土壤中有机氯农药检测实验室间比对结果分析

环境保护部标准样品研究所组织16家实验室开展了土壤中有机氯农药检测实验室间比对,以考察实验室分析土壤中有机氯农药的能力。实验室间比对检测样品为土壤基体有证标准样品。比对结果表明,参加比对实验室检测土壤中六六六、滴滴涕、艾氏剂、狄氏剂、环氧七氯、硫丹和氯丹等18种有机氯农药的结果满意率为75%~100%,18个检测项目中16个检测项目检测结果满意率在81%以上,其检测能力满足土壤中有机氯农药标准样品的定值要求。     

8种有机氯农药土壤标准样品研制

介绍了有机氯土壤基体标准样品的研制过程。土壤采自农药厂搬迁后待修复的场地,经低温烘干、研磨、筛分、混匀和灭菌等过程制备。选择土壤中检出频率和浓度水平较高的8种有机氯农药为目标化合物,分层随机抽取20瓶样品进行均匀性研究,结果显示均匀性良好。室温避光保存条件下采用气相色谱/质谱法对每个特性组分进行稳定性研究,12个月检验期内未发现有不稳定变化趋势。经16家实验室联合定值,使用传统和稳健两种统计技术对结果进行处理,给出8种有机氯土壤标准样品的标准值和不确定度。样品可用于环境基体中有机氯监测的质量保证与质量控制。     

微波辅助萃取法测定烟草中有机氯类农药残留量

建立了一种微波辅助萃取-固相萃取净化测定烟草中17种有机氯类农药残留量的新方法. 样品用V(正己烷):V(乙酸乙酯)＝1:1提取, 提取液经Florisil固相萃取柱净化后, 采用气相色谱-电子捕获检测器(GC-μECD)进行检测. 17种有机氯农药的0.01、 0.05 mg/kg和0.5 mg/kg加标回收率均在82%以上, RSD在0.11%～8.2%之间, 能满足当前烟草中有机氯农药残留的检测要求.     

固相萃取-毛细管气相色谱法测定中草药及其土壤中多种有机氯农药残留量

建立了中草药及其土壤中多种有机氯农药残留量的固相萃取-毛细管气相色谱(SPE-CGC)分析方法,并对7种中草药及其土壤中多种有机氯农药残留量的相关性进行了初步研究。样品以正己烷-丙酮用超声波提取,Florisil(1 g)固相萃取小柱快速净化提取物。采用SPB-5弹性石英毛细管柱分离样品,GC-ECD检测7种中草药及其土壤中的13种有机氯农药的残留量。方法的线性范围为1.26×10-10~2.24×10-7g/mL;检出限为6.4×10-11~6.1×10-10g/mL;加样平均回收率为87.3%~104.4%(RSD为1.1%~7.0%)。     

环境中有机氯农药残留异构体分析

为了了解城市中有机氯农药残留现状,分析了有机氯农药的污染源。2007年4月至2008年7月在应城市辖区内采集了农产品及其生长环境样品10类622份,人体生物材料样品42份,依据国标方法进行了DDT、HCH异构体含量检测。分类样品的各类异构体检出率差异明显,应城市存在新的HCH、DDT输入源,人体生物材料样品有机氯残留异构体特征均为降解终端状态。最后提出了应对农药残留的有效措施。     

超声波溶剂提取-气相色谱法测定烟草及烟草制品中19种有机氯农药残留

建立了超声波溶剂提取-气相色谱法同时测定烟草及其制品中19种有机氯农药残留。样品采用正己烷-丙酮超声提取,经Florisil固相萃取柱净化后,采用气相色谱-电子捕获检测法(GC-ECD)进行检测。结果发现,19种有机氯农药加标回收率均在72%以上,相对标准偏差(RSD)在0.1%～9.0%,能满足当前烟草中有机氯农药残留的同时快速检测要求。     

气相色谱-串联质谱多离子监测分析土壤中的有机氯农药残留

采用气相色谱-串联质谱(GC-EI-MS/MS)联用技术,结合索氏萃取提取及佛罗里硅土净化分析土壤中有机氯农药残留.通过对检测模式、母离子选择、碰撞能量、多反应监测的选择等条件优化,可实现20种有机氯农药的基线分离.在优化的条件下,有机氯农药的定量限为5.6×10-4～9.6 ng/mL;样品加标回收率为51.6%～130%.     

基于全二维气相色谱-四极杆飞行时间质谱法同时检测土壤中24种有机磷与20种有机氯农药残留

基于全二维气相色谱－四极杆飞行时间质谱（GC × GC－Q－TOF MS）建立了土壤样品中24种有机磷 和20种有机氯农药残留的快速同时检测方法,样品经索氏提取后直接采用全二维气相色谱进行分离,有效实 现了杂质与目标物的完全族分离效果。以24种有机磷和20种有机氯农药的高分辨精确质量特征离子进行定 量分析,结果表明,44 种农药均在 20～3 000 μg/L 质量浓度范围内呈线性关系,相关系数（r 2 ）为 0. 990 3～ 0. 999 9,检出限（LOD）为 0. 3～7. 9 μg/L;方法的平均回收率为 93. 0%,平均相对标准偏差（RSD,n = 5）为 6. 9%。该文可为土壤中农药残留的高通量快速筛查提供方法参考。     

气相色谱法同时测定山药和葛根中27种有机氯及拟除虫菊酯农药残留量

建立了山药和葛根中20种有机氯和7种拟除虫菊酯农药残留的提取、净化及其残留量测定的方法。样品采用丙酮-正己烷(4:3,V/V)提取,经凝胶渗透色谱净化后,采用气相色谱-电子捕获检测器检测。结果表明山药和葛根样品基质4水平添加条件下,27种农药的回收率(n=7)为80.1%～103.7%,相对标准偏差为1.9%～11%,最低检测限为0.09～1.82μg/kg,符合农药多残留检测要求。方法可用于山药和葛根中多种有机氯及拟除虫菊酯农药残留量的检测。     

土壤中多种有机氯及拟除虫菊酯类农药的GC-ECD测定

气相色谱法同时测定土壤中多种有机氯及拟除虫菊酯类农药。对土壤的分析结果：有机氯农药的检出限0．001～0、003μg／mL，拟除虫菊酯类农药检出限0.008～0．02μg／mL，线性相关系数0．9978～0．9999。用y（石油醚）：V（丙酮）=3：1超声波提取，有机氯农药回收率94．2％～124．0％，相对标准偏差为3．3％～8．8％（n=5）；拟除虫菊酯类农药回收率95．2％～118．3％，相对标准偏差为5．7％～7．1％（n=5）；方法适用于土壤样品中农药残留测定。     

Microwave extraction of organochlorine pesticides from soils

The purpose of this work was to develop a rapid, reliable and sensitive method for the extraction of organochlorine pesticides from soils using microwave energy with closed vessel technology. Three oven programs were assayed with two different solvent mixtures in order to achieve adequate experimental conditions for the complete extraction of organochlorine pesticides from the matrix. The method was validated using a certified reference soil material (CRM804-050).     

Supercritical fluid extraction of polychlorinated biphenyls and pesticides from soil. Comparison with other extraction methods.

A comparison is made of supercritical fluid extraction (SFE) with two other techniques widely used for the extraction of polychlorinated biphenyls (PCBs) and organochlorine pesticides in soil. Extraction conditions for the SFE of PCBs and pesticides were first determined. An experimental approach was set up to determine the influence of different extraction parameters such as pressure, extraction time, static and dynamic extraction, restrictor type and collection solvent for off-line SFE. The use of carbon dioxide at 50 degrees C and 20 MPa, 10 min static followed by 20 min dynamic extraction with collection in iso-octane were been found to be the optimum conditions. Two types of soil, with a low and high content of organic carbon, respectively, spiked with 16 PCBs and organochlorine pesticides with a wide range of volatility and polarity at a level of 5 ng/g dry matter, were used as test materials. Conventional solvent extraction gives a good extraction yield for soil with a low content of organic carbon, but for peat soil the recoveries decrease dramatically to 30% for DDE, DDT and PCB 138 and 153. The recoveries with Soxhlet extraction are good, but an extra clean-up step before analysis is necessary. SFE gives good extraction yields for PCBs and organochlorine pesticides, varying between 85 and 105% with a reproducibility of 5% for each component for both types of soil. SFE is a fast, clean and reproducible method for the extraction of PCBs and organochlorine pesticides from these two soil matrices.     

Preparation of reference material for organochlorine pesticides in a herbal matrix

The development of reference material for four organochlorine pesticides, namely hexachlorobenzene and three isomers of hexachlorocyclohexane (alpha-hexachlorocyclohexane, beta-hexachlorocyclohexane and gamma-hexachlorocyclohexane), in a ginseng root sample is presented. Raw materials (Panax ginseng) were purchased from a local market and confirmed to contain certain levels of incurred organochlorine pesticide residues by a validated gas chromatography-mass selective detection method. A total of more than 300 bottles each containing 25 g of samples were prepared after the materials had been freeze-dried, milled and thoroughly mixed. The homogeneity and stability of samples from randomly selected bottles were verified and the reference values were characterized using a highly precise isotope dilution gas chromatography-mass spectrometry (ID-GCMS) method that was recently developed by our laboratory. The purity of standard organochlorine chemicals was determined against certified reference materials to establish the accuracy of the ID-GCMS analysis. The concentrations (+/- expanded uncertainty) of hexachlorobenzene, alpha-hexachlorocyclohexane, beta-hexachlorocyclohexane and gamma-hexachlorocyclohexane in the reference material were 0.198 +/- 0.015, 0.450 +/- 0.022, 0.213 +/- 0.011 and 0.370 +/- 0.032 mg kg(-1), respectively. A portion (70 bottles) of the samples was also used in a proficiency testing (PT) scheme for assessing the testing capabilities of field laboratories. The consensus mean values of the PT obtained from the 70 participants were on the same order but deviated by -2.7 to -14.1% from those of the assigned reference values. Because of the wide spread of participants' data (relative standard deviation ranging from 44 to 56%), the PT results were not included in the calculation of the assigned values of the reference materials. The materials served as suitable reference materials to ascertain the quality control and validation processes for the determination of organochlorine pesticides in herbal matrices.     

Determination of organochlorine pesticides and their metabolites in soil samples using headspace solid-phase microextraction

An analytical procedure was developed using headspace solid-phase microextraction (HS-SPME) for the determination of organochlorine pesticides (OCPs) and their metabolites in sandy soil samples. The developed procedures involving fiber selection, temperature effect, absorption time, soil matrix and the addition of solvents of different polarity were optimized. Also, the results were compared to those achieved using Soxhlet extraction standard method. The 100-microm polydimethylsiloxane (PDMS) and 65-microm PDMS-divinylbenzene showed good extraction efficiency for 18 organochlorine pesticides. An increase in the extraction efficiency of organochlorine pesticides and the metabolites was observed when the temperature increased, and an optimum temperature of 70 degrees C for extracting OCPs was obtained. The application of other hydrophilic solvents had different effects on the extraction of organochlorine pesticides and the metabolites. Higher responses of OCPs were obtained when 5 ml of water was added to the soil. Good linearity of OCPs between 0.2 and 4 ng/g soil was observed. The relative standard deviation was found to be lower than 25%. Also the limits of detection were between 0.06 and 0.65 ng/g, which were lower than those obtained using Soxhlet extraction. Moreover, the optimized HS-SPME procedure was applied to the analysis of OCPs in certified reference material (CRM) 804-050 soil and compared with Soxhlet extraction procedure. Results obtained in this study were in good agreement with those obtained using Soxhlet extraction. The mean values obtained using HS-SPME technique were in the range of 16.5 to 1459.6 mg/kg, which corresponds to the recoveries of 68% to 127% of the certified values of CRM soil.     

Development and certification of reference materials for residues of organochlorine and organophosphorus pesticides in beef fat ACSL CRM 1 and 2

Beef fat samples were prepared and tested as candidate reference materials for organochlorine and organophosphorus pesticides. The CRMs consisted of beef fat spiked with pesticide solutions. One sample (ACSL CRM 1) was prepared containing close to 0.2 mg/kg of each of the organochlorine pesticides dieldrin and heptachlor epoxide. A second sample (ACSL CRM 2) was prepared containing close to 0.8 mg/kg of each of the organophosphorus pesticides diazinon, chlorpyrifos and ethion. The spiking levels and homogeneity of the materials were verified. The coefficients of variation of 5 analyses carried out to test between-jar homogeneity for each reference material were dieldrin, 3.5%; heptachlor epoxide, 1.1%; diazinon, 2.1%; chlorpyrifos, 1.2% and ethion, 3.1%. No instability in any of these compounds was detected over a twelve month period. The candidate reference materials were found to be suitable for certification by interlaboratory testing. The certification process was based on a two-stage nested design described in ISO Guide 35. Analysis of results reported by collaborating laboratories provided an assessment of the homogeneity of the reference materials. The certified values together with their upper and lower 95% confidence limits are: ACSL CRM 1*Dieldrin*0.199 mg/kg **(0.188, **0.210 mg/kg) *Heptachlor epoxide*0.194 mg/kg **(0.176, **0.212 mg/kg) ACSL CRM 2*Diazinon*0.805 mg/kg **(0.755, **0.855 mg/kg) *Chlorpyrifos*0.790 mg/kg **(0.728, **0.852 mg/kg) *Ethion*0.813 mg/kg **(0.746, **0.879 mg/kg). A certificate for each material was prepared according to the guidelines set out in ISO Guide 31.     

Development and certification of reference materials for residues of organochlorine and organophosphorus pesticides in beef fat ACSL CRM 1 and 2

Beef fat samples were prepared and tested as candidate reference materials for organochlorine and organophosphorus pesticides. The CRMs consisted of beef fat spiked with pesticide solutions. One sample (ACSL CRM 1) was prepared containing close to 0.2 mg/kg of each of the organochlorine pesticides dieldrin and heptachlor epoxide. A second sample (ACSL CRM 2) was prepared containing close to 0.8 mg/kg of each of the organophosphorus pesticides diazinon, chlorpyrifos and ethion. The spiking levels and homogeneity of the materials were verified. The coefficients of variation of 5 analyses carried out to test between-jar homogeneity for each reference material were dieldrin, 3.5%; heptachlor epoxide, 1.1%; diazinon, 2.1%; chlorpyrifos, 1.2% and ethion, 3.1%. No instability in any of these compounds was detected over a twelve month period. The candidate reference materials were found to be suitable for certification by interlaboratory testing. The certification process was based on a two-stage nested design described in ISO Guide 35. Analysis of results reported by collaborating laboratories provided an assessment of the homogeneity of the reference materials. The certified values together with their upper and lower 95% confidence limits are: ACSL CRM 1*Dieldrin*0.199 mg/kg **(0.188, **0.210 mg/kg) *Heptachlor epoxide*0.194 mg/kg **(0.176, **0.212 mg/kg) ACSL CRM 2*Diazinon*0.805 mg/kg **(0.755, **0.855 mg/kg) *Chlorpyrifos*0.790 mg/kg **(0.728, **0.852 mg/kg) *Ethion*0.813 mg/kg **(0.746, **0.879 mg/kg). A certificate for each material was prepared according to the guidelines set out in ISO Guide 31. Received: 25 April 1997 / Revised: 19 August 1997 / Accepted: 28 August 1997     

Pressurized liquid extraction of organochlorine pesticides from certified solid materials

In order to propose a versatile method to use in laboratories devoted to environmental analysis, a scheme for the determination of organochlorine pesticides from different solid matrices is evaluated. Pressurized liquid extraction is chosen as the sample preparation technique, followed by the purification of the extract by means of solid-phase extraction with Envi-carb cartridge (100 m(2)/g). Finally, the extracts are analyzed by programmed temperature vaporization (PTV)-gas chromatography (GC)-electron-capture detection and PTV-GC-mass spectrometry. The suitability of the method for the analysis of different matrices is determined by the extraction and analysis of four certified reference materials of solid matrices: CRM 804-050 (soil), SRM 1941b (organics in marine sediment), SRM 1944 (New York/New Jersey waterway sediment) and SRM 1649a (Urban Dust). Good statistical concordance between the results obtained and the certified or reference concentration are observed for most of the analyzed pesticides.     

Selective pressurized liquid extraction for multi-residue analysis of organochlorine pesticides in soil

A selective pressurized liquid extraction (SPLE) procedure capable of performing simultaneous extraction and clean-up has been demonstrated for multi-residue analysis of organochlorine pesticides (OCPs) in soil. The final method was performed at 100 degrees C for 3 x 10 min using acetone/n-heptane (1:1, v/v). Florisil was placed inside the extraction cell downstream the sample to remove interfering compounds. Extraction of two soil samples by SPLE gave a recovery which was over 80% for beta-endosulfan, endosulfan sulfate, p,p'-DDT and p,p'-DDE compared to PLE with off-line clean-up. The same trend was observed when applying the SPLE method to a certified reference soil sample (CRM 811-050) containing 13 OCPs, where the SPLE method gave 80-90% recovery vis-à-vis the PLE method with off-line clean-up. Feasibility of the SPLE method was further demonstrated by applying it to five real soil samples collected in Ethiopia.     

Development of pressurized liquid extraction and cleanup procedures for determination of organochlorine pesticides in soils

The scope of this work is the development of a rapid, reliable and sensitive method for the analysis of organochlorine pesticides from soils by pressurized liquid extraction (PLE). The effect of four parameters (temperature, pressure, static time and cell volume) on the extraction efficiency was studied. The great extracting power of the PLE causes the extraction of numerous interfering substances, so a more efficient purification of this extract was necessary. In this work several sorbents have also been assayed to carry out the purification of soil samples: Florisil, silica, alumina, carbon, as well as combinations of them. Finally, the proposed analytical method was validated using a certified reference soil material (CRM804-050) and the results were compared with those obtained by other extraction techniques (Soxhlet and microwave-assisted extraction).     

同位素稀释高分辨气相色谱-高分辨质谱法测定土壤中痕量有机氯农药残留

建立了同位素稀释高分辨气相色谱-高分辨质谱测定土壤中痕量有机氯农药残留的分析方法。采用加速溶剂法萃取土壤样品,以正己烷/丙酮(体积比为1:1)为提取溶剂,提取液经过Florisil硅土固相萃取小柱净化后,采用高分辨DB-5MS毛细管色谱柱(30 m×0.25 mm×0.25 μm)分离,以保留时间和同位素特征离子丰度比定性,同位素峰面积比定量。实验结果表明,方法的回收率为77.3%～114.5%,相对标准偏差(RSD)≤10.81%（n=5）,检出限均小于0.04 pg/g。应用该方法检测某地区表层土壤中的有机氯农药,结果表明该方法适合测定环境土壤背景中痕量有机氯残留。