白术中有机磷及氨基甲酸酯类农药残留量的测定

对白术中21种有机磷和氨基甲酸酯类农药残留量进行同时测定。在超声波辅助下溶剂提取,弗罗里硅土和中性氧化铝层析柱净化,选择离子-气相色谱-质谱(SIM-GC-MS)联用检测。农药混标在0.005~1.0μg/mL的浓度范围内线性良好,在0.2、0.05μg/mL两个水平添加回收率分别为81.2%~108.6%和89.8%~124.2%,相对标准偏差分别为4.6%~8.7%和5.3%~10.7%。本方法快速、灵敏、准确、可靠,可作为中草药中多种农药残留同时检测的一种方法。     

Comparison of Different d-SPE Sorbent Performances Based on Quick,Easy, Cheap,Effective, Rugged,and Safe (QuEChERS) Methodology for Multiresidue Pesticide Analyses in Rapeseeds

Pesticide extraction in rapeseed samples remains a great analytical challenge due to the complexity of the matrix, which contains proteins, fatty acids, high amounts of triglycerides and cellulosic fibers. An HPLC-MS/MS method was developed for the quantification of 179 pesticides in rapeseeds. The performances of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method were evaluated using different dispersive solid-phase extraction (d-SPE) sorbents containing common octadecylsilane silica/primary–secondary amine adsorbent (PSA/C18) and new commercialized d-SPE materials dedicated to fatty matrices (Z-Sep, Z-Sep⁺, and EMR-Lipid). The analytical performances of these different sorbents were compared according to the SANTE/12682/2019 document. The best results were obtained using EMR-Lipid in terms of pesticide average recoveries (103 and 70 of the 179 targeted pesticides exhibited recoveries within 70–120% and 30–70%, respectively, with low RSD values). Moreover, the limits of quantification (LOQ) range from 1.72 µg/kg to 6.39 µg/kg for 173 of the pesticides. Only the recovery for tralkoxydim at 10 μg/kg level was not satisfactory (29%). The matrix effect was evaluated and proved to be limited between −50% and 50% for 169 pesticides with this EMR-Lipid and freezing. GC-Orbitrap analyses confirmed the best efficiency of the EMR-Lipid sorbent for the purification of rapeseeds.     

气相色谱法测定4种中药材中有机氯农药残留量

建立了气相色谱法同时测定中药材天仙子、半夏、杜仲、吴茱萸中有机氯农药残留量方法。13种有机氯农药的浓度在1~100μg/L内线性关系良好(r>0.995 5),检出限为0.04~0.21μg/L,加标回收率为81.79%~100.50%,测定结果的相对标准偏差为0.28%~0.98%。     

共振光散射比浊法测定有机磷农药残留量

有机磷农药对人与动物的毒性作用较大,绝大多数有机磷农药都是剧毒的。因此,建立有效的检测有机磷农药残留的方法是非常重要的。目前检测有机磷农药的方法有：色谱法、光谱法、免疫法、生物传感器以及化学发光法等;农药速测卡也可以半定量或定量测定市售蔬菜中的有机磷农药残留。近年来共振光散射法（RLS）作为一种新的分析技术正得到越来越多的研究和应用。     

土壤中多种有机磷及氨基甲酸酯类农药残留量的气相色谱-质谱法测定

建立了气相色谱-质谱法测定土壤中12种有机磷和氨基甲酸酯类农药残留分析方法。以丙酮-石油醚(4∶1,V/V)为提取剂,采用超声波提取土壤中农药残留,经弗罗里土层析柱净化,气相色谱-质谱(选择离子模式)法同时测定了土壤中多种有机磷和氨基甲酸酯类农药。该法对0.1μg/mL和0.5μg/mL两个浓度添加水平的回收率分别为70.1%~119.0%和78.1%~119.1%,相对标准偏差分别为6.30%~9.80%和5.20%~8.23%。     

Liquid Chromatography-Tandem Mass Spectrometry for the Simultaneous Analysis of 353 Pesticides in the Edible Insect Tenebrio molitor Larvae (Mealworms)

Tenebrio molitor larvae (mealworm) is an edible insect and is considered a future food. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), a novel method for simultaneous analysis of 353 target analytes was developed and validated. Various sample preparation steps including “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) extraction conditions, number of acetonitrile-hexane partitions, and dispersive-solid phase extraction (dSPE) sorbents were compared, and the optimal conditions were determined. In the established method, 5 g of homogenized mealworms was extracted with acetonitrile and treated with QuEChERS EN 15662 salts. The crude extract was subjected to three rounds of acetonitrile-hexane partitioning, and the acetonitrile layer was cleaned with C18 dSPE. The final solution was matrix-matched and injected into LC-MS/MS (2 μL). For target analytes, the limits of quantitation (LOQs) were ≤10 μg/kg, and the correlation coefficient (r²) of calibration was >0.990. In recovery tests, more than 90% of the pesticides showed an excellent recovery range (70–120%) with relative standard deviation (RSD) ≤20%. For more than 94% of pesticides, a negligible matrix effect (within ±20%) was observed. The analytical method was successfully applied and used for the detection of three urea pesticides in 4 of 11 mealworm samples.     

气相色谱法测定坚果中8种拟除虫菊酯农药残留

建立了东盟进口坚果夏威夷果、开心果、杏仁中8种拟除虫菊酯农药残留的检测方法。样品采用乙腈作萃取溶剂超声波提取,经中性氧化铝串联弗罗里硅土小柱净化,组分经不同极性的两根毛细管柱进行分离,采用气相色谱法以ECD检测器检测坚果中8种拟除虫菊酯农药。该方法在0.01~1.0μg/m L浓度范围内具有良好的线性关系,相关系数为0.999 2~0.999 9;在农药添加浓度为10,20,50μg/kg时,回收率为71%~115%,相对标准偏差为4.5%~9.8%,检出限(LOD,S/N=3)为0.014~0.28μg/kg,定量下限(LOQ,S/N=10)为0.047~0.94μg/kg。该方法分离效果好,准确可靠,回收率高,方便快速,可用于坚果中农药残留的日常检测。     

Voltammetric determination of herbicide molinate in river water and rice samples using solid silver amalgam electrode fabricated with nanoparticles

The evaluation of the voltammetric behaviour and the determination of herbicide molinate were performed for the first time over the surface of solid amalgam electrode fabricated with silver nanoparticles using cyclic voltammetry and square-wave voltammetry techniques. The experimental and instrumental parameters were evaluated to reach the maximum analytical response for molinate. It was achieved when a medium composed of 0.04 mol L^?1 Britton–Robinson buffer at the pH value of 4.0 was used. Under these conditions, molinate showed one pronounced reduction peak at E_p = ?0.37 V (vs. Ag/AgCl 3 mol L^?1) that was characterised as an irreversible system. An analytical curve was constructed at the concentration range from 9.36 to 243.49 µg L^?1 and a limit of detection of 2.34 µg L^?1 was obtained. The amalgam electrode presented good stability during the measurements with relative standard deviation (RSD) values of 2.9% for the repeatability and 5.4% for the reproducibility. The voltammetric method developed here could be conveniently applied for the determination of molinate in river water and rice spiked samples at levels below those established on the legislations of European Union and Brazil with good accuracy (RSD of less than 5% for all samples). Comparison with HPLC technique was carried out and the results indicated satisfactory concordance. According to the results depicted here, the silver nanoparticles solid amalgam electrode showed itself highly sensitive and an interesting alternative for the routine analysis of molinate in water and food samples. Furthermore, it introduces an environmentally acceptable alternative to the mercury electrodes, most commonly used for determination of reducible pesticides.     

Review of thin-layer chromatography in pesticide analysis: 2014–2016

ABSTRACT

Publications reporting techniques and applications of thin-layer chromatography (planar chromatography) for the separation, detection, qualitative and quantitative determination, and preparative isolation of pesticides and their metabolites are reviewed for the period from November 1, 2014 to November 1, 2016. Analyses are described for a variety of sample types and pesticide classes. In addition to references on residue analysis, studies such as pesticide chromatographic retention, identification and characterization of natural pesticides, metabolism, bioactivity, degradation, soil mobility, and lipophilicity are covered. The unique advantages of thin-layer chromatography in presenting results as a stored image on an open stationary phase are addressed.