Determination of chlorpyrifos as a residue in rice by GC
Huang, W.; Zhang, J.Y.; Lu, C.H.; Hu, S.J.; Zhu, W.
Hua Xi Yi Ke da Xue Xue Bao 18(3): 262-264
1987
ISSN/ISBN: 0257-7712 PMID: 2445648 Document Number: 295995
The study dealt with the determination of chlorpyrifos as residue in rice. The results from extractions with several extractants, such as methyl alcohol-water, acetone-water and acetone, were compared. The effects of different cleanup columns on the determination were discussed. The experiments showed that the four kinds of common organophosphorus pesticides (feni-trothion, dimethoate, parathion and trichlorphon), which are similar to chlorpyrifos to some extent had different behavior in GC. The optimal conditions for the determination were found as follows: chlorpyrifos was extracted from rice with acetone and then with benzene, and finally transferred onto a magnesium silicate column and eluted with benzene. The chlorpyrifos was determined by GC by using flame photometric detector. The correlation coefficient of the standard curve of peak height-weight injected (from 1 ng to 50 ng) was 0.9996; the detection limit was 0.01 ppm; the relative standard deviation was 6.7% at 0.10 ppm of chlorpyrifos in rice; the recovery of chlorpyrifos was 78.8-106.6% from rice samples in concentration ranging 0.05 to 1.00 ppm in the determination of fortification standard.