A gas chromatography-tandem mass spectrometry (GC-MS/MS)
was established for the determination of
azocyclotin,
cyhexatin and
fenbutatin oxide residues in fruits and vegetables. Ethyl bromide magnesium in ether
solution and sodium tetraethylborate were used as the derivatization reagents
for
azocyclotin,
cyhexatin and
fenbutatin oxide are reported in this paper. Samples of fruits and vegetables were extracted
with hexane, and then a cleanup step using florisil SPE cartridge was applied. The
purified extract was derived by ethyl magnesium bromide and sodium
tetraethylborate, and then quantified by external standard method in multiple
reactions monitoring mode(MRM). Under the optimized conditions, the target
concentrations and peak areas were linearly correlated in the range of 0.01-2.00
mg/kg, and the correlation coefficients are greater than 0.99. Recovery studies
were carried out on spiked matrices (the representative sample of cabbage,
eggplant, potato, citrus and apple) with
azocyclotin,
cyhexatin and
fenbutatin oxide at spiking levels of 0.01、0.02、0.05 mg/kg. The mean recoveries were 76.2%-92.0%,
with relative standard deviations less than 8.5%. The response for the
derivatives of
azocyclotin and
cyhexatin by these two derivatization reagents were close, but the response for
the derivatives of
fenbutatin oxide by solution of sodium tetraethylborate in
water was about 1.69 times of ethyl
magnesium bromide in ether solution. The
response for the derivatives of
fenbutatin oxide by the solution of sodium tetraethylborate in water was 1.5-2.3 times
of ethyl magnesium bromide in ether solution. Organotin compounds were derived
by sodium tetraethylborate in water solution was more efficient, simple and
stable to meet the daily needs of laboratory testing.
