多壁碳纳米管固相萃取-气相色谱法测定蔬菜中甲氰菊酯农药的残留量
GC Determination of Residual Amount of Fenpropathrin in Vegetable with MWCNT′s-Solid Phase Extraction
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摘要: 蔬菜样品经乙腈提取,上清液蒸发至近干,加入正己烷溶解残渣后经多壁碳纳米管固相萃取柱(100 mg/6 mL)净化。以正己烷洗脱,收集流出液,蒸发至近干,加正己烷定容为5.00 mL,供气相色谱分析。分别用ZB-2和DB-5MS色谱柱进行分离,用电子捕获检测器进行检测。所得甲氰菊酯的线性范围为0.075~1.25 mg·L-1,用ZB-2和DB-5MS色谱柱的检出限(3S/N)分别为1.07,0.769 mg·kg-1。在0.075,0.25,1.00 mg·kg-1 3个添加水平下进行回收试验,甲氰菊酯的回收率在83.9%~103%之间,相对标准偏差(n=6)在0.60%~3.2%之间。Abstract: Sample of vegetable was extracted with acetonitrile, and the supernatant was taken and evaporated to near dryness. The residue was dissolved with n-hexane, and purified by passing through a column packed with 100 mg/6 mL of multiwall carbon nanotubes (MWCNT′s). The column was eluted with n-hexane. The eluate obtained was evaporated to near dryness and made up to 5.00 mL with n-hexane. The solution was used for GC analysis using either ZB-2 or DB-5MS chromatographic column for separation and ECD for detection. Linearity range of fenpropathrin was kept between 0.075-1.25 mg·L-1, with detection limits (3S/N) of 1.07 μg·kg-1 (with DB-5MS column) and 0.769 mg·kg-1 (with ZB-2 column). Tests for recovery and precision were tested by addition of 0.075, 0.25, 1.00 mg·kg-1 of standard solution, and analyzed by the proposed method, values of recovery obtained were in the range of 83.9%-103% and values of RSD′s (n=6) in the range of 0.60% -3.2%.