ABSTRACT
Organophosphate pesticides (OPPs) are involved in
human poisoning more frequently than any other
group of pesticides. They were developed in Germany
during World War II as substitutes for nicotine to
control aphids. The first compound synthesized was
tetraethylpyrophosphate (TEPP), which was an effec-
tive insecticide but unsuitable for agriculture because
of its high toxicity to mammals and propensity for
rapid degradation. The problem of its inadequate
chemical properties was partially resolved by the
introduction of parathion and its oxygen analog,
paraoxon. In subsequent years, parathion became
one of the most widely used organophosphorus
insecticides in the world (1). OPPs have been used extensively for agricultural
purposes for more than 50 years, providing well-
characterized and cost-effective treatments in a
wide range of crops. There are more than 200
different OPPs available in the marketplace account-
ing for 45% of the registered pesticides in the
USA and around 50% in the European Union
(EU) (2). Since 1997 the use of OPPs has declined. This
trend is likely to continue as their use is better
targeted, manufacturers rationalize commercial strate-
gies, and increasing legislation takes effect. However,
they continue playing a major role in crop protection
and still have a 24% share of the world insecticide
market. The primary uses of OPPs are on horticultural
crops, especially field vegetables where these products
are applied extensively (3). The widespread application of OPPs gives ample
possibilities for them to come into contact with the
environment, man, and animals, either incidentally or
intentionally, acutely or chronically, depending on
their use, their persistence, and their migrating pro-
perties. When their residues remain in food after
application on crops or reach the food, through
environmental pathways, chronic oral exposure of
humans can be expected constituting an important
risk for human health (1,4). All pesticides are subject to regulations that require
their registration for being stored, sold, supplied, and
used. These regulations included the establishment of
maximum residue limits (MRLs), which are set on the
basis of supervised field trials using pesticide applica-
tions in accordance with ‘‘good agricultural practices’’
(GAPs). Therefore, to ensure that MRLs are unlikely to be
exceeded, thus minimizing the exposure of consu-
mers to harmful or unnecessary intakes of pesticides,
regular determination of their residues in food is
required (2,3). Residue analysis methods should be extensively
validated and should provide low detection limits
and the best available precision and accuracy. At the
same time they must be simple and rapid, providing
quick analysis of complex foods (5). The aim of this
chapter is to examine critically the existing methodol-
ogies and techniques, including residue extraction,
cleanup, determination, and general methods of evaluation for OPPs analysis in food.
