A method for the determination of imidacloprid involving hydrolysis in
basic medium followed by gas chromatography-mass spectrometry and sel
ected ion monitoring was developed, The hydrolysis product which was e
xtracted with chloroform was found to be suitable for gas chromatograp
hic analysis, Further, clean-up is not necessary using the selected io
n monitoring mode, [H-2(10)]Anthracene was used as an internal standar
d, The applicable concentration range was 12.5-250.0 mu g kg(-1), the
detection limit was 2.5 mu g kg(-1) (98 pg) and the relative standard
deviation at the 125.0 mu g kg(-1) level was 0.7%, The method,vas appl
ied to the determination of the imidaclorpid in vegetable samples (tom
ato, cucumber, pepper and green beans). Recovery levels were between 9
4.3% and 105.8%.