用固相萃取-毛细管气相色谱法测定烟草中氨基甲酸酯农药残留量

用Ｆｌｏｒｉｓｉｌ小柱固相萃取分离纯化、气相色谱定性同时测定烟草中五种氨基甲酸酯类农药（西维因、叶蝉散、速灭威、呋喃丹、灭多威）。用ＯＶ－１０１毛纪管色谱柱为分离柱,火焰原子检测器（ＦＩＤ）检测。五种农药在１２ｍｉｎ内得到很好分离。线性范围１～２５ｇ／ｍＬ,最低检测限１１～１６ｎｇ。回收率范围为８５．０％～１０３．２％。     

固相萃取-高效液相色谱-串联质谱联用测定竹笋中残留的7种杀虫剂农药

建立了高效液相色谱-串联质谱(HPLC-MS/MS)同时测定竹笋中丁烯氟虫腈、毒死蜱、氯虫苯甲酰胺、氟虫腈、吡虫啉、茚虫威和辛硫磷7种农药残留的分析方法。样品用乙腈提取后,经PSA固相萃取小柱净化,采用Atlantis T3色谱柱分离,以0.1%甲酸水溶液(含5 mmol/L乙酸铵)和乙腈为流动相,梯度洗脱分离,在电喷雾离子源正、负离子模式下采用质谱多反应监测(MRM)模式检测。结果表明,7种农药在10～100 μg/L范围内具有良好的线性关系(相关系数r为0.9900～0.9994); 4、8、32 μg/kg添加水平下的平均回收率为76.0%～102.6%;相对标准偏差为3.2%～11.0%;7种农药的检出限为0.02～0.5 μg/kg,定量限为0.08～1.5 μg/kg。该方法准确度、灵敏度高,简单、快速,可满足竹笋中7种杀虫剂残留同时检测的要求。     

加速溶剂萃取-气相色谱法测定土壤中的有机磷农药残留

采用加速溶剂萃取法测定土壤中有机磷农药残留物。土壤样品与无水硫酸钠(1：2m/m)混合后,再加适量中性氧化铝和活性碳,用丙酮、甲醇(1：1,V/V)在加速溶剂萃取仪上以10．3Mpa、60℃提取10min,对土壤中10种有机磷农药的回收率在80．4％-113．7％之间。该法用于土壤中的有机磷农药残留测定,速度快,检出限为0．01—0．06μg/kg。     

气相色谱-质谱法同时测定中药中有机磷和有机氮农药残留量

研究了气相色谱-质谱法测定中药中13种有机磷和有机氮类农药残留的分析方法.以丙酮-乙腈(体积比3:7)为提取剂,采用超声波辅助提取中药中残留的农药,经弗罗里硅土及中性氧化铝柱层析净化,气相色谱-质谱同时检测中药中多种有机磷和有机氮类农药的残留量,取得了较好的效果.在0.1、0.05mg/kg两个水平的添加回收率分别为81%～118%和88%～119%,相对标准偏差分别为4.0%～9.9%和5.7%～9.5%.并应用选择离子监测(SIM)技术,排除了杂质的干扰,提高了分析方法的选择性,从而建立了中药中多种类型农药同时分析的新方法.     

水样中农药残留的液相色谱检测

综述了近十五年来液相色谱分析方法在环境水中农药残留分析中的应用,对各种常用的在线和离线样品预浓缩技术、检测器以及液相色谱与质谱等仪器的联用进行了讨论,并对液相色谱在农药残留分析中的应用前景进行了评价。     

生鲜牛乳中农药多残留分析方法研究

本文报道生鲜牛乳中不同类型农药的多残留同时快速检测方法。样品经乙腈、丙酮(1：1,V／V)混合溶剂提取,离心,C18固相萃取柱纯化、富集,采用毛细管气相色谱法,电子捕获检测器检测,进行定性、定量检测有机氯、有机磷和拟除虫菊酯等14种农药的残留量。本法的加标回收率为78．5％～104．6％(敌敌畏为63．2％);检出限为0．5～14．0μg／L;线性相关系数,r^2≥0．9922。     

Dynamic Microwave-assisted Extraction Online Coupled with QuEChERS for the Determination of Organophosphorus Pesticides in Cereals by Gas Chromatography

A rapid analytical method was first developed to detect organophosphorus pesticides(OPPs) in cereals, which used dynamic microwave assisted extraction(DMAE) coupled online with a modified quick, easy, cheap, effective, rugged, and safe(QuEChERS) method. Cereals samples were mixed with a certain amount of quartz, C₁₈ and the primary second amine(PSA), and extracted successively with the acetonitrile-water solution(80%, V/V) under microwave irradiation. The obtained eluate was directly introduced into a collection tube containing NaCl and MgSO₄. Finally, the supernate was evaporated and reconstructed, and determined by gas chromatographic spectrometry. Some factors affecting the experimental results were studied and optimized. The extraction and purification processes were carried out coinstantaneously and 12 samples could be treated in one step in 4 min. Low limits of detection(0.43-1.31 μg/kg) for OPPs were obtained in cereals. The relative standard deviations(RSDs) were 2.1%-9.3%. The recoveries of OPPs ranged from 76.1% to 100.2%. By combining the advantages of DMAE with QuEChERS, the sample pretreatment process was simple to operate, with little amount of organic solvent. The whole extraction process was completed in a closed environment, therefore it was very appropriate for daily analysis of OPPs in cereals.     

茶叶浸出液中农药残留表面拉曼光谱检测与初步定量分析

选取甲基对硫磷和水胺硫磷为研究对象,改良了传统的QuEChERS前处理工艺,以自制纳米金溶胶为增强基底,利用表面增强拉曼光谱(SERS)技术,对茶叶浸出液中的农药残留进行检测。通过比对两种有机磷农药的拉曼特征峰进行定性分析。同时,选取570,1034,1107和1202 cm^-1等拉曼位移附近的特征峰光谱数据,利用微分等数学手段,结合偏最小二乘法(PLSR)建立回归方程,预测样品中农药残留含量。所得预测数值与气相色谱-质谱联用(GC-MS)法检测值对比,验证本方法的可行性与可信度。结果表明:基于SERS技术对上述两种有机磷农药的检出限可达0.05 mg/L;通过数学模型分析建立回归方程,其线性相关系数范围为0.9077~0.9824,预测均方根误差(RMSEP)范围为0.77%~2.68%;利用回归方程得到的预测值与GC-MS检测结果基本接近,相对误差范围-5.16%~9.03%,回收率为81.4%~115.1%,说明可以用SERS技术对茶叶浸出液中的有机磷农药残留进行定性和初步定量分析。     

Fabrication of Au nanorod‐coated Fe3O4 microspheres as SERS substrate for pesticide analysis by near‐infrared excitation

Au nanorods coated Fe3O4 (Fe₃O₄@NRs) microspheres were designed as functional surface‐enhanced Raman scattering substrate with a feature of magnetic property and used for detection of pesticide residues that are annually used in agriculture by near‐infrared (NIR) excitation. With this strategy, the Fe₃O₄ microspheres were synthesized by hydrothermal method and surface functionalized with polyethylenimine, and then coated with Au nanorods densely. The Raman spectra were carried out by NIR excitation and 4‐ATP was chosen as the probe molecule. The results showed a good SERS activity of the Fe₃O₄@NRs microspheres. Moreover, this substrate could be used for pesticide analysis by portable Raman spectrometer with NIR excitation. Especially, the microspheres could be transferred from pesticides contaminated fruits peel to specially cleaned glass slide with the aid of the external magnetic field, by which the strong fluorescence of the apple components can be avoided while performing the pesticide analysis of fruits peel. Copyright © 2015 John Wiley & Sons, Ltd.     

Determination of chlorpyrifos and acephate in tropical soils and application in dissipation studies

A rapid and accurate method for the extraction and determination of the two organophosphorus insecticides, chlorpyrifos and acephate in top- and subsoil materials of three tropical clayey soils from Sarawak has been developed. Soil samples were extracted with ethyl acetate and the pesticides were determined by GC-FPD. High recoveries of 76–102% and 76–100% were obtained for acephate and chlorpyrifos respectively, at fortification levels of 0.01, 0.1 and 1 mg kg^?1 with standard deviations below 9.0%. The addition of water prior to the extraction was important for obtaining high and reproducible recoveries. The method did not require clean-up of the extracts prior to GC analysis and could be detected down to 0.01 mg kg^?1. A field study was conducted using the modified method to measure the degradation kinetics and migration of acephate and chlorpyrifos in one of the soils over a period of 84 days. The degradation of acephate and chlorpyrifos were rapid with half-lives of 3.3 and 8.7 days, respectively. Both pesticides were detected in subsoils 2 h after application at the deepest (50 cm) soil layers examined and at concentrations up to 5.42 mg kg^?1. Subsoil concentrations of acephate were higher than for chlorpyrifos, and subsoil concentrations of acephate peaked after it had started to degrade in the top soil. The subsoil concentrations of the pesticides were attributed to transport with soil particles (chlorpyrifos) and via solution (acephate) through pores and cracks present in the soil profiles. The study demonstrates the high mobility of even strongly retained and fast degrading pesticides under tropical humid conditions.