Determination of dicamba residue in vegetables using high performance liquid chromatography-tandem mass spectrometry

An analytical method using high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was developed for analysis of dicamba residue in Chinese cabbage,cucumber,tomato,cowpea,white radish,celery and shallot.The sample was extracted with V( acetonitrile) : V (formic acid) : V (water)=49.5 :0.2 :0.3 and salted-out by sodium chloride.After that,the sample was concentrated by rotary evaporator.Seperation was performed on a C18 column with gradient elution by mobile phase of methanol and 5 mmol/L ammonium formate,and finally detected with negative-ion electrospray ionization-mass spectrometry (ESI-MS) under multiple reaction monitoring (MRM) mode.The results showed that the linearity of method for dicamba was in the concentration range of 0.005 to 0.5 mg/L with the correlation coefficients of 0.999 7.The mean spiked recoveries of dicamba at 3 spiked levels (0.01,0.05,0.1 mg/kg) ranged from 80% to 120% with relative standard deviations (RSD,n =3) of 0.58%-18%.The limit of detection was 2.0 μg/kg for dicamba.The method is rapid,sensitive and suitable for determination of dicamba in vegetables.