毛细管气相色谱法测定中药中有机氯农药残留量

建立了江西省两种中药中有机氯农药残留量的气相色谱分析方法。样品以丙酮提取,在NaCl存在下,以正已烷进行液—液分配,提取液用H2SO4净化,采用DB—1701毛细管柱,GC—ECD检测有机氯农药残留量。最低检测限为1.0×10-3-5.0×10-3mg/kg,添加回收率为85.7%-115.2%,应用于实际样品中有机氯农药残留量的检测,获得了较为满意结果。     

Progress in the quality assurance of environmental trace organic analysis

An overview is given on the stepwise learning programmes undertaken to identify the main sources of error associated with the determination of the mandatory organic contaminants in the marine monitoring programmes. Details are given on the preparation and use of LRMs and CRMs to maintain analytical control and quantify the laboratory errors in relation to the measurement of changes in the environment.     

毛细管气相色谱法测定5种中草药中有机氯农药的残留量

建立了怀牛夕等 5种中草药中六六六及滴滴涕异构体含量的气相色谱分析方法。样品以石油醚 +丙酮在索氏提取器中提取 ,提取液以浓硫酸净化。采用SE 30弹性石英毛细管柱分离样品 ,GC ECD检测六六六、滴滴涕农药的残留量。方法的线性范围为 5 .7× 10 - 7～ 2 .8× 10 - 4μg ;最小检测量为 1.3× 10 - 1 4～ 2 .5×10 - 1 2 g ;加样平均回收率为 88.8%～ 99.1% ;RSD为 0 .9%～ 5 .3%。     

芳基汞化合物的性质研究——Ⅶ.邻位取代苯基氯化汞的质子分解反应

本文研究了邻位取代苯基氯化汞o-XC_6H_4HgCl(X=CH_3、H、Cl、Br、COOC_2H_5、NO_2)与HCl(NaI)在85％对氧陆圜水溶液中的质子分解反应,证明反应按S_El历程进行。视取代基不同,反应速度次序如下:CH_3>H>Cl>COOC_2H_5～Br>NO_2。从化学反应与紫外光谱的研究以及理论计算结果表明,p或π电子的邻位取代基对水原子有分子内配位,它对反应速度有重要影响。测定了15种p-、m-、o-取代苯基氯化汞在80％对氧陆圜水溶液中在40.0℃的质子分解反应的速度常数k_1,表明给电性取代基加速反应,吸电性取代基使反应减慢,这可以看作是反应中心在芳环上的芳基汞化合物的S_E1反应所具有的一个特点。     

毛细管气相色谱法同时测定水产品中的多氯联苯和有机氯农药残留量

建立了毛细管气相色谱法同时测定水产品中多氯联苯和有机氯农药的方法，用高氯酸与冰乙酸的混合溶液消化样品，以石油醚提取，浓硫酸净化后，用毛细管气相色谱法测定，方法的回收法为88％－110％，相对标准偏差为8％－19％（n=6)，检出限为0．08－0．60ug/kg，方法简便，快速，结果准确。     

生晒参、全须生晒参中19种有机氯残留农药的毛细管气相色谱测定

建立了生晒参、全须生晒参中19种有机氯农药残留的毛细管气相色谱分析方法。对样品中六六六的4种异构体、滴滴涕的5种异构体、四氯苯胺、六氯苯、五氯硝基苯、七氯、五氯苯胺、艾氏剂、百菌清、环氧七氯、狄氏剂及异狄氏剂共19种有机氯农药的残留量进行了测定。以石油醚-丙酮混合物作为提取剂,样品采用索氏提取,提取液用弗罗里硅土柱层析净化。采用OV-1701石英毛细管气相色谱柱分离样品,ECD检测器进行检测。在3个水平添加时的回收率(n=5)分别为75.7%~96.1%、78.8%~111.6%和81.7%~115·2%;相对标准偏差分别为2.4%~10.6%、2.1%~9.8%和1.4~10.0%。方法用于生晒参和全须生晒参样品中农药残留的测定,结果满意。     

Optimization and validation of organochlorine compounds in adipose tissue by SPE‐gas chromatography

Scientific evidence has shown an association between organochlorine compounds (OCC) exposure and human health hazards. Concerning this, OCC detection in human adipose samples has to be considered a public health priority. This study evaluated the efficacy of various solid‐phase extraction (SPE) and cleanup methods for OCC determination in human adipose tissue. Octadecylsilyl endcapped (C₁₈‐E), benzenesulfonic acid modified silica cation exchanger (SA), poly(styrene‐divinylbenzene (EN) and EN/RP₁₈ SPE sorbents were evaluated. The relative sample cleanup provided by these SPE columns was evaluated using gas chromatography with electron capture detection (GC–ECD). The C₁₈‐E columns with strong homogenization were found to provide the most effective cleanup, removing the greatest amount of interfering substance, and simultaneously ensuring good analyte recoveries higher than 70%. Recoveries > 70% with standard deviations (SD) < 15% were obtained for all compounds under the selected conditions. Method detection limits were in the 0.003–0.009 mg/kg range. The positive samples were confirmed by gas chromatography coupled with tandem mass spectrometry (GC‐MS/MS). The highest percentage found of the OCC in real samples corresponded to HCB, o,p′‐DDT and methoxychlor, which were detected in 80 and 95% of samples analyzed respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

A Photochemistry Technique Using Ultraviolet Irradiation Followed by Gas-Liquid Chromatography to Confirm the Identity of Some Organochlorine Pesticides

Abstract

A procedure involving ultraviolet (UV) irradiation followed by gas-liquid chromatographic (GLC) detection of photodecomposition products to confirm the identity of selected organochlorine pesticides is described. The Irradiation intensity was standardized by determining the position relative to the UV source which resulted in equal GLC peak heights for the parent compound and major photo-decomposition product after 8 minutes of exposure of a solution of heptachlor epoxide in isooctane. Chromatograms showing photo-decomposition patterns for 33 compounds are presented. Observations and comments on the applicability of this technique to organo-chlorine pesticide residue confirmation are reported.     

Trace Metal and Persistent Organochlorine Levels in Wood Bison (Bison bison athabascae) from the Mackenzie Bison Sanctuary

Abstract

Tissue samples were collected from ten healthy mature female wood bison (B. bison athabascae) for examination. Livers and kidneys were tested for toxic heavy metals and trace metals considered as essential nutrients for successful reproduction, while fat samples were analyzed for persistent chlorinated hydrocarbons. No elevated levels of toxic heavy metals (arsenic, cadmium, lead, mercury) were found and essential trace elements (copper, manganese, selenium, zinc) were within the acceptable ranges established for healthy cattle. All fat samples tested contained trace levels of α-BHC (mean value, 23 ppb) and lindane (mean value, 3 ppb).     

A Chemical Test for Determining Biological Availability of Aged Chemicals in Soil

Abstract

Aging is one of several processes that are known to affect exposure of chemicals to organisms by decreasing the available fraction of chemical contaminants in soil. This phenomenon has important implications in the assessment of the hazards of chemicals and regulations for soil cleanup. Passive sampling devices (PSDs) are potentially direct chemical indicators for assessing bioavailability of pesticides (and other chemicals). PSDs consist of lipophilic material within a semi-permeable membrane, similar to biological systems. In this study, a pesticide mixture was aged in soil for up to eight months. Earthworms and PSDs were placed in soil and chemical uptake into both was determined over time. Uptake rates into PSDs and maximum concentrations were observed to positively correlate with uptake rates and maximum concentrations in earthworms for both of the soil types studied (sandy loam, silt loam). These results indicate that PSDs may be used as a surrogate for earthworms and provide a chemical technique for assessing the availability of aged chemical residues in soil.