Arrays on disc for screening and quantification of pollutants

Abstract

A rapid compact disc based methodology for screening and quantification of organic pollutants in mandarin juices is presented. The assay is established on the coating conjugate indirect competitive principle and developed under disc-array configuration. The detection is based on the acquisition of attenuated reflective signals that were proportional to optical density of the immunoreaction product. The competitive assay is applied to quantify simultaneously, in a selective manner, non-systemic insecticides in mandarin juices. The detection limits were 0.2 and 0.1 ¿g L¿1 and the sensitivity 2.1 and 1.5 ¿g L¿1, for chlorpyrifos and fenthion, respectively. Pollutants were directly quantified after sample dilution in a total time of 40 min. Also, the implementation of positive and negative controls into the array configuration served as an automatic quality control test. The effect of thermal treatment on pesticide dissipation was studied and found that it was insignificant under the studied conditions. Recovery intervals ranged from 96¿105% to 94¿103%, for chlorpyrifos and fenthion, respectively and were similar to those obtained with gas chromatography coupled to mass spectrometry. In the current configuration, 64 samples can be simultaneously analyzed on a disc at a very competitive value, demonstrating its potential for high-throughput multiplexed screening applications for controlled monitoring programs in low-level labs or outside the lab setting