基于离子液体的单滴微萃取-毛细管电泳在线联用测定水体中3种溴酚类化合物

建立了基于离子液体的单滴微萃取-毛细管电泳联用测定溴酚类化合物的方法。考察了萃取剂种类与体积、萃取时间、有机溶剂、盐浓度及萃取温度对萃取效率的影响。确定了最佳萃取条件为:以1-丁基-3-甲基咪唑六氟磷酸盐(C₄MIM]PF₆])离子液体作为萃取剂,萃取时间为8 min,样品溶液中NaCl浓度为10%(质量分数),萃取温度为20 ℃。在最佳条件下,3种溴酚(4-溴酚、2,6-二溴酚和2,4,6-三溴酚)在1~100 mg/L范围内呈良好的线性关系,线性相关系数为0.9939~0.9988;检出限为0.3 mg/L (S/N=3);该方法对3种溴酚的富集倍数分别为115.8、327.0和569.8; 6次平行测定的相对标准偏差为5.21%~6.47%;对本地区自来水、河水和湖水的加标回收率为87.8%~96.7%。结果表明,该方法稳定可靠,适合于水体中溴酚类污染物的测定。

On-line coupling of ionic liquid-based single-drop microextraction and capillary electrophoresis for determination of three bromophenols in water samples

An ionic liquid-based single-drop microextraction (IL-SDME) procedure using IL as an extractant on-line coupled to capillary electrophoresis (CE) is proposed. The method is capable of quantifying trace amounts of bromophenols in water samples. The extraction parameters such as extraction solvent, extraction time, ionic liquid single-drop volume, ionic strength and organic solvent were systematically investigated. For the SDME of the three bromophenols, a C₄MIM]PF₆] microdrop was exposed for 8 min to the aqueous sample with 10% (w/w) NaCl and then was directly injected into a capillary column for analysis. Under the optimal conditions, good linear relationships were obtained in the concentration range of 1-100 mg/L with the correlation coefficients of 0.9939-0.9988 for the bromophenols. The detection limits of the three bromophenols were 0.3 mg/L. The RSDs of peak areas of the standards were 5.21%-6.47% (n=6). And the enrichment factors for the three bromophenols were 115.8, 327.0 and 569.8. The proposed method was applied to the determination of the three bromophenols in tap, river and lake waters with the recoveries of the three bromophenols in the range of 87.8%-96.7%. The method is suitable for the quantification of bromophenols in water samples.