分子印迹固相萃取-高效液相色谱法同时检测烟叶中磺酰脲类农药残留

以氯磺隆（CS）为模板分子,甲基丙烯酸为功能单体,三羟甲基丙烷三甲基丙烯酸酯为交联剂,在二氯甲烷氛围中,经沉淀聚合制备氯磺隆分子印迹聚合物（CS-MIP）微球。将该聚合物微球作为填料制得分子印迹固相萃取柱用于样品前处理,建立了分子印迹固相萃取-高效液相色谱（MIP-SPE-HPLC）同时检测烟叶中6种磺酰脲类除草剂残留的分析方法。针对氯磺隆、甲磺隆、苄嘧磺隆、苯磺隆、胺苯磺隆和烟嘧磺隆6种磺酰脲类除草剂,在烟叶中加标0.50~50 μg/g,经氯磺隆分子印迹固相萃取柱（CS-MIP-SPE）净化和富集,高效液相色谱（HPLC）检测,其平均回收率为77.60%~102.05%,相对标准偏差为0.16%~7.07%,检出限为0.08~0.46 μg/g。将MIP-SPE-HPLC方法用于实际农药残留检测,结果表明可同时满足烟叶中多种磺酰脲类除草剂残留量的检测要求。     

Determination of herbicide residues in soil in the presence of persistent organochlorine insecticides

Summary A rapid and reproducible gas-chromatographic method has been developed for determination of residues in soil of some widely used herbicides such as trifluralin, metribuzin, alachlor, acetochlor, metolachlor, pendimethalin, simazine, atrazine, prometryne, in the presence of persistent organochlorine insecticides (p,p-DDT, o,p-DDT, p,p-DDE, alpha-HCH, gamma-HCH, heptachlor). Determination of some herbicides by GC/ECD is difficult since their relative retention times on packed columns usually used for pesticide analysis are equal or close to those of some persistent organochlorine insecticides which can still be found almost everywhere, especially in cultivated soils. A 1.8 m column of 3% OV-225 + 5% SE-52 in a ratio of 1.4:0.9 gave good separation of all herbicides and insecticides mentioned. The influence of 6 solvents and solvent systems applied most frequently for soil extraction of pesticide residues on recovery of the compounds under study was examined. Acetonitrile was the most suitable extractant as it rendered highest residue recoveries and minimal amount of co-extractives. Residues of simazine, atrazine, and prometryne were determined in the same extracts by the use of NP-detector and a column of 5% Carbowax 20M. Recoveries of the compounds under study were in the interval of 86–103% without cleanup and 78–94% when cleanup was carriet out. The method can be used in pesticide monitoring of soil as it offers an opportunity for rapid determination of soil applied herbicides and persistent organochlorine insecticides which are some of the most common pollutants in cultivated soils.     

改性多壁碳纳米管固相萃取-高效液相色谱法测定农产品中痕量残留的4种有机氯农药

对多壁碳纳米管(MWNTs)的表面进行酸氧化处理制备了改性的MWNTs,并建立了以改性MWNTs作为固相萃取(SPE)吸附剂测定农产品中痕量残留的4种有机氯农药(p,p′-DDD、p,p′-DDT、o,p′-DDT、p,p′-DDE)的SPE-高效液相色谱(HPLC)分析方法。考察了氧化处理条件、SPE操作条件和色谱条件等对有机氯农药残留测定的影响,优化了实验条件。在优化实验条件下,4种农药在较宽线性范围内线性良好,相关系数为0.9978～0.9995,检出限为0.050 mg/L;在样品中分别添加0.10、2.0、50 mg/L的4种农药,其加标回收率为78%～104%,相对标准偏差(RSD)为2.7%～7.6%。MWNTs作为SPE填料用于陈皮、西洋参、卷心菜和茶叶等样品的净化效果良好,测定结果准确,灵敏度高,符合农产品中痕量农药残留的分析方法要求,为农产品中此类农药的痕量残留分析提供了有益的参考。     

改性多壁碳纳米管固相萃取测定农产品中苯氧羧酸类除草剂残留

通过对多壁碳纳米管(MWNTs)的表面酸氧化、表面共价接枝功能化,制备了改性MWNTs,将改性MWNTs作为一种新型的固相萃取吸附剂自制了固相萃取(SPE)柱,建立了以改性MWNTs作为SPE吸附剂测定农产品中痕量2甲4氯(MCPA)和2,4-滴(2,4-D)2种苯氧羧酸类除草剂的SPE/HPLC联用分析方法.考察了氧化处理、共价接枝、SPE柱操作和色谱条件等对实验结果的影响,并优化了实验条件.在优化实验条件下,2种除草剂在较宽质量浓度范围内线性关系良好,相关系数为0.9984～0.9995,检出限为0.020mg/L;对样品分别进行0.20、5.0、50 mg/L 3种水平的加标回收率实验,2种除草剂的加标回收率为81％～105％,RSD为3.2％～8.3％.该方法用于大豆、大米和茶叶等样品的净化,效果良好,测定结果准确、灵敏度高,符合农产品中低浓度农药残留的分析要求.     

Simultaneous determination of herbicide residues in tobacco using ultraperformance convergence chromatography coupled with solid‐phase extraction

A time‐saving and organic solvent efficient method to simultaneously determine six kinds of herbicide residues in tobacco using solid‐phase extraction for sample clean‐up and preconcentration and the highly sensitive ultraperformance convergence chromatography method was developed. Parameters for ultraperformance convergence chromatography, including the choice of stationary phase and modifiers, autobackpressure regulator pressure, column temperature, and the flow rate of mobile solvents, were optimized. The herbicide residues of napropamide, alachlor, quizalofop‐ethyl, diphenamid, metolachlor, and clomazone in tobacco samples were successfully separated and detected at levels as low as 0.0043–0.0086 mg/kg within 5 min using a nonpolar high strength silica C₁₈ selectivity for bases column and methanol as the cosolvent of the mobile phase of carbon dioxide (75–99.9%, v/v). Analysis of tobacco samples had recoveries of 69.8–95.0%, limit of quantitation of 0.0127–0.0245 mg/kg, limit of detection of 0.0043–0.0086 mg/kg, and correlation coefficient of >0.9990. Results support this method as an efficient alternative to current methodologies for the determination of herbicide residues in tobacco.     

高分辨质谱技术在农药残留检测中的应用

农药残留检测是农产品中有害物质控制的重要组成部分,随着农药残留限量标准体系的发展完善,农药残留检测方法也在不断进步。近年来质谱技术发展迅速,已被广泛应用于农药残留检测领域,高分辨质谱由于具有较高的分辨率和质量精确度,在复杂基质的农药多残留高通量检测中发挥着越来越重要的作用。本文从高分辨质谱与液相色谱、气相色谱及其他分离模式联用等方面出发,简述了近5年来高分辨质谱在农药残留检测中的应用,对目前高分辨质谱在农药残留检测应用中发现的问题进行了讨论,并对其未来发展趋势进行展望。     

Determination of forchlorfenuron residues in watermelon by solid-phase extraction and high-performance liquid chromatography

A method using solid-phase extraction for cleanup, followed by high-performance liquid chromatography with ultraviolet detection (HPLC/UV), was developed for the determination of forchlorfenuron residues in watermelon. The pesticide is extracted from the sample with acidic acetonitrile, and the extract is loaded onto a primary-secondary amine (PSA) column. The pesticide is eluted with acetone and determined by HPLC/UV. The PSA column was found to provide effective cleanup, removing the greatest number of sample matrix interferences. The acetonitrile extraction followed by the PSA cleanup provided recoveries of >95%, coefficients of variation (precision) of <10%, and sensitivity of 0.005 mg/kg, in agreement with the directives for method validation in residue analysis. The proposed method was successfully used to determine forchlorfenuron residue levels and dissipation rates in watermelon grown in an experimental greenhouse in Beijing, People's Republic of China.     

新型除草剂及其杂质的LC-MS和GC-MS分析

High performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI-MS) have been utilized to analyze the synthesized 2-(2-arylaminomethylphenoxy)pyrimidine derivatives, which are a new kind of environmentally benign herbicides and have passed the temporary pesticide registration. The identification of main product and impurities has been achieved according to the UV and mass spectra. Moreover, one impurity, introduced by the raw material in the last step of the synthetic route, was identified by GC-MS analysis. It can be concluded that the combination of chromatography and mass spectrometry, including LC-MS and GC-MS, provided a vital tool of the pesticide science.     

Evaluation of different sample treatments for determining pesticide residues in fat vegetable matrices like avocado by low-pressure gas chromatography-tandem mass spectrometry

A multi-residue method has been developed for determining 65 pesticide residues in greasy vegetable matrices such as avocado. Conventional organic solvent extraction assisted by a high-speed homogenizer was compared to pressurized liquid extraction (PLE) as extraction techniques. Following this, the lipophilic extract was purified using gel permeation chromatography (GPC). Alternative clean-up methods were also evaluated, as solid-phase extraction cartridges individually used and downstream coupled, but less effective lipophilic separation was archived. The pesticide residue determination was carried out using low-pressure gas chromatography coupled to tandem mass spectrometry (LP-GC-MS-MS), showing the applicability of this type of GC columns for the analysis of fat vegetable matrices. The proposed methodology was validated in avocado matrix. The recoveries were in the range 70-110%, with RSD values lower than 19%, at 12 and 50 microg/kg spiking levels. The limits of quantitation (LOQs) were in the range 0.04-8.33 microg/kg and the limits of detection (LODs) were between 0.01 and 2.50 microg/kg. All of them were lower than the maximum residue levels (MRLs) set by the European Union (EU) in avocado. The proposed method was evaluated analyzing pesticide residues in real avocado samples.     

高效液相色谱法测定大豆中13种三嗪类除草剂多残留量

建立了同时检测大豆中13种三嗪类除草剂多残留量的反相高效液相色谱(RP-HPLC)方法。样品经乙腈提取,凝胶渗透色谱和中性氧化铝SPE柱净化,然后采用RP-HPLC-二极管阵列检测法测定,外标法定量。对样品前处理和色谱分离条件进行了研究和优化。13种三嗪类除草剂在0.06~5.0 mg/L范围内线性良好,相关系数为0.9998~0.9999。在0.02~1.0μg/g浓度范围内,平均加标回收率在71.9%~101.9%之间,相对标准偏差为2.3%~10.7%。方法简便、快速,净化效果较好,可同时满足进、出口大豆中多种除草剂残留量的检验工作需要。     

应用搅拌棒吸附萃取-热脱附-气相色谱-质谱测定烟叶和茶叶中拟除虫菊酯类农药残留

应用搅拌棒吸附萃取(SBSE)技术分别萃取烟叶和茶叶中的5种拟除虫菊酯,并利用热脱附系统将萃取到的物质进行热脱附,然后通过气相色谱-质谱联用仪(GC-MS)进行分析测定。实验过程中对影响SBSE的因素及影响热脱附的条件进行了优化。在优化条件下,采用外标法分别对烟叶和茶叶中的5种拟除虫菊酯类农药残留进行了定量分析。结果表明,烟叶中5种拟除虫菊酯的检出限范围为3.3~11.4 ng,加标回收率为94.8%~103.4%,6次测定的相对标准偏差（RSD）为5.3%~8.6%;茶叶中5种拟除虫菊酯的检出限范围为4.2~10.5 ng,加标回收率为98.2%~110.1%,6次测定的RSD为5.0%~9.6%。实验证明该法具有较高的准确度、灵敏度和较好的重现性,可用于烟叶和茶叶中拟除虫菊酯类农药残留的快速分析测定。     

食品中农药残留分析的样品前处理技术进展*

本文综述了近年来食品中农药残留分析的样品前处理技术,重点对超临界流体萃取法在食品农药残留分析中的应用及其联用技术进行了评述;同时对固相微萃取、微波辅助萃取和凝胶渗透色谱法进行了总结。对食物中农药残留分析技术的发展方向进行了讨论。     

Determination of acidic herbicides in fruits and vegetables using liquid chromatography tandem mass spectrometry (LC-MS/MS)

The use of quick, easy, cheap, effective, rugged and safe method followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) was found to be the best combination for multiresidue determination of eight acidic herbicides in fruits and vegetables in terms of high recovery, short time of analysis, low cost and safety. Recent few articles were published for determination of different classes of acidic herbicides in single multiresidue method. In the present study, mass spectrophotometric conditions were individually optimised for eight acidic herbicides, namely 2,4-dichlorophenoxyacetic acid, bentazone, bromoxynil, fluazifop, fluroxypyr, imazethapyr, ioxynil and triclopyr to achieve maximum sensitivity and selectivity in multiple reaction monitoring (MRM) mode allowing simultaneous identification and quantification in a single run. Identity confirmation and quantitation were attained by using negative electrospray ionisation LC-MS/MS (ESI?) in MRM mode. Due to LC-MS/MS signal suppression, determination of pesticide residues was based on matrix-matched standard calculations. Most of the evaluated compounds showed a recovery ranging from 81% to 113% with relative standard deviations less than 16 % indicating acceptable precision. The precision and accuracy of the method were determined from recovery experiments on six replicates of spiked blank strawberry and green beans samples at 0.01, 0.05 and 0.1 mg/kg. The developed assay was linear over concentration range of 0.01–0.5 µg/mL, with correlation coefficient greater than 0.99 at the limit of quantitation 0.01 µg/mL. The proposed assay was successfully applied for the analysis of the studied acidic herbicides residues in two proficiency test samples. This wide scope assay protocol is applicable for monitoring acidic herbicides residues in fruits and vegetables by national regulatory authorities and accredited labs in order to help ensuring the safety of such widely used food products.     

Ultrasonic solvent extraction and nonaqueous CE for the determination of herbicide residues in potatoes

In the present work we address the development of a simple and effective method for the determination of triazine herbicide residues in horticultural products by CE in nonaqueous media (NACE). Potato samples were selected as a representative matrix of such foods with a nonfatty content. Isolation of the analytes from the sample matrix was accomplished by extraction with organic solvents, assisted by ultrasound; a clean‐up step of the organic extracts was carried out with SPE, using an Oasis MCX® sorbent to retain the analytes directly from the organic medium. The detection limits achieved in spiked potatoes (1.7–4.0 μg/kg) were lower than the default value of maximum residue level (MRL) established by current EU legislation for pesticide residues in foodstuffs. The results obtained were compared with HPLC in order to evaluate the performance of the NACE procedure.     

Recent advances in the thin-layer chromatography of pesticides: a review

Advances in the applications of thin-layer chromatography (TLC) and high-performance TLC for the separation, detection, identification, and determination of pesticides, other agrochemicals, and related compounds are reviewed for the period 2000-2002. Analyses are described for a variety of samples, such as food, biological, and environmental samples, and for residues of pesticides of various types, including insecticides, herbicides, and fungicides, belonging to different chemical classes. References are included for residue analysis, hydrophobicity studies, and the use of TLC and thin-layer radiochromatography for studies of pesticide metabolism, degradation, uptake, and related topics.     

Separation and determination of 2,4-D, dicamba and 2,4,5-T in tobacco by nonaqueous capillary electrophoresis

A practical method for residue analysis of 2,4-D, dicamba and 2,4,5-T in baked tobacco leaves has been developed using nonaqueous CE (NACE). The herbicide residues of 2,4-D, dicamba and 2,4,5-T in tobaccos were extracted by ultrasonication with ethyl acetate, followed by a cleanup procedure with gel permeation chromatography. The separation of 2,4-D, dicamba and 2,4,5-T by NACE was optimized based on orthogonal experiment design with four factors at three levels. The optimal NACE condition was established with the running buffer of 40.0 mmol/L ammonium acetate in 90% CH3CN (apparent pH 10.2), and the applied voltage of -25 kV over a capillary of 50 microm id x 46 cm (37.5 cm to the detector window), which gave a baseline separation of 2,4-D, dicamba and 2,4,5-T within 15 min. The LOD were ca. 0.4-0.6 microg/mL for the three herbicides, whereas the overall recovery ranged from 80.8 to 84.1%. The proposed method has been successfully applied to measure 300 real tobacco samples, and the residue profiles of the three herbicides in tobacco samples were obtained and evaluated.     

Dissipation dynamics and final residues of flutriafol in tobacco and soil using ultrasound-assisted extraction before liquid chromatography/tandem mass spectrometry

The dissipation dynamics and final residues of flutriafol on tobacco plant and soil were studied under field conditions. The residues of flutriafol in soil, green tobacco leaves and cured tobacco leaves were extracted by ultrasound-assisted extraction, cleaned up by dispersive solid-phase extraction and detected by liquid chromatography with tandem mass spectrometry. The limits of detection of flutriafol in soil, green tobacco leaves and cured tobacco leaves were 0.006, 0.033 and 0.033 mg·kg^?1, respectively. The limits of quantification of flutriafol in soil, green tobacco leaves and cured tobacco leaves were 0.02, 0.1 and 0.1 mg·kg^?1, respectively. Recoveries were 72.9–102% with relative standard deviations of less than 12% in soil and tobacco matrix. For field experiments, the half-lives of flutriafol in soil and green tobacco leaves were 9.2–11.5 and 9.5–11.1 days, respectively. At harvest, the final residue levels of flutriafol in cured tobacco leaves collected 21 days after one application at the recommended dosage were below 2.0 mg/kg. The maximum residue limit maximum residue limit (MRL) for flutriafol in tobacco has not yet been established in any countries. The data could help the Chinese Government to establish the MRL of flutriafol in tobacco and provide guidance on the proper use of flutriafol.     

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。     

高效液相色谱法同时检测棉织品中的9种有机氯农药残留

建立了高效液相色谱-二极管阵列检测器测定棉织品中9种有机氯农药含量的方法。采用丙酮-石油醚超声萃取法提取纺织品中的农药残留物,采用填料粒径为5 μm的ODS色谱柱,甲醇-磷酸水溶液(pH 2.27)体系为流动相,梯度洗脱,柱温30 ℃,流速0.8 mL/min,在波长230 nm下检测。9种农药在0.5~10 mg/L范围内峰面积与其浓度具有良好的线性关系(r2>0.9988)。该法简便、准确、灵敏度高、重现性好、回收率高(85.5%~99.6%),可用于纺织品中有机氯杀虫剂和除草剂含量的测定。     

Health risk assessment of neonicotinoid insecticide residues in pistachio using a QuEChERS-based method in combination with HPLC-UV

There is an increasing need to address the potential risks arising from combined exposures to multiple residues from pesticides in the diet. Pesticide residue-related pollution is a problem that arises because of the increased use of pesticides in agriculture to meet the growing demands of food production. In this study, pesticide residue data were obtained based on an optimized extraction method. For this purpose, we established a method based on qu ick, e asy, ch eap, e ffective, r ugged, and s afe (QuEChERS) extraction for simultaneous determination of imidacloprid (IMI) and acetamiprid (ACT) in pistachio nuts. The parameters influencing the QuEChERS method were the sample-to-water ratio and adsorbent amounts. As a result, both were optimized to improve the recovery of the analytes as well as the clean-up efficiency of the pistachio matrix. Our results indicated that a freeze-out step and use of primary and secondary amines as an adsorbent led to much cleaner chromatograms with lower baseline drift, without using graphitized carbon black and C₁₈-based adsorbent, which reduced both cost and time of analysis. Following extraction, the pesticide residues were separated and quantified by reverse-phase HPLC. For validation purposes, recovery studies were carried out using a concentration range from 20 to 2500 μg/L at nine levels. The suitable linearity, precision, and accuracy were obtained with HPLC–UV with recoveries of 70.37%–89.80% for IMI and 81.05%–113.57% for ACT, with relative standard deviations <12%. The validated method was successfully applied to the analysis of pistachio samples collected from a field trial to estimate maximum residue limits. There was no significant health risk for consumers via pistachio consumption.