GC-MS Determination of Residual Amounts of 15 Phenoxy-Hydroxy-Acid Herbicides in Rice

GC-MS was applied to the determination of residual amounts of 15 phenoxy-hydroxy-acid herbicides in rice. The optimized conditions found were as follows:1 extraction solvent was acetonitrile; 2 derivative temperature was 30℃; 3 derivative time was 20 min; 4 purified extraction column was Carbon TPT column. PerkinElmer Elite-5MS capillary column was used for GC separation. The full-scanning mode and the multiple reaction monitoring mode were adopted in MS determination. Linearity ranges of the 15 phenoxy-hydroxy-acid herbicides were found between 0.02 mg·L^-1 and 1.00 mg·L^-1 with detection limits (3S/N) in the range of 0.001-0.006 mg·kg^-1. On the base of blank sample, test for recovery was made by standard addition method and values of recovery found were in the range of 80.3%-103%, with RSD's (n=5) in the range of 4.9%-9.8%.