Chip-based capillary electrophoresis/mass spectrometry determination of carnitines in human urine
Chip-based capillary electrophoresis/mass spectrometry determination of carnitines in human urine
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DOI：
10.1021/ac0009346
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发表时间：
2001-02-01
影响因子：
7.4
通讯作者：
Harrison, DJ
中科院分区：
文献类型：
--
作者：
Deng, YZ;Henion, J;Harrison, DJ
描述了一种基于芯片的毛细管电泳/质谱（CE/MS）系统，用于从分析标准品和强化人尿提取物的混合物中对肉碱和选定的酰基肉碱进行CE分离和在线电喷雾检测。基于芯片的CE/MS实验有两种不同。实验室分别使用三台四极杆质谱仪和一台四极杆飞行时间质谱仪进行实验。两种系统使用的玻璃芯片都配备了微加工毛细管电泳（CE）通道，但使用了不同的电喷雾器。基于四极杆芯片的CE/MS实验采用微型耦合微喷雾器，通过CE毛细管通道出口的微液体结实现微电喷雾过程的耦合。所有四极CE/MS工作均采用选定的离子监测（SIM） CE/MS实验。QTOF CE/MS全扫描单质谱和MS/MS实验在另一实验室进行，采用精确的质量测量TOF质谱技术。QTOF系统所采用的电喷雾工艺的不同之处在于，插入的纳米电喷雾毛细管针被小心地贴在与CE通道出口孔对齐的帽底孔中。使用所述四极杆系统的SIM CE/MS提供了手动注入（加载）到芯片上的左旋肉碱和酰基左旋肉碱分析标准溶液的fmol水平的可接受的离子电流电泳图。此外，通过SIM CE/MS技术获得了在10-20杯/mL （35-124 muM）水平下添加了目标肉碱和酰基肉碱的人尿液的相应电泳图。SIM CE/MS电泳图的CE分离效率为2860个plates（峰宽半高法或N = 5.54 (T/W0.5(2))），肉碱和3个酰基肉碱在不到48 s的时间内被分离。相反，使用四极- tof技术，相同的样品可以被稀释2-4倍，以获得对目标化合物的类似检测器响应。在全扫描、单质谱仪模式（m/z 150-500）下，CE分离效率为2600板，但对季阳离子的质量测量精度小于5.0 ppm。在CE/MS/MS模式下，获得的全扫描碰撞诱导解离（CID）质谱，高质量离子的质量精度小于等于10 ppm，低质量产物离子的质量精度小于等于27 ppm。这些结果证明了芯片上CE分离和电喷雾质谱检测在合成混合物和人类尿液提取物中这些重要化合物的可行性。
A chip-based capillary electrophoresis/mass spectrometry (CE/MS) system is described for the CE separation and on-line electrospray detection of carnitine and selected acylcarnitines from mixtures of analytical standards as well as extracts of fortified human urine. Chip-based CE/MS experiments in two different. laboratories were carried out using a triple-quadrupole mass spectrometer and a quadrupole time-of-flight (QTOF) mass spectrometer, respectively. The glass chips used with both systems were comparably equipped with a microfabricated capillary electrophoresis (CE) channel but with different electro sprayers. The quadrupole chip-based CE/MS experiments employed a miniature coupled microsprayer, which allowed coupling of the microelectrospray process via a micro liquid junction at the exit of the CE capillary channel. Selected ion monitoring (SIM) CE/MS experiments were employed for all of the quadrupole CE/MS work. The QTOF CE/MS full-scan single MS and MS/MS experiments were carried out in another laboratory using accurate mass measurement TOF mass spectrometry techniques. The electrospray process that was employed with the QTOF system differed in that an inserted nano-electrospray capillary needle was carefully affixed into a hat-bottomed hole that was aligned with the CE channel exit orifice. SIM CE/MS using the described quadrupole system provided acceptable ion current electropherograms from fmole levels from analytical standard solutions of carnitine and acylcarnitines that were manually injected (loaded) onto the chip. In addition, the corresponding electropherograms for human urine fortified with the target carnitine and acylcarnitines at a 10-20 mug/mL (35-124 muM) level were obtained via SIM CE/MS techniques. The measured CE separation efficiency for the SIM CE/MS electropherograms was determined to be 2860 plates (peak width at half-height method or N = 5.54 (T/W0.5(2)), and carnitine and three acylcarnitines were separated in less than 48 s, In contrast, using quadrupole-TOF technologies, the same samples could be diluted by a factor of 2-4 to obtain a comparable detector response for the target compounds. In the full-scan, single mass analyzer mode (m/z 150-500), the CE separation efficiency was measured to be 2600 plates, but mass measurement accuracy was less than 5.0 ppm for the quaternary cations, In the CE/MS/MS mode, full-scan collision-induced dissociation (CID) mass spectra were obtained with a mass accuracy of less than or equal to 10 ppm for the higher mass ions and less than or equal to 27 ppm for the lower mass product ions. These results demonstrate the feasibility for on-chip CE separation and electrospray mass spectrometric detection for these important compounds in synthetic mixtures, as well as in human urine extracts.