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A magnetic particle based solid-phase enzyme linked immunosorbent assay (ELISA) for the determination of parts per billion levels of aldicarb and its sulfoxide and sulfone metabolites in water was developed. Sensitivity is estimated at 250 ppt based on a 90% B/Bo with results available in less than one hour. Photometric analysis of the final colored reaction was made using a specially designed microprocessor controlled photometer with extensive data reduction capability. Assay interference was not seen over a wide pH range and with high concentrations of inorganic ions. Results were shown to qualitatively correlate with HPLC and GC using a positive cutoff of 0.5 ppb. Quantitative comparisons were difficult due to the variable reactivities of aldicarb and its metabolites. This rapid, convenient method would be an excellent screening tool for large numbers of water samples with the potential for application in other matrices, as illustrated by a study on lemonade.
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