Wang Shuo, Zhang Jun, Yang Zhiyan, Wang Junping, Zhang Yan
Tianjin Key Laboratory of Food Nutrition and Safety, Faculty of Food Engineering and Biotechnolgy, Tianjin University of Science and Technology, People's Republic of China.
J Agric Food Chem. 2005 Sep 21;53(19):7377-84. doi: 10.1021/jf0509862.
Two competitive immunoassays, a laboratory assay based on microwell plates and a field test based on the use of polystyrene tubes, have been developed for the detection of endosulfan in agricultural products. The limit of detection for the microwell plate format was 0.8 +/- 0.1 microg/kg, and the limit of detection for the tube format was 1.6 +/- 0.2 microg/kg. A simple, rapid, and efficient extraction method was employed, and 76-112% recoveries of spiked samples were obtained. Methanol extracts of some agricultural product samples such as grape, carrot, spinach, and tobacco could be analyzed directly by immunoassay after dilution in 0.5% fish skin gelatin-phosphate buffered saline. In contrast, extracts of green tea caused significant interference in the assay, and a number of simple cleanup methods were ineffective in removing interference. However, use of the coagulating reagent polyvinyl pyrrolidone removed the matrix effect effectively. For the validation of the enzyme-linked immunosorbent assay (ELISA) tests, samples were analyzed by ELISA and gas chromatography (GC) after solid phase extraction. The relationship between data obtained using the tube assay and microwell assay was good (the lowest r(2) value was 0.94), and also, the immunoassay assay data correlated well with data obtained from GC analysis (the lowest r(2) value was 0.93). The developed immunoassay methods are the suitable methods for the rapid quantitative and reliable determination of endosulfan residues in agricultural products.
已开发出两种竞争性免疫测定方法，一种是基于微孔板的实验室测定法，另一种是基于使用聚苯乙烯管的现场测试法，用于检测农产品中的硫丹。微孔板形式的检测限为0.8±0.1微克/千克，管形式的检测限为1.6±0.2微克/千克。采用了一种简单、快速且高效的提取方法，加标样品的回收率为76-112%。一些农产品样品如葡萄、胡萝卜、菠菜和烟草的甲醇提取物在0.5%鱼皮明胶-磷酸盐缓冲盐水中稀释后可直接通过免疫测定进行分析。相比之下，绿茶提取物在测定中造成了显著干扰，许多简单的净化方法在去除干扰方面无效。然而，使用凝聚剂聚乙烯吡咯烷酮有效地消除了基质效应。为了验证酶联免疫吸附测定（ELISA）测试，样品在固相萃取后通过ELISA和气相色谱（GC）进行分析。管测定法和微孔板测定法获得的数据之间的关系良好（最低r²值为0.94），而且免疫测定数据与GC分析获得的数据也具有良好的相关性（最低r²值为0.93）。所开发的免疫测定方法是快速定量和可靠测定农产品中硫丹残留的合适方法。
