In the past few years, there has been increasing public
concern for food safety. This is because of the extensive
use of pesticides in agriculture. While pesticide use usually
increases agricultural productivity, accumulated pesticide
residues in treated plants present possible health risks to
consumers [1]. Toxicity and human health risk associated
with pesticide contamination in foods have made it necessary
to limit pesticide residues in our foods [2]. Detection
and quantification of pesticide residues in food samples are
essential to verify whether these pesticides are within
limits, the so-called ‘‘maximum residue limits (MRL)’’.
This regulation was established by the European Commission
and other regulatory authorities. Many developed
countries have adopted this regulation to oversee and
manage their food safety affair. However, in developing
countries such as Thailand, good agricultural practices are
not fully complied with.
Watermelon (Citrullus vulgaris Schrad.) is one of the
most common types of melons. Watermelon is a sweet,