毛细管电泳结合压力辅助电动进样测定水样中4种酚类雌激素

在毛细管电泳的胶束电动色谱（MEKC）模式下，采用压力辅助电动进样（PAEKI）的进样方式在线富集4种酚类雌激素（PEs）。对影响PAEKI的进样电压、进样时间等进行考察，并与传统的压力进样比较。结果表明，在最优的PAEKI条件下（-9 kV，0.3 psi（约2.1 kPa），0.4 min），4种PEs在7 min内基线分离，线性关系良好，相关系数（r）大于0.9936，己烷雌酚和双烯雌酚的线性范围为0.05~5 mg/L、双酚A和己烯雌酚的线性范围为0.1~10 mg/L；检出限（S/N=3）为0.0071~0.017 mg/L，富集倍数为11~15。使用该MEKC-PAEKI法对自来水和湖水水样进行测定，得到定量限（S/N=10）分别为0.029~0.064 mg/L和0.033~0.079 mg/L；加标回收率为75.6%~110.1%，相对标准偏差（n=5）为4.6%~11.8%。PAEKI不需要使用其他试剂，只需对电泳仪的参数进行适当调整即可实现对分析物的在线富集，简单、快速、自动化程度高。

Determination of four phenolic estrogens in water samples by pressure-assisted electrokinetic injection coupled with capillary electrophoresis

A capillary electrophoresis (CE) method was developed for the simultaneous separation and determination of four phenolic estrogens (PEs), in which pressure-assisted electrokinetic injection (PAEKI) was adopted as the on-line concentration method to enrich the PEs. Several parameters affecting PAEKI conditions such as injection voltage and injection time, were systematically investigated and compared with the usual parameters. Under the optimized PAEKI conditions (-9 kV, 0.3 psi (ca. 2.1 kPa), 0.4 min), the four PEs separated completely within 7 min. Good linearities were attained in the range of 0.05-5 mg/L for hexestrol and dienestrol, and 0.1-10 mg/L for bisphenol A and diethylstilbestrol, with correlation coefficients (r) over 0.9936. The limits of detection (S/N=3) were 0.0071-0.017 mg/L, and enrichment factors ranged from 11 to 15 compared to normal hydrodynamic injection. The combined micellar electrokinetic chromatographic-PAEKI method developed was used to determine the PEs in tap water and lake water samples; limits of quantification (S/N=10) of 0.029-0.064 mg/L and 0.033-0.079 mg/L were attained, respectively, by the two sample types. Furthermore, recoveries ranged from 75.6% to 110.1% with relative standard deviations (n=5) within 4.6%-11.8%. To use this PAEKI method, researchers would only need to adjust the parameters of the CE apparatus to perform on-line enrichment of analytes, without using other reagents; this demonstrates the simplicity, rapidity, and highly automated nature of this method.