Use of a structural analogue versus a stable isotope labeled internal standard for the quantification of angiotensin IV in rat brain dialysates using nano-liquid chromatography/tandem mass spectrometry
Use of a structural analogue versus a stable isotope labeled internal standard for the quantification of angiotensin IV in rat brain dialysates using nano-liquid chromatography/tandem mass spectrometry
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DOI：
10.1002/rcm.2950
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发表时间：
2007-01-01
影响因子：
2
通讯作者：
Michotte, Yvette
中科院分区：
文献类型：
--
作者：
Lanckmans, Katrien;Sarre, Sophie;Michotte, Yvette
定量微透析液中的低浓度神经肽需要一种选择性和灵敏的分析技术，如纳米液色谱/电喷雾电离串联质谱仪(NanoLC/ESI-MS/MS)。然而，我们观察到由于基质效应，该方法的准确性降低。事实上，电喷雾质谱检测对基质效应非常敏感。此外，透析液是小分子、多肽和其他基质化合物的复杂混合物，可以影响感兴趣神经肽的电离效率和样品中多肽的稳定性。在本文报道的这项研究中，我们调查了使用内标(IS)是否可以纠正这些基质效应。作为神经肽的模型化合物，我们使用血管紧张素IV(Ang IV)。我们比较了结构类似物(去甲亮氨酸-Ang IV)和稳定同位素标记(SIL)类似物的使用。无论采用哪种ISS方法，都能提高方法的线性度。只有使用sIL-IS，才能提高进样的重复性，提高方法的精密度和准确度。最后，两个ISS都能够纠正透析液中Ang IV的降解，延长了样品可能的保存期。我们的结论是，结构类似物不适合作为IS，在使用NanoLC/ESI-MS/MS检测透析液中的Ang IV时，sIL类似物的应用是必不可少的。版权所有(C)2007 John Wiley&Sons，Ltd.
Quantifying low concentrations of neuropeptides in microdialysates requires a selective and sensitive analysis technique, such as nano-liquid chromatography/electrospray ionization tandem mass spectrometry (nanoLC/ESI-MS/MS). However, we observed reduced accuracy of the method due to matrix effects. Indeed, ESI-MS detection is known to be sensitive to matrix effects. Moreover, dialysates are complex mixtures of small molecules, peptides and other matrix compounds that can influence the ionization efficiency of the neuropeptide of interest and the stability of the peptide in the samples. In the study reported in this paper, we investigated whether the use of an internal standard (IS) can correct for these matrix effects. As a model compound for neuropeptides we used angiotensin IV (Ang IV). We compared the use of a structural analogue (norleucinel-Ang IV) with a stable isotope labeled (SIL) analogue. Linearity of the method was improved when either of the proposed ISs were applied. Only when using the SIL-IS could the repeatability of injection and the method's precision and accuracy be improved. Finally, both ISs were able to correct for degradation of Ang IV in dialysates, prolonging the possible storage period of the samples. We conclude that the structural analogue is not suited as an IS and that the application of a SIL analogue is indispensable when quantifying Ang IV in dialysates using nanoLC/ESI-MS/MS detection. Copyright (c) 2007 John Wiley & Sons, Ltd.