毛细管电泳法测定水体中四环素类抗生素的基质效应及场放大进样技术的应用

比较了毛细管电泳（CE）和高效液相色谱（HPLC）技术对水体中4种四环素类抗生素（四环素、土霉素、金霉素及强力霉素）的分离效果。实验考察了水体的基质效应（pH值和水硬度）对分离的影响，优化了电泳条件，在压力进样模式（HDI）下，9.0 min内4种抗生素可达到基线分离，与HPLC相比，CE可以节省一半左右的分析时间。该方法具有良好的线性关系，检出限（LOD）在0.28~0.62 mg/L之间，迁移时间和峰面积的相对标准偏差（RSD）（n=6）分别为0.42%~0.56%及2.24%~2.95%；自来水和鱼塘水中加标回收率分别在96.3%~107.2%之间和87.1%~105.2%之间。此外，利用场放大电动进样（FASI）对目标物进行柱内预浓缩，检测灵敏度较HDI进样模式提高，LOD降至17.8~35.5 μg/L，迁移时间和峰面积的RSD（n=6）分别为0.85%~0.95%及1.69%~3.43%。CE具有样品前处理简单、分析速度快的特点，对环境水体中抗生素的检测具有明显的优势。

Matrix effect and application of field-amplified sample injection in the analysis of four tetracyclines in waters by capillary electrophoresis

The system abilities of two chromatographic techniques, capillary electrophoresis (CE) and high performance liquid chromatography (HPLC), were compared for the analysis of four tetracyclines (tetracycline, chlorotetracycline, oxytetracycline and doxycycline). The pH, concentration of background electrolyte (BGE) were optimized for the analysis of the standard mixture sample, meanwhile, the effects of separation voltage and water matrix (pH value and hardness) effects were investigated. In hydrodynamic injection (HDI) mode, a good quantitative linearity and baseline separation within 9.0 min were obtained for the four tetracyclines at the optimal conditions; the analytical time was about half of that of HPLC. The limits of detection (LODs) were in the range of 0.28-0.62 mg/L, and the relative standard deviations (RSDs) (n=6) of migration time and peak area were 0.42%-0.56% and 2.24%-2.95%, respectively. The obtained recoveries spiked in tap water and fishpond water were at the ranges of 96.3%-107.2% and 87.1%-105.2%, respectively. In addition, the stacking method, field-amplified sample injection (FASI), was employed to improve the sensitivity, and the LOD was down to the range of 17.8-35.5 μg/L. With FASI stacking, the RSDs (n=6) of migration time and peak area were 0.85%-0.95% and 1.69%-3.43%, respectively. Due to the advantages of simple sample pretreatment and fast speed, CE is promising in the analysis of the antibiotics in environmental water.