Article ID Journal Published Year Pages File Type
1245814 Talanta 2007 7 Pages PDF
Abstract

A statistical approach for the analysis of complex samples by immunoassay is proposed in this article. Two enzyme-linked immunosorbent assays (ELISAs), one of them in the conjugate-coated format and the other in the antibody-coated format, were evaluated for their suitability to the analysis of mixtures of three organodithiophosphorus pesticides: azinphos-methyl, azinphos-ethyl and phosmet. It was found that the apparent affinity of the antibody to each analyte changed in the presence of a cross-reacting compound in the antibody-coated ELISA format, but not when the conjugate-coated ELISA format was used. The assays were thereafter applied to the analysis of mixtures of the three recognized pesticides. With the conjugate-coated ELISA format, accurate and precise determinations of mixtures could be performed if an azinphos-methyl standard curve was employed, with recoveries between 71% and 130% and with coefficients of variation lower than 12.7%. Neither accurate nor precise measurements could be accomplished with the enzyme immunoassay using the antibody-coated ELISA format, independently of the standard curve used. It is thought that the study presented here will have applicability in a variety of cases where the analytical goal is semiquantitative screening based on the total quantity of an unknown mixture of related compounds.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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