Determination of pyrethroids in chicken egg samples: development and validation of a confirmatory analytical method by gas chromatography/mass spectrometry

The aim of this study was to develop and validate an efficient analytical method based on gas chromatography/tandem mass spectrometry (GC/MS/MS) for detection and quantification of six pyrethroids residues (Phenothrin, Permethrin, Cyfluthrin, Cypermethrin, Deltamethrin and Fenvalerate) in chicken eggs. The method was based on a preliminary liquid–liquid extraction of albumen‐free yolk samples, followed by a clean‐up by solid‐phase extraction. GC/MS/MS analyses were carried out in the selected reaction monitoring mode. Validation parameters such as specificity, detection capability, decision limit, precision, recovery, stability and ruggedness were determined, resulting in compliance with Decision 2002/657/EC. No complicated apparatus are required; moreover, low volumes of organic solvents and a nonintensive manual labour are required. These low costs and simple procedure, based on rapid and safe operations, may represent a useful tool in the routine analysis of pyrethroids pesticides, in the place of the currently used conventional techniques.     

出口鳗鱼中溴氰菊酯残留量的气相色谱分析

建立了出口鳗鱼中溴氰菊酯残留量的气相色谱检测方法.样品经乙腈提取、弗罗里硅土柱净化后,经气相色谱分离,ECD检测器检测.样品在0.002～0.010mg/kg范围内添加,平均回收率在79.2%～85.9%之间,变异系数在4.2%～5.8%之间.以S/N=3计算,方法检出限为2.0 μg/kg.结果表明,该法简便、灵敏、准确,适用于出口鳗鱼中溴氰菊酯残留量的分析.     

固相萃取气相色谱法测定水中的溴氰菊酯

采用C18固相萃取法预处理富集，石油醚作为洗脱剂，用气相色谱仪对水中的浚氰菊酯进行了测定。该方法简便，经济，节省了萃取剂的用量，减少了样品的用量和预处理时间，具有较好的灵敏度、准确度和精密度，最低检测浓度为0．1μg/L，回收率达83％以上。     

菊酯农药水悬浮剂的研究

对10%溴氰菊酯水悬浮剂的小试配方进行研究,通过对多种润湿分散剂、增稠剂、防冻剂等助剂的筛选,确定了最佳助剂组合,研制出性能稳定、质量可靠的悬浮剂产品。简单叙述了产品的生产工艺路线、技术指标及发展前景。     

4种农药对意大利蜜蜂的毒力测定

利用摄入法测定联苯菊酯、溴氰菊酯、双甲脒和氟胺氰菊酯对意大利蜜蜂工蜂的毒性。结果表明,4种农药对意大利蜜蜂工蜂的LC50分别为16.263、62.900、302.784、1001.755mg/L。     

Relative effectiveness of topical, filter paper and grain applications of deltamethrin, and associated behaviour of Rhyzopertha dominica (F.) strains

The susceptibility of stored grain pests to insecticides may be assessed by different types of bioassay application methods such as topical, impregnated filter papers and grain treatments. Pests may behave differently when in contact with pesticides and these changes in behaviour may contribute to their tolerance of pesticide. To compare the three application methods and determine how Rhyzopertha dominica (F.) behaved on contaminated filter papers and treated grain, experiments were carried out on four strains of this species. The strains were of known susceptibility to deltamethrin; three were from Brazil (BR4, BR6 and BR7) and one from the United Kingdom (UK1). BR4 and UK1 were susceptible strains, and BR6 and BR7 were resistant strains. Behavioural responses of the pest to deltamethrin were compared between resistant and susceptible strains by measuring the walking response of individuals on deltamethrin impregnated filter papers and the repellent effect of treated wheat grain. The body weights of strains were compared. The results showed resistance ratios of 21, 175 and 17 times between the most susceptible and the most resistant strains, following topical, filter paper and grain applications, respectively. The most resistant strain walked less on contaminated filter papers while the most susceptible strain did not change its walking pattern. Deltamethrin showed no repellent effect, neither on impregnated filter papers or in treated wheat grain. The body weights differed among the strains but were not associated with the level of tolerance to deltamethrin.     

菠菜表面农残的SERS无损检测方法研究

本文针对菠菜农药残留量超标问题,建立了一种能够快速、无损地对菠菜表面农药残留量进行检测的方法。利用表面增强拉曼光谱技术（SERS,Surface Enhanced Raman Scattering）采集含农药（溴氰菊酯）和不含的两组菠菜样本的SERS光谱,结合一阶导加Norris求导法、Savitzky-Golay卷积求导法进行光谱预处理,使用判别分析法和距离匹配法建立定性分析模型,成功区分两组菠菜样本,模型预测准确率最高可达到100%;使用偏最小二乘法建立了菠菜表面溴氰菊酯残留量的多个定量分析模型,研究发现差谱模型效果最好,其校正集相关系数（Rc）和预测集相关系数（Rp）分别为0.9908,0.9552,校正均方根误差（RMSEC）和预测均方根误差（RMSEP）分别为0.0802,0.23。结果表明,运用SERS方法能够很好地实现菠菜表面溴氰菊酯残留量的无损定性和定量检测分析,且无需任何前处理,对其它农产品中农药残留量的快速、无损检测具有借鉴意义。      

双填料固相萃取-紫外分光光度法检测茶汤中农药残留

以沉淀聚合法制备溴氰菊酯和吡虫啉分子印迹聚合物,然后干法裝柱制备双填料固相萃取柱考察其吸附性能,利用紫外分光光度计确定溴氰菊酯和吡虫啉的最大吸收波长,采用扫描电子显微镜对聚合物进行表征。实验结果表明溴氰菊酯在220 nm处吸收峰较大,而吡虫啉在270 nm处有最大吸收峰,且两种聚合物均具有较好的吸附能力。溴氰菊酯和吡虫啉在10~60 mg/L浓度范围内线性关系良好(R²>0.99),当以甲醇为活化溶剂、1 mL/min的流速上样、10%乙酸甲醇溶液作为洗脱剂时,该萃取柱对不同茶汤中溴氰菊酯和吡虫啉的加标回收率分别为83.15%~110.19%和80.61%~90.73%。对萃取柱8次重复利用结果证明该双填料萃取柱具有较好的再生性,可应用于茶叶中溴氰菊酯和吡虫啉农药的定量检测。     

基于表面增强拉曼光谱技术的苹果汁中溴氰菊酯农药残留的快速定量分析

针对苹果汁中农药残留量超标问题,采用共焦显微拉曼仪,研究了针对苹果汁中溴氰菊酯农残量的快速检测方法。分别以乙醇溶液(对照)、苹果汁溶液为背景溶液,分别采用拉曼光谱技术、表面增强拉曼光谱技术(SurfaceEnhanced Raman Scattering,SERS)采集含农药(溴氰菊酯)的两种样本的拉曼光谱与SERS光谱,并结合一阶导加Norris求导法进行光谱预处理,进而使用偏最小二乘方法建立两种样本溶液中溴氰菊酯残留量的拉曼光谱定量分析模型与SERS光谱定量分析模型,并对两种模型进行对比分析。结果表明,乙醇中溴氰菊酯溶液样本的拉曼光谱定量分析模型的校正集相关系数可达到0.9634,而SERS模型校正集相关系数可达到0.9995,最大误差不超过0.1 mg/kg。苹果汁中溴氰菊酯样本的拉曼光谱模型校正集相关系数为0.9355,最大误差不超过0.02 mg/kg;而SERS模型校正集相关系数为0.9870,最大误差不超过0.1 mg/kg。结果表明,拉曼光谱技术对快速检测苹果汁中的农药残留量具有可行性。     

Experimental determination of pesticide processing factors during extraction of seed oils

ABSTRACT

Processing Factors (PFs) reflect the concentration or dilution of pesticide residues resulting from food processing. PFs are key elements to demonstrate the compliance of processed foods with Maximum residue levels (MRLs) as set by Regulation 396/2005. While efforts have been made by the European Food Safety Authority (EFSA) and by national authorities to compile PFs from processing studies, such PFs are not available for all pesticides/processed product combinations. The EU vegetable oil and proteinmeal industry association (FEDIOL) has therefore developed a theoretical approach to approximate MRLs in crude vegetable oils and fats, based on the partition coefficient (log P_ow) of the pesticides and on the oil content of the raw materials. To substantiate this approach, a pilot-scale processing study was initiated with rapeseeds spiked with selected pesticides and the experimental PFs for these pesticides determined. The aims of this study were (i) to study the reliability of pilot-scale conditions for PF determination and (ii) to assess the experimental PFs obtained in comparison to the theoretical PFs proposed by FEDIOL. This study demonstrated that production yields obtained for crude oil and meal in this processing study are similar to those in industrial processes even if differences were observed in the individual production steps (mechanical or solvent extraction steps). The experimental PFs obtained confirmed that the chosen fat-soluble pesticides did concentrate in the oil fraction. For metalaxyl-M having a log P_ow lower than 3, a partitioning between the oil and the meal was observed, as expected. By comparing the experimental PFs and theoretical PFs, it can be concluded that the FEDIOL approach can be recommended as a suitable tool when PFs derived from specific processing studies are missing. Similar studies on pesticides with wider ranges of log P_ow are required in order to complete our conclusions on default PFs for vegetable oils.