Enzyme Inhibition and Enzyme-Linked Immunosorbent Assay Methods for Carbamate Pesticide Residue Analysis in Fresh Produce

Abstract

An acetylcholinesterase inhibition method was employed for detection of 21 carbamate pesticides in bananas, peaches, strawberries, and tomatoes. Each of these four agricultural commodities was spiked with 0.1 to 10 ppm of each of the 21 carbamates and individual detection levels were determined. Similar responses and detection limits were observed for all four produce when tested for a given carbamate. The detection levels ranged from 0.1 ppm for carbofuran and 3-hydroxycarbofuran to 6 ppm for promecarb and aldicarb sulfoxide. These results are generally at or below the tolerances established by the Environmental Protection Agency for these commodities. Positive samples from the enzyme inhibition screening were also analyzed with the carbaryl-specific enzyme-linked immunosorbent assay (ELISA) kit. The detection limits for carbaryl and carbofuran were 2.0 ppb and 8.0 ppb, respectively. The other carbamates did not exhibit cross-reactivity even at high ppb levels. Thus, the enzyme inhibition assay and ELISA are simple and fast screening procedures for the detection of carbamate pesticide residues in food commodities.