Immunoassays are powerful tools when applied to the detection of pesti
cides, Immunochemical methods are a rapid and cost effective companion
to traditional chromatographic methods, A competitive enzyme-linked i
mmunosorbent assay for the quantitation of chlorpyrifos using antibody
bound to a magnetic particle solid phase is described, The immunoassa
y is applied to a variety of environmental samples including water, ai
r, and crop matrices, Water samples require no sample preparation wher
eas application to other matrices requires some preparation, e.g., ext
raction, clean-up, and dilution, Each matrix presents particular chall
enges when applying an immunochemical technique, The performance of th
e method meets the guidelines of the Environmental Protection Agency O
ffice of Prevention, Pesticide, and Toxic Substances and is comparable
with chromatographic methods.