Large volume sample stacking of cationic tetracycline antibiotics toward 10 ppb level analysis by capillary electrophoresis with UV detection
Large volume sample stacking of cationic tetracycline antibiotics toward 10 ppb level analysis by capillary electrophoresis with UV detection
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DOI：
10.1002/elps.201600189
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发表时间：
2016-11
期刊：
影响因子：
2.9
通讯作者：
Xingyi Wu;Zhongqi Xu;Zhuoer Huang;Chaoying Shao
中科院分区：
文献类型：
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作者：
Xingyi Wu;Zhongqi Xu;Zhuoer Huang;Chaoying Shao
本文旨在建立一种在常规紫外检测下分析四环素类抗生素（包括四环素、氯四环素、土霉素和强力霉素）的灵敏CE方法。在这里，采用大体积样品堆积来实现目标的毛细管预富集。为了实现大体积的样品堆积，必不可少的步骤是将大体积的样品（从进口到检测窗口的毛细总长度的83.3%左右）进行水动力加载。然后，增加预留电压以将样品基质推出毛细管。由于样品溶液（pH 4.6）和BGE （pH 11.0）的pH值不同，当样品基质从毛细管中移除时，阳离子tc会变成负电荷。最后，阴离子tc被堆放在入口，用于随后的分离。虽然在电荷转化过程中存在样品损失，但lod比常规流体动力注入CE法提高了40倍左右。结果表明，lod范围为8.1 ~ 14.5 μg/L，约为10 ppb，接近电化学发光或激光诱导荧光检测TCs的水平。偏移次数和峰面积的rsd分别为0.19 ~ 0.24%和0.97 ~ 2.54%。在自来水中添加TCs，回收率在95 ~ 112%之间。该方法简便、快速、灵敏，可用于TCs的定量分析。
This paper aimed to build up a sensitive CE method for the analysis of tetracyclines (TCs) antibiotics (including tetracycline, chlorotetracycline, oxytetracycline, and doxycycline) with conventional UV detection. Here, the large volume sample stacking was applied to achieve in capillary preconcentration of the targets. To achieve large volume sample stacking, the essential step was a large volume of sample (around 83.3% of total capillary length from inlet to detection window) hydrodynamically loaded. Then, the reserved voltage was added in order to push the sample matrix out of the capillary. Due to different pH between sample solution (pH 4.6) and BGE (pH 11.0), the cationic TCs would turn into negatively charged while the sample matrix was removing from the capillary. Finally, the anionic TCs were stacked at the inlet for the subsequent separation. Although the loss of sample existed during their charge transformation, the LODs could be improved around 40 times than that obtained by normal hydrodynamic injection CE method. Here, the LODs were in the range of 8.1–14.5 μg/L, around 10 ppb that close to the level by electrochemiluminescence or laser‐induced fluorescence detection of TCs by CE. The precision was characterized by RSDs of migration times and peak areas, which were in the range of 0.19–0.24% and 0.97–2.54%, respectively. The recoveries of the developed method were in the range of 95–112% by spiking TCs in the tap water. The proposed inline preconcentration CE method could be a simple, speed, and sensitive method for the quantitative analysis of TCs.