Musharraf Syed Ghulam, Shoaib Muhammad, Kumar Dileep, Najam-Ul-Haq Muhammad
H,E,J, Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan.
Chem Cent J. 2012 Aug 31;6(1):93. doi: 10.1186/1752-153X-6-93.
Pyrethroids are widely used for the control of pests and insects, as pyrethroids are believed to pose little risk to human health and environment. However, exposure to the pyrethroids exceeding the label directions might adversely affect human health and environment. Hence a careful selection of environment friendly household product is required that must contain exactly the label claimed pyrethroids amount.
A sensitive and robust TLC-densitometric method for simultaneous quantification of commonly used synthetic pyrethroids including esbiothrin, alpha-cypermethrin and cis/trans permethrin in agricultural and domestic products has been developed and validated. TLC aluminum sheets, precoated with 0.2 mm thick layer of silica gel 60 F-254, were used for chromatographic process. Densitometric analysis of chromatoplates was carried out in absorbance mode at corresponding λmax of each pyrethroid. Equally valid common mobile phase for all pyrethroids consisted of hexane-dichloromethane-ethylacetate-formic acid (8:1.5:0.4:0.1 v/v/v/v) which provided sharp and symmetrical peaks of esbiothrin, alpha-cypermethrin, trans-permethrin and cis-permethrin, at Rf 0.31, 0.53, 0.6 and 0.65, respectively. Linear regression data for respective calibration curves showed a good linearity for all pyrethroids with r = 0.991-0.996. Limits of detection (LOD) and limits of quantification (LOQ) for all pyrethroids were found in the range of 1.6-2.8 and 4.9-8.5 ng/spot, respectively.
The developed method is applicable for separating the mixture of pyrethroids and at the same time, it is also valid for separating their isomers. The method is reproducible, precise and accurate for the quantitative determination of pyrethroids in agricultural and domestic products.
拟除虫菊酯被广泛用于控制害虫和昆虫，因为人们认为拟除虫菊酯对人类健康和环境几乎没有风险。然而，接触超过标签说明用量的拟除虫菊酯可能会对人类健康和环境产生不利影响。因此，需要谨慎选择环保型家用产品，该产品必须精确含有标签所宣称的拟除虫菊酯含量。
已开发并验证了一种灵敏且稳健的薄层色谱-密度测定法，用于同时定量测定农产品和家用产品中常用的合成拟除虫菊酯，包括乙虫菊酯、α-氯氰菊酯和顺式/反式氯菊酯。使用预涂有0.2毫米厚硅胶60F-254层的薄层铝板进行色谱分析。在每种拟除虫菊酯相应的最大吸收波长处，以吸光度模式对色谱板进行密度测定分析。对所有拟除虫菊酯均有效的通用流动相由己烷-二氯甲烷-乙酸乙酯-甲酸（8:1.5:0.4:0.1 v/v/v/v）组成，该流动相分别在比移值0.31、0.53、0.6和0.65处提供乙虫菊酯、α-氯氰菊酯、反式氯菊酯和顺式氯菊酯尖锐且对称的峰。各校准曲线的线性回归数据表明，所有拟除虫菊酯均具有良好的线性，r = 0.991 - 0.996。所有拟除虫菊酯的检测限（LOD）和定量限（LOQ）分别在1.6 - 2.8和4.9 - 8.5 ng/斑点范围内。
所开发的方法适用于分离拟除虫菊酯混合物，同时也适用于分离它们的异构体。该方法对于农产品和家用产品中拟除虫菊酯的定量测定具有可重复性、精密度和准确性。
