Abstract:The fluorine content determination of worm nitrile for samples.LC/MS-MS（liquid mass spectrometry-mass spectrometry）method was used to determine fluorine content of nitrile，used the graphitized carbon as an adsorbent，purification of multi-walled carbon nanotubes.This method has high sensitivity，good repeatability，thoroughly completely separation effect，as well as good operability，suitable for the determination of fluorine worm cyanide residue content in vegetables.