred over Method 3520 for the analysis of these classes of compounds. However, the recovery of phenols may be optimized by using Method 3520, and performing the initial extraction at the acid pH.4.0APPARATUS AND MATERIALS4.1Separatory funnel - 2-liter, with polytetrafluoroethylene (PTFE) stopcock.4.2Drying column - 20 mm ID Pyrex® chromatographic column with Pyrex® glass wool at bottom and a PTFE stopcock.NOTE:Fritted glass discs are difficult to decontaminate after highly contaminated extracts have been passed through. Columns without frits may be purchased.Use a small pad of Pyrex® glass wool to retain the adsorbent. Prewash theglass wool pad with 50 mL of acetone followed by 50 mL of elution solvent priorto packing the column with adsorbent.CD-ROM3510C - 1Revision 3December 19964.3Kuderna-Danish (K-D) apparatus.4.3.1Concentrator tube - 10-mL, graduated (Kontes K-570050-1025 or equivalent).A ground-glass stopper is used to prevent evaporation of extracts.4.3.2Evaporation flask - 500-mL (Kontes K-570001-500 or equivalent). Attach toconcentrator tube with springs, clamps, or equivalent.4.3.3Snyder column - Three-ball macro (Kontes K-503000-0121 or equivalent).4.3.4Snyder column - Two-ball micro (Kontes K-569001-0219 or equivalent).4.3.5Springs - 1/2 inch (Kontes K-662750 or equivalent).NOTE:The following glassware is recommended for the purpose of solvent recovery during the concentration procedures requiring the use of Kuderna-Danishevaporative concentrators. Incorporation of this apparatus may be requiredby State or local municipality regulations that govern air emissions of volatileorganics. EPA recommends the incorporation of this type of reclamationsystem as a method to implement an emissions reduction program. Solventrecovery is a means to conform with waste minimization and pollutionprevention initiatives.4.4Solvent vapor recovery system (Kontes K-545000-1006 or K-547300-0000, Ace Glass 6614-30, or equivalent).4.5Boiling chips - Solvent-extracted, approximately 10/40 mesh (silicon carbide or equivalent).4.6Water bath - Heated, with concentric ring cover, capable of temperature control (± 5E C). The bath should be used in a hood.4.7Vials - 2-mL, glass with PTFE-lined screw-caps or crimp tops.4.8pH indicator paper - pH range including the desired extraction pH.4.9Erlenmeyer flask - 250-mL.4.10Syringe - 5-mL.4.11Graduated cylinder - 1-liter.5.0REAGENTS5.1Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination. Reagents should be stored in glass to prevent the leaching of contaminants from plastic containers.CD-ROM3510C - 2Revision 3December 1996CD-ROM 3510C - 3Revision 3December 19965.2Organic-free reagent water - All references to water in this method refer to organic-freereagent water, as defined in Chapter One.5.3Sodium hydroxide solution (10 N), NaOH. Dissolve 40 g NaOH in organic-free reagentwater and dilute to 100 mL. Other concentrations of hydroxide solutions may be used to adjustsample pH, provided that the volume added does not appreciably change (e.g., <1%) the totalsample volume.5.4Sodium sulfate (granular, anhydrous), Na SO . Purify by heating to 400E C for 4 hours24in a shallow tray, or by precleaning the sodium sulfate with methylene chloride. If the sodium sulfateis precleaned with methylene chloride, a method blank must be analyzed, demonstrating that thereis no interference from the sodium sulfate. Other concentrations of acid solutions may be used toadjust sample pH, provided that the volume added does not appreciably change (e.g., <1%) the totalsample volume.5.5Sulfuric acid solution (1:1 v/v), H SO . Slowly add 50 mL of H SO (sp. gr. 1.84) to 5024 24mL of organic-free reagent water.5.6Extraction/exchange solvents - All solvents must be pesticide quality or equivalent.5.6.1Methylene chloride, CH Cl , boiling point 39E C. 225.6.2Hexane, C H , boiling point 68.7E C.6145.6.32-Propanol, CH CH(OH)CH , boiling point 82.3E C. 335.6.4Cyclohexane, C H , boiling point 80.7E C. 6125.6.5Acetonitrile, CH CN, boiling point 81.6E C.36.0SAMPLE COLLECTION, PRESERVATION, AND HANDLINGSee the introductory material to this chapter, Organic Analytes, Sect. 4.1.7.0PROCEDURE7.1Using a 1-liter graduated cylinder, measure 1 liter (nominal) of sample. Alternatively, ifthe entire contents of the sample bottle are to be extracted, mark the level of sample on the outsideof the bottle. If high analyte concentrations are anticipated, a smaller sample volume may be takenand diluted to 1-L with organic-free reagent water, or samples may be collected in smaller samplebottles and the whole sample used.7.2Pipet 1.0 mL of the surrogate spiking solution into each sample in the graduated cylinder(or sample bottle) and mix well. (See Method 3500 and the determinative method to be used fordetails on the surrogate standard solution and matrix spiking solution).7.2.1For the sample in each batch (see Chapter One) selected for use as a matrixspike sample, add 1.0 mL of the matrix spiking standard.7.2.2If Method 3640, Gel-Permeation Cleanup, is to be employed, add twice thevolume of the surrogate spiking solution and the matrix spiking standard, since half of the extract is not recovered from the GPC apparatus. (Alternatively, use 1.0 mL of the spiking solutions and concentrate the final extract to half the normal volume, e.g., 0.5 mL instead of1.0 mL).7.3Check the pH of the sample with wide-range pH paper and adjust the pH, if necessary, to the pH indicated in Table 1, using 1:1 (v/v) sulfuric acid or 10 N sodium hydroxide. Lesser strengths of acid or base solution may be employed, provided that they do not result in a significant change (<1%) in the volume of sample extracted (see Secs. 5.3 and 5.5).7.4Quantitatively transfer the sample from the graduated cylinder (or sample bottle) to the separatory funnel. Use 60 mL of methylene chloride to rinse the cylinder (or bottle) and transfer this rinse solvent to the separatory funnel. If the sample was transferred directly from the sample bottle, refill the bottle to the mark made in Sec. 7.1 with water and then measure the volume of sample that was in the bottle.7.5Seal and shake the separatory funnel vigorously for 1 - 2 minutes with periodic venting to release excess pressure. Alternatively, pour the exchange solvent into the top of the Snyder column while the concentrator remains on the water bath in Sec. 7.11.4.NOTE:Methylene chloride creates excessive pressure very rapidly; therefore, initial venting should be done immediately after the separatory funnel has been sealedand shaken once. The separatory funnel should be vented into a hood to avoidexposure of the analyst to solvent vapors.7.6Allow the organic layer to separate from the water phase for a minimum of 10 minutes. If the emulsion interface between layers is more than one-third the size of the solvent layer, the analyst must employ mechanical techniques to complete the phase separation. The optimum technique depends upon the sample and may include stirring, filtration of the emulsion through glass wool, centrifugation, or other physical methods. Collect the solvent extract in an Erlenmeyer flask. If the emulsion cannot be broken (recovery of < 80% of the methylene chloride, corrected for the water solubility of methylene chloride), transfer the sample, solvent, and emulsion into the extraction chamber of a continuous extractor and proceed as described in Method 3520, Continuous Liquid-Liquid Extraction.7.7Repeat the extraction two more times using fresh portions of solvent (Secs. 7.2 through 7.5). Combine the three solvent extracts.7.8If further pH adjustment and extraction is required, adjust the pH of the aqueous phase to the desired pH indicated in Table 1. Serially extract three times with 60 mL of methylene chloride, as outlined in Secs. 7.2 through 7.5. Collect and combine the extracts and label the combined extract appropriately.7.9If performing GC/MS analysis (Method 8270), the acid/neutral and base extracts may be combined prior to concentration. However, in some situations, separate concentration and analysis of the acid/neutral and base extracts may be preferable (e.g. if for regulatory purposes the presence or absence of specific acid/neutral or base compounds at low concentrations must be determined, separate extract analyses may be warranted).7.10Perform the concentration (if necessary) using the Kuderna-Danish Technique (Secs.7.11.1 through 7.11.6).CD-ROM3510C - 4Revision 3December 19967.11K-D technique7.11.1Assemble a Kuderna-Danish (K-D) concentrator (Sec. 4.3) by attaching a 10-mLconcentrator tube to a 500-mL evaporation flask.7.11.2Attach the solvent vapor recovery glassware (condenser and collection device)(Sec. 4.4) to the Snyder column of the K-D apparatus following manufacturer's instructions.7.11.3Dry the extract by passing it through a drying column containing about 10 cm ofanhydrous sodium sulfate. Collect the dried extract in a K-D concentrator. Rinse the Erlenmeyer flask, which contained the solvent extract, with 20 - 30 mL of methylene chloride and add it to the column to complete the quantitative transfer.7.11.4Add one or two clean boiling chips to the flask and attach a three-ball Snydercolumn. Prewet the Snyder column by adding about 1 mL of methylene chloride to the top of the column. Place the K-D apparatus on a hot water bath (15 - 20E C above the boiling point of the solvent) so that the concentrator tube is partially immersed in the hot water and the entire lower rounded surface of the flask is bathed with hot vapor. Adjust the vertical position of the apparatus and the water temperature as required to complete the concentration in 10 -20 minutes. At the proper rate of distillation the balls of the column will actively chatter, butthe chambers will not flood. When the apparent volume of liquid reaches 1 mL, remove the K-D apparatus from the water bath and allow it to drain and cool for at least 10 minutes.7.11.5If a solvent exchange is required (as indicated in Table 1), momentarily removethe Snyder column, add 50 mL of the exchange solvent, a new boiling chip, and reattach the Snyder column. Alternatively, pour the exchange solvent into the top of the Snyder column while the concentrator remains on the water bath in Sec. 7.11.4. Concentrate the extract, as described in Sec. 7.11.4, raising the temperature of the water bath, if necessary, to maintain proper distillation.7.11.6Remove the Snyder column and rinse the flask and its lower joints into theconcentrator tube with 1 - 2 mL of methylene chloride or exchange solvent. If sulfur crystals are a problem, proceed to Method 3660 for cleanup. The extract may be further concentrated by using the technique outlined in Sec. 7.12 or adjusted to 10.0 mL with the solvent last used.7.12If further concentration is indicated in Table 1, either the micro-Snyder column technique (7.12.1) or nitrogen blowdown technique (7.12.2) is used to adjust the extract to the final volume required.7.12.1Micro-Snyder column techniqueIf further concentration is indicated in Table 1, add another clean boiling chip to the concentrator tube and attach a two-ball micro-Snyder column. Prewet the column by adding0.5 mL of methylene chloride or exchange solvent to the top of the column. Place the K-Dapparatus in a hot water bath so that the concentrator tube is partially immersed in the hot water. Adjust the vertical position of the apparatus and the water temperature, as required, to complete the concentration in 5 - 10 minutes. At the proper rate of distillation the balls of the column will actively chatter, but the chambers will not flood. When the apparent volume of liquid reaches 0.5 mL, remove the K-D apparatus from the water bath and allow it to drain and cool for at least 10 minutes. Remove the Snyder column, rinse the flask and its lower joints into the concentrator tube with 0.2 mL of methylene chloride or the exchange solvent, and adjust the final volume as indicated in Table 1, with solvent.CD-ROM3510C - 5Revision 3December 19967.12.2Nitrogen blowdown technique7.12.2.1Place the concentrator tube in a warm bath (35E C) and evaporate thesolvent to the final volume indicated in Table 1, using a gentle stream of clean, drynitrogen (filtered through a column of activated carbon).CAUTION:New plastic tubing must not be used between the carbon trap andthe sample, since it may introduce contaminants.7.12.2.2The internal wall of the tube must be rinsed several times withmethylene chloride or appropriate solvent during the operation. During evaporation, thetube must be positioned to avoid water condensation (i.e., the solvent level should bebelow the level of the water bath). Under normal procedures, the extract must not beallowed to become dry.CAUTION:When the volume of solvent is reduced below 1 mL, semivolatileanalytes may be lost.7.13The extract may now be analyzed for the target analytes using the appropriate determinative technique(s) (see Sec. 4.3 of this Chapter). If analysis of the extract will not be performed immediately, stopper the concentrator tube and store refrigerated. If the extract will be stored longer than 2 days it should be transferred to a vial with a PTFE-lined screw-cap or crimp top, and labeled appropriately.8.0QUALITY CONTROL8.1Any reagent blanks, matrix spikes, or replicate samples should be subjected to exactly the same analytical procedures as those used on actual samples.8.2Refer to Chapter One for specific quality control procedures and Method 3500 for extraction and sample preparation procedures.9.0METHOD PERFORMANCERefer to the determinative methods for performance data.10.0REFERENCESNone.CD-ROM3510C - 6Revision 3December 1996CD-ROM 3510C - 8Revision 3December 1996METHOD 3510CSEPARATORY FUNNEL LIQUID-LIQUID EXTRACTION。
植物油中邻苯二甲酸酯类化合物的一步萃取方法
臭氧_活性炭工艺对饮用水中邻苯二甲酸酯的去除
邻苯二甲酸酯是一种广泛使用的增塑剂 , 是一类重要的全球性有机污染物[1] . 最近研究发 现一些 PAEs 表现出雌激素或抗雄激素作用[2] , DBP 的摄入量应限制在 66μg·(kg·d) - 1 ,婴 儿 对 PA Es 总 摄 入 量 可 能 会 超 过 这 个 标 准[3 ] . PA Es 在饮用水和水源水中频频被检出[4 ~ 8 ] , 饮用水常规处理工艺对 PA Es 的去除率很低 , 水源水和出厂水中均能检测出 DEP 和 DB P[9 ] , 有时 甚 至 出 厂 水 中 PA Es 的 浓 度 超 过 水 源 水[10 ] . 由于饮用水常规处理工艺对 PA Es 的去 除效率有限 ,迫切需要采用新的工艺 ,以保证饮 用水安全.
的报道 , 本文主要是研究臭氧2活性炭工艺对 为水和甲醇 ,流量 1 mL/ min ,检测波长 λ= 224
PA Es 的去除效果 ,并推测活性炭的饱和时间 , nm ,人工进样 10 μL ,定量检测下限为 1 μg/ L .
验证工艺的可行性并提出合适的运行参数.
水样前处理采用固相萃取法 ( SPE) , SPE 小柱
吸附等温线 :用经过 GAC 吸附的自来水来 在 6 mg/ L 以下.
配制 2 mg/ L 的 DMP 、DEP 和 DB P 溶液. 在 250
mL 的磨口瓶中装入 DMP 、DEP 或 DB P 溶液
200 mL , 加入一定质量的 ZJ215 活性炭 , 放入
20 ℃的恒温震荡水浴 ,平衡时间 5 h ,达到平衡
附等温线法 ,考虑到实验费用和时间 ,在本实验
中采用吸附等温线法估算活性炭饱和时间. 实
验数据运用 Freundlich 公式拟合 :
q = Kc1/ n
《药物分析学报:英文版》投稿攻略-发表论文
药物分析学报:英文版一、发表说明本团队专注于论文写作与发表服务,擅长案例分析、编程仿真、图表绘制、理论分析等,论文写作、发表300起,具体价格信息联系:本团队并非任何杂志编辑中心,本中心是专业代发论文的机构,与各个杂志社具有长期良好的合作关系,也就是我们通过我们的特殊渠道将论文送给杂志社我们特定的内部人处理论文,保证较高的上稿率,以解决投稿人投稿后焦急的等待与石沉大海的结局。
通过我们可以较为容易达到发表的目地,当然,论文的质量也是重要的基础。
二、期刊简介如下是西安交通大学主办、教育部主管的学术理论刊物,2011年1月由“Academic Journal of Xi’an Jiaotong University:《西安交通大学学报(英文版)》”,经报请教育部、科技部、新闻出版总署批准,于2011年2月更名为“Journal of Pharmaceutical Analysis(JPA,药物分析学报)”。
JPA为国内外公开发行的英文学术期刊,季刊。
JAP主要集中反映与药品质量、用药安全和分析方法等相关的最新研究成果,重点报道:(1)中药(药材、成药、方剂、注射剂)分析;(2)药物复杂体系分析;(3)生物技术药物质量控制技术与方法;(4)药物体内作用过程分析;(5)药物发现过程中的定量与定性分析;(6)分子药理学中的示踪分析;(7)生物药剂学中的定量分析;(8)临床检验与生物分析等。
栏目有:Review、Original Articles 和 Short Communication。
JPA是世界上第一份有关药物分析的专业学术期刊,主编由西安交通大学医学院药物研究所所长、中国药学会药物分析专业委员会主任委员贺浪冲教授担任。
JPA目前被美国《化学文摘》(CA)和荷兰《医学文摘》(EM)收录,并进入中文科技期刊数据库、万方数据库、中国学术光盘数据库(CNKI) 和重庆维普数据库等多家国内著名检索系统。
ReviewPaperQuantitative bioanalytical and analytical method development of dibenzazepine derivative, carbamazepine: A revieworiginalArticle Development and validation of a GC-FID method for quantitative analysis of oleic acid and related fatty acidsORIGlNAL ARTICLEDetermination of cilostazol and its active metabolite 3,4-dehydro cilostazol from small plasma volume by UPLC-MS/MSSHORT COMMUNICATION Capillary electrophoresis to determine entrapment efficiency of a nanostructured lipid carrier loaded with piroxicamINFORMATION Application of analytical instruments in pharmaceutical analysisBioautography and its scope in the field of natural product chemistryORIGINAL ARTICLENon-covalent binding analysis of sulfamethoxazole to human serum albumin:Fluorescence spectroscopy, UV-vis, FT-IR, voltammetric and molecular modelingSHORT COMMUNICATIONIsolation and characterization of a degradation product in leflunomide and a validated selective stability-indicating HPLC-UV method for their quantificationINFORMATIONApplication of analytical instruments in pharmaceutical analysisReviewPaperQuantitative bioanalytical and analytical method development of dibenzazepine derivative, carbamazepine: A revieworiginalArticle Development and validation of a GC-FID method for quantitative analysis of oleic acid and related fatty acidsREVIEW ARTICLEMeasurement uncertainty in pharmaceutical analysis and its applicationORIGINAL ARTICLEMetabolic profiling of plasma from cardiac surgical patients concurrently administered with tranexamic acid:DI-SPME-LC-MS analysisINFORMATIONApplication of analytical instruments in pharmaceutical analysisORIGINAL ARTICLECharge-transfer interaction of drug quinidine with quinol, picric acidand DDQ:Spectroscopic characterization and biological activity studies towards understanding the drug-receptor mechanismINFORMATION Application of analytical instruments in pharmaceutical analysisREVIEW PAPERDevelopment of forced degradation and stability indicating studies of drugs-A review0RIGINAL ARTICLEDirect detection and identification of active pharmaceutical ingredients in intact tablets by helium plasma ionization (HePI) mass spectrometryINFORMATI0NApplication of analytical instruments in pharmaceutical analysisREVIEW PAPERChemometrics: A new scenario in herbal drug standardizationORIGINAL ARTICLEQuantification of anandamide, oleoylethanolamide and palmitoylethanolamide in rodent brain tissue using high performance liquid chromatographyelectrospray mass spectroscopyINFORMATIONApplication of analytical instruments in pharmaceutical analysisREVIEW PAPERPioglitazone:A review of analytical methodsORIGINAL ARTICLERisk evaluation of impurities in topical excipients:The acetol caseSHORT COMMUNICATIONSimultaneous determination of borneol and its metabolite in rat plasma by GC-MS and its application to pharmacokinetic studyINFORMATIONApplication of analytical instruments in pharmaceutical analysisSynthesis of carbon nanosheet from barley and its use as non-enzymatic glucose biosensor0RIGINALARrICLEQuantitation of bivalirudin, a novel anticoagulant peptide, in human plasma by LC-MS/MS: Method development, validation and application to pharmacokineticsLiquid chromatography tandem mass spectrometry method for the estimation of lamotrigine in human plasma:Application to a pharmacokinetic studySimultaneous quantification of prodrug oseltamivir and its metabolite oseltamivir carboxylate in human plasma by LC-MS[MS to support a bioequivalence studyA sensitive, simple and rapid HPLC-MS/MS method for simultaneous quantification of buprenorpine and its N-dealkylated metabolitenorbuprenorphine in human plasmaSPECIALISSUE:HPLCinpharmaceuticalanalysisFused-core particle technology in high-performance liquid chromatography: An overviewREVIEWPAPERApplication of LC–MS/MS for quantitative analysis of glucocorticoids and stimulants in biological fuids0RIGINALARTICLEChiral separation of bavachinin in Fructus Psoraleae and rat plasma by liquid chromatography using permethylated-p-CD as a chiral selectorSHORTCOMMUNICATIONA novel and rapid microbiological assay for ciprofoxacin hydrochlorideORIGINAL ARTICLEPharmacokinetic study of inosiplex tablets in healthy Chinese volunteers by hyphenated HPLC and tandem MS techniquesSHORT COMMUNICATIONI Simultaneous determination of five diterpenoid alkaloids in Herba Delphinii by HPLC/ELSDRapid determination of anti-estrogens by gas chromatography/mass spectrometry in urine:Method validation and application to real samplesImmobilized enzyme reactors in HPLC and its application in inhibitor screening:A reviewSimultaneous determination of pioglitazone and candesartan in human plasma by LC-MS/MS and its application to a human pharmacokinetic studySchisandra chinensis (Turcz.) BaillSimultaneous determination of telmisartan and amlodipine in human plasma by LC-MS]MS and its application in a human pharmacokinetic studyORIGINAL ARTICLESeparation and enrichment of trace ractopamine in biological samples by uniformly-sized molecularly imprinted polymersSHORT COMMUNIC ATION An analytical method for Fe(Ⅱ)and Fe(Ⅲ)determination in pharmaceutical grade iron sucrose complex and sodium ferric gluconate complexORIGINAL ARTICLESIdentification and determination of the major constituents in traditional Chinese medicine Longdan Xiegan Pill by HPLC-DAD-ESI-MSINFORMATIONPublished the papers of GC-MS analysis—Traditional ChinesemedicineRECRUITMENTLecturer/Professor Wanted at Xi'an Jiaotong UniversityREVIEWApplications of HPLC/MS in the analysis of traditional Chinese medicinesORIGlNAL ARTICLESDetermination of phthalate esters in physiological saline solution by monolithic silica spin column extraction methodINFORMATION Published papers about fingerprint and quality control of traditional Chinese medicineRECRUITMENTLecturer/Professor Wanted at Xi'an Jiaotong UniversityORIGINAL ARTICLEHighly sensitive chemiluminescence technology for protein detection using aptamer-based rolling circle amplification platformINFORMATION Published papers about food safetyRECRUITMENTChair Professors and Visiting Professors of "Chang Jiang Scholars Program"Liquid chromatography coupled with time-of-flight and ion trap mass spectrometry for qualitative analysis of herbal medicinesDetection of captopril based on its enhanced resonance lightscattering signals of fluorosurfactant-capped gold nanoparticlesLC-ESI-MS/MS,a modified method for simultaneous quantification of isoflavonoids,flavonoids,alkaloids and saponins in a Chinese herbal preparation Gegen-Qinlian decoctionStudy on chromatographic fingerprint of sarcandra glabra (Thunb.) by microwave-assisted extraction coupled to HPLC/DAD。
微萃取技术
微萃取技术摘要:固相微萃取技术集采样、萃取、浓缩和进样于一体,简便、快速、经济安全、无溶剂、选择性好、且灵敏度高。
本文对固相微萃取的萃取方式和原理、工作条件的选择及优化、应用及局限做了综述,并对该技术的新进展给予了展望。
关键词:固相微萃取;条件优化;应用局限;新进展萃取是从样品基体中分离出目标化合物的必须步骤。
传统的萃取方法操作繁琐、费时, 需消耗大量毒性有机溶剂, 危害人体健康和污染环境。
因此, 无溶剂萃取技术的研究和开发成为分析化学的一大前沿课题。
固相萃取(Solid Phase Extraction, SPE)装置简单、溶剂消耗量少, 可用于现场预处理, 但操作繁琐、空白值高、易堵塞吸附柱而导致重现性不够理想[1]。
1989 年, Paw lizyn 等[2]在SPE的基础上发展了固相微萃取(Solid Phase Microextraction, SPM E)技术。
均匀涂渍在硅纤维上的圆柱状吸附剂涂层在萃取时既继承了SPE 的优点, 又有效克服了其缺陷,操作简单, 重现性好, 从萃取到进样完全不使用有机溶剂, 解吸快速、完全, 不需要对气相色谱仪进行改装[3]。
固相微萃取装置状似一色谱进样器,由手柄( holder)和萃取头( fiber)构成,其基本功能表现在提取浓缩和色谱进样,前者实际上是组分从复杂基质中的分离过程[4]。
SPME 技术集萃取、浓缩和进样于一体[5]。
1.固相微萃取的萃取方式和原理SPME 的操作方式有两种:一种是将SPME萃取纤维直接插入较洁净的液体样品中, 称为直接SPME法。
其萃取速度由分析物从样品基底到萃取涂层的传质过程控制, 涉及液体中的对流传质和分析物在萃取涂层中的扩散[6]; 另一种是将SPM E 萃取纤维置于液体或固体样品的顶空进行萃取, 即顶空固相微萃取法(Headspace SPM E, 简称HS-SPM E)。
涉及分析物从样品挥发至顶空、再扩散至萃取涂层以及在萃取涂层中的扩散三个过程。
食品包装材料中邻苯二甲酸酯含量的检测和迁移规律
学试剂有限公司),16种邻苯二甲酸酯混标(美国o2si 公司);塑料袋、矿泉水瓶、保鲜袋、保鲜膜、一次性纸杯、一次性塑料杯、吸管、装油塑料瓶和硬纸饮料盒:市售。
1.2 仪器设备GCMS-QP2010 Ultra 气质联用仪(日本岛津);Anke TDL-40B 型离心机(上海安亭科学仪器厂);烘箱(上海一恒科学仪器有限公司);混匀器(德国IKA 公司);超声波清洗器(广州市吉普超声波电子设备有限公司);HZT-A500电子天平(福州华志科学仪器有限公司)。
1.3 实验方法1.3.1 模拟物浸泡液的选择和配制根据中华人民共和国国家标准GB 31604.1—2015《食品安全国家标准 食品接触材料及制品迁移实验通则》,选用适用所有食品类别的4%的乙酸溶液和适用于非酸性食品、含酒精饮料、部分乳及乳制品的50%乙醇。
4%乙酸配制:取40 mL 冰乙酸,用一级纯水稀释转移至1 000 mL 容量瓶中,定容后混匀静置,留待使用;50%乙醇的配制:取500 mL 无水乙醇,用一级纯水稀释转移至1 000 mL 容量瓶中,定容后混匀静置,留待使用。
0 引言邻苯二甲酸酯,又称酞酸酯,简称PAEs ,俗称塑化剂,是邻苯二甲酸形成的酯的统称。
当PAEs 被用作塑料增塑剂时,一般指的是邻苯二甲酸与4~15个碳的醇形成的酯,常见的有邻苯二甲酸二正丁酯(DBP)、邻苯二甲酸二乙基己基酯 (DEHP)等。
PAEs 是塑料制品中用量最大的添加剂,它被普遍应用于玩具、食品包装材料、乙烯地板和壁纸、个人护理用品等产品中[1]。
PAEs 同时也是一类环境内分泌干扰物,其具有生殖毒性、致癌性和致畸性,且已经被研究证实[2-3],积累到一定程度将对人体的健康产生严重的危害。
目前国内对PAEs 化学分析测定方法最为普遍的是气相色谱法和气相色谱-质谱法[4]。
本文通过对10种食品接触材料中邻苯二甲酸酯的测定及迁移量影响的初步研究,基本了解常用食品包装材料中的邻苯二甲酸酯及邻苯二甲酸酯的迁移规律;旨在为食品接触材料在日常生活中的规范使用及工业应用上的规范合理提供一定的参考依据。
固相萃取-高效液相色谱法测定水中邻苯二甲酸酯类的方法研究
和DOPg ̄J人优 先控制污染物黑名单 ]。
在82.1%一109_2%之间 ,测定结果 令人满意 。
邻苯二 甲酸酯 类是环 境 中的痕量污染 物 ,在 测定 2 实验部分
前需 要对其进 行富集 。传统 的富集方法 是液液萃 取 , 2.1 仪 器
该 方法不仅 回收率低 ,而且还有 操作 复杂 ,T作 强度
增 大塑料 的可 塑性和强度 ,还 可用于农 药 、涂料 、印 法及 固相膜萃取 预富集方法 。Brossa L等人m建立 了利
染 、化妆品和香料等的生产 j。近年来 ,随着邻苯二 甲 用在线 固相萃取 和液 质色谱联 用检测水 体 中环 境激素 酸酯类 的大量使 用对生 态环境造 成 了污染 ,因此 国 内 的新方法 ,并在 实际水样 检测 出 了邻苯 二 甲酸二正 丁
1 引言
果好 ,操 作简单 ,省时省 力等特点[5】。戴树桂 等 使用
邻 苯二甲酸 ̄(phthalate esters, PAEs)是环境激素 c。 固相 萃取 柱 和C 键 合硅 胶 固相萃 取膜 ,研 究 了环
类物 质 中的一类 化合 物 l。它们 主要用 作增 塑剂 ,以 境水样 中邻苯二 甲酸酯类 化合 物的 固相萃取 预富集方
2 2 试剂 .
甲醇 、 乙 醚 和丙 酮 均 为H P L C 色谱纯 ( 上 海埃彼化
学试剂有 限公 司 ) 。 无 水硫酸钠 为分析纯 , 使用前在
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8082方法
METHOD 8082POLYCHLORINATED BIPHENYLS (PCBs)BY GAS CHROMATOGRAPHY1.0SCOPE AND APPLICATION1.1Method 8082 is used to determine the concentrations of polychlorinated biphenyls (PCBs) as Aroclors or as individual PCB congeners in extracts from solid and aqueous matrices. Open-tubular, capillary columns are employed with electron capture detectors (ECD) or electrolytic conductivity detectors (ELCD). When compared to packed columns, these fused-silica, open-tubular columns offer improved resolution, better selectivity, increased sensitivity, and faster analysis. The target compounds listed below may be determined by either a single- or dual-column analysis system. The PCB congeners listed below have been tested by this method, and the method may be appropriate for additional congeners.Compound CAS Registry No.IUPAC #Aroclor 101612674-11-2-Aroclor 122111104-28-2-Aroclor 123211141-16-5-Aroclor 124253469-21-9-Aroclor 124812672-29-6-Aroclor 125411097-69-1-Aroclor 126011096-82-5-2-Chlorobiphenyl2051-60-712,3-Dichlorobiphenyl16605-91-752,2',5-Trichlorobiphenyl37680-65-2182,4',5-Trichlorobiphenyl16606-02-3312,2',3,5'-Tetrachlorobiphenyl41464-39-5442,2',5,5'-Tetrachlorobiphenyl35693-99-3522,3',4,4'-Tetrachlorobiphenyl32598-10-0662,2',3,4,5'-Pentachlorobiphenyl38380-02-8872,2',4,5,5'-Pentachlorobiphenyl37680-73-21012,3,3',4',6-Pentachlorobiphenyl38380-03-91102,2',3,4,4',5'-Hexachlorobiphenyl35065-28-21382,2',3,4,5,5'-Hexachlorobiphenyl52712-04-61412,2',3,5,5',6-Hexachlorobiphenyl52663-63-51512,2',4,4',5,5'-Hexachlorobiphenyl35065-27-11532,2',3,3',4,4',5-Heptachlorobiphenyl35065-30-61702,2',3,4,4',5,5'-Heptachlorobiphenyl35065-29-31802,2',3,4,4',5',6-Heptachlorobiphenyl52663-69-11832,2',3,4',5,5',6-Heptachlorobiphenyl52663-68-01872,2',3,3',4,4',5,5',6-Nonachlorobiphenyl40186-72-9206CD-ROM8082 - 1Revision 0December 19961.2Aroclors are multi-component mixtures. When samples contain more than one Aroclor,a higher level of analyst expertise is required to attain acceptable levels of qualitative and quantitative analysis. The same is true of Aroclors that have been subjected to environmental degradation ("weathering") or degradation by treatment technologies. Such weathered multi-component mixtures may have significant differences in peak patterns than those of Aroclor standards.1.3Quantitation of PCBs as Aroclors is appropriate for many regulatory compliance determinations, but is particularly difficult when the Aroclors have been weathered by long exposure in the environment. Therefore, this method provides procedures for the determination of selected individual PCB congeners. The 19 PCB congeners listed above have been tested by this method.1.4The PCB congener approach potentially affords greater quantitative accuracy when PCBs are known to be present. As a result, this method may be used to determine Aroclors, some PCB congeners, or "total PCBs," depending on regulatory requirements and project needs. The congener method is of particular value in determining weathered Aroclors. However, analysts should use caution when using the congener method when regulatory requirements are based on Aroclor concentrations.1.5Compound identification based on single-column analysis should be confirmed on a second column, or should be supported by at least one other qualitative technique. This method describes analytical conditions for a second gas chromatographic column that can be used to confirm the measurements made with the primary column. GC/MS Method 8270 is also recommended as a confirmation technique when sensitivity permits (Sec. 8.0).1.6This method also describes a dual-column option. The option allows a hardware configuration of two analytical columns joined to a single injection port. The option allows one injection to be used for dual-column analysis. Analysts are cautioned that the dual-column option may not be appropriate when the instrument is subject to mechanical stress, many samples are to be run in a short period, or when highly contaminated samples are analyzed.1.7The analyst must select columns, detectors and calibration procedures most appropriate for the specific analytes of interest in a study. Matrix-specific performance data must be established and the stability of the analytical system and instrument calibration must be established for each analytical matrix (e.g., hexane solutions from sample extractions, diluted oil samples, etc.). Example chromatograms and GC conditions are provided as guidance.1.8The MDLs for Aroclors vary in the range of 0.054 to 0.90 µg/L in water and 57 to 70 µg/kg in soils. Estimated quantitation limits may be determined using the data in Table 1.1.9This method is restricted to use by, or under the supervision of, analysts experienced in the use of gas chromatographs (GC) and skilled in the interpretation of gas chromatograms. Each analyst must demonstrate the ability to generate acceptable results with this method.2.0SUMMARY OF METHOD2.1 A measured volume or weight of sample (approximately 1 L for liquids, 2 g to 30 g for solids) is extracted using the appropriate matrix-specific sample extraction technique.2.2Aqueous samples are extracted at neutral pH with methylene chloride using Method 3510 (separatory funnel), Method 3520 (continuous liquid-liquid extractor), or other appropriate technique. CD-ROM8082 - 2Revision 0December 19962.3Solid samples are extracted with hexane-acetone (1:1) or methylene chloride-acetone (1:1) using Method 3540 (Soxhlet), Method 3541 (automated Soxhlet), or other appropriate technique.2.4Extracts for PCB analysis may be subjected to a sulfuric acid/potassium permanganate cleanup (Method 3665) designed specifically for these analytes. This cleanup technique will remove (destroy) many single component organochlorine or organophosphorus pesticides. Therefore, Method 8082 is not applicable to the analysis of those compounds. Instead, use Method 8081.2.5After cleanup, the extract is analyzed by injecting a 2-µL aliquot into a gas chromatograph with a narrow- or wide-bore fused silica capillary column and electron capture detector (GC/ECD).2.6The chromatographic data may be used to determine the seven Aroclors in Sec. 1.1, individual PCB congeners, or total PCBs.3.0INTERFERENCES3.1Refer to Methods 3500 (Sec. 3.0, in particular), 3600, and 8000 for a discussion of interferences.3.2Interferences co-extracted from the samples will vary considerably from matrix to matrix. While general cleanup techniques are referenced or provided as part of this method, unique samples may require additional cleanup approaches to achieve desired degrees of discrimination and quantitation. Sources of interference in this method can be grouped into three broad categories.3.2.1Contaminated solvents, reagents, or sample processing hardware.3.2.2Contaminated GC carrier gas, parts, column surfaces, or detector surfaces.3.2.3Compounds extracted from the sample matrix to which the detector will respond.3.3Interferences by phthalate esters introduced during sample preparation can pose a major problem in PCB determinations.3.3.1Common flexible plastics contain varying amounts of phthalate esters which areeasily extracted or leached from such materials during laboratory operations. Interferences from phthalate esters can best be minimized by avoiding contact with any plastic materials and checking all solvents and reagents for phthalate contamination.3.3.2Exhaustive cleanup of solvents, reagents and glassware may be required toeliminate background phthalate ester contamination.3.3.3These materials can be removed through the use of Method 3665 (sulfuricacid/permanganate cleanup).3.4Cross-contamination of clean glassware routinely occurs when plastics are handled during extraction steps, especially when solvent-wetted surfaces are handled. Glassware must be scrupulously cleaned.Clean all glassware as soon as possible after use by rinsing with the last solvent used. This should be followed by detergent washing with hot water, and rinses with tap water and organic-free CD-ROM8082 - 3Revision 0December 1996CD-ROM 8082 - 4Revision 0December 1996reagent water. Drain the glassware, and dry it in an oven at 130E C for several hours, or rinse with methanol and drain. Store dry glassware in a clean environment. NOTE:Oven-drying of glassware used for PCB analysis can increase contaminationbecause PCBs are readily volatilized in the oven and spread to other glassware.Therefore, exercise caution, and do not dry glassware from samples containinghigh concentrations of PCBs with glassware that may be used for trace analyses.3.5Elemental sulfur (S ) is readily extracted from soil samples and may cause 8chromatographic interferences in the determination of PCBs. Sulfur can be removed through the use of Method 3660.4.0APPARATUS AND MATERIALS4.1Gas chromatograph - An analytical system complete with gas chromatograph suitable for on-column and split-splitless injection and all required accessories including syringes, analytical columns, gases, electron capture detectors (ECD), and recorder/integrator or data system.4.2GC columnsThis method describes procedures for both single-column and dual-column analyses. The single-column approach involves one analysis to determine that a compound is present, followed by a second analysis to confirm the identity of the compound (Sec. 8.4 describes how GC/MS confirmation techniques may be employed). The single-column approach may employ either narrow-bore (# 0.32 mm ID) columns or wide-bore (0.53 mm ID) columns. The dual-column approach involves a single injection that is split between two columns that are mounted in a single gas chromatograph. The dual-column approach employs only wide-bore (0.53 mm ID) columns. A third alternative is to employ dual columns mounted in a single GC, but with each column connected to a separate injector and a separate detector.The columns listed in this section were the columns used to develop the method performance data. Listing these columns in this method is not intended to exclude the use of other columns that may be developed. Laboratories may use other capillary columns provided that they document method performance (e.g., chromatographic resolution, analyte breakdown, and MDLs) that equals or exceeds the performance specified in this method.4.2.1Narrow-bore columns for single-column analysis (use both columns to confirmcompound identifications unless another confirmation technique such as GC/MS is employed).Narrow bore columns should be installed in split/splitless (Grob-type) injectors.4.2.1.130 m x 0.25 or 0.32 mm ID fused silica capillary column chemicallybonded with SE-54 (DB-5 or equivalent), 1 µm film thickness.4.2.1.230 m x 0.25 mm ID fused silica capillary column chemically bonded with35 percent phenyl methylpolysiloxane (DB-608, SPB-608, or equivalent), 2.5 µm coatingthickness, 1 µm film thickness.4.2.2Wide-bore columns for single-column analysis (use two of the three columnslisted to confirm compound identifications unless another confirmation technique such as GC/MS is employed). Wide-bore columns should be installed in 1/4 inch injectors, with deactivated liners designed specifically for use with these columns.4.2.2.130 m x 0.53 mm ID fused silica capillary column chemically bonded with35 percent phenyl methylpolysiloxane (DB-608, SPB-608, RTx-35, or equivalent), 0.5 µmor 0.83 µm film thickness.4.2.2.230 m x 0.53 mm ID fused silica capillary column chemically bonded with14% cyanopropylmethylpolysiloxane (DB-1701, or equivalent), 1.0 µm film thickness.4.2.2.330 m x 0.53 mm ID fused silica capillary column chemically bonded withSE-54 (DB-5, SPB-5, RTx-5, or equivalent), 1.5 µm film thickness.4.2.3Wide-bore columns for dual-column analysis (choose one of the two pairs ofcolumns listed below).4.2.3.1Column pair 130 m x 0.53 mm ID fused silica capillary column chemically bonded with SE-54(DB-5, SPB-5, RTx-5, or equivalent), 1.5 µm film thickness.30 m x 0.53 mm ID fused silica capillary column chemically bonded with 14%cyanopropylmethylpolysiloxane (DB-1701, or equivalent), 1.0 µm film thickness.Column pair 1 is mounted in a press-fit Y-shaped glass 3-way union splitter (J&W Scientific, Catalog No. 705-0733) or a Y-shaped fused-silica connector (Restek, CatalogNo. 20405), or equivalent.4.2.3.2Column pair 230 m x 0.53 mm ID fused silica capillary column chemically bonded with SE-54(DB-5, SPB-5, RTx-5, or equivalent), 0.83 µm film thickness.30 m x 0.53 mm ID fused silica capillary column chemically bonded with 14%cyanopropylmethylpolysiloxane (DB-1701, or equivalent), 1.0 µm film thickness.Column pair 2 is mounted in an 8 in. deactivated glass injection tee (Supelco, Catalog No. 2-3665M), or equivalent.4.3Column rinsing kit - Bonded-phase column rinse kit (J&W Scientific, Catalog No. 430-3000), or equivalent.4.4Volumetric flasks - 10-mL and 25-mL, for preparation of standards.5.0REAGENTS5.1Reagent grade or pesticide grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.NOTE:Store the standard solutions (stock, composite, calibration, internal, and surrogate standards) at 4E C in polytetrafluoroethylene (PTFE)-sealed containers CD-ROM8082 - 5Revision 0December 1996CD-ROM 8082 - 6Revision 0December 1996in the dark. When a lot of standards is prepared, it is recommended that aliquotsof that lot be stored in individual small vials. All stock standard solutions mustbe replaced after one year or sooner if routine QC (Sec. 8.0) indicates a problem.All other standard solutions must be replaced after six months or sooner if routineQC (Sec. 8.0) indicates a problem.5.2Sample extracts prepared by Methods 3510, 3520, 3540, 3541, 3545, or 3550 need to undergo a solvent exchange step prior to analysis. The following solvents are necessary for dilution of sample extracts. All solvent lots should be pesticide quality or equivalent and should be determined to be phthalate-free.5.2.1n-Hexane, C H 6145.2.2Isooctane, (CH )CCH CH(CH )332325.3The following solvents may be necessary for the preparation of standards. All solvent lots must be pesticide quality or equivalent and should be determined to be phthalate-free.5.3.1Acetone, (CH )CO 325.3.2Toluene, C H CH 6535.4Organic-free reagent water - All references to water in this method refer to organic-free reagent water as defined in Chapter One.5.5Stock standard solutions (1000 mg/L) - May be prepared from pure standard materials or can be purchased as certified solutions.5.5.1Prepare stock standard solutions by accurately weighing about 0.0100 g of purecompound. Dissolve the compound in isooctane or hexane and dilute to volume in a 10-mL volumetric flask. If compound purity is 96 percent or greater, the weight may be used without correction to calculate the concentration of the stock standard solution.5.5.2Commercially-prepared stock standard solutions may be used at any concentration if they are certified by the manufacturer or by an independent source.5.6Calibration standards for Aroclors5.6.1 A standard containing a mixture of Aroclor 1016 and Aroclor 1260 will includemany of the peaks represented in the other five Aroclor mixtures. As a result, a multi-point initial calibration employing a mixture of Aroclors 1016 and 1260 at five concentrations should be sufficient to demonstrate the linearity of the detector response without the necessity of performing initial calibrations for each of the seven Aroclors. In addition, such a mixture can be used as a standard to demonstrate that a sample does not contain peaks that represent any one of the Aroclors. This standard can also be used to determine the concentrations of either Aroclor 1016 or Aroclor 1260, should they be present in a sample. Prepare a minimum of five calibration standards containing equal concentrations of both Aroclor 1016 and Aroclor 1260by dilution of the stock standard with isooctane or hexane. The concentrations should correspond to the expected range of concentrations found in real samples and should bracket the linear range of the detector.5.6.2Single standards of each of the other five Aroclors are required to aid the analystin pattern recognition. Assuming that the Aroclor 1016/1260 standards described in Sec. 5.6.1 have been used to demonstrate the linearity of the detector, these single standards of the remaining five Aroclors are also used to determine the calibration factor for each Aroclor.Prepare a standard for each of the other Aroclors. The concentrations should correspond to the mid-point of the linear range of the detector.5.7Calibration standards for PCB congeners5.7.1If results are to be determined for individual PCB congeners, then standards forthe pure congeners must be prepared. The table in Sec. 1.1 lists 19 PCB congeners that have been tested by this method along with the IUPAC numbers designating these congeners. This procedure may be appropriate for other congeners as well.5.7.2Stock standards may be prepared in a fashion similar to that described for theAroclor standards, or may be purchased as commercially-prepared solutions. Stock standards should be used to prepare a minimum of five concentrations by dilution of the stock standard with isooctane or hexane. The concentrations should correspond to the expected range of concentrations found in real samples and should bracket the linear range of the detector.5.8Internal standard5.8.1When PCB congeners are to be determined, the use of an internal standard ishighly recommended. Decachlorobiphenyl may be used as an internal standard, added to each sample extract prior to analysis, and included in each of the initial calibration standards.5.8.2When PCBs are to be determined as Aroclors, an internal standard is not used,and decachlorobiphenyl is employed as a surrogate (see Sec. 5.8).5.9Surrogate standards5.9.1When PCBs are to be determined as Aroclors, decachlorobiphenyl is used as asurrogate, and is added to each sample prior to extraction. Prepare a solution of decachlorobiphenyl at a concentration of 5 mg/L in acetone.5.9.2When PCB congeners are to be determined, decachlorobiphenyl is recommendedfor use as an internal standard, and therefore, cannot also be used as a surrogate. Therefore, tetrachloro-meta-xylene may be used as a surrogate for PCB congener analysis. Prepare a solution of tetrachloro-meta-xylene at a concentration of 5 mg/L in acetone.6.0SAMPLE COLLECTION, PRESERVATION, AND HANDLING6.1See Chapter Four, Organic Analytes for sample collection and preservation instructions.6.2Extracts must be stored under refrigeration in the dark and analyzed within 40 days of extraction.CD-ROM8082 - 7Revision 0December 19967.0PROCEDURE7.1Sample extraction7.1.1Refer to Chapter Two and Method 3500 for guidance in choosing the appropriateextraction procedure. In general, water samples are extracted at a neutral pH with methylene chloride using a separatory funnel (Method 3510) or a continuous liquid-liquid extractor (Method 3520) or other appropriate procedure. Solid samples are extracted with hexane-acetone (1:1) or methylene chloride-acetone (1:1) using one of the Soxhlet extraction (Method 3540 or 3541) procedures, ultrasonic extraction (Method 3550), or other appropriate procedure.NOTE:Use of hexane-acetone generally reduces the amount of interferences that are extracted and improves signal-to-noise.7.1.2Reference materials, field-contaminated samples, or spiked samples should beused to verify the applicability of the selected extraction technique to each new sample type.Such samples should contain or be spiked with the compounds of interest in order to determine the percent recovery and the limit of detection for that sample type (see Chapter One). When other materials are not available and spiked samples are used, they should be spiked with the analytes of interest, either specific Aroclors or PCB congeners. When the presence of specific Aroclors is not anticipated, the Aroclor 1016/1260 mixture may be an appropriate choice for spiking. See Methods 3500 and 8000 for guidance on demonstration of initial method proficiency as well as guidance on matrix spikes for routine sample analysis.7.2Extract cleanupRefer to Methods 3660 and 3665 for information on extract cleanup.7.3GC conditionsThis method allows the analyst to choose between a single-column or a dual-column configuration in the injector port. Either wide- or narrow-bore columns may be used. See Sec.7.7 for information on techniques for making positive identifications of multi-componentanalytes.7.3.1Single-column analysisThis capillary GC/ECD method allows the analyst the option of using 0.25-0.32 mm ID capillary columns (narrow-bore) or 0.53 mm ID capillary columns (wide-bore). The use of narrow-bore (0.25-0.32 mm ID) columns is recommended when the analyst requires greater chromatographic resolution. Use of narrow-bore columns is suitable for relatively clean samples or for extracts that have been prepared with one or more of the clean-up options referenced in the method. Wide-bore columns (0.53 mm ID) are suitable for more complex environmental and waste matrices.7.3.2Dual-column analysisThe dual-column/dual-detector approach involves the use of two 30 m x 0.53 mm ID fused-silica open-tubular columns of different polarities, thus different selectivities towards the target compounds. The columns are connected to an injection tee and ECD detectors. CD-ROM8082 - 8Revision 0December 19967.3.3GC temperature programs and flow rates7.3.3.1Table 2 lists GC operating conditions for the analysis of PCBs asAroclors for single-column analysis, using either narrow-bore or wide-bore capillarycolumns. Table 3 lists GC operating conditions for the dual-column analysis. Use theconditions in these tables as guidance and establish the GC temperature program andflow rate necessary to separate the analytes of interest.7.3.3.2When determining PCBs as congeners, difficulties may be encounteredwith coelution of congener 153 and other sample components. When determining PCBsas Aroclors, chromatographic conditions should be adjusted to give adequate separationof the characteristic peaks in each Aroclor (see Sec. 7.4.6).7.3.3.3Tables 4 and 5 summarize the retention times of up to 73 Aroclor peaksdetermined during dual-column analysis using the operating conditions listed in Table 2.These retention times are provided as guidance as to what may be achieved using theGC columns, temperature programs, and flow rates described in this method. Note thatthe peak numbers used in these tables are not the IUPAC congener numbers, butrepresent the elution order of the peaks on these GC columns.7.3.3.4Once established, the same operating conditions must be used for theanalysis of samples and standards.7.4Calibration7.4.1Prepare calibration standards as described in Sec. 5.0. Refer to Method 8000(Sec. 7.0) for proper calibration techniques for both initial calibration and calibration verification.When PCBs are to be determined as congeners, the use of internal standard calibration is highly recommended. Therefore, the calibration standards must contain the internal standard (see Sec. 5.7) at the same concentration as the sample extracts. When PCBs are to be determined as Aroclors, external standard calibration should be used.NOTE:Because of the sensitivity of the electron capture detector, the injection port and column should always be cleaned prior to performing the initialcalibration.7.4.2When PCBs are to be quantitatively determined as congeners, an initial five-pointcalibration must be performed that includes standards for all the target analytes (congeners).7.4.3When PCBs are to be quantitatively determined as Aroclors, the initial calibrationconsists of two parts, described below.7.4.3.1 As noted in Sec. 5.6.1, a standard containing a mixture of Aroclor 1016and Aroclor 1260 will include many of the peaks represented in the other five Aroclormixtures. Thus, such a standard may be used to demonstrate the linearity of thedetector and that a sample does not contain peaks that represent any one of theAroclors. This standard can also be used to determine the concentrations of eitherAroclor 1016 or Aroclor 1260, should they be present in a sample. Therefore, an initialfive-point calibration is performed using the mixture of Aroclors 1016 and 1260 describedin Sec. 5.6.1.CD-ROM8082 - 9Revision 0December 1996RF 'A s ×C isA is ×C sCD-ROM 8082 - 10Revision 0December 19967.4.3.2Standards of the other five Aroclors are necessary for patternrecognition. These standards are also used to determine a single-point calibration factorfor each Aroclor, assuming that the Aroclor 1016/1260 mixture in Sec. 7.3.4.1 has beenused to describe the detector response. The standards for these five Aroclors shouldbe analyzed before the analysis of any samples, and may be analyzed before or after theanalysis of the five 1016/1260 standards in Sec. 7.3.4.1.7.4.3.3In situations where only a few Aroclors are of interest for a specificproject, the analyst may employ a five-point initial calibration of each of the Aroclors ofinterest (e.g., five standards of Aroclor 1232 if this Aroclor is of concern) and not use the1016/1260 mixture described in Sec. 7.4.3.1 or the pattern recognition standardsdescribed in 7.4.3.2.7.4.4Establish the GC operating conditions appropriate for the configuration (single-column or dual column, Sec. 7.3). Optimize the instrumental conditions for resolution of the target compounds and sensitivity. A final temperature of 240-270E C may be required to elute decachlorobiphenyl. Use of injector pressure programming will improve the chromatography of late eluting peaks.NOTE:Once established, the same operating conditions must be used for bothcalibrations and sample analyses.7.4.5 A 2-µL injection of each calibration standard is recommended. Other injectionvolumes may be employed, provided that the analyst can demonstrate adequate sensitivity for the compounds of interest.7.4.6Record the peak area (or height) for each congener or each characteristic Aroclorpeak to be used for quantitation.7.4.6.1 A minimum of 3 peaks must be chosen for each Aroclor, and preferably5 peaks. The peaks must be characteristic of the Aroclor in question. Choose peaks inthe Aroclor standards that are at least 25% of the height of the largest Aroclor peak. Foreach Aroclor, the set of 3 to 5 peaks should include at least one peak that is unique tothat Aroclor. Use at least five peaks for the Aroclor 1016/1260 mixture, none of whichshould be found in both of these Aroclors.7.4.6.2Late-eluting Aroclor peaks are generally the most stable in theenvironment. Table 6 lists diagnostic peaks in each Aroclor, along with their retentiontimes on two GC columns suitable for single-column analysis. Table 7 lists 13 specificPCB congeners found in Aroclor mixtures. Table 8 lists PCB congeners withcorresponding retention times on a DB-5 wide-bore GC column. Use these tables asguidance in choosing the appropriate peaks.7.4.7When determining PCB congeners by the internal standard procedure, calculatethe response factor (RF) for each congener in the calibration standards relative to the internal standard, decachlorobiphenyl, using the equation that follows.where:。
PVC制品中增塑剂DEHP含量的测定
82Vol.36 No.11 (Sum.199)November 2008理化测试文章编号:1005-3360(2008)11-0082-04邻苯二甲酸二(2-乙基己酯)(DEHP)作为聚氯乙烯(PVC)的增塑剂被广泛应用。
DEHP与PVC分子之间以范德华力和氢键相连,可随时间的推移,由PVC制品中迁移出来,对环境造成污染;另外,DEHP可通过呼吸、饮食和皮肤接触进入人体内,使人慢性中毒[1]。
目前DEHP的测定方法主要为气相色谱法[2-7],例如美国环保总局为测定水中DEHP而采用的GC-ECD-MS法[4];Hao-Yu Shen建立的GC-EI-SIM-MS法[5];张双灵等建立的食品塑料袋中DEHP的GC-FID检测法[7]。
GC检测器易受其他有机物污染,灵敏度波动较大,对样品的前处理要求较高,且邻苯二甲酸酯类增塑剂沸点较高,要求有较高的汽化温度及柱温,因而GC测定DEHP的应用受到了限制。
李满秀等[8]利用Fenton反应产生的羟基自由基与邻苯二甲酸酯水解产生的邻苯二甲酸钠反应,生成具有荧光的羟基邻苯二甲酸钠,然后采用荧光法间接测定样品中的邻苯二甲酸酯。
本实验在此基础上建立了荧光光度法测定PVC制品中DEHP的方法,该方法降低了对仪器设备的要求,为制定相关标准、保障医用材料和食品包装材料的安全提供了依据。
1 实验部分1.1 仪器与试剂摘 要 :建立了荧光光度法间接测定聚氯乙烯(PVC)制品中邻苯二甲酸二(2-乙基己酯)(DEHP)含量的方法。
PVC制品中的DEHP经超声提取后,碱性水解生成邻苯二甲酸钠,将其置于pH值为7.6的磷酸盐缓冲溶液中,同Fenton反应产生的羟基自由基(•OH)反应,生成具有荧光的羟基邻苯二甲酸钠,测定其荧光强度可求出DEHP的含量。
DEHP浓度在4.28×10-2 ~2.14 mg/ml范围内与荧光强度呈线性关系,相关系数为0.9954。
本测定方法操作简便,具有较高的灵敏度和准确度。
四大名醋挥发性香气成分的测定与比较分析
四大名醋挥发性香气成分的测定与比较分析李慧;韩建欣;李婷;赵欣;杨宇霞;杨林娥;王如福【摘要】采用顶空固相微萃取气质联用对四大名醋的香气成分进行分析,共检出酸类、酯类、醇类、醛类、酮类、酚类、杂环类和其他类共8大类化合物.其中,山西老陈醋、永春老醋、保宁醋和镇江香醋中分别检出39,22,30,32种呈香物质.山西老陈醋中酯类和杂环类物质检出的种类和含量最多.四大名醋香气成分迥异,各有千秋.%The volatile compounds in Chinese four famous vinegars are analyzed by headspace solid-phase microextraction(HS-SPME) and gas chromatography-mass spectrum(GC-MS),mainly including acids,esters alcohols,aldehydes,ketones,phenols and heterocyclie compounds and others.The results show that 39,22,30,32 kinds of volatile components are identified from four famous vinegars respectively.Shanxi mature vinegar has the most species of volatile compounds.The relative content and species of esters and heterocyclic compounds are the highest in Shanxi mature vinegar.The components are different and distinctive in Chinese four famous vinegars.【期刊名称】《中国调味品》【年(卷),期】2017(042)004【总页数】5页(P154-158)【关键词】四大名醋;香气成分;顶空固相微萃取;气相色谱-质谱联用【作者】李慧;韩建欣;李婷;赵欣;杨宇霞;杨林娥;王如福【作者单位】山西省生物研究所,太原030006;山西省生物研究所,太原030006;山西省生物研究所,太原030006;山西省生物研究所,太原030006;山西省生物研究所,太原030006;山西省生物研究所,太原030006;山西农业大学,山西晋中030800【正文语种】中文【中图分类】TS264.22山西老陈醋、镇江香醋、保宁醋、永春老醋名扬四海,被称为“中国四大名醋”。
气相色谱―质谱法快速测定液态乳中塑化剂残留
气相色谱―质谱法快速测定液态乳中塑化剂残留摘要建立了基于气相色谱-质谱技术同时检测液态乳中15种邻苯二甲酸酯塑化剂的方法。
称取1 mL液态乳样品,放入30 mL螺口玻璃离心管内,再向试管内添加0.5 g 氯化钠和5 mL乙腈,漩u混合1 min,于2 000×g离心5 min,然后取1 mL上清液于气相色谱-质谱仪上采用选择离子模式和峰面积外标法对邻苯二甲酸酯塑化剂进行定量分析。
结果表明,15种塑化剂能达到有效分离,保留时间的范围为10.84~28.08 min,塑化剂的检出限范围为3~15 μg/L。
在每种塑化剂添加量为0.1 mg/L时,塑化剂回收率范围为82%~94%;在每种塑化剂添加量为1 mg/L时,塑化剂回收率范围为80%~91%。
在2种添加浓度下,每种塑化剂的相对标准偏差均≤8%。
该方法具有简单、快速、溶剂消耗少、准确度和精密度高的优点。
关键词塑化剂;邻苯二甲酸酯;液态乳;气相色谱-质谱法中图分类号 TS207.5 文献标识码 A 文章编号 1007-5739(2017)08-0248-02邻苯二甲酸酯(PAEs)是塑料工业最广泛采用的一类塑化剂,主要用于提高高分子塑料制品的弹性、延展性和柔软度。
2011年初,台湾部分食品生产企业违法使用邻苯二甲酸酯类非食用物质配制起云剂,导致下游生产企业的产品受到污染。
该事件迅速扩散至香港、大陆及海外地区,引起世界范围的广泛关注,成为国际食品安全事件[1]。
2012年,塑化剂事件再度来袭,个别知名白酒企业相继被曝光塑化剂含量超标[2]。
2013年,卫生部将婴幼儿食品、白酒、食用油、方便面等纳入塑化剂风险监测的重点食品[3]。
PAEs与高分子塑料之间通过范德华力和氢键联结,彼此保持独立的化学性质。
由于结合不紧密,所以容易从塑料迁移至环境中。
PAEs 是脂溶性物质,一旦进入人体,会快速蓄积在脂肪组织内,从而导致人体内存留高浓度的塑化剂[4]。
16种邻苯二甲酸酯在不同极性溶剂中的提取率与辛醇水分配系数的关系
16种邻苯二甲酸酯在不同极性溶剂中的提取率与辛醇水分配系数的关系作者:姚少芳陆慧珍来源:《食品安全导刊·中旬刊》2021年第07期摘要:本文以食用油作为基质,采用极性溶剂乙腈提取,非极性溶剂正己烷萃取,得到16种邻苯二甲酸酯类化合物及其内标的回收率,确定16种邻苯二甲酸酯在不同极性溶剂中的提取率与辛醇水分配系数的关系:在极性溶剂中,对于低lg Kow(lg Kow5)的PAEs (BMPP、DPP、DHXP、DCHP、DEHP、DNOP、DNP及其内标)由于其脂溶性较大,更易被非极性溶剂萃取。
关键词:邻苯二甲酸酯;极性;辛醇水分配系数邻苯二甲酸酯(Phthalate Esters,PAEs),又称酞酸酯,是邻苯二甲酸衍生物,化学结构系由一个刚性平面芳烃与两个可塑的非线性脂肪侧链组成,一般为无色油状粘稠液体。
PAEs 主要用作塑料增塑剂和软化剂,以提高制品的可塑性和强度[1]。
PAEs为弱极性至中等极性的一类化合物,水溶性低,易溶于乙腈、正己烷、二氯甲烷、丙酮等大部分有机溶剂[2]。
辛醇水分配系数(Octanol-Water Partition Coefficient,Kow)为某一化合物在正辛醇与水相中浓度之比,即化合物在辛醇相中的平衡浓度与水相中该化合物非离解形式的平衡浓度的比值。
正辛醇是一种长链烷烃醇,在结构上与生物体内的碳水化合物和脂肪类似,因此,可用辛醇水分配体系来模拟研究生物-水体系。
有机物的辛醇水分配系数是衡量其脂溶性大小的重要理化性质。
目前文献报道的PAEs的检测方法有气相色谱法[3]、高效液相色谱法[4]、气相色谱-质谱法[5]、液相色谱-质谱法[6]等。
其中,质谱法因灵敏度高、抗干扰能力强等优势,在PAEs的检测中应用广泛。
结合GC-MS在易挥发化合物定性定量方面的优良性能,采用GC-MS进行检测。
1 材料与方法1.1 材料、仪器与试剂食用油(市售);Agilent 7890B-5977B气相色谱-质谱联用仪(美国Agilent公司,配EI离子源);SIGMA 3K15台式高速冷冻离心机(德国SIGMA公司);IKA MS3 basic涡旋混合器(德国IKA公司);ME204E万分之一天平(广州市东南科技创科技有限公司);乙腈(色谱纯)、正己烷(色谱纯)均购于美国Honeywell公司;16种邻苯二甲酸酯混标(纯度均高于95%):北京曼哈格生物科技有限公司;16种邻苯二甲酸酯氘代同位素混标(纯度均高于95%):北京曼哈格生物科技有限公司。
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ORIGINAL PAPERExtraction of phthalate esters from water and beverages using a graphene-based magnetic nanocomposite prior to their determination by HPLCQiuhua Wu &Min Liu &Xiaoxing Ma &Weina Wang &Chun Wang &Xiaohuan Zang &Zhi WangReceived:16September 2011/Accepted:12December 2011/Published online:24December 2011#Springer-Verlag 2011Abstract We have developed a highly sensitive microex-traction method for the preconcentration of some phthalate esters such as diethyl phthalate,di-n -propylphthalate,di-n -butyl-phthalate,dicyclohexyl-phthalate,and diethyl-hexyl phthalate prior to their determination by HPLC.It is based on a magnetic graphene nanocomposite as an effective adsorbent.The effects of the amount of the extractant com-posite employed,extraction time,pH values,salt concentra-tion and desorption conditions were investigated.Under the optimum conditions,the enrichment factors range from 1574to 2880.Response is linear in the concentration range from 0.1to 50ng mL −1.The limits of detection (at S /N 03)were between 0.01and 0.04ng mL −1.The method was successfully applied to the determination of five phthalate esters in water and beverage samples.Keywords Magnetic graphene nanocomposite .Microextraction .Phthalate esters .High performance liquid chromatographyIntroductionEach year,large quantities of phthalate esters (PAEs)are produced all over the world for the manufacture of a wide variety of common consumer goods.PAEs are used princi-pally as plasticizers to improve flexibility,workability and durability of polymeric materials,but they can also be foundin products such as paints,adhesives,inks,and cosmetics [1,2].PAEs are bound to polymers through weak secondary molecular interactions with polymer chains.Since they are not chemically but only physically bound to the polymer,they can be released easily from products,migrate into environment,and,consequently,pollute water,soil,air and food products [3].PAEs have become ubiquitous pollutants in the environment,and several PAEs are suspected to be human cancer causing agents and endocrine disruptors.The United States Environmental Protection Agency (US EPA)has listed PAEs as the priority contaminants [4,5].Very recently,a variety of food contamination cases have been reported by different media in Taiwan due to the addition of cloudy agents and emulsifiers in food processing,and many foods including some beverages were heavily contaminated with PAEs,such as DEP,DEHP and DBP.The intensive use of PAEs and their pollutions have become a more and more serious problem worldwide and also a major public health concern.Therefore,for the sake of human health and envi-ronment protection,the development of simple,sensitive and reliable analytical methods for the determination of these compounds in different samples is necessary.To measure a trace level of contaminants in a sample,sample preconcentration is usually necessary before instru-mental analysis.Up to now,various pretreatment techniques have been attempted to extract PAEs from different samples,such as liquid-liquid extraction (LLE)[6,7],solid-phase extraction (SPE)[8–13],solid-phase microextraction (SPME)[14–18],liquid-phase microextraction (LPME)[19],LPME method based on the solidification of a floating organic microdrop (LPME-SFO)[20],accelerated solvent extraction (ASE)[21],stir-bar sorptive extraction (SBSE)[22],single-drop microextraction (SDME)[23],dispersive liquid-liquid microextraction (DLLME)[24–26],hollowQ.Wu :M.Liu :X.Ma :W.Wang :C.Wang :X.Zang :Z.Wang (*)Key Laboratory of Bioinorganic Chemistry,College of Science,Agricultural University of Hebei,Baoding 071001,Hebei,Chinae-mail:zhiwang1963@Microchim Acta (2012)177:23–30DOI 10.1007/s00604-011-0752-7fiber-based liquid-phase microextraction(HF-LPME)[27], polymer monolith microextraction(PMME)[28],super-critical fluid extraction[29],and ultrasound-assisted emulsification–microextraction(USAEME)[30].Among them,SPE and SPME are the mostly used techniques for environmental analysis.However,SPE could be tedious and time-consuming;for SPME,the SPME fibers are relatively expensive and the polymer coatings are fragile and easily broken.Recently,a new mode for SPE,based on the use of magnetic or magnetically modified adsorbents called magnetic solid-phase extraction(MSPE)has been developed. Compared with traditional adsorbents,magnetic adsorbents can make separation process easier and faster without the need of additional centrifugation or filtration procedures.MSPE can avoid the time-consuming column passing operations encountered in SPE.Thus far,magnetic adsorbents have been widely applied in many fields including analytical chemistry, medicine,biotechnology,and so on.However,there are only a very few reports about their use for the extraction of PAEs.Niu et al.have prepared alginate-polymer-caged, C18-functionalized magnetic titanate nanotubes for the fast and efficient extraction of PAEs from water samples [31].Zhang et al.have prepared barium alginate caged Fe3O4@C18magnetic nanoparticles for the preconcentra-tion of PAEs from environmental water samples[32]. More recently,Meng et al.have reported applying polypyrrole-coated magnetic particles for the micro solid-phase extraction of PAEs in water[33].However,the magnetic adsorbents in these studies were mainly applied to the analysis of water samples,and their applications for more complex matrix sam-ples were not reported.Graphene(G),a novel carbon material,is one-atom-thick two-dimensional(2D)layers of sp2-bonded carbon[34]. With a large delocalizedπ-electron system,G can form a strongπ-stacking interaction with the benzene ring[35],so it could be a good adsorbent for the adsorption of benzenoid form compounds.So far,G-based composites have been applied for the extraction of polycyclic aromatic hydrocar-bons[36]and pyrethroid pesticides[37].However,the applications of G-based magnetic nanocomposite as the adsorbent for the extraction or removal of organic pollutants are still very few in the literature although the introduction of magnetic properties into G could combine the high adsorption capacity of the G and the separation conve-nience of the magnetic materials.Chandra et al.have prepared magnetite-reduced graphene oxide composites for arsenic removal[38].Cao et al.have applied mag-netic CoFe2O4-functionalized graphene sheets to remove methyl orange[39].Luo et al.have used Fe3O4@SiO2/ graphene for the extraction and determination of sulfon-amide antibiotics in water samples[40].The aim of the present work was to explore the potential application of G-based magnetic nanocomposite(G-Fe3O4)for the extraction of PAEs in water and beverage samples. Five PAEs including diethyl-phthalate(DEP),di-n-propyl-phthalate(DPP),di-n-butyl phthalate(DBP),dicyclohexyl phthalate(DCP),and diethylhexyl-phthalate(DEHP)were selected as model compounds.Several important experi-mental parameters affecting the extraction efficiencies such as the amount of the G-Fe3O4,extraction time,desorption conditions,sample pH,and salt addition were studied.To the best of our knowledge,this is the first report about the use of G-Fe3O4for the determination of PAEs in water and beverage samples.ExperimentalReagents and materialsGraphite powder(50meshes)was purchased from the Boaixin Chemical Reagents Company(Baoding,China). Standards of PAEs(DEP,DPP,DBP,DCP and DEHP)were purchased from Aladdin-reagent(/).Ammonium ferrous sulfate and ammonium ferric sulfate were obtained from Chengxin Chemical Reagents Company(Baoding,China).Acetonitrile,acetone, hydrochloric acid(HCl),sodium hydroxide(NaOH),and all other reagents were purchased from Beijing Chemical Reagents Company(/).The water used throughout the work was double-distilled on a SZ-93 automatic double-distiller purchased from Shanghai Yarong Biochemistry Instrumental Factory(http://yarong.instrument. /).A mixture stock solution containing each of DEP,DPP, DBP,DCP,and DEHP at100.0μg mL−1was prepared in methanol.A series of standard solutions were prepared by mixing an appropriate amount of the stock solution with double-distilled water in a10mL volumetric flask.All the standard solutions were stored at4°C and protected from light.G and G-Fe3O4was synthesized according to the method reported in our previous work[41],and characterized by scanning electron microscopy.River water was collected from Tang River(Baoding, China);bottled water and beverages were purchased from local supermarket.Apparatus and HPLC proceduresHPLC was carried out on a LC-20AT liquid chromatogra-phy(Shimadzu,/)with two LC-20AT VP pumps and a SPD-20A UV/vis detector. Chromatographic separations were performed on a Promosil C18column(150mm×4.6mm I.D.,5.0μm)from Agela Technologies(/).The24Q.Wu et al.mobile phase was methanol-water with the following gradient elution:0–4min,from 68%methanol to 70%methanol;4–45min,from 70%methanol to 95%meth-anol;45–50min,95%methanol to 68%methanol.The flow rate of the mobile phase was 1mL min −1.The UV monitoring wavelength was chosen at 225nm.The size and morphology of the magnetic nanoparticles were observed by scanning electron microscopy (SEM)using a FEI Quanta 200F field emission electron microscope (/default.aspx )operated at 30kV .The magnetic property was analyzed using a JDM-13vibrating sample magnetometer (/newjlu/)at room temperature.MSPE procedureThe MSPE procedure for the extraction of the five PAEs from the samples:Firstly,25mg G-Fe 3O 4was added into 300mL of sample solution,and then the mixture was placed on a slow-moving platform shaker and equilibrated for 15min.Secondly,a strong magnet was deposited at the bottom of the beaker and the G-Fe 3O 4was isolated from the solution.After about 5min,the solution became limpid and the supernatant was decanted.Then the residual solution and G-Fe 3O 4was totally transferred to a 10mL centrifuge tube.The G-Fe 3O 4was aggregated again by positioning a magnet to the outside of tube wall so that the residual solution could be completely removed by pipette.Finally,the preconcentrated analytes were eluted from the isolated particles with 0.5mL acetone by vortexing for 10s.After positioning a magnet to the outside of the centrifuge tube,the supernatant solution was collected using a micropipette.Three replicate desorptions were performed.The desorption solutions were combined together and transferred to a 2mL microcentrifuge tube,and then evaporated to dryness under a mild nitrogen stream.The residue was dissolved in 100.0μL methanol and 20.0μL was injected into the HPLC system for analysis.For calibration curve,a series of working solutions con-taining each of the PAEs at seven concentration levels of 0.1,0.5,2.0,5.0,10.0,20.0and 50.0ng mL −1were pre-pared.For each level,five replicate experiments wereperformed according to the MSPE procedure.The recovery test was carried out by spiking the PAEs standard solution into the samples at two concentration levels (0.5and 5.0ng mL −1).Results and discussionCharacterization of the magnetic graphene nanoparticles The SEM images of both the G and G-Fe 3O 4are shown in Fig.1.As can be seen from Fig.1a ,G has a crumpled silk wave-like carbon sheet structure,which is a characteris-tic feature of the single-layer graphene sheets.Iron oxide nanoparticles were also successfully coated on the sur-face of the G to form a G-Fe 3O 4nanocomposite (Fig.1b ).The average size of the Fe 3O 4nanoparticle estimated from the SEM observation was about 20nm.The Fe 3O 4nanoparticles were well distributed on graphene sheets,which were nearly flat and had a big area up to several square micrometers.Some nanoparticles were slightly aggregated due to the close to saturation loading degree.It is important that the adsorbents possess sufficient mag-netic properties to realize rapid separation under a magnetic field.Figure 2shows the VSM magnetization curves of the Fe 3O 4and G-Fe 3O 4nanoparticles at 298K.Both Fe 3O 4and G-Fe 3O 4exhibit typical superparamagnetic behavior.The saturation magnetization intensity of Fe 3O 4and G-Fe 3O 4were 71.9and 72.8emu g −1,respectively,which are suffi-cient for their magnetic separation from a solution with a strong magnet.Effect of the amount of G-Fe 3O 4In order to select the optimum MSPE conditions for the extraction of the PAEs,300mL double-distilled water spiked with 5ng mL −1each of the five PAEs was used to study the extraction performance of the MSPE under differ-ent experimental conditions.All the experiments were per-formed in triplicate and the means of the results were used foroptimization.Fig.1Scanning electron micrographs of G (a )and G-Fe 3O 4composite (b )Extraction of phthalate esters from water and beverages 25The equilibrium adsorption quantity (q eq in mg g −1)of the analyte by the magnetic graphene nanocomposite was calculated by q eq ¼C 0ÀC eqmV Where C 0(mg L −1)represents the initial concentration of the analyte,C eq (mg L −1)is the equilibrium concentration of the analyte remaining in the solution,V (L)is the volume of the aqueous solution,m (g)is the weight of the magnetic graphene nanocomposite.The value of q eq is related to C 0.To investigate the adsorption capacity of the G-Fe 3O 4toward the target compounds,25mg G-Fe 3O 4was added into 300mL of aqueous solution containing each of DEP,DPP,DBP,DCP and DEHP at 100.0μg mL −1.The values of q eq for DEP,DPP,DBP,DCP,and DEHP were 122,440,526,443,and 581mg g −1,respectively.To choose the optimum amount of the adsorbent (G-Fe 3O 4),the amount of the G-Fe 3O 4required for the quantitative extraction of the PAEs was investigated with the extraction time of 20min.According to the results shown in Fig.3,among the amounts investigated,i.e.,6,12,18,25,30and 50mg,the maximum extraction efficiency was obtainedat 25mg of G-Fe 3O 4(corresponding to its concentration 0.083mg/mL in the sample).When the amount of the adsorb-ents was above 25mg,the curves turned out to be flat,and there was no distinct increase of the extraction efficiency.Therefore,25mg G-Fe 3O 4was selected.The results proved that the G-Fe 3O 4sorbent has a high adsorption capacity and a good extraction efficiency can be achieved by using only a small amount of the sorbent.Extraction timeExtraction time is also an important parameter affecting the extraction efficiency to a large extent.For the study of the effect of the extraction time on the extraction efficiency of the PAEs,different extraction times were investigated.The results indicated that the recoveries of all the PAEs were enhanced with increased extraction time from 1to 15min,and then remained almost unchanged.Hence,the extraction time of 15min was selected.This result showed that the extraction equilibrium could be attained in a very short time.Influence of sample solution pH and salinityThe pH of the sample solution could play an important role for the adsorption of the analytes to the sorbents by both affecting the existing form of the compounds and their charge species and densities on the sorbents surface.The effect of sample pH on the extraction efficiency was inves-tigated in the pH range of 2.0–10.The experimental results showed that the extraction efficiency almost had no signif-icant changes with the changes of the pH of the sample solution.This could be because the PAEs exist as neutral molecules under ordinary conditions and are relatively insusceptible to the changes of sample solution pH.Normally,the pH of the water samples was in the range from 6.0to 7.0;the pH of Coca-Cola and green tea was about 2.5and 6.0.Therefore,there is no need to adjust the pH of the sample solution.In most cases,the addition of salt can decrease the solubil-ity of organic analytes (salting-out effect)and increase the-80-60-40-20020406080M a g n e t i z a t i o n (e m u g -1)Applied magnetic field (Oc)Fig.2VSM magnetization curves of Fe 3O 4and G-Fe 3O 420406080100R e c o v e r y (%)The amount of G - Fe 3O 4 (mg)Fig.3Effect of G-Fe 3O 4dosage on the extraction efficiency of the PAEsTable 1Analytical performance data for the PAEs by the MSPE technique PAEsLR (ng mL −1)rRSD (%)(n 06)EF LOD (ng mL −1)DEP 0.1-500.9986 5.622680.02DPP 0.1-500.9999 4.528200.02DBP 0.1-500.9999 5.628800.01DCP 0.1-500.9993 4.625560.03DEHP0.1-500.99985.215740.04LR linear range.26Q.Wu et al.distribution constant,but on the other hand,it can also in-crease the viscosity of the solution,which will reduce the extraction capability and the diffusion coefficient.To investi-gate the effect of sample salinity on the extraction recoveries of the analytes,different concentrations of NaCl,i.e.0,0.5, 1.0,2.0,5.0%(w/v)were added into the solution.The result showed that no significant effect on the extraction recoveries of the PAEs was observed with the addition of NaCl from0to 5%.So,there is no need to add salt to the sample solution for the experiment and the effect of salinity in real samples on the extraction of the analytes should be negligible. Desorption conditionsIt is necessary to completely desorb the analytes from the G-Fe3O4particles for further HPLC–UV analysis.In this work, acetonitrile,methanol and acetone were tried as the desorp-tion solvent for the desorption of the analytes from theTable2Comparison of presented method with other microextraction techniquesMethods Linearity(ng mL−1)LOD(ng mL−1)RSD(%)EF Samples RefSPE-HPLC-UV0.6–500.12–0.17 4.1–5.9600water[9]SPE-HPLC-UV 2.0–1000.18–0.86––water[10]SPE-HPLC-UV0.01–200.002–0.033 3.7–6.7–water[44] SPME-GC-MS0.1–200.003–0.085 1.38–21.7–bottled water[18] SPME-GC-FID a–0.003–3.429 1.69–13.51–bottled beer[16]MIP b-SPME-GC-MS0.01–100.0022–0.021 1.5–8.04–water[42]SFO-LPME-GC-MS0.05–1000.02–0.05 5.5–7.7307–412water[45]SPE-HPLC-FD c0.1–200.019–0.039–500water[11] DLLME-HPLC-UV2–1000.68–1.36 2.2–3.7174–212water[43] PMME-HPLC-UV3–50000.7–3.7 1.4–7.7–Cosmetic product[28] MSPE-HPLC-UV0.1–200.019–0.059–500–1000water[32] MSPE-HPLC-UV0.1–500.01–0.04 4.5–5.61574–2880water and beverage This methoda FID:flame ionization detector.b MIP:molecularly imprinted polymer.c FD:fluorescence detector.Table3Recoveries obtained in the determination of PAEs in spiked water and beverage samplesPAEs Spiked(ng mL−1)Bottled water(n05)River water(n05)Cola(n05)Green tea(n05)Found (ng mL−1)R b(%)RSD(%)Found(ng mL−1)R b(%)RSD(%)Found(ng mL−1)R b(%)RSD(%)Found(ng mL−1)R b(%)RSD(%)DEP0.0nd a nd a nd a nd a0.50.4386.0 5.10.4080.0 5.70.4386.0 5.90.4182.0 5.55.0 4.4288.4 4.8 4.3587.0 5.9 4.2585.06.2 4.1583.0 5.8 DPP0.0nd a nd a nd a nd a0.50.4488.0 5.20.4284.0 6.20.4590.0 4.20.4794.0 4.95.0 4.5791.4 4.1 4.5891.6 5.4 4.6392.6 4.4 4.6192.2 4.7 DBP0.0nd a0.12nd a nd a0.50.4590.0 5.50.65106.0 5.20.4488.0 5.40.4182.0 4.65.0 4.6192.2 4.6 5.17101.06.2 4.7294.4 6.1 4.3086.0 5.1 DCP0.0nd a nd a nd a nd a0.50.4794.0 4.80.52104.0 5.90.4590.0 5.60.4692.0 5.45.0 4.8296.4 4.2 4.8897.6 6.3 4.6893.6 5.5 4.7294.4 5.2 DEHP0.0nd a0.15nd a nd a0.50.4386.0 5.70.6498.0 4.60.52104.0 4.70.4896.0 4.75.0 4.7895.6 5.0 4.7592.0 5.1 4.7595.0 5.8 4.5891.6 5.0a nd:not detected;b R:recovery of the method.Extraction of phthalate esters from water and beverages27magnetic adsorbents.The results showed that the eluting power of acetone was much stronger than methanol and acetonitrile.Thus acetone was selected as the desorption solvent.The influence of the acetone volume on the desorp-tion efficiency of the analytes was also investigated.It was found that the quantitative desorption of the analytes were achieved with 1.5mL (0.5mL each time and three times)of acetone.The combined desorption solution (1.5mL)in a 2mL microcentrifuge tube was evaporated to dryness under a mild nitrogen stream.The residues were dissolved in 100.0μL methanol and 20.0μL was injected into the HPLC system for analysis.Analytical performanceUnder the above optimized conditions,some analytical per-formance parameters,including linear range (LR),correla-tion coefficients (r ),and limit of detection (LOD)were investigated.The characteristic calibration data obtained are listed in Table 1.The linear response was observed over the concentration range of 0.10–50ng mL −1,with the r ranging from 0.9986to 0.9999.The LODs (S /N 03)rangedbetween 0.01and 0.04ng mL −1for the PAEs.The enrich-ment factors (EF ),defined as the ratio between the analyte concentration in 0.1mL methanol and the initial analyte concentration in the aqueous samples,were in the range between 1574and 2880,indicating that the graphene-based magnetic nanocomposite exhibited a high adsorption capacity for the analytes.To assess the precision of the measurement,the repeat-ability study was carried out by performing six parallel experiments at the concentration of 2ng mL −1for each of0Fig.4The typical chromatograms of (a )blank sample and (b )sample spiked with PAEs at each concentration of 0.5ng mL −1(225nm).(A )River water sample;(B )Coca Cola sample;Peak identification:(1)DEP,(2)DPP,(3)DBP,(4)DCP,(5)DEHPTable 4Analytical results in the determination of the PAEs in certified reference materials (n 04)SampleCertified (ng mL −1)Found (ng mL −1)Recovery (%)RSD (%)DEP 10.09.393.0 5.1DPP 10.09.595.0 4.5DBP 10.09.595.0 4.3DC P 10.09.797.0 4.2DEHP10.09.696.03.828Q.Wu et al.the PAEs.The resultant repeatabilities expressed as the relative standard deviations(RSDs)varied from4.5%to 5.6%.The above results suggest that the present method has a high sensitivity,wide linear range and good precision.Comparison with other extraction methodsThe performance of the current method for the extraction and determination of the PAEs in water samples were com-pared with the other reported extraction methods from the viewpoint of LR,LODs,RSDs and EF.The comparison results are shown in Table2.It can be seen from Table2 that the EF of the current method is much better than that obtained with SPE,DLLME and SFO-LPME methods.For the MSPE-HPLC-UV method with Fe3O4@C18@barium alginate(Ba2+-ALG)as the adsorbent[32],its sensitivity was similar to the present method,but the dosage used (20mg per100mL sample)was higher than that of the present method(8.3mg per100mL sample).This indicated that the G-Fe3O4has a high adsorption ability for the PAEs. Compared with traditional adsorbents,magnetic adsorbents can make separation process easier and faster without the need of additional centrifugation or filtration procedures and also can avoid the time-consuming column passing opera-tions encountered in SPE.Therefore,it was much easier to deal with large volume samples to obtain high enrichment factors and high pared with the non-selective extraction methods,such as LPME and DLLME, SPE,MSPE and MIP-SPE have a better sample clean-up ability,which are more suitable for the extraction of the analytes in complicated matrix samples.Analysis of real samplesIn order to validate the applicability of the developed method, it was applied to determine the analytes in bottled water,river water,Cola and green tea samples.The results are shown in Table3.Among the four samples,no PAEs were detected in bottled water,Coca-Cola or green tea samples.Trace levels of DBP(0.12ng mL−1)and DEHP(0.15ng mL−1)were found in river water.The recoveries for the PAEs were in the range from80.0%to106.0%,which showed that the developed method was feasible in the application of real sample analysis. The typical chromatograms of the PAEs for the river and Coca Cola samples are shown in Fig.4.The accuracy of the developed method was further eval-uated by determining the PAEs in Standard Reference Material for Environment Water after an appropriate dilu-tion.The results obtained with the current method are in good agreement with the certified values(Table4),indicat-ing that the method is reliable for the determination of the PAEs in real samples.ConclusionsIn the present study,a G-based magnetic nanocomposite was synthesized and used as an effective adsorbent for the pre-concentration of some PAEs in water and beverage samples. The sorbent could extract and enrich the PAEs from the samples efficiently and the use of magnetic nanocomposite as the adsorbent endowed the method with an easy separation of the adsorbent from sample solution.The G-Fe3O4used in this work has the merits of excellent adsorption capacity and strong magnetism.The results indicated that the developed method was fast and efficient for the preconcentration of trace levels of PAEs in water and beverage samples and the adsor-bent could have a great potential for the enrichment of other environmental pollutants in other aqueous samples. 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