Amperometric determination of pesticides using a biosensor based on a polishable graphie-epoxy biocomposite

The determination of organophosphorus and carbamate pesticides was carried out using an amperometric transducer based on a robust, polishable and easily mechinable biocomposite. The biocomposite material contains graphite powder, a non-conducting epoxy resin and acetylcholinesterase. The enzyme retains its bioactivity in the rigid epoxy-graphite matric. Measurements were carried out with acetylhiocholine as a substrate. Thiocholine produced by enzymatic hydrolysis was oxidized electrochemically at 70 mV (vs. Ag/AgCl in pH 7.0 buffered solution with 0.1 M phosphate and 0.1 m KCl). The decrease rate of substrate steady-state current after the addition of pesticide was used for evaluation. The method of construction allows for the repetitive use of the electrode. Simple polishing procedures are used to regenerate the bioactive transducer surface.     

有机磷农药酶生物传感器研究进展

酶生物传感器（EBS）以简单、廉价、易于微型化等优势成了有机磷农药（OPs）传统分析方法的最佳替代品。本文从识别OPs的酶及识别机理、电化学EBS、酶的固定化技术、高分子材料的酶固定载体不同角度综述了有机磷农药酶生物传感器研究近况，并重点介绍了一次性丝网印刷酶电极。     

Comparison of polydimethyl siloxane stationary phases with 5% and 50% phenyl substitution for the separation of organophosphorus and organonitrogen pesticides under optimized gas chromatographic conditions

The CGC analysis of 25 organophosphorus and organonitrogen pesticides was optimized on two different stationary phases, namely a 5% diphenyl dimethyl silicone (SE-54 type) and a 50% diphenyl dimethyl silicone (OV-17 type) by selecting the best temperature program conditions, using computer simulation.     

Determination of acidic chlorinated pesticides in water: Comparison of official EPA method 515.1 and liquid-solid extraction HPLC/UV and HPLC/PBMS analyses

Summary A comparison of the official EPA method 515.1 for determination of chlorinated acidic pesticides and a modification of it is illustrated. Extraction of the analytes from water and their determination and quantitation is by gas chromatography-electron capture detection (GC-ECD), liquid chromatography-UV detection and liquid chromatography-particle beam mass spectrometry. Although HPLC-PBMS was found to be less sensitive than the GC-ECD method, it was, nevertheless, more sensitive than HPLC-UV. The modified method is simpler, quicker and allows more accurate determination of pesticides in aqueous samples.Deceased July 31, 1996     

消旋反式菊酸α—氰基—4—氟—3—苯氧基苄酯的合成

含氟拟除虫菊酯的合成是近年来新型高效拟除虫菊酯研究工作的方向之一。该类化合物由于具有高效、低毒、广谱、低残留、无致癌、致畸作用,有的还具有低鱼毒,杀螨的特性,因此倍受注目。西德拜尔公司开发的百治菊酯(Baythroid)(1)便是其中一种高效杀虫剂。     

高效液相色谱-串联质谱法测定蜂蜜中9种农药残留

建立了同时测定蜂蜜中9种苯并咪唑类和新烟碱类农药的全自动固相萃取-高效液相色谱-串联质谱检测方法。蜂蜜样品用磷酸盐缓冲液（pH=7.8）溶解，超声提取，经亲水亲脂平衡（hydrophilic-lipophilic balance，HLB）固相萃取小柱净化，氮吹浓缩，定容，过滤膜后进行高效液相色谱-串联质谱分析，采用多反应监测（MRM）模式测定，以内标法定量。结果表明，在0.002~0.05 mg/L范围内9种农药呈现出较好的线性关系（相关系数r² ≥ 0.99），检出限和定量限分别为0.1~1.0 μg/kg和0.3~2.0 μg/kg。对阴性蜂蜜，在5.0、10.0、20.0 μg/kg 3个水平下分别进行加标回收试验，测出9种农药的平均回收率在78.2%~101.2%之间，相对标准偏差为1.3%~14.3%（n=6）。该方法可适用于大批量蜂蜜样品的快速准确测定。     

南极鲍鱼样品中有机氯农药的测定

报道了中国南极长城站周围及某国的一个排污口的鲍鱼样品中有机氯农药的残留量。测定结果显示鲍鱼样品中有机氯农药的含量HCHs为ND－1.87ng/g，DDTs为ND－6.61ng/g干重，有机氯农药的回收率为46％－75％。     

Quantitative determination of organochlorine pesticides in sewage sludges using soxtec,soxhlet and pressurized liquid extractions and ion trap mass–mass spectrometric detection

A new analytical method is described for the determination of organochlorine pesticides (OCPs) in sewage sludges using GC-ion trap-MS–MS. In this work, 16 organo-chlorine pesticides (OCPs) listed by the US Environmental Protection Agency (US EPA) as priority pollutants were separated and quantified. Sludge samples from three of Kuwaits wastewater treatment plants (WWTPs) were analyzed for organochlorine pesticides (OCPs). Spiked sludge samples were extracted with a mixture of (1:1 v/v) dichloromethane (DCM)/hexane. The extracts were cleaned on a silica/aluminum oxide column, then transferred to a gel permeation chromatography (GPC) column, before undergoing further silica/aluminum oxide clean-up; the presence of OCPs was then confirmed by GC-ion trap-MS–MS. Three extraction techniques, soxtec, soxhlet, and pressurized liquid extractions were utilized, compared and validated using the spiked sludge samples. The methods were validated in term of accuracy (recovery) and precision (RSD). The method recovery values varyied from 76.1 to 92.9% for the three extraction techniques.     

Multi-Residue Analysis of Some Polar Pesticides in Water Samples with SPE and LC–MS–MS

In the present study a multi-residue analytical method was developed for monitoring some polar pesticides such as acephate, methamidophos, carbofuran, isoproturon, dimethoate in water with SPE (solid-phase extraction) and LC–MS–MS. Acetochlor was taken as surrogate, and alachlor as internal standard. SPE with different types of columns was compared with LLE (liquid-liquid extraction). Further, the breakthrough volume for different pesticides was determined. The results showed that the selected pesticides can be determined very sensitively with LC–MS–MS. The minimum detectable quantity (MDQ) for each pesticide was about 1.0 ng. To date, SPE cartridge studies showed that the Oasis HLB cartridges were suitable for further studies. However, for Oasis HLB cartridge, different pesticide showed different breakthrough volume. The results showed that for acephate and methamidophos, the breakthrough volume was about 30 mL of water sample, much less than the breakthrough volume of other pesticides studied. Because of the higher vapor pressure and higher Henry's constant of methamidophos, dimethoate and carbofuran, much attention should be paid on their losses in the evaporation step of the experiment. This analytical method can be applied to determine pesticide contamination in environmental water samples. Revised: 12 September 2005 and 21 October 2005     

Retention behavior and solvent optimization of organochlorine pesticides in solid-phase extraction

Summary Plots of capacity factor and retention time vs. elution solvent composition were proved to be useful to interpret the retention behavior of Kepone and its metabolites in a reversed-phase solid-phase extraction and to optimize the elution solvent. The percent recovery of Kepone was largely improved when the solvent was optimized. The standard deviations of the results of extractions were also improved upon the optimization of the solvent.