气相色谱-质谱法测定陈皮及其制品中的三氯杀螨醇和拟除虫菊酯残留量

GC-MS Determination of Residual Amounts of Dicofol and Pyrethroids in Dried Orange Peel and Its Products

样品2.000 0g,加水2mL或4mL浸润,再加入乙酸乙酯-正己烷(1+1)混合液5mL,超声5min,提取2次。合并的提取液吹干,残渣用乙酸乙酯-正己烷(1+1)混合液2mL溶解,经被氧化的改性多壁碳纳米管净化后,其中的三氯杀螨醇和8种拟除虫菊酯农药采用气相色谱-质谱法测定。以Rtx-1701毛细管色谱柱为固定相进行气相色谱分离。质谱分析中采用选择离子监测模式,外标法定量。9种农药的质量浓度在0.010~1.0mg·L^(-1)内与其峰面积呈线性关系,检出限(3S/N)在3.5~6.0μg·kg^(-1)之间。按标准加入法在3个浓度水平上进行回收试验,回收率在84.8%~105%之间,测定值的相对标准偏差(n=6)在3.1%~8.2%之间。

The sample （2. 000 0 g） was soaked with water （2 mL or 4 mL）, and then was extracted ultrasonically twice, with 5 mL of a mixture of ethyl acetate and hexane （1 ＋1） for 5 rain. The combined extract was dried by blowing, and the residue was dissolved with 2 mL of a mixture of ethyl acetate and hexane （1＋1）. After the solution was purified by oxidization modified multi-walled carbon nanotubes （MWNTs）, dicofol and 8 pyrethroid pesticides in the sample were determined by GC-MS. Rtx-1701 capillary column was used as stationary phase for gas chromatography separation. SIM was adopted in MS, and external standard method was used for quantification. Linear relationships between values of peak area and mass concentration of 9 pesticides were found in the range of 0. 010--1.0 mg · L-1 , with detection limits （3S/N） in the range of 3. 5--6.0 μg · kg^- 1. Test for recovery was made by standard addition at 3 concentration levels, giving results in the range of 84. 8%- 105%, with RSDs （n=6） ranged from 3.1% to 8. 2%.