【摘要】 目的比较适用于茶叶中毒死蜱测定的样品前处理方法。方法茶叶经过研磨后准确称取5.00 g,加入30 ml丙酮或乙酸乙酯,涡旋混匀,通过超声、浸泡后超声、振荡3种方式提取,提取液于40℃旋转蒸发至近干;再将提取液用3 ml丙酮∶二氯甲烷(1∶1体积比)分3次溶解(1 ml×3)后通过Carb/NH2柱净化,净化液用氮气吹至近干;最后,使用丙酮定容至1 ml。Rtx-1701石英毛细管色谱柱分离,GC-FPD测定,外标法定量。结果超声、浸泡和振荡提取的回收率分别为87.4%~111.7%、84.6%~106.8%和88.5%~107.8%,相对标准偏差(RSD)分别为5.94%~7.00%、6.18%~6.73%和6.30%~6.98%。结论 3种不同提取方法的回收率均满足实验要求,超声提取省时,浸泡过夜后超声提取节省人力,振荡提取经典,但不适用于大批量样品,实际工作中可根据具体情况选择。更多还原

【Abstract】 Objective To compare sample pretreatment methods about the determination of chlopyrifos in tea. Methods Tea samples were grounded and collected( 5. 00 g),adding 30 ml acetone or ethyl acetate to the samples,and then the samples were vortexmixed and extracted by ultrasound,soaking and ultrasound,and oscillation. The extract was rotarily evaporated to near dryness at 40 ℃,then dissolved in 3 ml of acetone: dichloromethane( 1∶1 by volume) for 3 times( 1 ml × 3) and then purified by a Carb/NH2 column and blown to nearly dry with nitrogen; finally,the residues were dissolved to constant volume 1 ml with acetone,and then separated with Rtx-1701 quartz capillary column,detected with GC-FPD,and external standard method was used for quantification. Results The recoveries of ultrasonic,soaking and oscillatory,oscillation were within87. 4%-111. 7%,84. 6%-106. 8% and 88. 5%-107. 8%,respectively. The relative standard deviations( RSDs) were within 5. 94%-7. 00%,6. 18%-6. 73% and 6. 30%-6. 98%,respectively. Conclusion The recovery rate of three different extraction methods all meet the requirement of experiment. Ultrasonic extraction saves time,soaking overnight after ultrasonic extraction save manpower,and oscillation extraction is classical,but not suitable for large quantities of samples. Actual work can be based on the specific circumstances of choice.更多还原