Halvorsen T G, Pedersen-Bjergaard S, Rasmussen K E
School of Pharmacy, University of Oslo, Norway.
J Chromatogr A. 2001 Feb 9;909(1):87-93. doi: 10.1016/s0021-9673(00)00868-2.
A newly developed disposable device for liquid-phase microextraction (LPME) was evaluated for the capillary electrophoresis (CE) of the antidepressant drug citalopram (CIT) and its main metabolite N-desmethylcitalopram (DCIT) in human plasma. CIT and DCIT were extracted from 1 ml plasma samples through hexyl ether immobilised in the pores of a porous polypropylene hollow fibre and into 25 microl of 20 mM phosphate buffer (pH 2.75) present inside the hollow fibre (acceptor phase). Prior to extraction, the samples were made strongly alkaline in order to promote LPME of the basic drugs. Owing to the high ratio between the volumes of sample and acceptor phase, and owing to high partition coefficients, CIT and DCIT were enriched by a factor of 25 to 30. In addition, sample clean-up occurred during LPME since salts, proteins and the majority of endogenic substances were unable to penetrate the hexyl ether layer. Since the extracts were aqueous, they were injected directly into the CE instrument. Limits of quantification (S/N= 10) for CIT and DCIT in plasma were 16.5 ng/ml and 18 ng/ml respectively, while the limits of detection (S/N=3) were 5 ng/ml and 5.5 ng/ml respectively. This enabled CIT (and DCIT) to be analysed within the therapeutic range by LPME-CE and detection limits were comparable with previously reported HPLC methods.
一种新开发的用于液相微萃取（LPME）的一次性装置，用于人血浆中抗抑郁药物西酞普兰（CIT）及其主要代谢物N-去甲基西酞普兰（DCIT）的毛细管电泳（CE）分析。CIT和DCIT从1 ml血浆样品中通过固定在多孔聚丙烯中空纤维孔中的己基醚进行萃取，并进入中空纤维内部存在的25 μl 20 mM磷酸盐缓冲液（pH 2.75）（接受相）中。在萃取之前，将样品调至强碱性以促进碱性药物的LPME。由于样品和接受相的体积比很高，且分配系数也很高，CIT和DCIT的富集倍数为25至30。此外，在LPME过程中发生了样品净化，因为盐、蛋白质和大多数内源性物质无法穿透己基醚层。由于提取物是水性的，它们被直接注入CE仪器中。血浆中CIT和DCIT的定量限（S/N = 10）分别为16.5 ng/ml和18 ng/ml，而检测限（S/N = 3）分别为5 ng/ml和5.5 ng/ml。这使得通过LPME-CE能够在治疗范围内分析CIT（和DCIT），并且检测限与先前报道的HPLC方法相当。
