Abstract:

A new method using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for the analysis of six phenoxy acid herbicide residues in cereals has been developed. The optimized sample pretreatment procedure consisted of extraction with acetonitrile, acidification with acetic acid and cleanup before the analysis on a LC-ESIMS/MS instrument. Separated analytes were determined using multiple reaction monitoring (MRM). Quantitation was performed using external standard method. The proposed method displayed a detection limit between 0.005 and 0.01 mg/kg and good linearity over the range from 0.01 to 0.5 mg/L, with a r2 ＞ 0.99. At a spike level of 0.2 mg/kg, mean recoveries from rice ranged between 86.1% and 96.8% for different analytes. The method is simple, efficient and sensitive, and its each performance characteristic meets the requirements for the determination of phenoxy acid herbicide residues in cereasl at home and abroad.

Key words: phenoxy acid herbicides, cereal, liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS)