利用微波消解和高效液相色谱荧光检测法测定环境水样中痕量硒

基于微波消解和正相液相色谱－荧光检测测硒法,实现了对环境水样中亚纳克级硒的测定。考察了ＨＮＯ３和Ｈ２ＳＯ４－Ｈ２Ｏ２两种消化体系及其工作条件,方法检出限分别可达 ７．２和 １０．４ ｐｇ Ｓｅ,对标准参考物质的回收率分别为９９．４±２．０和９７．８±２．５％,在０～１．５ｎｇＳｅ范围内有线性关系（Ｒ２＜０．９９６）。对北京地区 ４种不同类型水体水样含硒量进行了分析测定（２ｍＬ样品）,其浓度范围为 ０．２０～０．９０μｇ／Ｌ,标准加入回收率为９９．１％～１０３．４％。     

用固相萃取技术富集水中多环芳烃

系统地研究了淋洗剂强度、用量和有机改性剂的加入对固相萃取水中多环芳烃回收率的影响。研究表明,二氯甲烷和苯的洗脱效果较好,回收率为８７％～１０２％;当淋洗剂的用量超过１．５ｍＬ时,对多环芳烃的回收率没有明显的影响;向自来水样中加入２０％有机改性剂可明显改善多环芳烃的回收效果,使回收率达到８９％～１０８％。     

用离子色谱法测定环境样品中甲酸、乙酸、草酸

用离子色谱法分析环境样品中甲酸、乙酸、草酸,操作简便,灵敏度较好,线性范围宽。甲酸、乙酸、草酸的检出限分别为０．０２ｍｇ／Ｌ、０．１０ｍｇ／Ｌ、０．０４ｍｇ／Ｌ;样品加标回收率分别为９３％～１０６％、９４％～１０８％、９２％～１０８％;相对标准偏差分别为１．２％、２．４％、２．７％;工作曲线的线性范围分别为０．００～３０ｍｇ／Ｌ、０．００～３０ｍｇ／Ｌ、０．００～５０ｍｇ／Ｌ。该法可用于酸雨、大气     

酶联免疫吸附分析法测定土壤试样中的阿特拉津

报道一种高灵敏度，高重现性的酶联免疫吸附分析法（ＥＬＩＳＡ）对土壤试样中阿特拉津的测定。测定的线性范围为０．０５￣５．０μｇ／Ｌ，由１４条标准曲线求得的最低检出限在０．０１８￣０．２４μｇ／Ｌ之间，线性相关系数ｒ＝０．９９２２。加标土样分别用含水甲醇和含水乙腈提取的效率都接近１００％，提取液用重蒸水１：２００稀释后可消除基质效应和溶剂效应的影响，加标平均回收率为９９．６％。     

吹扫-捕集/气相色谱-质谱联用法测定城市饮用水中挥发性卤代烃

采用吹扫-捕集器富集了城市饮用水样中11种挥发性卤代烃,经气相色谱法分离后用质谱法选择性离子监测模式进行定量测定,所测定的卤代烃,除含量相对较高的三氯甲烷外,线性范围在0．04～11．0μg·L^-1之间;检出限（S／N=3）均小于6pg·L^-1。对方法的回收率及精密度作了试验,测得回收率在85．6％～126．1％之间,相对标准偏差（n=7）在2．06％～3．87％之间。     

土壤中痕量水胺硫磷的微波辅助萃取-固相微萃取-GC-MS法测定

研究了微波辅助萃取(MAE)-固相微萃取(SPME)联合萃取、气相色谱-质谱法(GC-MS)测定土壤中水胺硫磷的分析方法；采用正交设计试验优化了微波升温程序、萃取温度、萃取时间、萃取溶剂体积等MAE条件；研究了SPME萃取涂层、萃取时间、解吸温度等对萃取效率的影响；方法的线性范围在1．O～20μg/L之间，检出限为O．49ng/g；测定25、100ng/g加标土壤样品，回收率分别为79％和107％。RSD分别为2．6％和6．5％；方法综合了MAE快速高效和SPME富集浓缩的优点，以水为萃取溶剂，特别适合于固体样品中痕量有机物的分析。     

吹扫-捕集气相色谱法测定水中三卤甲烷

通过优化吹扫-捕集条件与色谱条件,建立了吹扫-捕集与气相色谱电子捕获检测联用法,实现了水中三卤甲烷的快速、简便且高灵敏的测定．通过测定系列标准溶液制定了一澳二氯甲烷、二澳一氯甲烷、三澳甲烷3种物质的标准曲线,并验证了方法的精密度、准确度、加标回收率及选择性．结果表明,水样体积为4mL时,加标回收率在93．17％～103．00％之间,相关系数在0．998-0．999之间,相对标准偏差均小于5％,3种物质的检出限分别为2．660、2．310、2．773μg／L．     

流动气体捕集法测定贯叶连翘提取物中大孔树脂残留物

采用流动气体捕集法,通过GC／MS法测定贯叶连翘提取物中大孔树脂残留物—苯、甲苯和二乙烯苯。与萃取、回流和顶空进样三种处理方式比较,自制的流动气体捕集装置能够很好地收集待测成分并有效地消除干扰。整体(流动气体捕集法处理 含量测定)检出限和回收率(苯：0．3ng/g,99．0％;甲苯：0．8ng／g,99．5％;二乙烯苯：0．5ng／g,99．2％),与GC／MS法所得结果(苯：0．1ng／g,99．2％;甲苯：0．2ng／g,99．4％;二乙烯苯：0．1ng／g,99．2％)无显著差别,说明该法有较低的检出限和良好的回收率。经其他3种方式处理后,检出限变差回收率下降。结果证明流动气体捕集法适于中药提取物中大孔树脂残留物的定量检测。     

固相萃取搅拌棒萃取-气相色谱分析海水中的多环芳烃

利用固相萃取搅拌棒（SBSE）萃取海水中的多环芳烃，然后用热解吸脱附-气相色谱分析。研究了萃取时间、添加NaCl浓度对萃取效率的影响。实验结果表明，SBSE方法对16种多环芳烃的萃取回收率分别在33．5％～122．4％之间；对标准样品的检出限为2．74-13．5ng／L；方法RSD为3．8％～13．1％。用此方法测定了大连海岸海水中的多环芳烃含量。     

分析型超临界流体萃取的应用研究

设计安装了一台超临界流体萃取（ＳＦＥ）装置。以二氧化碳为萃取剂,采用带泵头冷冻的往复泵能满足１０μＬ／ｍｉｎ～５ｍＬ／ｍｉｎ流速和２５ＭＰａ工作压力的要求,最高工作压力可达３５ＭＰａ。不锈钢萃取池体积为０．５ｍＬ和１．０ｍＬ两种规格,萃取样品的收集是用溶剂（己烷）吸收的。实验中主要进行了中药蛇床子中有效成分欧前胡素的萃取研究,对影响欧前胡素回收率的重要因素如温度、压力、密度、萃取时间及萃取改性剂等进行了考察。     

Efficiency of Different Methods and Solvents for the Extraction of Polycyclic Aromatic Hydrocarbons from Soils

The efficiencies of supercritical fluid extraction (SFE), accelerated solvent extraction (ASE), Soxhlet, and ultrasonic extraction in the analysis of polycyclic aromatic hydrocarbons (PAHs) in soils were evaluated. Solvents with different polarity were used to extract the PAHs from two soils, one with high and one with low contamination level. ASE showed good results with all solvents almost independent of the solvent polarity and the best results with acetone-toluene (1 : 1). Ultrasonic extraction with acetone-toluene for the uncontaminated soil and acetone-ethanolamine for the highly contaminated also showed good recoveries. The time-consuming Soxhlet extraction with pentane or dichloromethane was less effective. The PAH recovery from SFE was related to the soil matrix or the contamination level. The best extraction conditions (CO 2 /10% pentane) are successful for the soil with a low contamination level and a high humic acid content whereas the extractions of the highly contaminated soil gave poor results irrespective of the solvent used.     

Theoretical optimization of analyte collection in analytical supercritical fluid extraction

Summary Optimizing the extracted analyte collection step in analytical supercritical fluid extraction (SFE) is of key importance in achieving high analyte recoveries and extraction efficiencies. Whereas the extraction step in SFE has been well characterized both theoretically and experimentally; the analyte collection step after SFE has few theoretical guidelines, aside from a few empirical studies which have appeared in the literature. In this study, we have applied several theoretical approaches using experimental data to optimize analyte trapping efficiency in SFE. A vapour-liquid equilibrium model has been formulated to predict the trapping efficiency for extracted solute collection in a open collection vessel. Secondly, a simple solution thermodynamic model for predicting solute (analyte) activity coefficients in various trapping solvents has been shown to have utility in predicting collection efficiencies. Finally, effective trapping efficiency after SFE using sorbent media is related to the extent of analyte breakthrough on the sorbent-filled trap after depressurization of supercritical fluid. Using experimental data determined via physico-chemical gas chromatographic measurements (i. e., specific retention volumes), we have shown the relationship between analyte breakthrough volume off of the trapping sorbent and volume of depressurized fluid through the collection trap. The above theoretical guidlines should prove of value to analysts in designing and optimizing the best conditions for trapping analytes after extraction via analytical SFE. Names are necessary to report factually on available data; however the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the products to the exclusion of others that may also be suitable.     

Determination of polycyclic aromatic hydrocarbons in marine sediments using a new ASE-SFE extraction technique

In order to determine PAHs in marine sediment samples by GC/MS(SIM) a new extraction approach of ASE-SFE was evaluated using combined accelerated solvent extraction (ASE, dynamic and static mode) and supercritical fluid extraction (SFE, dynamic mode) without further purification of the sample. The solvents used for ASE-SFE were methylene chloride and carbon dioxide. The recovery data, precision and accuracy of the whole method were evaluated statistically. The average recoveries of PAHs, based on deuterated internal standards were 77% for 2-3-ring PAHs, 85% for 4-ring PAHs, 88% for 5-ring PAHs and 97% for 6-ring PAHs. The extraction time required for the ASE-SFE technique was 30 min, which is longer than in the case of independent use of ASE and shorter compared to SFE. ASE-SFE recoveries of PAHs from SRM marine sediment are comparable for (2-3-ring, 4-ring PAHs) or higher (5-ring, 6-ring PAHs) than reported for the conventional extraction methods of ASE and SFE. Method detection limits of (MDL) were statistically estimated. MDL values obtained for 15 PAHs compounds vary between 0.06 ngg(-1) and 3.54 ngg(-1).     

Determination of polycyclic aromatic hydrocarbons in marine sediments using a new ASE-SFE extraction technique

In order to determine PAHs in marine sediment samples by GC/MS(SIM) a new extraction approach of ASE-SFE was evaluated using combined accelerated solvent extraction (ASE, dynamic and static mode) and supercritical fluid extraction (SFE, dynamic mode) without further purification of the sample. The solvents used for ASE-SFE were methylene chloride and carbon dioxide. The recovery data, precision and accuracy of the whole method were evaluated statistically. The average recoveries of PAHs, based on deuterated internal standards were 77% for 2–3-ring PAHs, 85% for 4-ring PAHs, 88% for ¶5-ring PAHs and 97% for 6-ring PAHs. The extraction time required for the ASE-SFE technique was 30 min, which is longer than in the case of independent use of ASE and shorter compared to SFE. ASE-SFE recoveries of PAHs from SRM marine sediment are comparable for (2–3-ring, 4-ring PAHs) or higher (5-ring, 6-ring PAHs) than reported for the conventional extraction methods of ASE and SFE. Method detection limits of (MDL) were statistically estimated. MDL values obtained for 15 PAHs compounds vary between 0.06 ngg^?1 and 3.54 ngg^?1.     

离线超临界流体萃取和气相色谱-红外-质谱联用测定水中有机污染物

利用吸附剂ＧＤＸ－３０１对黄河水中的有机污染物富集并以超临界ＣＯ２脱附后,通过气相色谱、色谱－红外－质谱联用技术对各目标分析物逐一定性,并比较了超临界ＣＯ２萃取和溶剂洗脱的结果。实验表明,在２０ＭＰａ,６０℃,４０ｍｉｎ条件下进行超临界ＣＯ２萃取时的萃取效率和溶剂萃取效率相当或略高。     

SFE of PAHs from soils with a high carbon content and analyte collection via combined liquid/solid trapping

Polynuclear aromatic hydrocarbons (PAHs) are recovered from a soil with a high carbon content (ca. 50%) with supercritical fluid extraction (SFE) as well as with conventional Soxhlet extraction. The influence of temperature and modifier volume on SFE efficiency and the effect of a combined liquid/solid trap for analyte collection are investigated in this study. Such traps, which make analyte collection and clean-up possible in one step, are compared with conventional analyte collection in pure organic solvents. A comparison between reproducibility and efficiency of SFE and Soxhlet extraction is presented.     

基于轻质萃取剂的溶剂去乳化分散液-液微萃取-气相色谱法测定水样中多环芳烃

以密度小于水的轻质溶剂为萃取剂,建立了无需离心步骤的溶剂去乳化分散液-液微萃取-气相色谱(SD-DLLME-GC)测定水样中多环芳烃的新方法。传统分散液-液微萃取技术一般采用密度大于水的有机溶剂为萃取剂,并需要通过离心步骤促进分相。而本方法以密度比水小的轻质溶剂甲苯为萃取剂,将其与丙酮(分散剂)混合并快速注入水样,获得雾化体系;然后注入乙腈作为去乳化剂,破坏该雾化体系,无需离心,溶液立即澄清、分相;取上层有机相(甲苯)进行GC分析。考察了萃取剂、分散剂、去乳化剂的种类及其体积等因素对萃取率的影响。以40 μL甲苯为萃取剂,500 μL丙酮为分散剂,800 μL乙腈为去乳化剂,方法在20～500 μg/L范围内呈现出良好的线性(r2=0.9942～0.9999),多环芳烃的检出限(S/N=3)为0.52～5.11 μg/L。用所建立的方法平行测定5份质量浓度为40 μg/L的多环芳烃标准水样,其含量的相对标准偏差为2.2%～13.6%。本法已成功用于实际水样中多环芳烃的分析,并测得其加标回收率为80.2%～115.1%。     

Off-line SFE-CGC-ECD analysis of 2,4-D and Dicamba residues in real sugar cane,rice and corn samples

Determination of 2,4-D (2,4-dichlorophenoxyacetic acid) and Dicamba (2-methoxy-3,6-dichlorobenzoic acid) residues in sugar cane, rice, and corn was carried out both by solid liquid extraction (SLE), as already described in the literature, and by a supercritical fluid extraction (SFE) method developed in our laboratory. The extracts were esterified and cleaned-up by passing through a Florisil column. Extracts were analyzed by high resolution gas chromatography, with electron capture detection. The tested methods presented good recoveries (above 90%); the SFE CO₂/acetone method showed better extraction efficiencies (extracted 30 % more herbicide in real samples), shorter extraction time and lower organic solvent consumption than the SLE method.     

Harmful azo colorants in leather. Determination based on their cleavage and extraction of corresponding carcinogenic aromatic amines using modern extraction techniques

This study concerns the possibilities of using microwave-assisted extraction (MAE) or supercritical fluid extraction (SFE) for detection of harmful azo colorants in leather. After degreasing of the leather sample with SFE there follows a reductive cleavage of the azo colorants to their corresponding aromatic amines in the MAE or SFE equipment. The aromatic amines are subsequently extracted using either MAE or SFE and then finally determined by liquid chromatography with diode-array detection. The results have been compared with recoveries obtained using the German DIN method 53316. This standard method, based on conventional solvent extraction, is used in several European countries. Overall much better recoveries were obtained using MAE or SFE. With both MAE and SFE the amine recoveries of spiked leather samples were generally above 50%. The average recoveries were 62% for MAE and 60% for SFE (solvent collection) compared to 24% with the DIN method. For genuine leather samples the recoveries decreased, especially for benzidine. In this case the average values for MAE, SFE and DIN were 54, 38 and 19%, respectively. The quantification limits in leather samples using MAE or SFE were below 1 mg/kg for all amines investigated. The within-laboratory precision was generally better than 10%, varying somewhat with the analyte considered. With the proposed methodology, the amount of hazardous organic solvents used could be decreased and the sample throughput increased with at least a factor of two with less manual handling compared to the DIN method.     

Determination of 16 polycyclic aromatic hydrocarbons in environmental water samples by solid-phase extraction using multi-walled carbon nanotubes as adsorbent coupled with gas chromatography–mass spectrometry

A solid-phase extraction (SPE) using multi-walled carbon nanotubes (MWCNTs) as adsorbent coupled with gas chromatography–mass spectrometry (GC–MS) method was developed for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Several condition parameters, such as extraction adsorbents, elution solvents and volumes, and sample loading flow rate and volume were optimized to obtain high SPE recoveries and extraction efficiency. 150 mg MWCNTs as sorbent presented high extraction efficiency of 16 PAHs due to the large specific surface area and high adsorption capacity of MWCNTs compared with the commercial C18 column (250 mg/2 mL). The calibration curves of 16 PAHs extracted were linear in the range of 20–5000 ng L⁻¹, with the correlation coefficients (r²) between 0.9848 and 0.9991. The method attained good precisions (relative standard deviation, RSD) from 1.2% to 12.1% for standard PAHs aqueous solutions; method recoveries ranged in 76.0–125.5%, 74.5–127.0%, and 70.0–122.0% for real spiked samples from river water, tap water and seawater, respectively. Limits of detection (LODs, S/N = 3) of the method were determined from 2.0 to 8.5 ng L⁻¹. The optimized method was successfully applied to the determination of 16 PAHs in real environmental water samples.