Abstract:

A method for simple and rapid determination of azocylotin, cyhexatin, triphenyltin hydroxide and fenbutatin
oxide pesticide residues in livestock and poultry meat was developed by sodium tetraethylborate derivatization and gas
chromatography coupled to tandem mass spectrometry (GC-MS/MS). Samples were extracted with 1% formic acidacetonitrile,
and then the extract was ethylated by sodium tetraethylborate, and cleaned up on a florisil SPE column.using
an eluant composed of n-hexane and acetone (99:1, V/V). The pesticide residues were separated on an HP-5MS capillary
column, and finally analyzed by GC-MS/MS with selected reaction monitoring (SRM) mode. The fragmentation pathways and
mechanisms of the ethylated derivatives of 3 pesticides were discussed. The results showed that under optimized conditions, a
good linear relationship was observed within the concentration range of 20～500 μg/L for cyhexatin and triphenyltin, and 20～200
μg/L for fenbutatin oxide, with correlation coefficients greater than 0.997. The average recoveries from the representative sample
matrices of chicken and pork spiked at concentration levels of 0.03 and 0.10 mg/kg, were 82.4%?109.6%, with the relative
standard derivations (RSD) ranging from 4.1% to 8.9%. The limits of quantification (LOQs) of the proposed method for cyhexatin,
triphenyltin hydroxide and fenbutatin oxide were 0.01, 0.01 and 0.02 mg/kg, respectively.

Key words: sodium tetraethylborate (NaBEt4), gas chromatography-tandem mass spectrometry (GC-MS/MS), azocylotin, cyhexatin, triphenyltin hydroxide, fenbutatin oxide, livestock and poultry meat