Automated flow fluorescent immunoassay for part per trillion detection of the neonicotinoid insecticide thiamethoxam

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• 作者：Hee-Joo Kim ; Weilin L. Shelver ; Eul-Chul Hwang ; Ting Xu and Qing X. Li
• 关键词：Thiamethoxam ; Kinetic exclusion assay ; KinExA ; Immunoassay ; ELISA ; Insecticide
• 刊名：Analytica Chimica Acta
• 出版年：2006
• 出版时间：30 June 2006
• 年：2006
• 卷：571
• 期：1
• 页码：66-73
• 全文大小：400 K

文摘

An ultra sensitive automated flow fluorescent immunoassay was developed using the KinExA™ 3000 system for quantitative analysis of the neonicotinoid insecticide thiamethoxam. Five new monoclonal antibodies were obtained and screened with a competitive ELISA. One monoclonal antibody designated as E6VI was evaluated for sensitivity, selectivity and solvent tolerance with the KinExA. Sensitivity determined from the concentration of half-maximal inhibition (IC₅₀) was obtained by plotting KinExA signals to a four-parameter sigmoidal curve as a function of analyte concentrations. For the most sensitive clone, the IC₅₀ and the limit of detection were approximately 30 pg ml⁻¹ and 16 pg ml⁻¹, respectively. Cross-reactivity was estimated by measuring the equilibrium constants (K_d) for four other neonicotinoid insecticides (clothianidin, imidacloprid, dinotefuran, and acetamiprid). E6VI was very specific to thiamethoxam with <0.11 % cross-reactivity for tested neonicotinoids. An excellent correlation (r² = 0.99) was obtained between spiked and measured concentrations of thiamethoxam in stream and tap water, potato, cucumber, and apple samples.