| A simple, rapid and sensitive spectrofluorimetric
method was developed for the determination of disyston,
ethion and phorate in environmental water samples.
The procedure is based on the oxidation of these pesticides
with cerium (IV) to produce cerium (III), and its fluorescence
was monitored at 368 ± 3 nm after excitation at
257 ± 3 nm. The variables effecting oxidation of each
pesticide were studied and optimized. Under the experimental
conditions used, the calibration graphs were linear
over the range 0.2–15, 0.1–13, 0.1–13 ng mL-1 for disyston,
ethion and phorate, respectively. The limit of
detection and quantification were in the range 0.034–0.096
and 0.112–0.316 ng mL-1, respectively. Intra- and interday
assay precisions, expressed as the relative standard
deviation (RSD), were lower than 5.2 % and 6.7 %,
respectively. Good recoveries in the range 86 %–108 %
were obtained for spiked water samples. The proposed
method was applied to the determination of studied pesticides
in environmental water samples. |