Capillary electrophoresis with in-capillary solid-phase extraction sample cleanup.
Capillary electrophoresis with in-capillary solid-phase extraction sample cleanup.
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DOI：
10.1021/ac062159l
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发表时间：
2007-02
影响因子：
7.4
通讯作者：
Luohong Zhang;Xing-Zheng Wu
中科院分区：
文献类型：
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作者：
Luohong Zhang;Xing-Zheng Wu
建立了一种毛细管内固相萃取(SPE)-毛细管电泳（CE）方法，该方法不仅具有高的预富集系数，而且在实际复杂样品的毛细管内壁上不吸附。长约3mm的固相萃取吸附剂被填充在毛细管的入口端。在毛细管上的吸附剂后打开一个直径约为30微米的孔。样品溶液从入口端装入，样品废弃物从孔中流出。在样品加载一段时间后，从入口端引入一个1.5 mm长的甲醇塞，迫使其通过吸附剂和孔。然后，在孔和毛细管出口端之间施加分离电压，进行正常CE。在上样时间为120 min时，2,4-二氯酚和2,4,5-三氯酚的CE峰高与浓度成正比，在0.08 ~ 5 ng/mL范围内，检出限分别为25和17 pg/mL。对氯酚类化合物的CE检测灵敏度提高了16000倍，而CE的分离效率仅略有下降。以氯酚类和表面活性剂十六烷基三甲基溴化铵的混合物为对象，该方法可以消除样品加载过程中吸附物质在内壁上的吸附问题。将该方法直接应用于某河流下游水体中氯酚的测定，测定值为0.02 ppb，与离线hplc实验结果吻合较好。
An in-capillary, solid-phase extraction (SPE)-capillary electrophoresis (CE) method, with not only high preconcentration factor but also no adsorption on the inner capillary wall of absorbing species in real complex samples, has been developed with a hole-opened capillary. The SPE sorbents approximately 3 mm in length was packed in the inlet end of the capillary. A hole approximately 30 microm in diameter was opened after the sorbents on the capillary. Sample solutions were loaded from the inlet end, and the sample wastes flowed out from the hole. After a certain time of the sample loading, a 1.5-mm-long methanol plug was introduced from the inlet end and forced to pass by the sorbents and the hole. Then, a separation voltage was applied between the hole and the outlet end of the capillary to carry out normal CE. When the sample loading time was 120 min, CE peak heights of the 2,4-dichlorophenol and 2,4,5-trichlorophenol were proportional to their concentration in a range of 0.08-5 ng/mL, and their detection limits were 25 and 17 pg/mL, respectively. A 16,000-fold sensitivity enhancement was obtained for CE of the chlorophenols with only a little decrease in CE separation efficiency. It was also demonstrated with the mixture of the chlorophenols and a surfactant cetyltrimethylammonium bromide that the present method could eliminate the adsorption problem of absorbing species on the inner wall during sample loading. Furthermore, the SPE-CE was directly applied to determination of chlorophenols on the level of 0.02 ppb in downstream water of a river, and the results agreed well with those obtained with off-line SPE-HPLC experiments.