SCI 自己总结的句法

前言In particular, some heavy metals, such as As, Cd, Cr, Hg, and Pb, may be extremely toxic to humans, even at low concentrations.Metal elements such as Na, K, Ca, Mg, Fe, Cu, Zn and Mn, are essential nutrients for human growth。

Other metals, such as arsenic (As), lead (Pb), cadmium (Cd) and methyl forms of mercury (Hg) have no biological roles and their presence causes environmental pollution. Even at very low concentrations, all these elements can be toxic both for man and other living species because they bind with cellular structures and hinder the performance of certain vital functionsThe amount of micro- and macro-elements(微量和大量元素) in honey depends on its botanical origin and soil composition on which the plants grow.The determination of trace elements in vegetable oil s is one of the criteria for the assessment of quality regarding freshness and the storable period. Traces of heavy metals in vegetable oils are known to affect the rate of oxidation. Moreover, some of the metals are the subject of food legislation. Hence, determination of trace metals in vegetable oils is important.（测油脂中金属的意义）Honey was one of the first sources of sugar used by man, but in addition to its great nutritional importance, they also present medicinal qualities, working as antioxidant, fungicidal, and bactericidal against Staphylococcus aureus and Escherichia coli, and may also be used as a food preservative.Determination of trace elements in vegetable oil is one of the criteria for the assessment of quality of oil in regard to freshness, keeping properties and storability.The presence of heavy metals in edible oils is due to both endogenous factors, connected with the plant metabolism, and hexogenous factors due to contamination during the agronomic techniques of production and the collection of olives and seeds during the oil extraction and treatment processes, as well as systems and materials of packaging and storage.Trace levels of metal ions (Cu, Fe, Mn, Co, Cr, Pb, Cd, Ni, and Zn) are known to have adverse effect on the oxidative stability of edible oilsDue to the large commercial expansion of Brazilian honey, it is necessary to have an efficient quality control of this productSediments accumulate high volumes of contaminants compared to the water column. As a result,benthic organisms are more at risk of contamination compared to pelagic organisms.底栖生物更具风险Arsenic is ubiquitous in the biosphere and undergoes uptake and bioaccumulation through food chains, followed by alkylation to form a variety of arsenicals in organisms. Arsenic circulation in the marine environment has been extensively studied.研究进展The usual methods for the determination of Pb2+ in solution involve potentiometry, spectrophotometry, atomic absorption spectrometry. Electrochemical method is one of the most favorable techniques for the determination of heavy metal ions, because of its low cost, high sensitivity, easy operation and the ability of analyzing element speciationIn previous works However, the use of extraction methods is usually time consuming and labor-intensive, and requires relatively large volume of high-purity and toxic solventsOwing to the peculiar characteristics of ICP-MS (low detection limits, multielemental capacity, wide linear range, etc.) the numberof papers dealing with the analysis of food samples by ICP-MS has increased in recent yearsThe determination of metals in vegetable oils and fats has been under investigation for several years and is still a formidable problem. Several methods for this analysi s, including……The determination of inorganic constituents in honey is not a trivial task due to the low concentration of the analytes and also the high-level carbohydratesAiming to determine mineral and trace elements in honey, different techniques have been us ed , includingICP-MS presents advantages to determine minerals and trace elements in honey due to its multielement capacity and high sensitivity and excellent limits of detection.As a rule(通常来说), to determine microelements in oil and petroleum products, one usually uses atomic absorption spectrometry.Often the analyte concentrations in the analysis of real oil and petroleum products appear below the LOD for the methods listed, which may be due to the extremely low concentrations ofinorganic microcomponents (REE, for example, may be present at a level of a few ng/kg and even lower) and also to losses at the sample preparation step.But the determination of iodine is quite difficult because of its volatility and possible redox reactions.The result was coincident with the conclusion of Hou et al. [12] for the ashing of biological samples.However,tests for the accuracy of determining metals upon the direct injection of crude oil samples into mass spectrometers is complicated by the lack of metal standards in oil and the necessity of high dilution for the viscous samples of crude oil. In addition, the injection of high amounts of organic solvents into the plasma results in a deterioration of the precision of measurements, which leads to the growth of LOD for most elements because of the formation of carbon-containing ions. (直接进样的风险性)In contrast to the large number of reports on arsenicals in marine organisms, there are fewer data on arsenic speciation in fresh-water organisms.现有测有方法的缺点：However, the commented methods present some disadvantages, such as the low stability of the analyte in the organic diluted standard solutions, the need for organometallic standards for calibration and the use of dangerous organic solvents that require special conditions for their handling (mask, gloves, hood).提出研究内容The major goal of the present work was to compare different techniques of oil sample preparation to elemental analysis by ICP MS using Tengiz oil and diesel fuel as examplesThe aim of the present work is to develop an accurate FI-ICP-MS method with a vapour generation sample introduction device for the determination of As, Cd and Hg in vegetable oils.仪器描述For this study, the following equipments were used: Block digester (Tecnal, Brazil) with perfluoroalkoxy vessels (PFA; Savillex, Minnetonka, USA), Microwave digestion system (Ethos 1600, Milestone, Italy) with PFA closed vessels, Soft-ware MatLab 2011a (Mathworks, Natick, USA), ICP-OES with radial view configuration (Varian, Mulgrave, Australia), and quadrupole ICP-M S (820-MS, Varian , Mulgrave , Australia).The aim of this study was to evaluate four metals (Cd, Pb, Cr, and As) content, which are considered among the most dangerous to humans, in honeys from nine areas of southern ItalyAccordingly(因此), the aim of the present study was to determine zinc (Zn), chromium，(Cr), cadmium (Cd) and lead (Pb) content of benthic fauna in the southeast coast of the Caspian Sea, where the major fish restocking programs are conducted at.Over the years several empirical tools were developed to assess the pollution level of aquatic environments reflecting not only the impact of individual pollutants, but also the combined effect of multiple pollutants. Among these tools,one of the most frequently used is the potential ecological risk index (RI), that applies the method developed by Ha¨ kanson (1980).The aims of the present study were: (1) to characterize the levels of some heavy metals (As, Cd, Pb, and Hg) in surface water, sediments, and benthic oligochaetes in four major rivers in Calabria, southern Italy; (2) to explore the level of heavy metals contamination of monitored rivers by three different approaches: a comparison with national environmental quality standards for freshwater, a compar-ison with international sediment quality guidelines, and the application of Ha¨ kanson potential ecological risk index实验采样和样品During 2012, ninety honey samples were collected directly from beekeepers in nine geographical areas of southern Italy (ten honey samples for each area; Fig. 1 ).Three sampling sites were selected (Fig. 1 ): north Miank-aleh [(NM), stations 1 and 2], South Miankaleh [(SM), stations 3 and 4] and Gharesoo coast [(GC), stations 5 and 6]. Site selection was performed based on priorities related to the restocking programs.（采样地点选择依据）实验过程器皿清洗Before use, all glassware and plastic containers were cleaned by washing with 10 % ultra-pure grade HNO3for at least 24 h and then copiously rinsed with ultra-pure water.实验过程After the addition of HNO3, the sample went through a predigestion of 8 h at room temperature in a closed vessel. Then,it was added to 1 m L of 30 % m m−1H2O2and the sample went through an overnight predigestion. After that, this mixture was heated in a block digester at 90 °C for 3 h, and the final volume of all samples was adjusted to 15 m L.Replicate 5.0 g samples were diluted with 10 mL of carbon tetrachloride and then extracted with 10mL of 2N nitric acid by subjecting the samples to ultrasonic intensification.Limits of quantitations (LOQs) were defined as 10 times the standard deviation of the signal from reagent blanks, after correction for sample weight and dilution.数据处理工具表达Differences between metal concentrations in different geographical areas were analysed using Student’s t test. A Pearson’s correlation test was conducted to determine the linear correlation among the variables. Differences between means at the 95 % (p<0.05) confidence level were considered statistically significant. Data were expressed as mean± standard deviation.优化实验表达Diverse buffer solutions were tested for their suitability in the determination of Pb in presence of SPADNS, as follows: NaHCO3-NaOH, borax-NaOH, K2HPO4-NaOH, K2HPO4-borax. The most suitable buffer system for the determination of Pb was founded to be NH3-NH4Cl. In this buffer solution, peak height is more than other buffers (Table 1)In this study Triton X-100 was selected as the surfactant since it has a medium hydrophilic–lipophilic balance value（为什么要选这个提取剂）However, the concentration of NaBH4 did not affect the signal of As and Hg when the concentration was greater than 0.5%.（当大于多少时不影响信号变化）In order to investigate the effect of pH on the peak height, pH was increased from 7.0 to 10.0 by addition of ammonia.Similarly, at constant NaBH4 concentration（固定硼氢化钾的浓度）, the signal of Cd increased significantly with the concentration of HCl as long as it was less than 1.2% v/v, whereas the signals of As and Hg increased slightly with the HCl concentration.The optimum ligand concentration was 3.5 ×10-5 MThe influence of several anions and cations on determination of Pb was studiedTable 3 presents the results of the elemental analysis of oil using different sample preparation techniques. With autoclave digestion, the found concentrations of V and Cr were higher than those using the RCC. This might be explained by the fact that vanadium can occur in oil as organoelement species……From our experiments, we found that when the concentrations of oil and Triton X-100 were too large, the injected emulsion could not be completely evaporated, although the signals of the elements studied were large. When the ratio of the concentration of oil to the concentration of Triton X-100 was too large, we could not get a stable oil emulsion.试剂的选择：In this study,several common modifiers, including Pd, NH4NO3 ,NH4H2 PO4, L -cysteine, oxalic acid, boric acid, and citric acid, were tested for the best signals of the elementsstudied. After preliminary studies, we found that signals of most elements studied increased when Pd was used as modifier. Pd has been used as the chemical modifier to improve the signals of certain volatile elements in many ETV-ICP-MS applications. The effect of Pd concentration on ion signal is shown in Fig. 1. As shown, Zn and Cd signals increased with increase of Pd concentration and reached a maximum when the concentration was 200 and 400 mg/ml, respectively.After evaluation, 300 mg/ml (20 ml) of Pd was chosen as the optimum modifier concentration in the ETV-ICP-MS analysis.数据分析数据的描述The Pb content in honey samples ranged from 0.010 to 1.390 mg kg- 1, with an average value of 0.289 mg kg- 1 (Table 4 ). These values were lower than those found in Polish honey (Dobrzancki et al. 1994), in Egyptian honey (4.200 mg kg- 1) (Rashed andSoltan 2004), and in Saudi Arabia honey (1.81 mg kg- 1) (Bibi et al. 2008). Current results were higher than those found in German honey. Generally, our results were similar to or higher than those found in Italian honeys by other authors (Table 5 )……. Basso Pollino, Collina Materana, Vulture Melfese, Leccese, and Cilento honeys do not show any significant differences in Pb concentrations.Tarantino is characterized by a high presence of industries (ironand steel), power stations and refineries. Camastra-Dolo-miti Lucane is mainly agricultural-pastoral,with a low population density, and it is included in the Natural Park of Dolomiti Lucane, representing one of the main green lungs of southern Italy.In addition, it should not be underestimated that the Cr content in honey depends on the weather condition.Pearson correlation coefficients were calculated between the three metals. Statistically significant positive correlations were detected between Pb and Cd, Pb and Cr, and Cd and Cr contents (p <0.001). These correlations allow the speculation that the polluting sources involve the simultaneous presence of metals. These results disagree with that found by Roman and Popiela ( 2011), while Frı ´as et al. ( 2008) found a direct statistical correlation between Cd and Pb contents in Tenerife honey.The heavy metal concentrations were in the order As>Pb>Hg>Cd in all of the water samples, and in the order As>Pb>Cd>Hg in the sediment and oligochaete samplesThere was quite a big difference in the dominant As species in the medicines from fields, which might depend on the growing conditions and their genetic properties.图表的描述Table 1 shows the heavy metal concentrations found in the water, sediment, and oligochaete samples taken from the Calabrian rivers.As can be seen from Fig 1cThe stripping voltammogram for the blank and sample solution was shown in fig 2.As can be seen in this figure, …..This phenomenon indicates that the complex isFrom Table 3, it can be seen thatthe dependence of the peak height on ligand concentration is shown in Fig 4aThe mean(±standard deviation) and range of the concentrations of the metals in black and green olives are given in Table 5The amount decreased with the order of Sn, Fe, Zn, Cu, Pb, Cr, Ni, Cd and Co, respectively.In the comparison of the concentration of trace elements among black and green olives, differences were observed.These variations could be from olive varieties, distribution of elements in the soil, maturation and processing method of olives, packing material, as well as environmental and weather conditionsThe contents of Cr, Co and Ni were similar in all table olive samples. Also no significant differences of these metal levels were found between olive types ( p > 0.05)Mg was the most abundant among the elements quantified.The effects of ashing time and temperature on the recoveries of Sr, Ba, Mo, La, Ce, Nd and Zr are illustrated in Figs. 2 and 3, respectively.The recoveries of rare earth elements (REEs) showed a tendency first to increase and then to decrease with increasing ashing time and temperature.(先增长后降低)This could be due to the fact that the solubility of REE oxides depends on the preparation procedureIt could be due to the removal of more volatile matrix during the pyrolysis stage and alleviating the nonspectroscopic interferences at vaporization stage.。