Development of an enzyme-linked immunosorbent assay to carbaryl. 2. Assay optimization and application to the analysis of water samples
1997
Abad, A. | Montoya, A.
The effect of several physicochemical factors on the analytical characteristics of an immunoassay to carbaryl has been studied and this information used to optimize the assay. The immunoassay is based on the LIB-CNH36 monoclonal antibody (MAb) and employs a heterologous coating conjugate. The optimized enzyme-linked immunosorbent assay (ELISA), performed in a high salt concentration buffer with bovine serum albumin instead of Tween 20, has a carbaryl I50 of 0.058 ppb and a detection limit of 0.010 ppb, which means a 4-fold improvement in the assay sensitivity with respect to the nonoptimized conditions. The assay proved to be very specific for carbaryl since not even 1-naphthol, the main carbaryl metabolite, was recognized. Water samples with very different conductivities were spiked with carbaryl at 0.05, 0.1, and 0.5 ppb and directly analyzed by the developed ELISA. The mean recovery was 112%, and the mean coefficient of variation was 10.7%, which proves the suitability of the method to determine carbaryl in waters at such low levels.
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