扫集-胶束电泳检测鱼塘水中季铵盐类除草剂

Determination of Quaternary Ammonium Herbicides in Pond Water by SPE with Sweeping-MEKC Method

鉴于农业生产中大量使用季铵盐类农药造成的环境水污染问题,本文应用固相萃取与扫集-胶束电泳(Sweeping-MEKC)相结合的方法分析鱼塘水中的百草枯、敌草快和野燕枯3种季铵盐类除草剂。考察了缓冲液的浓度、pH值、十二烷基磺酸钠(SDS)浓度、有机添加剂种类及浓度、分离电压及其进样时间等对分离检测的影响,优化的电泳分析条件为:缓冲液为pH2.6的50mmol/L磷酸盐缓冲液(含体积分数20%的乙腈),40mmol/L十二烷基磺酸钠,6.895kPa压力进样160s,分离电压为-22kV,紫外检测波长为198nm,柱温为20℃。含季铵盐除草剂的鱼塘水经过Oasis WCX固相萃取柱富集后在上述优化电泳条件下进行分析,百草枯、敌草快及野燕枯的检出限(LOD)(S/N=3)分别为0.07,0.05和0.02μg/L,线性范围分别为0.2~100、0.15~100和0.05~100μg/L;加样回收率为89.3%~107.1%,相对标准偏差为4.5%~11.4%。该方法灵敏度高,可实际应用于鱼塘水中季铵盐类除草剂农药残留分析。

As great quantities of quaternary ammonium herbicides were used in agricultural production. In this article, conditions have been optimized for simultaneous determination of paraquat （PQ）,diquat （DQ） and difenzoquat （DF）by sweeping-MEKC with diode array detector （DAD） after their preconcentration by solid phase extraction （SPE）. concentration of SDS and organic modifier, separation The influence of concentration of buffer, pH, voltage and injection time on the separation of quaternary ammonium herbicides were studied. An optimal separation condition was obtained by using background buffer containing 40 mmol/L SDS, 50 mmol/L NaH2PO4 and 20% acetonitrile at pH2.6 with 20℃ ,the separation voltage at -22 kV, the sample injection time for 160 s at 6.895 kPa and 198 nm detection. The calibration curves 0.15-100 μg/L for diquat and 0.05 showed good linearities in the range of 0.2-100μg/L for paraquat, PQ, DQ and DF were 0.07, 0.05 an quaternary ammonium herbicides range from 4.5% to 11.4%. The method can the agricultural pond water. 100 μg/L for difenzoquat, the limits of detections（S/N = 3）for d 0.02 μg/L respectively. The relative recoveries of the three d from 89.3% to 107.1% with relative standard deviation ranging be applied in the detection of quaternary ammonium herbicides in the agricultural pond water.