Magnetic beads-based immunoassay as a sensitive alternative for atrazine analysis

A new immunoassay strategy for sensitive atrazine determination based on magnetic beads is reported. The immuno-method is a competitive solid-phase immunoassay where the anti-atrazine antibody is immobilized on the magnetic beads surface and fixed at the reaction cell bottom using a simple magnet, which generates a magnetic field. Analyte and HRP (horseradish peroxidase) tracer compete for active sites of antibody. After the immunointeractions antibody-analyte and antibody-tracer, atrazine quantification from the sample is performed by injection of the chemiluminescence Substrate (luminol, hydrogen peroxide and p-iodophenol), Different antibodies (polylgG anti-atrazine Ab I and affinity purified polylgG anti-atrazine Abl) were tested in this Configuration. Also, optimum concentration of antibody-covered magnetic beads was set Lip (8 mg/l Ab 11). Finally, the performance of magnetic beads-based immunoassay for atrazine determination was evaluated demonstrating that the magnetic beads-based immunoassay is one of the most sensitive method for atrazine determination (LoD = 3 pg/l. IC50 = 37 pg/l, DR = 10-1000 pg/l). (C) 2008 Published by Elsevier B.V.