以冰乙酸-乙腈溶液为萃取溶剂,采用乙二胺-N-丙基硅烷(PSA)、C18和石墨化炭黑固相材料分散净化技术,以气相色谱-电子捕获检测器测定银鱼中6种拟除虫菊酯类农药(联苯菊酯、甲氰菊酯、高效氯氟氰菊酯、氯氰菊酯、氰戊菊酯和溴氰菊酯).该方法在0.05~1.0 mg·L-1范围内呈线性关系.方法的检出限(3S/N):氯氰菊酯为0.02 mg·kg-1,其余5种拟除虫菊酯均为0.01 mg·kg-1.以银鱼试样为基体,加入两种不同浓度的6种拟除虫菊酯标准溶液作回收试验,测得回收率在82.9%~106.1%之间,相对标准偏差(n=6)在2.9%~7.1%之间.

Six pyrethroid pesticides,namely bifenthrin,fenpropathrin,cyhalothrin,cypermethrin,fenvalerate and deltamethrin,in whitebait were determined simultaneously by GC with ECD after separation by dispersive solid phase extraction (DSPE).Sample of whitebait was extracted homogeneously with glacial acetic acid-acetonitrile solution as dispersion agent.The extract obtained was purified by DSPE through cycle-shaking with ethylene diamine-N-propylsilane (PSA),C18 and graphitized carbon black.The supernatant was used for GC-ECD analysis.Linearity ranges found were in the same range of 0.05-1.0 mg·L-1 for the 6 pyrethroid pesticides.Detection limits (3S/N) of the method obtained were 0.01 mg·kg-1 for cypermethrin and 0.02 mg·kg-1 for the other 5 pyrethroid pesticides.Tests for recovery and precision were made by addition of standard solutions of the 6 pyrethroid pesticides with 2 different concentrations to whitebait sample which was then analyzed by the proposed method.Values of recovery obtained were in the range of 82.9%-106.1% and values of RSD′s (n=6) were in the range of 2.9%-7.1%.