糙米中毒死蜱残留量的气相色谱分析法

作者改进了有机磷农药毒死蜱在糙米中残留量的分析方法,探讨了提取条件、净化方法等对测定的影响。在分析条件下,本法的检出限为0.01ppm;当样品中毒死蜱残留量为0.1ppm时,变异系数为6.7％;对稻米样进行毒死蜱加标回收试验,其回收率为78.8～105.6％。

DETERMINATION OF CHLORPYRIFOS AS RESIDUE IN RICE BY GC

The study dealt with the determina-tion of chlorpyrifos as residue in rice.The results from extractions with severalextractants, such as methyl alcohol-water,acetone-water and acetone, werecompared. The effects of different clean-up columns on the determination werediscussed. The experiments showed thatthe four kinds of common organphos-phorus pesticides (feni-trothion, dimethoa-te, parathion and trichlorphr?n), whichare similar to chlorpyrifos to some extenthad different behavior in GC. The optimalconditions for the determination werefound as follows:chlorpyrifos was extract-ed from rice with acetone and then withbenzene, and finally transferred onto amagnesium silicate column and eluted withbenzene. The chlorpyrifos was determined by GCby using flame photometric detector.Thecorrelation coefficient of the standardcurve of peak heigh-weigh injected(from1 ng to 50 ng) was 0.9996; the detectionlimit was 0. 01 ppm; the relative standarddeviation was 6.7 %at 0.10 ppm of chlorpy-rifos in rice; the recovery of chlorpyrifoswas 78.8-106. 6% from rice samples in con-centration ranging 0.05 to 1.00 ppm in thedetermination of fortification standard.