Chemiluminescence based technique for the detection of methyl parathion in water and fruit beverages

Organophosphorus (OP) pesticides, being used extensively in agricultural practices, are highly toxic even at trace levels and their detection with high sensitivity is a challenging task. The present study addresses the development of a chemiluminescence (CL) based flow injection technique for the sensitive detection of methyl parathion (MP). Different fruit samples were spiked with MP and extracted according to the AOAC method. A mean recovery of 84.3%-103.1% was obtained for MP spiked fruit juice samples with 0.18%-9.29% reproducibility (RSD). The assay specificity was attributed to the use of highly specific immunological reactions. Competitive binding was monitored between free MP and MP-Horseradish Peroxidase (MP-HRP) with immobilized anti-MP IgY antibodies in an immunoreactor column. The unbound MP-HRP conjugate eluted out of the column as a non retained component and was reacted with urea-H2O2 (U-H2O2) and luminol. The photons generated during the biochemical interaction were determined by a photomultiplier tube (PMT) based detector, and were found to be directly proportional to the MP concentration. In the present investigation, IgY has proved advantageous over the IgG class of immunoglobulins in terms of yield, stability, cost effectiveness and enhancement of assay sensitivity. Using the proposed CL method, MP was detected in samples and showed linearity in the range of 0.001-500 ng mL(-1) with a limit of quantification (LOQ) of 0.005 ng mL(-1) and with a limit of detection (LOD) of 0.001 ng mL(-1). The current findings show that this method can provide valuable information for the estimation of the pesticide traces in water and fruit beverages.