Abstract: Gas chromatography-mass spectrometry was used to determine thiocyanate residues in dairy products (mainly liquid milk and milk powder). Samples were extracted by shaking before derivatization based on the replacement reaction of pentafluorobenzyl bromide with thiocyanate. The derivatization products were separated using a high-speed refrigerated centrifuge and scanned in the selected ion monitoring mode. Thiocyanate was qualified based on retention time and ion abundance ratio and quantified by external standard method. High recovery, sensitivity, accuracy and reproducibility were found in the quantitative range of 0.02－50.0 mg/kg. The method was characterized by simple pretreatment, easy operation, low cost and time saving, and applicable for the rapid determination of thiocyanate residues in dairy products.

Key words: thiocyanate, derivatization, gas chromatography-spectrometry (GC-MS), dairy products