Marai L, Kuksis A
J Chromatogr. 1983 Oct 7;268(3):447-60. doi: 10.1016/s0021-9673(01)95443-3.
Methods are described for simultaneous quantitation of Krebs cycle and related acids by gas chromatography--mass spectrometry using deuterium-labelled acids and n-butyl-d9-esters of the organic acids as internal standards. Using sulphuric acid as esterification catalyst, only lactic, succinic, fumaric, malic, maleic and citric acids were found to be stable to hydrogen exchange and could be used as reference standards in the deuterated form. In contrast, pyruvic, oxalacetic, alpha-ketoglutaric and malonic acids were found to exchange their deuterium readily and could not be employed for this purpose. All the acids could be quantitated using n-butyl-d9-esters of reference organic acids as internal standards, following a separate preparation of the n-butyl derivatives of the unknown acids. The method is suitable for routine analysis of organic acids at the picogram level in perchloric acid extracts of tissues.
描述了通过气相色谱 - 质谱联用技术同时定量测定三羧酸循环及相关酸的方法，该方法使用氘标记的酸和有机酸的正丁基 - d9酯作为内标。以硫酸作为酯化催化剂时，发现只有乳酸、琥珀酸、富马酸、苹果酸、马来酸和柠檬酸对氢交换稳定，并且可以以氘代形式用作参考标准。相比之下，发现丙酮酸、草酰乙酸、α - 酮戊二酸和丙二酸很容易交换它们的氘，因此不能用于此目的。在分别制备未知酸的正丁基衍生物之后，所有的酸都可以使用参考有机酸的正丁基 - d9酯作为内标进行定量。该方法适用于组织高氯酸提取物中皮克水平有机酸的常规分析。
