微波萃取方法3546
微波辅助萃取全部全解ppt课件

4.温度差: 是被提取组分扩散与传质的前提,没有浓度差或 浓度差很小,提取过程就不能进行
5.温度: 由于存在微波下的分子运动,因而温度不需要与传 统提取工艺过程中的一样高;也可能导致体系温度过度上 升,为减小温度的影响,可将微波提取过程分次进行 微波萃取在不同温度下的提取效果是不同的,当其他条件 一样时,热态比冷态的提取效果要好
微波辅助萃取 (Microwave Aided Extraction,MAE)
• 微波辅助萃取又称微波萃取(MAE),是微波和传统的溶剂 萃取法相结合后形成的一种新的萃取方法,因其具有快速 、高效、省溶剂、环境友好等优点,微波萃取是在有机分 析中得到了广泛的应用。
微波萃取机理
• 微波萃取技术是将微波技术和萃取技术相结合,利用极性 分子可以迅速吸收微波能量来加热一些具有极性的溶剂, 达到萃取样品中目标化合物、分离杂质的目的。微波加热 不同于一般的常规加热方式,常规加热是由外部热源通过 热辐射由表及里的传导方式加热。微波加热是材料在电磁 场中由介质吸收引起的内部整体加热。微波加热意味着将 微波电磁能转变成热能,其能量是通过空间或介质以电磁 波的形式来传递的,对物质的加热过程与物质内部分子的 极化有着密切的关系。
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食品分析
食 旧方法 用 色 素 的 提 取
新方法
天然食用色素制备方法大致可分为溶剂提取法、组织 培养法、粉碎法,压榨法、酶反应法、微生物,发酵 法和人工化学合成天然色素法等。其中最常用的方法 是溶剂提取法即浸取法, 但传统的浸取方法存在着浸 取时间长、劳动强度大、原料预处理能耗大、热敏性 组分易破坏等缺点
1. 微波革取用于天然产物提取的应用前景 2. 进一步缩短样品处理的时间 3. 进一步探讨萃取机理 4. 开发微波萃取新技术和其他技术联用 5. 开发微波萃取在线检测新技术 6. 将微波萃取的实验室研究扩大为工业化研究
微波辅助提取法原理

微波辅助提取法原理
微波辅助提取法是一种新兴的化学分离技术,在植物提取、食品分析和药物制备等领域得到了广泛的应用。
它相对于传统的提取方法具有快速、高效、环保等优点。
微波辅助提取法的原理是基于微波的能量作用于物质时,使其分子间振动,产生摩擦和热量,加速物质的扩散和渗出,从而加速提取过程。
一般来说,微波辅助提取法可以分为以下几个步骤:
1.样品预处理
针对不同的提取物,需进行不同的制备方法,例如:颗粒样品的处理方法是先将样品碾碎,并将其加入一定量的溶剂进行搅拌,得到均匀的混合物后就可以进行提取了。
2.微波加热
将用溶剂混合后的样品置于微波反应器内,施加一定功率的微波辐射,通过加热使样品酵解、水解、分解等,从而达到物质的提取目的。
通常情况下,微波加热可以比传统加热更快更有效,能够在数分钟至数十分钟内完成提取。
3.离心分离
将经过微波加热的样品放入离心机中进行处理,通过离心加快样品的渗出,使可溶性的物质和溶解液分离。
将离心分离后的澄清液移入试管中,离心机离能沉淀悬浮在上面的不溶性颗粒物。
4.溶液浓缩
将澄清液移入旋转蒸发仪中,利用的加热和旋转的引力加速溶液蒸发,从而使提取物质量得以浓缩和升高。
总之,微波辅助提取法是一种快速、高效的提取化学物质的方法。
其原理是通过微波能量作用于物质,使物质分子间振动,达到加速提取物质的速率和效率的目的。
在不断完善和发展中,将为植物提取、药物制备等领域的发展提供新的技术支撑。
微波萃取技术

微波萃取技术摘要:微波萃取技术区别于传统的溶剂萃取,作为一种新型高效的萃取技术,是近年来的研究热门课题。
微波可以穿透萃取介质,直接加热物料,能缩短萃取时间和提高萃取效率。
本文对近年的微波萃取技术以及其研究做了综述,介绍了微波萃取的特点,主要影响因素及其应用.关键词:微波;微波萃取;高效Technology of Microwave Assisted ExtractionAbstract:Microwave assisted extraction has attracted growing interest as it allows rapid extractions of solutes from solid matrices in recent years, with high extraction efficiency comparable to that of the classical techniques. Microwave assisted extraction consists of heating the extraction in contact with the sample with microwaves energy。
But unlike classical heating, microwaves heat all the samples simultaneously without heating the vessel。
Therefore,the solution reaches its boiling point very rapidly, leading to very short extraction time。
This review gives a brief presentation of the theory of microwave and extraction systems. A discussion of themain parameters that influence the extraction efficiently, and its applications.Key Words: Microwave ; Microwave assisted extraction; efficiency溶剂萃取是重要的传质单元操作]1[,其基本原理是通过溶质在两种互不相溶(或部分互溶)的液相之间不同的分配性质来实现液体混合物中某一单独或多种组分的分离或提纯。
微 波 萃 取 技 术

常规的微波萃取方法是把极性溶剂(如 丙酮)或极性溶剂和非极性溶剂混合物(如丙 酮+正己烷,或甲醇+乙酸等),与被萃取样品 混合,装入微波制样容器(一般为PFA杯)中, 在密闭状态下,放入微波制样系统中加热。 根据被萃取组分的要求,控制萃取压力或温 度和时间;加热结束时,把样品过滤,滤液 直接进行测定,或作相应处理后进行测定。 一般情况下,微波萃取加热时间约5~10分 钟,萃取溶剂和样品总体积不超过制样杯体 积的1/3。
(2)另一类由非极性分子组成,它们基本上不吸 收或很少吸收微波,这类物质有聚四氟乙烯、聚丙 烯、聚乙烯、聚砜等、塑料制品和玻璃、陶瓷等, 它们能透过微波,而不吸收微波。这类材料可作为 微波加热用的容器或支承物。
(3)金属导体材料能很好的反射微波,可做其密封 材料。
二、微波萃取设备及萃取步骤
1.设备 带有控温附件的微波制样设备,微波萃取用
3. 萃取时间
微波萃取时间与被测物样品量、溶剂体积和 加热功率有关。一般情况下,萃取时间在1015min内。在萃取过程中,一般加热开始1-2min即 可达到所要求的萃取温度。
4. 溶液pH值
溶液的pH值也会对微波萃取的效率产生一定 的影响,针对不同的萃取样品,溶液有一个最佳 的用于萃取的酸碱度。有文献考察了从土壤中萃 取除草剂三嗪时分别用NaOH、NH3-NH4Cl、HAc、 NaAc和HCl调节溶剂pH值对回收率的影响。研究 结果表明:当溶剂的pH值介于4.7~9.8时,除草剂 三嗪的回收率最高。
2. 微波的特性
1) 金属材料不吸收微波,只能反射微波。 2) 绝缘体可以透过微波,它几乎不吸收微波的能量。如
玻璃、陶瓷、塑料(聚乙烯、聚苯乙烯)、聚四氟乙烯、 石英、纸张等,它们对微波是透明的,微波可以穿透它 们向前传播。 3)极性分子的物质会吸收微波(属损耗因子大的物质), 如:水烯材料)。
微波萃取技术.

而微波加热是一个内部加热过程,微波直接
作用于内部和外部的介质分子,使整个物料
被同时加热,即为“体加热”过程,从而可
克服传统的传导式加热方式所存在的温度上 升较慢的缺陷。
一、微波萃取原理
传导加热
对流加热
微波加热
微波加热示意图
传统加热示意图
图 1 两种加热方式的比较
一、微波萃取原理
微波萃取离不开合适的溶剂,因此微波 萃取可作为溶剂提取的辅助措施。溶剂提取 法是根据中草药中各种成分在溶剂中的溶解
微波炉
微波炉的基本外形和构造
①门安全联锁开关--确保炉门打开,微波炉不能工作,炉门关上, 微波炉才能工作;
②视屏窗--有金属屏蔽层,可透过网孔观察食物的烹饪情况;
③通风口--确保烹饪时通风良好;
④转盘支承--带动玻璃转盘转动; ⑤玻璃转盘--装好食物的容器放在转盘上,加热时转盘转动,使食 物烹饪均匀; ⑥控制板--控制各档烹饪; ⑦炉门开关--按此开关,炉门打开。
一、微波萃取原理
微波萃取主要是利用微波强烈的热效应, 但微波加热方式不同于传统的加热方式。在 传统的加热方式中,容器壁大多由热的不良 导体制成,热由器壁传导至溶液内部需要一
定的时间;此外,液体表面气化而引起的对
流传热将形成自内而外的温度梯度,因而仅
一小部分液体与外界温度相当。
一、微波萃取原理
普通的外加热方式将热量由外向内传递,
微波炉
微波炉的加热时间: 要视材料及用量而定,还和食物新鲜程度、含水量有 关。由于各种食物加热时间不一,故在不能肯定食物 所需加热时间时,应以较短时间为宜,加热后可视 食物的生熟程度再追加加热时间。否则,如时间太长, 会使食物变得发硬,失去香、色、味。按照食物的种类 和烹饪要求,调节定时及功率(温度)旋钮,可以仔细 阅读说明书,加以了解。 食品放入微波炉解冻或加热,若忘记取出,如果时 间超过2小时,则应丢掉不要,以免引起食物中毒。
微波萃取-EPA3546方法

METHOD 3546MICROWAVE EXTRACTION1.0SCOPE AND APPLICATION1.1Method 3546 is a procedure for extracting water insoluble or slightly water soluble organic compounds from soils, clays, sediments, sludges, and solid wastes. The method was developed and validated on commercially-available solvent extraction systems. The procedure uses microwave energy to produce elevated temperature and pressure conditions (i.e., 100 -115E C and 50 - 175 psi) in a closed vessel containing the sample and organic solvent(s) to achieve analyte recoveries equivalent to those from Soxhlet extraction (Method 3540), using less solvent and taking significantly less time than the Soxhlet procedure. Other systems and other types of vessels may be used, provided that the analyst can demonstrate appropriate performance for a specific application.1.2This method is applicable to the extraction of semivolatile organic compounds, organophosphorus pesticides, organochlorine pesticides, chlorinated herbicides, phenoxyacid herbicides, substituted phenols, PCBs, and PCDDs/PCDFs, which may then be analyzed by a variety of chromatographic procedures. The method may also be applicable for the extractionof additional target analytes, provided that the analyst demonstrates adequate performance for the intended application (see Method 3500 and Chapter Two).1.3This method has been validated for solid matrices containing 50 to 10,000 µg/kg of semivolatile organic compounds, 250 to 2,500 µg/kg of organophosphorus pesticides, 10 to5,000 µg/kg of organochlorine pesticides and chlorinated herbicides, 50 to 2,500 µg/kg of substituted phenols, 100 to 5,000 µg/kg of phenoxyacid herbicides, 1 to 5,000 µg/kg of PCBs, and 10 to 6000 ng/kg of PCDDs/PCDFs. The method may be applicable to samples containing these analytes at higher concentrations and may be employed after adequate performance has been demonstrated for the concentrations of interest (see Method 3500).1.4This method only is applicable to solid samples with small particle sizes. If practical, soil/sediment samples may be air-dried and ground to a fine powder prior to extraction. Alternatively, if worker safety or the loss of analytes during drying is a concern, soil/sediment samples may be mixed with anhydrous sodium sulfate or pelletized diatomaceous earth. The total mass of material to be prepared depends on the specifications of the determinative method and the sensitivity required for the analysis, but 2 - 20 g of material are usually necessary and can be accommodated by this extraction procedure.1.5This method has been validated using a solvent mixture of hexane and acetone (1:1) from matrices such as soil, glass-fibers and sand. Other solvent systems may be employed, provided that adequate performance can be demonstrated for the analytes of interest (see. Sec. 7.4).1.6Prior to employing this method, analysts are advised to consult the base method for each type of procedure that may be employed in the overall analysis (e.g., Methods 3500, 3600, 5000, and 8000) for additional information on quality control procedures, development of QC acceptance criteria, calculations, and general guidance. Analysts also should consult the disclaimer statement at the front of the manual and the information in Chapter Two, Sec.2.1, for3546-1Revision 0November 2000guidance on the intended flexibility in the choice of methods, apparatus, materials, reagents, and supplies, and on the responsibilities of the analyst for demonstrating that the techniques employed are appropriate for the analytes of interest, in the matrix of interest, and at the levels of concern.In addition, analysts and data users are advised that, except where explicitly specified in a regulation, the use of SW-846 methods is not mandatory in response to Federal testing requirements. The information contained in this method is provided by EPA as guidance to be used by the analyst and the regulated community in making judgments necessary to generate results that meet the data quality objectives for the intended application.1.7This 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 METHOD2.1Samples are prepared for extraction by grinding to a powder and loaded into the extraction vessel.2.2The appropriate solvent system is added to the vessel and sealed.2.3The extraction vessel containing the sample and solvent system is heated to the extraction temperature (see Sec. 11.9) and extracted for 10 minutes (or as recommended by the instrument manufacturer).2.4The mixture is allowed to cool. The vessel is opened and the contents are filtered. The solid material is rinsed and the various solvent fractions are combined.2.5The extract may be concentrated, if necessary, and, as needed, exchanged into a solvent compatible with the cleanup or determinative procedure being employed.3.0DEFINITIONSSee Sec. 5.0 of Chapter 1 and the manufacturer’s instructions for definitions associated with this analytical procedure.4.0INTERFERENCES4.1Refer to Method 3500.4.2If necessary, Florisil and/or sulfur cleanup procedures may be employed. In such cases, proceed with Method 3620 and/or Method 3660.3546-2Revision 0November 20005.0SAFETYThis method does not address all safety issues associated with its use. The laboratory is responsible for maintaining a safe work environment and a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in this method. A reference file of material safety data sheets (MSDSs) should be available to all personnel involved in these analyses.The use of solvents combined with the operational parameters associated with this method will give rise to relatively elevated temperature and pressure conditions in the extraction vessels that can present potential safety concerns in the laboratory. Common sense laboratory practices can be employed to minimize these concerns. However, the following sections describe additional steps that should be taken.5.1The extraction vessels are at elevated temperatures and pressure after the extraction stage. Allow the vessels to cool before opening (the use of a water bath is recommended for this purpose) and always monitor the temperature and pressure by re-connecting the control vessel to the apparatus prior to opening the vessels5.2During the heating step, some solvent vapors may escape through the vesselliner/seal cover. Follow the manufacturer's directions regarding the vessel assembly and instrument setup to prevent release of solvent vapors to the laboratory atmosphere.5.3The instrument may contain flammable vapor sensors and should be operated with all covers in place and doors closed to ensure proper operation of the sensors. If so equipped, follow the manufacturer's directions regarding replacement of extraction vessel seals when frequent vapor leaks are detected.6.0EQUIPMENT AND SUPPLIESThe mention of trade names or commercial products in this manual is for illustrative purposes only, and does not constitute an endorsement or exclusive recommendation for use by EPA. The products and instrument settings cited in SW-846 methods represent those products and settings used during method development or subsequently evaluated by the Agency. Glassware, reagents, supplies, equipment, and settings other than those listed in this manual may be employed provided that method performance appropriate for the intended RCRA application has been documented as described in Sec. 2.1 of Chapter Two.6.1Microwave solvent extraction apparatus6.1.1The temperature performance requirements necessitate that themicrowave extraction system be capable of sensing the temperature to within ± 2.5E C and automatically adjusting the microwave field output power within 2 seconds of sensing.Temperature sensors should be accurate to ± 2E C. Temperature feedback controlprovides the primary performance mechanism for the method.6.1.2Microwave extraction vessels are needed. Vessels are available that canaccommodate 1-g to 20-g samples. Vessels should be transparent to microwave energy, relatively inert to reagents and sample components, and capable of withstanding the3546-3Revision 0November 20003546-4Revision 0November 2000temperature and pressure requirements (minimum conditions of 200E C and 200 psi)necessary to perform this procedure. Follow the manufacturer’s instructions regarding cleaning, handling, and sealing the vessels.6.2Apparatus for determining percent dry weight6.2.1Drying oven 6.2.2Desiccator 6.2.3Crucibles - porcelain or disposable aluminum 6.3Apparatus for grinding - capable of reducing particle size to < 1 mm.6.4Analytical balance - capable to weighing to 0.01 g.6.5Apparatus for separating sample from solvent extract6.5.1Glass funnels 6.5.2Filter paper 6.5.3Pasteur pipettes6.6Vials for collection of extracts - 40-mL or 60-mL, or other appropriate volume, pre-cleaned, open top screw-cap with PTFE-lined silicone septum..7.0REAGENTS AND STANDARDS7.1Reagent 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.7.2Organic-free reagent water. All references to water in this method refer to organic-free reagent water as defined in Chapter One.7.3Drying agents7.3.1Sodium sulfate (granular anhydrous), Na 2SO 4.7.3.2Pelletized diatomaceous earth.7.3.3The drying agents should be purified by heating at 400E C for 4 hours in ashallow tray, or by extraction with methylene chloride. If extraction with methylene chloride is employed, then a reagent blank should be prepared to demonstrate that the drying agent is free of interferences.7.4Extraction solventsThis method has been validated using a 1:1 mixture of hexane and acetone from matrices such as soil, glass-fibers, and sand. Other solvent systems may have applicability in microwave extraction, provided that at least one component absorbs microwave energy.The choice of extraction solvent will depend on the analytes of interest and no single solvent is universally applicable to all analyte groups. Whatever solvent system is employed, including those specifically listed in this method, the analyst must demonstrate adequate performance for the analytes of interest, at the levels of interest. At a minimum, such a demonstration will encompass the initial demonstration of proficiency described in Sec. 8.2 of Method 3500, using a clean reference matrix. Method 8000 describes procedures that may be used to develop performance criteria for such demonstrations as well as for matrix spike and laboratory control sample results.Hexane is a water-immiscible solvent and acetone is a water-miscible solvent. The purpose of the water-miscible solvent is to facilitate the extraction of wet solids by allowing the mixed solvent to penetrate the layer of water of the surface of the solid particles. The water-immiscible solvent extracts organics compounds with similar polarities. The polarity of acetone may also help extract polar analytes in mixed solvent systems.All solvents should be pesticide quality or equivalent. Solvents may be degassed prior to use.8.0SAMPLE COLLECTION, PRESERVATION, AND HANDLING8.1See the introductory material to this Chapter, Organic Analytes, Section 4.1.8.2Solid samples to be extracted by this procedure should be collected and stored as any other solid samples containing semivolatile organics.9.0QUALITY CONTROL9.1Refer to Chapter One and Method 8000 for specific Quality Control procedures and to Method 3500 for sample preparation quality control procedures. Each laboratory should maintain a formal quality assurance program. The laboratory should also maintain records to document the quality of the data generated.9.2Before processing any samples, the analyst should demonstrate that all parts of the equipment in contact with the sample and reagents are interference-free. This is accomplished through the analysis of a solid matrix method blank (e.g., clean sand). Each time samples are extracted, and when there is a change in reagents, a method blank should be prepared and analyzed for the compounds of interest as a safeguard against chronic laboratory contamination. Any method blanks, matrix spike samples, or replicate samples should be subjected to the same analytical procedures (see Sec. 11.0) as those used on actual samples.9.3All instrument operating conditions should be recorded.3546-5Revision 0November 20009.4Surrogate standards should be added to samples when listed in the appropriate determinative method.10.0CALIBRATION AND STANDARDIZATIONThere are no calibration or standardization steps associated with this sample extraction procedure other than establishing the extraction conditions in Section 11.9.11.0PROCEDURE11.1Sample preparationThe sample preparation steps vary with the type of sample to be extracted, as described below. Where practical, samples should be air-dried and ground to a fine powder before extraction. However, where such steps are not practical because of concerns about loss of the more volatile analytes or potential contamination of the laboratory from high concentration samples, samples may be mixed with a drying agent such as sodium sulfate or pelletized diatomaceous earth prior to extraction.11.1.1Sediment/soil samplesDecant and discard any water layer on a sediment sample. Mix the sample thoroughly, especially composited samples. Discard any foreign objects such as sticks, leaves, and rocks. Air dry the sample at room temperature for 48 hours in a glass tray or on hexane-rinsed aluminum foil. Alternatively, mix the sample with an equal volume ofanhydrous sodium sulfate or pelletized diatomaceous earth until a free-flowing powder is obtained.NOTE:Dry, finely-ground soil/sediment allows the best extraction efficiency fornonvolatile, nonpolar organics, e.g., 4,4'-DDT, PCBs, etc. Air-drying may not beappropriate for the analysis of the more volatile organochlorine pesticides (e.g.,the BHCs) or the more volatile of the semivolatile organics because of lossesduring the drying process. Worker safety may be an issue with the drying of soilscontaining PCDDs/PCDFs as well.NOTE:Drying should always be performed in a hood, to avoid contamination of the laboratory.11.1.2Waste samplesMultiphase waste samples must be prepared by the phase separation method in Chapter Two before extraction. This extraction procedure is for solids only.11.1.3Dry sediment/soil and dry waste samples amenable to grindingGrind or otherwise reduce the particle size of the waste so that it either passes through a 1-mm sieve or can be extruded through a 1-mm hole. Disassemble grinderbetween samples, according to manufacturer's instructions, and decontaminate with soap3546-6Revision 0November 20003546-7Revision 0November 2000%dry weight 'g of dry sample g of samplex 100and water, followed by acetone and hexane rinses. The notes in Sec. 11.1.1 also apply to the grinding process.11.1.4Gummy, fibrous, or oily materials not amenable to grindingCut, shred, or otherwise reduce in size these samples to allow mixing andmaximum exposure of the sample surfaces for the extraction. The analyst may addanhydrous sodium sulfate, pelletized diatomaceous earth, sand, or other clean, dryreagents to the sample to make it more amenable to grinding.11.2Determination of percent dry weightWhen sample results are to be calculated on a dry weight basis, a second portion ofsample should be weighed at the same time as the portion used for analytical determination.WARNING:The drying oven should be contained in a hood or vented. Significant laboratorycontamination may result from drying a heavily contaminated sample.11.2.1Immediately after weighing the sample for extraction, weigh 5-10 g of thesample into a tared crucible. Dry this aliquot overnight at 105E C. Allow to cool in adesiccator before weighing.11.2.2Calculate the % dry weight as follows:11.3Grind a sufficient weight of the dried sample from Sec. 11.1 to yield the sample weight needed for the determinative method (usually 10 - 30 g). Grind the sample until it passes through a 10-mesh sieve.11.4Transfer the ground sample to an extraction vessel. The weight of a specificsample that a vessel will contain depends on the bulk density of the sample and the amount of drying agent (if any) that was added to the sample in order to make it suitable for extraction. Analysts should ensure that the sample aliquot extracted is large enough to provide the necessary sensitivity.11.5Prepare a method blank using an aliquot of a clean solid matrix such as quartz sand of the approximate weight of the samples. If a drying agent is added to the field samples being extracted, it must also be added to the method blank, in order to assess the possible contribution of the drying agent to the blank results.11.6Add the surrogates listed in the determinative method to each sample and method blank. Add the surrogates and the matrix spike compounds appropriate for the project to the two additional aliquots of the sample selected for spiking. If a drying agent is added to the field samples being extracted, it must also be added to the matrix spike aliquots, in order to assess the effect of the drying agent.11.7Add approximately 25 mL of the appropriate solvent system to the vessel and seal the vessel as instructed by the manufacturer.11.8Place the extraction vessel into the instrument and proceed with apparatus setup as instructed by the instrument manufacturer. If recommended by the manufacturer, include additional vessels containing water or other materials to the apparatus in order to ensure that all samples are exposed to a consistent amount of microwave energy across extraction batches.11.9Recommended extraction conditionsTemperature:100-115E CPressure:50-150 psiTime at Temperature:10 - 20 minCooling:To room temperatureFiltering/Rinsing:With same solvent system11.9.1Optimize the conditions, as needed, according to the manufacturer'sinstructions. In general, the pressure is not a critical parameter, since it is a result of the solvent system vapor pressure at the elevated temperature.11.9.2Once established, the same procedure should be used for all samplesextracted for the same type of analysis.11.10Begin the extraction according to the instructions provided by the manufacturer.11.11Allow the extracts to cool to room temperature once the extractions are complete. After cooling, open the vessels and proceed with filtering and rinsing, combining all the filtrates.11.12The extract is now ready for concentration, cleanup, or analysis, depending on the extent of interferants and the determinative method to be employed. Refer to Method 3600 for guidance on selecting appropriate cleanup methods. Excess water present in extracts may be removed by filtering the extract through a bed of anhydrous sodium sulfate. Certain cleanupand/or determinative methods may require a solvent exchange prior to cleanup and/or analysis.12.0DATA ANALYSIS AND CALCULATIONSThere are no calculations explicitly associated with this extraction procedure. See the appropriate determinative method for the calculation of final sample results.13.0METHOD PERFORMANCEReference 4 presents a large body of information and specific data on a number of analytes. It provides the basis for a major portion of the performance work associated with this procedure. References 3 and 5 are reports of similar, more specific, studies. References 6 to 8 deal specifically with phenols. All of the method validation studies described in this method were performed using microwave apparatus operating at 2450 MHz.13.1Chlorinated pesticidesSingle-laboratory accuracy data were obtained for chlorinated pesticides extracted from soil, glass-fiber, and sand matrices. Concentrations of each target analyte ranged between 5003546-8Revision 0November 2000and 1,000 µg/kg. Four real-world split samples contaminated with pesticides and creosotes were also used (obtained from US EPA ERT, Edison, NJ). The latter were extracted by an independent laboratory using standard Soxhlet procedures and results compared to those obtained with this procedure. All samples were extracted using 1:1 hexane:acetone. Extracts were analyzed by the appropriate determinative method. Method blanks and five spiked replicates were included. Work was also carried out to assess the level of degradation of thermally labile pesticides and it was found that no significant degradation takes place under the procedure described in this method. The data are reported in detail in Reference 4. Data summary tables are included in Method 8081.13.2Semivolatile organicsSingle-laboratory accuracy data were obtained for semivolatile organics extracted from soil, glass-fiber, and sand samples. Concentrations of each target analyte were about 500µg/kg. All samples were extracted using 1:1 hexane:acetone. Extracts were analyzed by the appropriate determinative method. Method blanks and five spike replicates were included. The data are reported in detail in Reference 4. Data summary tables are included in Method 8270.13.3PAHsSingle-laboratory accuracy data were obtained for PAHs extracted from five reference materials comprising marine sediments (HS-3, HS-4, and HS-5, all from the National Research Council of Canada), lake sediments (SRM-1491, from the National Institute of Science and Technology), and a soil contaminated with creosote (SRS103-100, from Fisher Scientific, Fairlawn, NJ). Work was also conducted with soil, glass-fiber, and sand samples spiked between 100 and 2,000 µg/kg. All samples were extracted using 1:1 hexane:acetone. One real-world split sample contaminated with creosote and pesticides was also used (obtained from US EPA ERT, Edison, NJ). The latter was extracted by one laboratory using standard Soxhlet procedures and results compared to those obtained with this procedure. Extracts were analyzed by the appropriate determinative method. Method blanks, spikes and five spiked replicates were included. The data are reported in detail in Reference 4. Data summary tables are included in Method 8270.13.4PCBsSingle-laboratory accuracy data were obtained for PCBs extracted from three reference materials (EC-1, EC-2, EC-3 - from Environment Canada). Work was also conducted with soil, glass-fiber, and sand samples spiked between 200 and 10,000 µg/kg (total PCBs). All samples were extracted using 1:1 hexane:acetone. Extracts were analyzed by the appropriate determinative method. Method blanks, spikes and spike duplicates were included for the low concentration spikes; matrix spikes were included for all other concentrations. The data are reported in detail in Reference 4. Data summary tables are included in Method 8082.13.5Chlorinated herbicides (phenoxyacid herbicides)Multi-laboratory accuracy data were obtained for chlorinated herbicides extracted from a certified spiked material (obtained from ERA, Arvada, CO). This soil was spiked by ERA at 100µg/kg. All samples were extracted using 1:1 hexane:acetone. Extracts were analyzed by Method 8151. Method blanks and three replicates from five laboratories were included. Data summary tables are included in Method 8151.3546-9Revision 0November 200013.6PhenolsSingle-laboratory accuracy data were obtained for phenols extracted from a number of spiked soils and real-world split soils. Concentrations ranged between 200 and 10,000 µg/kg. All samples were extracted using 1:1 hexane:acetone. Extracts were analyzed by the appropriate determinative method. The data are reported in detail in References 4 to 8. Data summary tables are included in Method 8041.Multi-laboratory accuracy data were obtained for phenols extracted from a certified spiked material (obtained from ERA, Arvada, CO). This soil was spiked by ERA at 250 µg/kg. All samples were extracted using 1:1 hexane:acetone. Extracts were analyzed by Method 8041. Method blanks and three replicates from five laboratories were included. Data summary tables are included in Method 8041.13.7Organophosphorus pesticides and chlorinated herbicidesMulti-laboratory performance data were obtained for organophosphorus pesticides extracted from a certified spiked material (obtained from ERA, Arvada, CO). This soil was spiked by ERA at 250 µg/kg. All samples were extracted using 1:1 hexane:acetone. Extracts were analyzed by Method 8141. Method blanks and three replicates from five laboratories were included. Data summary tables are included in Method 8141.13.8Dioxins and furansSingle-laboratory accuracy data were obtained for dioxins and furans extracted from two soil reference materials (DX-1 from Environment Canada and SRM-1944 from NIST) containing the analytes of interest at concentrations between 10 and 6,000 ng/kg. All samples were extracted using 1:1 hexane:acetone. Extracts were analyzed by the appropriate determinative method. Method blanks, spikes and spike duplicates were included for the low concentration spikes; matrix spikes were included for all other concentrations. The data are reported in detail in References 9 and 10.14.0POLLUTION PREVENTION14.1Pollution prevention encompasses any technique that reduces or eliminates the quantity and/or toxicity of waste at the point of generation. Numerous opportunities for pollution prevention exist in laboratory operation. The EPA has established a preferred hierarchy of environmental management techniques that places pollution prevention as the management option of first choice. Whenever feasible, laboratory personnel should use pollution prevention techniques to address their waste generation. When wastes cannot be feasibly reduced at the source, the Agency recommends recycling as the next best option.14.2For information about pollution prevention that may be applicable to laboratories and research institutions consult Less is Better: Laboratory Chemical Management for Waste Reduction available from the American Chemical Society's Department of Government Relations and Science Policy, 1155 16th St., NW Washington, D.C. 20036, (202) 872-4477.3546-10Revision 0November 200014.3Extraction of organic compounds using microwave extraction conforms with EPA's pollution prevention goals. The volumes of solvent employed are generally smaller than with other extraction procedures.15.0WASTE MANAGEMENTThe Environmental Protection Agency requires that laboratory waste management practices be conducted consistent with all applicable rules and regulations. The Agency urges laboratories to protect the air, water, and land by minimizing and controlling all releases from hoods and bench operations, complying with the letter and spirit of any sewer discharge permits and regulations, and by complying with all solid and hazardous waste regulations, particularly the hazardous waste identification rules and land disposal restrictions. For further information on waste management, consult The Waste Management Manual for Laboratory Personnel available from the American Chemical Society at the address listed in Sec. 14.2.16.0REFERENCES1K. Ganzler, A. Salgo and K. Valko. Microwave Extraction: A novel Sample Preparation Method for Chromatography. J. Chrom., 371, 299-306 (1986).2.J. R. J. Paré, J. M. R. Bélanger, and S. S. Stafford. Microwave-Assisted process (MAP TM):A new tool for the analytical laboratory. Tr. Anal. Chem. 13, 176-184 (1994).3.V. Lopez-Avila, R. Young, and W. F. Beckert. Microwave-Assisted Extraction of OrganicCompounds from Standard Reference Soils and Sediments. Anal. Chem. 66, 1097-1106 (1994).4.K. Li, J. M. R. Bélanger, M. P. Llompart, R. D. Turpin, R. Singhvi, and J. R. J. Paré.Evaluation of rapid solid sample extraction using the microwave-assisted process (MAP TM) under closed-vessel conditions. Spectros. Int. J. 13 (1), 1-14 (1997).5.R. McMillin, L. C. Miner, and L. Hurst. Abbreviated microwave extraction of pesticides andPCBs in soil. Spectros. Int. J. 13 (1), 41-50 (1997).6.M. P. Llompart, R. A. Lorenzo, R. Cela, and J. R. J. Paré. Optimization of a microwave-assisted extraction method for phenol and methylphenol isomers in soil samples using a central composite design. Analyst, 122, 133-137 (1997).7.M. P. Llompart, R. A. Lorenzo, R. Cela, J. R. J. Paré, J. M. R. Bélanger, and K. Li. Phenoland methylphenol isomers determination in soils by in-situ microwave-assisted extraction and derivatisation. J. Chromatogr. A 757, 153-164 (1997).8.M. P. Llompart, R. A. Lorenzo, R. Cela, K. Li, J. M. R. Bélanger, and J. R. J. Paré.Evaluation of supercritical fluid extraction, microwave-assisted extraction and sonication in the determination of some phenolic compounds from various soil matrices. J.Chromatogr. A, 774, 243-251 (1997).3546-11Revision 0November 2000。
微波萃取技术及其应用

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微波萃取与传统热萃取的区别
➢ 传统的热萃取方式
热传导,热辐射方式由外向内进行。 热源→容器→样品
➢ 微波萃取方式
分子极化,离子导电方式直接对样品加热。 热源→样品→容器
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微波萃取与其它萃取技术的比较
➢ 优点
溶剂用量少,快速,可同时测多个样品,设备简单等。
➢ 缺点
被萃取物质必须对微波有吸收;萃取容器需要冷却。
开罐式聚焦微波萃取系统(FMAE)
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微波萃取技术与分析检测仪器的在线联用
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微波萃取技术的应用
➢ 在环境分析中的应用。 ➢ 在化工分析中的应用。 ➢ 在食品分析中的应用。 ➢ 在生化分析中的应用。 ➢ 在药物分析中的应用。 ➢ 在天然产物成分提取中的应用。
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在环境分析中的应用
❖ 国内外已有很多将MAE应用于中药中有 效成分提取的文献报道。
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微波辅助萃取—气相色谱—质谱联用 分析石蒜中的加兰他敏
❖ 前苏联科学家首次分离出了加兰他敏。 ❖ 加兰他敏是一种具有可逆性和选择性的
乙酰胆碱酯酶抑制剂(AChE),可以作 为治疗AD的药物。
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加兰他敏的传统提取方法概述
➢ 对土壤,沉积物和水中各种污染物的萃取。 ➢ 萃取对象:
有机污染物:多环芳烃(PAHs),多氯联苯(PCBs),石油烃(PHs),
邻苯二甲酸酯,酚类,苯等。
重金属,有毒元素及其化合物:锡,汞,砷,铅。 农药残留:杀虫剂,除草剂。
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在化工分析中的应用
➢ 在石油化工中,用于对聚合物及其添加物进行过 程监控和质量控制。 ➢ 萃取对象:
微波辅助萃取

微波辅佑襄助萃取微波特点MAE特点MAE是指利用微波能强化溶剂萃取效率,即利用微波加热来加速溶剂对固体样品中目标萃取物(重要是有机化合物)的萃取过程。
微波具有波动性、高频特性以及热特性或非热特性(生物效应)等特点。
快速高效样品及溶剂中的偶极分子在高频微波能的作用下,高速速度变换其正、负极,产生偶极涡流、离子传导和高频率摩擦,从而在短时间内产生大量的热量。
偶极分子旋转导致的弱氢键分裂、离子迁移等加速了溶剂分子对样品基体的渗透,待分析成分很快溶剂化,使微波萃取时间显著缩短。
加热均匀微波加热是透入物料内部的能量被物料汲取转换成热能对物料加热,形成的物料受热方式,整个物料被加热,无温度梯度,即微波加热具有均匀性的优点。
微波加热具有选择性微波对介电性质不同的物料呈现出选择性的加热特点,介电常数及介质损耗小的物料,对微波的入射可以说是"透亮"的。
溶质和溶剂的极性越大,对微波能的汲取越大,升温越快,促进了萃取速度。
而对于不汲取微波的非极性溶剂,微波几乎不起加热作用。
所以,在选择萃取剂时肯定要考虑到溶剂的极性,以达到最佳效果。
生物效应(非热效应)由于大多数生物体内含有极性水分子,在微波场的作用下引起猛烈的极性震荡,从而导致细胞分子间氢键松弛,细胞膜结构电击穿分裂,加速了溶剂分子对基体的渗透和待提取成分的溶剂化。
因此,利用MAE从生物基体萃取待分析的成分时,能提高萃取效率。
MAE技术与其它技术的比较任何一种萃取技术都是为了从基体中快速、高效地分别出待分析成分,但是由于基体的多而杂性及萃取技术的不同特点,常常在选取萃取方法的时候必需考虑到分析的目的和分析方法的费用、操作的繁简、时间的多寡等因素。
与传统的萃取技术相比,MAE技术突出的优点在于溶剂用量少,快速,可同时测定多个样品;有利于萃取热不稳定的物质,萃取效率高,设备简单,操作简单。
机理特点微波萃取的机理微波是指波长在1mm至1m之间、频率在300MHz至30000MHz之间的电磁波,它介于红外线和无线电波之间。
天然产物中化学成分提取的新方法 ———微波萃取法

天然产物中化学成分提取的新方法———微波萃取法【摘要】自 1986 年 Ganzler 首先报道了微波用于天然产物中化学成分的提取后 ,微波萃取技术已成为近年来发展较快的一种新型提取技术 ,因它具有速度快、效率高、耗能少、时间短以及有利于环保等优点 ,目前广泛应用于食品、生物、制药、环境样品及天然产物提取等各领域中.文章从微波萃取的原理、特点、条件入手 ,对微波萃取技术在天然产物化学成分提取中的应用进行讨论.【关键词】微波萃取法;天然产物;化学成分天然产物中化学成分的提取是一项耗时、耗能、耗溶剂的工作.目前,传统的提取方法主要有溶剂提取法和水蒸气蒸馏法,但这些方法都存在着提取效率低、溶剂消耗量大、提取周期长、能源消耗大等缺点.随着科学技术的快速发展,一批新技术、新设备应运而生,如超声波萃取、超临界流体萃取、加压逆流提取、旋流提取等技术,其中超临界流体萃取由于设备复杂、运行成本高、提取范围有限等问题,在应用上受到限制,而超声波萃取和微波萃取被广泛应用到实验室. 所谓微波萃取技术(Microwave2assisted extraction technique )是指使用微波及合适的溶剂在微波反应器中从各种物质中提取各种化学成分的技术和方法.这种技术非常符合环境保护的要求,是一种全新的“绿色”萃取技术.本文对微波萃取技术的机制、特点和在天然产物提取中的应用进行阐述,并进一步展望其发展趋势及应用前景.1 微波萃取的机制微波与无线电波、红外辐射、可见光等同属于电磁波,通常是指频率在300~300 GHz 间的电磁波,因比无线电波更为微小,故称之为“微波”,最早应用于通讯与军事. 1986 年Ganzler 首先报道了微波用于天然产物成分的提取,20 年来,此项技术已广泛应用于食品、生物、制药、环境样品及天然产物提取.目前,对微波萃取机制的解释,Pare 等提出的假设得到广大学者的认同,他们认为微波萃取是指高频电磁波穿透萃取媒质,到达植物物料内部维束管和腺细胞内,使细胞内的温度突然升高,连续的高温使其内部压力超过细胞空间膨胀的压力,从而导致细胞破裂;细胞内的有效物质自由流出,在较低的温度下溶解于萃取媒质,再通过进一步过滤和分离,便获得萃取物料.针对Pare 提出微波破壁[3]的假设,也有一些学者提出了异议. 郝金玉等对新鲜银杏叶微波辅助提取后微观结构的变化观察发现,植物细胞结构发生明显的变化,主要表现在有质壁分离现象,细胞器、淀粉粒等胞内物质被破坏,但微波辅助提取没有使细胞壁破裂. 无论微波破壁与否,微波对极性物质的提取的优越性,已得到了众多研究者的肯定.2 微波萃取的工艺流程微波萃取的大致工艺流程如下:原料预处理(清洗、切片或粉碎)→溶剂与物料混合→微波萃取→过滤→浓缩→分离→萃取成分.3 微波萃取的方法微波萃取的方法可分为:常压法、高压法、连续流动法.3.1 常压法即在敞口容器中进行微波萃取,其优点是样品容量大、安全性能好、容器便宜;缺点是原料容易污染、挥发性成分容易损失、有时消解不完全.3.2 高压法指物料在密闭消解罐中进行消解.因为消解罐为密闭容器,消解时产生的高压提高了酸的沸点;密闭时也产生高温提高了反应速度,减少了反应时间;酸也不会损失,节约了酸的用量,减少了酸雾对其他容器的腐蚀.3.3 连续流动萃取法就是将微波在线消解与流动注射联用(有关这方面的报道较少).4 微波萃取的特点微波萃取技术作为一种新型的萃取技术,有着明显的特点.首先,借介质从内部加热萃取,可有效地保护物料中的有效成分,纯度高、萃取率高;其次,对萃取物有高选择性,因其对极性分子的选择性加热从而其选择性地溶出;第三,速度快,省时.传统方法需要几小时或十几小时,而微波萃取只需要几秒到几分钟,可节省50 %~90 %的时间;最后,安全、节能、无污染、生产设备简单、节省投资.5 影响微波萃取的因素影响微波萃取的主要工艺参数包括萃取溶剂、萃取功率和萃取时间,其中萃取溶剂的选择对萃取结果的影响至关重要.5.1 萃取溶剂的影响首先,溶剂的极性对萃取效率有很大的影响,另外,还要求溶剂对分离成分有较强的溶解能力,对萃取成分的后续操作干扰较少.目前根据文献报道已用于微波萃取的溶剂有:甲醇、丙酮、乙酸、二氯甲烷、正己烷、乙腈、苯、甲苯等有机溶剂和硝酸、盐酸、氢氟酸、磷酸等无机溶剂,以及乙烷2丙酮、二氯甲烷2甲醇、水2甲苯等混合溶剂. 对于不同的基体,使用的溶剂可能完全不同.5.2 萃取温度和萃取时间的影响萃取温度应该低于萃取溶剂的沸点,不同的物质最佳萃取回收温度不同.而萃取时间与被测样品量、溶剂体积和加热功率有关,一般情况下为10~15 min ,对于不同的物质,最佳萃取时间不同.5.3 溶液pH的影响关于此类的报道不多.熊国华等在土壤中萃取除草剂三嗪的实验中, 分别用了NaOH, NH3NH4 Cl ,HAc-NaAc 和HCl 调节溶液的pH,考查了不同溶液pH对回收率的影响.结果表明:当溶液的pH介于4.7~9.8时,除草剂三嗪的回收率最高.5.4 试样中的水分或湿度的影响因为水分能够有效吸收微波能产生温度差,所以待处理物料中含水量的多少对萃取回收率的影响很大,因此对于不含水分的物料,要采取再湿的方法,使其具有适宜的水分.5.5 基体物质的影响基体物质对微波萃取结果的影响是因为基体物质中含有对微波吸收较强的物质,或是某种物质的存在导致微波加热过程中发生化学反应.6 微波萃取的应用6.1 生物碱类Ganzler K等采用微波技术从不同物质中提取生物活性碱. 在最佳实验条件下,鹰爪豆碱的微波提取率从传统方法的52.3 %提高到80.3 %;从羽扇豆种子中提取金雀花碱,也与传统的振摇提取法相比,提取率提高了20 %,大大缩短了提取时间并节约了大量溶剂.范志刚等研究微波技术对麻黄碱浸出量影响的实验中,比较了微波提取与常规煎煮方法. 结果表明微波提取麻黄碱的浸出量明显高于煎煮法,并且半量麻黄粗粉浸出量明显高于全量麻黄饮片. 邓远辉等在微波提取黄连小檗碱的实验中,以干固物和小檗碱含量测定结果为目标,比较了微波提取与回流两种方法.干固物测定结果表明,在单位时间内微波处理较回流提取具有明显的优势;以小檗碱含量测定结果表明,回流提取高于微波提取.6.2 黄酮类目前,微波对黄酮类物质的提取已取得了良好的效果,有较多文献报道了微波用于中草药中黄酮类物质的提取.张梦军等用均匀设计法进行分析表明,甘草黄酮的最佳提取条件为:固∶液=1∶8 ,乙醇浓度为38 %或78 %,微波功率288 W或388 W , -提取时间1 min或3 min ,提取率为24.6 g·L -1,明显高于水提法的11.4 g·L -1.王鲁石等、刘志勇等分别进行了荆芥叶、荆芥根中总黄酮含量测定的实验,实验结果表明,微波辅助提取荆芥中总黄酮提取时间由常规法的2 h缩短为20 min ,提取液中总黄酮的含量由常规法的0.71 %提高到1.11 %.李芙蓉等、陈斌等、王娟等分别进行了葛根中总黄酮提取的实验.李芙蓉的实验采用比色法测定总黄酮的含量.结果表明葛根中总黄酮含量为0.34 %,平均回收率为97.6 %. 王娟等通过均匀设计考查微波频率、辐射时间、溶剂用量、浸泡时间、原料粉碎等参数对葛根中总黄酮提取效果的影响,实验表明在255 W、辐射15 min、固∶液=1∶9、粉碎度为40 目、浸泡时间1 h条件下干浸膏产率最高,与传统工艺比较,有缩短了提取时间,减少了溶剂用量以及干浸膏中总黄酮含量较高等优点.研究结果表明,微波对葛根素的分子结构并未造成破坏.段蕊等、李嵘等进行了银杏中黄酮含量的测定实验,用微波处理5 min后,以70 %乙醇回流提取1 h ,得到提取物中黄酮类物质的量比未用微波处理的高出188 %,纸层析表明在使用的微波温度下,黄酮类物质性质不发生变化.还有许多研究人员作了微波提取黄酮类物质的实验,如鲁建江等作了车前草中总黄酮的微波提取及含量测定的实验,结果表明车前草中总黄酮含量由原来的2.8 %~3.5 %提高到3.74 %;孙萍等作了狭叶红景天总黄酮的微波提取及含量测定实验,结果表明微波萃取不但缩短了提取时间,样品中总黄酮的含量达到2.11 %;王莉等作了新疆马齿苋中总黄酮的微波提取及含量测定实验,结果表明总黄酮的含量达到5.79 %.6.3 蒽醌类郝守祝等研究了微波技术对大黄游离蒽醌浸出量的影响,实验考查了微波频率、物料粒径、浸出时间 3 个因素对提取率的影响,结果表明物料粒径对蒽醌成分浸出影响极为显著,微波频率对蒽醌成分浸出影响显著,浸出时间对蒽醌成分浸出有一定影响.微波提取技术对大黄游离蒽醌的提取率明显高于常规煎煮法及乙醇回流法.吉林大学胡秀丽等试验研究了大黄总蒽醌的微波辅助提取、超声提取和索氏提取方法,并利用分光光度法测定了提取液中总蒽醌的含量.结果表明微波辅助提取法的提取率最高1.91 %,是超声法的1.13倍,是索氏提取法的1.29倍. 微波辅助提取法仅需10 min ,而索氏法和超声法分别需要90 ,30 min.微波辅助提取法用于中药大黄的提取,具有高效、省时的特点.6.4 皂苷类用微波技术提取植物皂苷的报道比较多,目前,已有应用微波技术提取重楼中重楼皂苷和高山红景天中的高山红景天苷的报道. 王家强等的重楼皂苷的微波提取论文中指出,微波5 min能达到常规加热2 h的效果,而且杂质少,微波提取10 min皂苷就已提取完毕.郭振库等对黄芩中黄芩苷的提取作了研究,通过正交设计方案研究了溶剂性质、加热时间、微波处理压力对黄芩中黄芩苷提取率的影响,显示最佳提取条件为:微波功率850 W ,以35 %乙醇为溶剂、提取压力0~15 mPa、恒压时间30 s,即可获得较高的得率,在此条件下,与采用35 %乙醇为溶剂、固∶液=1∶60、提取时间30 min的超声波萃取技术相比,提取率高了10 %左右.6.5 多糖类多糖是一类具有生物活性的大分子物质,在调节免疫、抗氧化、降血糖、抗病毒以及抗肿瘤等方面有显著的作用. 多糖传统提取方法为水煎醇沉法,提取时间一般为8 h左右.现在,微波技术已用于某些生物材料的多糖提取中,如板蓝根多糖的提取、新疆党参多糖的提取、黄芩多糖的提取、甘草多糖的提取、肉苁蓉多糖的提取、天花粉多糖的提取、天仙果多糖的提取、马齿苋多糖的提取、刺五加多糖的提取、红景天根和叶多糖的提取、茶叶多糖的提取等等,这些植物中多糖的提取一般分为 2 种方法:一种是用微波技术直接提取,结果表明反应时间缩短了1/12 ,多糖的含量均高于传统的方法,并具有高效节能、杂质含量少的优点;另一种是先用微波处理几分钟,然后用水煎煮法提取,结果表明多糖的含量均高于单一的水煎煮法,同时也缩短了时间.6.6 挥发油类微波技术提取挥发油类物质,国内外已有较多的研究.在阐述研究成果的同时,专家们提出了挥发油在提取过程中应注意的几个问题:1 不同植物的挥发油不同,要求微波提取时微波的功率也要有所不同. 2 微波辐射的时间不可过长,否则可导致挥发油中不稳定成分的降解. 3 微波功率不可过高,否则挥发油来不及冷凝就跑掉了,导致挥发油产量的降低.Chen S 进行了微波辅助提取迷迭香、薄荷叶中的挥发油实验,实验主要研究了微波功率、辅助时间以及物料量等因素对微波提取率的影响.结果表明微波加热的类型与组分的介电常数决定,在固定微波功率后,提取率与物料的特性、微波强度和持续时间、溶剂种类、固液比例以及加样量有关.陈宏伟等运用微波技术从荆芥叶中提取挥发油并对其含量进行测定.结果反应时间由原来的5 h缩短为20 min,荆芥叶挥发油含量由0.89 %提高到1.10 %.新疆石河子大学药学院鲁建江等人从藿香、魁蒿叶、红花、佩兰、新疆孜然果实、新疆党参根茎叶、红景天等植物中用微波技术提取挥发油,均得到了较好的效果,提取率均高于水蒸气蒸馏法且时间短.6.7 其他微波技术不仅用于以上化学成分的提取,用此技术也可以提取萜类化合物、有机酸、香料、色素、植物油、氨基酸、维生素等等. 宗乾收等。
微波萃取常用方法

微波萃取常用方法(食品、农产品、土壤)1.多环芳烃类的抗生素、农药、杀虫剂等
取样量:1-5克
萃取剂:30ml二氯甲烷
微波萃取程序:
1,10分钟,300-500W,120°C
2,20分钟,200-500W,120°C
3,排风 20分钟
2.有机磷类杀虫剂(包括DDT、绿色杀虫剂等) 取样量:1-5克
萃取剂:40ml 丙酮/正己烷(1+1)
微波萃取程序:
1,10分钟,300-500W,120°C
2,20分钟,200-500W,120°C
3,排风 20分钟
3.除草剂:
取样量:1-5克
萃取剂:20ml 乙醇
微波萃取程序:
1,10分钟,300-500W,90°C
2,10分钟,200-500W,90°C
3,排风 10分钟
备注;
1,取样量:土壤一般1-2g,干性的食品、饲料、农产品等1-2g,新鲜农产品2-5g
2,样品必须预先按规定粉碎
3,微波功率根据样品数适当设置
4,萃取完成后需根据分析仪器的要求过滤浓缩。
微波萃取技术

微波萃取技术节选自:郭振库金钦汉《微波萃取技术》(吉林大学化学系,长春,130023)摘要:微波萃取技术在有机污染物和有害金属分离的研究和应用方面出现了令人鼓舞的进展。
微波萃取方法具有方便、快速、试剂消耗低、回收率高和可用水作萃取溶剂的优点。
本综述介绍了微波萃取技术的原理、方法、设备和应用研究现状。
关键词:微波萃取技术设备方法综述一、概述现在,绝大多数的分析样品需要使用原子吸收光谱仪(AAS)、电感耦合等离子体发射光谱仪(ICP-AES)、气/液相色谱仪(GC/LC)、质谱仪、分子光谱仪等进行其中成分或元素的测定。
这些检测仪器一般都需用均匀液体样品,因此需要对原始样品进行消解、萃取、抽提或分离,然后才可能用上述仪器加以测定。
目前,常规样品萃取方法有分液漏斗法、超声萃取法或Soxhlet(索氏)提取法。
这些萃取法一般要用几小时或一天的时间,有些样品所需的萃取时间更长。
这些常规前处理方法不仅制样时间长,试剂用量大并对环境造成一定程度的污染,而且准确性和精密性已经不适应现代快速测定的要求。
此外,常规前处理方法长的制样时间,不能满足需要确定样品有效成分组成和结构的分析研究要求。
自Ganzler等人[1]报导用微波加热促进溶剂萃取污染土壤中的有机化合物以来,分析样品的微波萃取法由于萃取时间短、选择性好、回收率高、试剂用量少、污染低、可用水作萃取剂[2]的优点和可自动控制制样条件等而得到了分析工作人员的认同[3],因而在设备研究、应用开发、机理探讨方面均有可喜的研究报导。
虽然微波萃取土壤中的有机污染化合物已有标准方法EPA3546[4],但就目前而言,微波萃取的应用对象还比较少,与微波消解技术相比,微波萃取技术及其应用研究工作还处于最初的阶段[5],微波萃取法还是一种相对年轻的样品处理方法[6]。
要使微波萃取法成为一个分析样品制备的常规方法,还需要做更多的技术研究和应用研究工作。
粮食、蔬菜、水果、茶叶、咖啡豆、中药、化妆品和乳制品是日常生活中的必需品,这些商品的品质和有害物质检验,样品数量多,要求快速测定,这是微波萃取技术最有应用前景的领域。
EPA3546-微波萃取

方法3546微波萃取 技术翻译;刘金云 mail:piery2006@ 1.0范围及应用1.1方法3546从是土壤﹑黏土﹑积沉物﹑废淤泥和固体弃物中提取可溶于水或微溶于水的有机化合物的程序.场购买剂统本方法是在市上可到的溶萃取系上发并展得到证实有效性的.本个样剂程序利用微波能源在一装有品和有机溶的闭产密的罐中生高温压条高件萃取,达到和索氏萃取(方法3540)相等的分析物回收率它,而使用的溶剂对较时间相少,所花的也比索氏萃取少。
证种应一旦分析者明某用方法具有合适的性能,它统它类分析者也可采用其的系或其型的容器.1.2挥发本方法适用于半性有机化合物,酯农药有机磷酸,氯农药有机,氯剂含除草,苯氧剂酸除草,酚类取代,氯联苯多(PCBs),PCDDs/PCDFs,这过种谱些均可通各的色方法分析.它标本方法也适用于其的目分析物的萃取,证标一旦分析者明在萃取此目分析物(参见方法3500册及本手第二章)时,够此程序具有足的性能.1.3对本方法于固体基体含有50-10,000μg/kg 挥发半性有机化合物,250-2,500μg/kg 酯农药的有机磷酸,10-5,000μg/kg 的氯农药氯剂有机和含除草,50-2,500μg/kg 酚类的取代,100-5,000μg/kg 苯氧剂的酸除草,1-5,000μg/kg 的PCBs 及10-6000ng/kg 的PCDDs/PCDFs 证实会这已有效。
本方法可能适用于含些分析浓样标浓围见物更高度的品,在目度范(方法3500内够证)的性能得到足的明之后,可采用本方法。
1.4仅细颗组样实话本方法适用于由微粒成的固体品。
如果可行的,在萃取之前,土壤/积样应气并研细风时沉物品放在空中干燥磨成微的粉末。
如果在干有工作安全及损问题分析物失,土壤/积样应与沉物品无钠处水硫酸混合或造成硅藻土粒作替代理。
预处总决测试灵理材料的重量取于方法的要求及分析所要求的敏度,一般地,需要的样为品2-20g 时来调节,同可以利用此萃取程序。
微波萃取法

1. 微波是波长为0.1-100cm (即频率为1011-108Hz)的一种电磁波,具有波粒二象性。
人们对微波的利用是在通讯技术中作为一种运载信息的工具或者它本身被作为一种信息,而微波协助萃取是把微波作为一种与物质相互作用的能源来使用。
微波作为能源,还可用于食物的烹饪,物料的烘干,促进化学反应。
目前,用作能源的微波,其频率是2450MHz。
微波协助萃取是在传统的有机溶剂萃取基础上发展起来的一种新型萃取技术。
它有如下特点:快速,只需几分钟;节省能源;降低环境污染;是又一种萃取方法,具有萃取选择性;可避免样品的许多成分被分解;操作方便;提取回收率高。
2. 方法原理:作为一种电磁波,微波具有吸收性、穿透性、反射性,即:它可为极性物如水等选择性吸收,从而被加热,而不为玻璃、陶瓷等非极性物吸收,具穿透性。
金属要反射微波。
分子对微波具有选择性吸收,极性分子可吸收微波能,然后弛豫,以热能形式释放能量,或者说由于极性分子的两偶极在微波的较低频电磁场中将有时间欲与外电场达成一致而振荡,但微波频率要比分子转动频率快,迫使分子在转动时太快速取向而通过碰撞、磨擦放能生热。
分子对不同频率的微波吸收能力不同。
将水与含有金属离子的水溶液相比,用微波辐射,后者温升更高。
这可用微波的传导机理解释:溶液中的离子在交变电场作用下迁移,由于不断碰撞产生热能。
水要吸收微波,加上盐的作用,盐水吸收微波后温升更高。
从实验看,相比于一般的热源,微波有使被加热物温度升高快的优点,象加热用的容器:玻璃、塑料不会升温,而内盛的含水物升温快,表面无孔的物体(如鸡蛋)在加热前,必须划开表皮后,再放入微波炉中加热,否则表面无孔的物体受热膨胀,会爆裂。
用塑料带装含水物体,用微波辐照加热时,须敞口,否则含水物体加热后,气体膨胀出现炸裂现象。
这些事实表明微波加热是“内加热”。
用电炉加热则是利用了空气的对流,玻璃器皿的热传导作用,这种加热方式能量损失大。
微波被物质选择性吸收的程度,可用物质的介质损耗角正切Tanδ来描述:tanδ= ε’’/ ε’式中, ε’’为物质的介电损失因子,ε’为物质的介电常数。
微波萃取技术

微波萃取技术摘要:微波萃取技术区别于传统的溶剂萃取,作为一种新型高效的萃取技术,是近年来的研究热门课题。
微波可以穿透萃取介质,直接加热物料,能缩短萃取时间和提高萃取效率。
本文对近年的微波萃取技术以及其研究做了综述,介绍了微波萃取的特点,主要影响因素及其应用.关键词:微波;微波萃取;高效Technology of Microwave Assisted ExtractionAbstract:Microwave assisted extraction has attracted growing interest as it allows rapid extractions of solutes from solid matrices in recent years, with high extraction efficiency comparable to that of the classical techniques. Microwave assisted extraction consists of heating the extraction in contact with the sample with microwaves energy。
But unlike classical heating, microwaves heat all the samples simultaneously without heating the vessel。
Therefore,the solution reaches its boiling point very rapidly, leading to very short extraction time。
This review gives a brief presentation of the theory of microwave and extraction systems. A discussion of themain parameters that influence the extraction efficiently, and its applications.Key Words: Microwave ; Microwave assisted extraction; efficiency溶剂萃取是重要的传质单元操作]1[,其基本原理是通过溶质在两种互不相溶(或部分互溶)的液相之间不同的分配性质来实现液体混合物中某一单独或多种组分的分离或提纯。
美国EPA3546 新方法---微波快速溶剂萃取技术

美国EPA3546新方法---微波快速溶剂萃取技术刘伟张明祥杨海鹏(美国CEM公司,北京,100013)摘要:由加拿大环保局和美国CEM共同开发的MARSX快速微波溶剂萃取技术,是世界上唯一专利的微波萃取技术,也是唯一符合美国EPA3546方法的仪器。
MARSX获98年度全美R&D100大奖,低功率先行非脉冲微波磁控管技术实现连续高精确过程控制反应,MARSX利用闭环反馈控制技术,通过高精度高频率的温压控制系统精确调节微波能量输出激发极性试剂,并且内置CARBOFLON加热和极化非极性试剂,实现了快速完全的样品萃取制备,大大提高了现代气/液相色谱测定精度和效率。
其主要特点是: 快速, 安全,批量大,样品量大,节省溶剂,污染小。
前言样品预处理是样品分析过程中最关键、最耗时的环节。
在现代化实验室高度重视速度和效率的今天,探索快速、高效、简便、自动化的样品预处理新方法已成为当代分析化学的前沿课题和重要研究方向之一。
萃取是分离和提纯物质的一种常用方法,为GC、HPLC等有机分析方法提供样品前处理。
传统的萃取方法由于费时、费试剂、效率低、重现性差等缺点,已不能满足分析发展的需要,于是先后出现了微波辅助萃取(MAE)、超临界流体萃取(SFE)和加速溶剂萃取(ASE)等萃取方法。
但由于技术、成本和效率等问题,一些萃取方法在使用中受到了限制,而微波萃取则克服了以上的缺点, 表现出了巨大的应用潜力和良好的发展前景。
自从1986年匈牙利学者Ganzler提出了微波萃取法并从土壤、种子、食品、饲料中萃取分离化合物以来[1],微波萃取技术以高效、低耗、无污染,成为近年来萃取技术的佼佼者,被誉为“绿色”萃取技术。
微波是指频率为300到300 000MHz的电磁波,介于红外线和无线电波之间。
民用微波频率一般采用2450MHz,所对应能量大约为0.96J/mol,微波的量子能级属于范德华力(分子间作用力)的范畴,与化合物键能相差甚远[2]。
实验三 用微波萃取

三.实验器材与试剂 器材 层析柱,恒流泵,旋转式真空蒸发器,试管,烧 杯和量筒等。 试剂 HZ—818树脂(华东理工大学华震科技有限公司), 乙醇等。
茶多酚为淡黄至褐色略带茶香的水溶液、灰 白色粉状固体或结晶,味涩。易溶于水、乙醇、 乙酸乙酯,微溶于油脂。对热、酸较稳定, 160℃油脂中30min仅降解20%.PH2-7稳定, PH≥8,和光照下易氧化聚合。遇铁变绿黑色络 合物。略有吸潮性,水溶液的PH在3-4之间,碱 性条件下易氧化褐变。具有优越的抗氧化能力。 在油脂、食品、医药、化妆品及饮料等领域具有 广泛的应用前景。
(1)微波功率500W:
萃取阶段1——设定微波功率500W,时间45s。
萃取阶段2——微波功率0W,时间10s。 萃取阶段3——微波功率500W,时间5 s。 萃取阶段4——微波功率0W,时间10s。 萃取阶段5——微波功率500W,时间5 s。
(2)微波功率200W:将萃取阶段1、3、5的微波功率改为200W, 其余相同。
开真空泵抽滤,收集滤液,弃去固体残渣。
6、用量筒量滤液体积,并用下述实验Ⅲ的分析方法测
定茶多酚含量。按下式计算茶多酚的提取收率:茶多
酚提取收率=ρ ×V/m×100% 式中:ρ —茶多酚含量(㎎/ml) V—滤液的体积(ml) M—萃取时所用的茶叶总质量(㎎) (3-6-1)
7、萃取结束后,用清洁剂和少量的水倒入烧瓶内,用 软刷刷洗,并用水洗净。烧瓶底部的换能器尽量不要碰 到水,万一碰到水,就要用干布擦干,在通风处晾干。 (三)普通热水萃取 1、称取同样5g粉碎后的茶叶末,加入100ml的水,放入 烧瓶内,80℃水浴加热浸取,立即计时,按下列时间间 隔取样分析茶多酚含量:1、3、5、7、10、15、20、30、 40min。每次取样2-3ml,用小三角漏斗过滤后,分别测 定滤液中茶多酚含量(mg/ml),总共萃取40min结束。 以茶多酚含量为纵坐标,时间为横坐标,画出茶多酚的 萃取曲线。曲线基本达水平的时间作为最适萃取时间。 2、根据上述所求得的最适萃取时间,在相同条件下, 再进行一次萃取,但中间不取样。将萃取后的固液混合 物抽滤,除去固体残渣。然后量滤液体积,并测定滤液 中茶多酚含量,按上述公式计算萃取收率。
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方法3546微波萃取 如在实际分析中发现问题,请Mail 至:piery2006@1.0范围及应用1.1方法3546从是土壤﹑黏土﹑积沉物﹑废淤泥和固体弃物中提取可溶于水或微溶于水的有机化合物的程序.场购买剂统本方法是在市上可到的溶萃取系上发并展得到证实有效性的.本程序利用微波能源个在一样剂装有品和有机溶的闭密的罐中产生高温压条高件萃取,达到和索氏萃取(方法3540)相等的分析物回收率它,而使用的溶剂对较时间相少,所花的也比索氏萃取少。
证种应一旦分析者明某用方法具有合适的性能,分析者也可采它统它类用其的系或其型的容器.1.2挥发本方法适用于半性有机化合物,酯农药有机磷酸,氯农药有机,氯剂含除草,苯氧剂酸除草,酚类取代,氯联苯多(PCBs),PCDDs/PCDFs,这过种谱些均可通各的色方法分析.它标本方法也适用于其的目分析物的萃取,证一旦分析者明标在萃取此目分析物(参见方法3500册及本手第二章)时,此程序具有够足的性能.1.3对本方法于固体基体含有50-10,000μg/kg 挥发半性有机化合物,250-2,500μg/kg 酯农药的有机磷酸,10-5,000μg/kg 氯农药的有机氯和含除剂草,50-2,500μg/kg 酚类的取代,100-5,000μg/kg 苯氧剂的酸除草,1-5,000μg/kg 的PCBs 及10-6000ng/kg 的PCDDs/PCDFs 证实已有效会这。
本方法可能适用于含些分析浓样标浓围物更高度的品,在目度范见(方法3500)内够证的性能得到足的明之后,可采用本方法。
1.4仅细颗组样实话本方法适用于由微粒成的固体品。
如果可行的,在萃取之前,土壤/积样应气并研细沉物品放在空中干燥磨成微的粉末。
风时如果在干有工作安全及损问题分析物失,土壤/积样应与钠沉物品无水硫酸混合或造成硅藻土粒处作替代理。
预处总决测试灵理材料的重量取于方法的要求及分析所要求的敏度,一般地,需要的样为品2-20g 时来调节,同可以利用此萃取程序。
1.5烷酮剂从纤本方法利用已和丙的混合溶土壤,玻及砂子萃取已证实有效。
一旦目标够证它剂组分析物的性能得到足的明之后,分析者也可使用其的溶合。
1.6在议参总使用此方法之前,建分析者考在体分析中可能用到的基本方法(例如,方法3500,3600,5000及8000获关质﹑)的程序,以便取有品控制程序QC 允收标﹑计导应参册准的建立算及一般性指的更多信息。
分析者也考本手前面诺的《不承宣言》及第二章第2.1节的信息,灵选择﹑仪﹑﹑试剂﹑以便于在活地方法器材料供应,术标﹑标质及在展示所使用的技适用于目分析物目基及处标于目的浓围度范内分责时够获析者的任,分析者能得更多的信息。
议数规说另外,有必要建分析者和据使用者,除非在范中有明确明,使用SW-846并应联测试办中的方法不是付邦要求的强制性法。
为国环本方法中所包含的信息美保导署提供的指为,目的是规分析者或法局在应过用程产数质标生符合据品目结的果时,利用此方法断作出判。
1.7仅经过训练本方法限于的分析者,练监或是在有熟分析者的控下进行.个每分析者须必展示够获能使用此方法得可接受结果的能力.2.0方法概述2.1样预处进萃取的品先磨成粉末理,然后装萃取容器中。
2.2剂组并闭向容器中加入合适的溶合密。
2.3将样剂组热温装有品和萃取溶合的容器加至萃取度(第11.9节温),在此度下萃取10钟仪产议分(或按照器生商的建)。
2.4将将开并将内质混合物冷却。
容器打容器物过滤。
将质种剂组固体物冲洗,各溶结分被合在一起。
2.5质浓缩将它换进纯测试萃取物可以被,如果有必要和需要,交能同所使用的提或剂程序相容的溶中。
3.0定义关本分析程序相义请参见的定第一章5.0节产导和生商的指。
4.0干扰4.1参见方法3500。
4.2罗如果有必要,可以使用佛里西和/纯或硫的提程种况序。
此情继续下,使用方法3620和/或3660。
5.0安全过关问题实验负责维个环本方法未提及使用程中相的安全。
室持一安全的工作境及建立份与当一前OHSA 规范关关内学相的注性文件,容涉及到本方法所述的化品的安处个与过关员够获数参全理。
每此分析程中相的人都能得材料安全据信息的照文件。
剂参数产对较温压条本方法所使用的溶和操作能在萃取容容器中生相高的度及强件,这实验内会产在室个隐实验识这隐生一潜在的安全患。
采用室安全操作常可降低些还应该患。
此外,采取如下节骤几所述的步。
5.1阶过还处较温压开在萃取段后,萃取容器于高的度和强下。
在打之前将,先容器来达开过将仪冷却(推荐使用水浴到此目的)。
在打罐之前,通控制罐再次接到器上来监温压控度和强。
5.2热骤间在加步期,剂气会从衬垫一些溶蒸罐的密封/跑设密封盖中出。
在置仪器和组时请仪产导书剂气挥发实验气装罐的候,按照器生商的指,防止溶蒸至室的空中。
5.3仪气应时应将器可能含可燃性蒸感器,在操作所有的盖子盖上﹑门关所有的上,应以确保感器的运当经侦测气正常行。
按此操作仍常到有体泄漏时请产,遵循生商的导换指更萃取罐密封盖。
6.0仪器及供应册标场产本手中提到的商名或一些市品均只为释说作解并明用途,不成为EPA 使用时书专门产的背或的推荐品。
SW-846产仪设国方法中所引用的品和器置代表着美环护境保署(USEPA 研来评时产仪设)在究方法及其后估所使用的品和器置。
非本册﹑试剂﹑应手中所列出的玻璃器皿供﹑仪器和设置也可以使用它们,只要在此RCRA 应时够用能提供合适的方法性能(此RCRA 应用已按照第二章第2.1节所述予以文件化)。
6.1剂仪微波溶萃取器6.1.1温统应温在度性能方面,要求微波萃取系感度能达到±2.5够应℃,且能在感两内动调节场输后的秒自微波的出功率温应够。
度感器能准确至±2温馈℃。
度反控为制本方法提供主要的性能机制。
6.1.2需要一些微波萃取罐。
萃取罐能盛装1-20g 样的品。
萃取罐是透明的可通过对与试剂样发应够微波能量,具有相的惰性,不和品成分生反,且能承受此程序必要的温压为度和强(最少200℃和200psi 清处请)。
萃取罐的洗,理及密封遵循生产导商的指。
6.2测试仪干重百分率的器6.2.1炉干燥6.2.2剂干燥6.2.3钳锅-质铝钳锅瓷或一次性用的6.3研仪磨器-够样研能使品微粒大小磨至小于1mm.6.4分析天平-够称能量至0.01g.6.5将样剂品同溶萃取物分离的装置6.5.1玻璃漏斗6.5.2滤纸6.5.3巴氏吸管6.5瓶收集萃取物的小-40mL,60mL 它或其合适的积容,预清净先洗干,有PTFE(聚氟烯四乙)边缘开有机硅隔膜的口螺旋盖.7.0试剂及标准品7.1测试学药为试剂级所有用到的化品均等.别说除非有特明,试剂国所有的均符合美学协会试剂员会规化分析委的格要求,获规在那可得此格说明.它级试剂其等的也可以使用,预纯够会测试只要是先探明其度足高不降低的准确度.7.2试剂不含有机物的水.为试剂本方法中提到的水均不含有机物的水,见试第一章中剂义水的定.7.3剂干燥7.3.1钠硫酸(颗状粒,结不含晶水),Na 2SO 4.7.3.2捣碎的硅藻土.7.3.3剂应干燥在400浅盘热℃下放于中加4时过氯烷来纯小或通二甲萃取提.如果使氯烷用二甲萃取,则须备个试剂剂证剂扰制一空白溶以明干燥中不存在干.7.4剂萃取溶本方法使用1:1烷酮从的已和丙的混合物土壤﹑纤维证玻璃和砂子的基体中萃取已实有效.它剂组其的溶合也应可用到微波萃取中,组只要至少有一分吸收微波的能量. 选择剂决标萃取溶取于目分析物,没种剂有一溶适用于所有的分析群体.哪不管是使用种剂组溶合(专门剂包括那些本方法列出的溶),分析者须必证标处对应明目分析物于浓围内时的度范,够具有足的性能.种证净参达此明至少包括使用干的照基体到方法3500第8.2节练证所述的熟度原始明.方法8000来为这种证﹑描述的程式可用明基掺实验样标体料及室控制品建立性能准.烷与已水不互溶,而酮与丙可水混溶.与剂过剂使用可水互溶的溶的目的是通混合溶渗层透固体微粒表面的水,来进湿促的固体样品被萃取. 剂须农药级级所有的溶都必是等或同品.剂气溶在使用之前可除去其中的体. 8.0样品收集,储存和处理8.1参见无机分析物第4.1节绍内的介性容. 8.2样应与它挥发样使用本程序萃取的固体品其含有半性有机物的固体品采取相同的收集﹑储藏方法.9.0品质控制9.1关质参册相的品控制程序考本手第一章及方法8000.关样备质有品制的品控制程请参序考方法3500.个实验应当维书质证项每室都持面的品保目.实验应当维室也持记录,将产数质生的据品予以文件化.9.2处样在理任何的品之前,须证实仪分析者必器的各个样触试剂部分有同品接且不扰含有干.这骤过个一步通分析一固体基体方法空白(例如,净干的沙子)来完成.每次萃样时当试剂变时取品及有化,应当备个它标都制一方法空白分析的目化合物,以防止有实验污慢性的室染.所有的方法空白,掺样复样应该与实际样历经基体料品或制品都品相同的分析程序(见第11.0节).9.3仪条应当记录所有的器操作件都予以.9.4关测试标时相的方法中有列出使用代用准溶液,应样加入至品中.10.0校正及标准化 样没关标骤本品萃取程序有相的校正或准化步,除了第11.0节条建立萃取的件外. 11.0程序11.1样备骤随样态变品的制步被萃取的品形而化,以下有作描述当实际时。
可操作,样应将它风并研细当品在萃取前先干磨成微的粉末。
然而,关挥发由于注到容易的分会损浓样会对实验污骤时样析物被失掉或高度的品室造成潜在的染而此步不可行,品剂钠研在萃取前可同干燥(例如硫酸)或磨碎的硅藻土混合。
11.1.1积沉物/样土壤品样层将样匀别复样样倒去沉淀物品表面的水。
品充分的混合均,特是合性的品。
去除树树将样盘烷过铝温品中的枝,叶及岩石。
品置于玻璃中或用已冲洗的箔上,在室下风样干品48时小。
另外地,可以将样与积品相同体的钠捣无水硫酸或碎的硅藻土混搅动合,直到形成能自由的粉末。
备注并细:干燥磨土壤/积为挥发﹑极沉物能不性的非性有机物(例如:4,4′DDT,PCBs)提供最佳的萃取率。
风干可能不适用挥发氯农药于分析容易的有机(例如:BHCs 挥发较挥发为风过会这损)或半性有机物中易的,因干程中造成些有机物的失。
在干燥含有PCDDs/PCDFs 时个值问题的土壤,工作安全也是得注意的。
备注应橱进实验污:干燥常在中行,避免造成室染。
11.1.2废样弃物品废样须过来备多相同弃物品在萃取之前必通相分离方法制。
11.3研容易磨的干积燥沉物/废样土壤及干燥的弃物品研过它将废颗减过磨或通其方法弃物粒的大小小到能通1mm 筛网从的或能1mm 的挤样与样间孔中出。
在品品之,椐产说根生商的明将研开磨机拆皂污,用肥和水除去酮烷染,接着用丙和已冲洗。