微波辅助萃取-气相色谱法测定茶叶中多种有机氯和拟除虫菊酯农药残留

建立了茶叶中18种有机氯和9种拟除虫菊酯农药残留微波辅助萃取．气相色谱分析方法。运用正交设计法对微波萃取条件进行了优化,茶叶样品用正己烷-二氯甲烷混合溶N（1：2,V／V）进行萃取,萃取液用弗罗里硅土和中性氧化铝混合层析柱净化,采用J＆WDB-1701毛细管柱分离,GC．ECD法同时测定。在0．4、0．2、0．1ml（0．5μg／m1有机氯农药＋1．0μg／ml拟除虫菊酯农药）三个水平添加时的平均回收率（n=5）分别为80．9％～118．5％、88．4％～120．7％、80．9％～116．3％;相对标准偏差分别为2．09％～6．70％、1．89％～6．49％、1．98％～11．87％。该方法的检出限为：有机氯农药0．0004～0．0048mg／kg,拟除虫菊酯农药0．0033～0．0400mg／kg。     

正已烷萃取法测定进口水果中六六六、滴滴涕

采用气相色谱法（带有电子捕获检测器ECD），以正已烷、丙酮为提取溶剂，用浓硫酸磺化法净化提取液，对进口水果中的六六六、滴滴涕各4种异构体农药进行了多残留检测。结果表明：以正己烷与丙酮的混合提取剂的提取效果好，其平均回收率范围为93．7％-122．7％，相对标准偏差分别为1％-6％，在程序升温的条件下，8种农药可很好地分离，检出限范围为0．0006—0．006mg／kg，准确度和精确度均达到了进口水果中六六六、滴滴涕农药残留分析的要求。     

黄瓜中噻嗪酮、三唑酮残留量的测定

利用气相色谱-质谱(GC-MS)，电子轰击(EI)法同时测定了黄瓜中噻嗪酮、三唑酮残留量。试样经丙酮-石油醚提取，二氯甲烷萃取，无水硫酸钠干燥，浓缩。选择灵敏度高、干扰少的检测离子，用选择离子监测(SIM)方式测定了其中两种农药残留。噻嗪酮，三唑酮的检出限量分别为0．13和0.013mg／kg，标准添加(0．013-1mg／kg)的回收率为71．1％～123％，测定的相对标准偏差(RSD)为3、4％～17％。     

Carb／PSA固相萃取净化一气相色谱质谱法测定茶叶中的34种农药成分

建立了茶叶中34种农药多残留的气相色谱质谱分析方法。茶叶样品用乙腈一次性提取后,经Carb／PsA固相萃取小柱净化,气相色谱质谱定性定量。添加回收试验的结果表明：34种农药的平均回收率70％124％,相对标准偏差为0．2%-14．9％。方法的检出限为0．1-25．0μg／kg。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求。     

分散固相萃取-气相色谱法快速测定茶叶中27 种常见含卤素农药残留

采用分散固相萃取-气相色谱法对茶叶中27 种含卤素农药残留量进行测定。经丙酮-正己烷（l∶1,V/V）提取后,直接加入无水硫酸钠、硅镁型吸附剂及活性炭净化,使用DB-17毛细管气相色谱柱、微电子捕获检测器,对茶叶中27 种含卤素农药残留量进行测定。该方法样品平均加标回收率为82.2%～113.4%,相对标准偏差为1.2%～6.0%;茶叶中27 种含卤素农药多残留检出限为0.005～0.075 mg/kg。     

基质固相分散-气质联用法测定荞头中多种拟除虫菊酯类农药残留量

试样中加入石墨化碳黑-XAD-2担体（质量比1：1），分散混匀，再用丙酮-正己烷（体积比1：2）提取，提取液浓缩后用GC-MS测定，外标法定量。当添加水平为0．025mg／kg-1.0mg／kg时，方法回收率在72．1％-127．8％之间。RSD为1．5％-16．6％，检出限是0．025mg／kg-0．060mg／kg。采用保留时间和选择监视离子丰度比对阳性样品进行确证。该法简便、快速、灵敏，各项技术指标均满足残留检测的要求。     

固相萃取－气相色谱法同时检测茶叶中多种农药和多氯联苯残留

建立茶叶中21种有机氯、拟除虫菊酯类农药和多氯联苯(polychlorinated biphenyls,PCBs)残留固相萃取(solid-phase extraction,SPE)-气相色谱分析方法。用正己烷-丙酮(1:1,V/V)提取,经Envi-Carb/NH2复合固相萃取柱净化,采用RTX-5毛细管柱分离,气相色谱-电子捕获检测器(gas chromatography-electron caputure detector,GC-ECD)检测。在0.02、0.05、0.3mg/kg三个添加水平,平均回收率为68.64%～125.62%,相对标准偏差(relative standard deviation,RSD)为1.05%～12.78%,该方法的检测限(detection of limit,LOD)在0.0022～0.0129mg/kg之间,适用于茶叶试样中痕量残留的分析。     

茶叶中优乐得和菊酯类农药的监测与污染评价

采用气相色谱分离，ECD测定茶叶中优乐得、甲氰菊酯、氰戊菊酯的残留量。结果：对3种农药检测的回收率范围为72．0％-100.3％，相对标准偏差为2．5％-5．6％，最小检出限为O．01μg／mL-0．05μg／mL。采用本文的测定方法检测了采自福鼎、永川、蜀永、缙云山和川茶五个茶园的茶叶样品中的优乐得和菊酯类农药含量，结果表明不同茶园的茶叶中优乐得和菊酯类农药的检出量差异很大。同时，对这几种茶叶的农药残留进行了污染评价。     

气相色谱-质谱法测定纺织品中6种苯氧羧酸类农药残留量

为测定纺织品中6种苯氧羧酸类农药残留量，采用酸性丙酮水溶液提取试样，提取液经二氯甲烷液-液分配提取后，再用甲醇-三氟化硼乙醚溶液甲酯化，经正己烷提取，用配有质量选择检测器的气相色谱仪（GC／MSD）测定。经前处理条件试验，气相色谱-质谱条件选择试验，气相色谱／质谱阳性确证条件试验，回收率、精密度和测定低限技术指标均完全满足检测需要。     

烟草中有机磷农药的多残留气相色谱分析方法

本文报道了一种简单、快速、准确测定15种有机磷农药的多残留分析方法，样品经丙酮提取，加入氯化钠析出丙酮，再加二氯甲烷萃取，经无水硫酸钠干燥浓缩，经活性炭─545助滤剂柱层析，丙酮淋洗浓缩后气相色谱测定。方法回收率：添加1×10~(-6)，平均回收率为100.56％±8.99%，变异系数为8.94％；添加0.5×10~(-6)，平均回收率为100.93％±10.47％，变异系数为10.37％。最小检出量为0.005～0.lng，除敌敌畏和敌百虫外，相关系数均在0.9941以上，达到极显著水平，完全符合农药多残留分析方法的要求。     

气相色谱-质谱联用法测定茶叶中21种农药残留

该实验建立了茶叶中21种农药残留的气相色谱-质谱（GC-MS）多反应监测模式（MRM）定性、定量分析检测方法,探讨不同 提取方法、提取溶剂、浓缩方式等试验因素对茶叶农药多残留测定结果的影响。 结果表明,以正己烷-丙酮（1∶1,V/V）混合溶剂超声提 取、氮吹浓缩,用气相色谱-质谱法对茶叶样品中21种农药进行定性定量检测,21种农药在0.05～1.00 μg/mL范围内呈良好的线性 关系,相关系数（R2）为0.998 0～0.999 9。 在茶叶样品中分别添加质量浓度0.05 mg/kg、0.20 mg/kg、0.40 mg/kg的农药组分,平均回收率 为83.46%～92.13%,相对标准偏差（RSD）为4.88%～8.51%,检出限为0.002 7～0.021 9 mg/kg,该方法具有前处理简便快捷、灵敏度 高、成本低等优点,在实际茶叶农药残留检测中得到了广泛应用,能满足日常的茶叶农药残留检测。     

Optimization of a One‐Step Method for the Multiresidue Determination of Organophosphorous Pesticides in Camellia Oil

Due to the widespread use and potential toxicity of organophosphorous pesticides (OPs), multiresidue monitoring of OPs in camellia oil has become increasingly important. A simple, rapid, and effective matrix solid‐phase dispersion extraction for the determination of 15 organophosphorous pesticides in camellia oil is described. Related important factors influencing the extraction efficiency, such as type of sorbent material, eluting solvent, and ratio of sample/sorbent were studied and optimized. The best results were obtained using 0.5 g of camellia oil, 1.5 g of white carbon black as dispersant sorbent, and 5 mL of acetonitrile: ethyl acetate (2:1, V/V) as eluting solvent. Method validation was performed in order to study sensitivity, linearity, precision, and accuracy. Average recoveries ranged between 76.7% and 102.9% with relative standard deviation values from 2.9% to 13.7% at 2 concentration levels (10 and 100 μg/kg). The method limit of detection at or below the regulatory maximum residue limits for the pesticides was achieved. Practical Application: A simple, rapid, and effective method for multiresidue determination of organophosphorous pesticides in camellia oil was developed. The sample preparation could finish in 5 min.     

An empirical analysis of the impact of EU’s new food safety standards on china’s tea export

Stricter pesticide residue standards have severe negative impacts on the trade in developing countries, leading to a considerable decrease in the export of food and agricultural products from developing countries. For example, officials of the EU Health and Consumer Protection Bureau published the new EU Act 2000/42/EC on 30 June 30, 2000. This act amended the maximum residue levels (MRLs) for some pesticides. From 1 July 1, 2001 onwards, the EU implemented new 134 MRLs for pesticides in tea products. This measure above will limit market entry opportunities and will lead to a decrease in exports from these developing countries. This study aimed to utilise the Gravity Model in international trade, to empirically analyse the impact of the new EU Food Safety Act on the major tea exporters of the world. It is shown that the new EU Food Safety Act has had a significant impact on the major tea exporters of the world as shown in the decline in export volume. Quantitative analysis indicates that tea export has reduced by 61.6% following the MRL reduction to 5% significance level. In recent years the Chinese tea traded to EU supported the accuracy of this conclusion. Practically, China’s tea exported to the EU did not drop fast as the theoretical result shows.     

Rapid screening for pesticides using automated online sample preparation with a high-resolution benchtop Orbitrap mass spectrometer

For pesticide analysis in food products a common approach is to develop a fast multi-residue method that is capable of identifying and quantifying a large number of analytes in various matrices. This study demonstrates rapid screening and accurate mass confirmation of 116 pesticides in oranges and hazelnuts using an automated online sample preparation method with turbulent-flow chromatography technology coupled to a high-resolution benchtop Orbitrap? mass spectrometer. The limits of quantification (LOQs) for the majority of analytes are well below the maximum residue limit (MRL) set by the European Union and the Japanese government. The recoveries were in the range of 70-120% for over 75% of analytes in both matrices. The present methodology is suitable for routine pesticides analysis in food safety laboratories.     

QuEChERS-超高效液相色谱-串联质谱法同时检测大米中5种农药残留

目的明确贵阳市大中型生活超市散售大米中5种农药的残留情况。方法通过样品前处理方法的筛选,建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)同时测定大米中仲丁灵、戊唑醇、甲氧虫酰肼、嘧菌酯和茚虫威5种农药残留的分析检测方法。样品经1.0%乙酸乙腈提取分离,PSA净化,采用UHPLC-MS/MS检测,外标法定量。结果 5种农药在0.001~0.50 mg/L质量浓度范围内,峰面积与对应的质量浓度间有良好的线性关系,相关系数均大于0.99;5种农药在0.002、 0.01、 0.1和1.0mg/kg水平下的平均回收率为88%~111%,相对标准偏差分别为0.45%~9.33%(n=5),方法定量限均为0.002mg/kg。结论本方法满足农药残留检测分析要求,适用5种农药在大米中的多残留准确定性和定量分析。     

Optimization of QuEChERS Procedure Coupled to GC-ECD for Organochlorine Pesticide Determination in Carrot Samples

An optimised version of the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method for simultaneous determination of 14 organochlorine pesticides in carrots was developed using gas chromatography coupled with electron-capture detector (GC-ECD) and confirmation by gas chromatography tandem mass spectrometry (GC-MS/MS). A citrate-buffered version of QuEChERS was applied for the extraction of the organochlorine pesticides, and for the extract clean-up, primary secondary amine, octadecyl-bonded silica (C18), magnesium sulphate (MgSO₄) and graphitized carbon black were used as sorbents. The GC-ECD determination of the target compounds was achieved in less than 20 min. The limits of detection were below the EU maximum residue limits (MRLs) for carrots, 10–50 μg kg^?1, while the limit of quantification did exceed 10 μg kg^?1 for hexachlorobenzene (HCB). The introduction of a sonication step was shown to improve the recoveries. The overall average recoveries in carrots, at the four tested levels (60, 80, 100 and 140 μg kg^?1), ranged from 66 to 111 % with relative standard deviations in the range of 2–15 % (n?=?3) for all analytes, with the exception of HCB. The method has been applied to the analysis of 21 carrot samples from different Portuguese regions, and β-HCH was the pesticide most frequently found, with concentrations oscillating between less than the limit of quantification to 14.6 μg kg^?1. Only one sample had a pesticide residue (β-HCH) above the MRL, 14.6 μg kg^?1. This methodology combines the advantages of both QuEChERS and GC-ECD, producing a very rapid, sensitive and reliable procedure which can be applied in routine analytical laboratories.     

三重四极杆气相色谱质谱联用法测定茶叶中31种农药残留

目的 建立一种简便、快速、安全、价格低廉的三重四级杆气相色谱质谱联用仪法(QuEChERS-GC-MS/MS)测定茶叶中的31种农药残留的分析方法。方法 以0.5%的乙酸-乙腈(v/v)溶液作为溶剂,以加入无水硫酸镁、醋酸钠进行浸提,浸提后用硅酸镁、乙二胺-N-丙基硅烷化硅胶(PSA)、C18和石墨化炭黑(GCB)净化试剂净化,净化液用氮吹仪浓缩至干,用0.5%的乙酸-乙腈定容至,采用内标法定量,气相色谱-质谱联用仪(GC-MS/MS)同时测定31种农药残留。结果 31中农药的线性相关系数达到0.999以上,检测限(LOD)为0.01~0.05mg/kg。同时采用红茶和绿茶作为基质本底, 用加标回收评价了该方法的精密度和重现性,31种农药的平均回收率为85%-105%,相对标准偏差为0%-10%。结论 该方法操作简便快捷、检测成本低,方法的灵敏度、准确度和精密度符合茶叶中农药残留测定的技术要求。 关键词: QuEChERS; 三重四级杆气相色谱质谱联用仪; 农药残留; 茶叶     

Validation of an enzyme-linked immunosorbent assay for qualitative screening of neomycin in muscle, liver, kidney, eggs and milk

A rapid and sensitive enzyme-linked immunosorbent assay (ELISA) was used for the qualitative screening analysis of neomycin in food of animal origin (muscle, liver, kidney, eggs and milk) at levels corresponding to the European Union maximum residue limit (MRL) set for this substance. The method validation was performed according to the criteria of Commission Decision 2002/657/EC established for qualitative screening methods. In this regard, the following parameters were determined: detection capability (CCβ), specificity, detection limit (LOD), quantification limit (LOQ), recovery, precision, linearity and ruggedness. LODs ranged from 5.7 microg kg(-1) in kidney to 29.3 microg kg(-1) in milk; LOQs ranged from 11.4 microg kg(-1) in kidney to 59.7 microkg(-1) in eggs. The recoveries from spiked samples at the MRL, half the MRL and double the MRL levels ranged from 65.8% to 122.8%, with a coefficient of variation (CV) between 5.9% and 28.6%. The CCβ value was less than the MRL for all examined matrices. Moderate variations of some critical factors in the sample pretreatment for muscle, milk and eggs were deliberately introduced for ruggedness evaluation and had a slight but not statistically significant effect on method performance. The proposed method is suitable for qualitative screening analysis of neomycin in the above-mentioned food in conformity with current European Union performance requirements.     

An Applicable Strategy for Improvement Recovery in Simultaneous Analysis of 20 Pesticides Residue in Tea

It is important to have a reliable method to analyze pesticides in tea, a beverage commonly consumed in Iran. A validated method was developed for the determination of 20 pesticides in tea based on QuEChERS sample preparation and capillary gas chromatography‐quadrupole mass spectrometry in selective ion monitoring mode (GC‐MS/SIM) using triphenyl methane (TPM) solution as an internal standard. We used fortified, extracted, and cleaned‐up tea samples instead of calibration standards for quantitation, which substantially reduced adverse matrix‐related effects and negative recovery affected by graphite carbon black (GCB) on pesticide analysis. The recovery of pesticides at 3 concentration (40, 60, and 240 ng/g) ranged from 79.5% to 111.4% (n = 3). The method had acceptable repeatability with RSDr < 20%. The limits of quantification (LOQ) for all pesticides were ≤20 ng/g. The analytical results of the proposed method were in good agreement with proficiency test results (FAPAS, 19116). The recoveries and repeatabilities were in accordance with the criteria set by SANCO Guideline. The validated method was suitable for the analysis of pesticides in tea.     

茶鲜叶中拟除虫菊酯类农药残留的检测方法

拟除虫菊酯农药用量少,杀虫效果好,广泛应用于茶园害虫的控制,是我国出口茶叶中必检的农药。为实现茶叶生产危害分析关键控制点(HACCP)体系中农药残留的源头控制,提供农残源头监督检验方法依据,避免大量使用农药对茶园土壤环境造成的污染,开发茶鲜叶中菊酯类农药的多残留检测方法有重要的实践意义。本实验用V(石油醚)∶V(丙酮)=1∶1混合溶剂提取,经弗罗里硅土柱层析净化除去干扰物质,采用气相色谱,微电子捕获检测器(μECD)测定茶鲜叶中主要的6种拟除虫菊酯类农药残留量。方法最低检出浓度为0.005～0.01mg/kg;茶鲜叶中拟除虫菊酯农药的添加浓度为0.05、0.2、1.0mg/kg,其回收率在83.6%～104.5%,相对标准偏差(RSD)为2.7%～10.2%,符合农药残留分析要求。