Thermal Degradation of Small Molecules: A Global Metabolomic Investigation.
Thermal Degradation of Small Molecules: A Global Metabolomic Investigation.
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DOI：
10.1021/acs.analchem.5b03003
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发表时间：
2015-11-03
影响因子：
7.4
通讯作者：
Siuzdak G
中科院分区：
文献类型：
--
作者：
Fang M;Ivanisevic J;Benton HP;Johnson CH;Patti GJ;Hoang LT;Uritboonthai W;Kurczy ME;Siuzdak G
热过程被广泛应用于小分子化学分析和代谢组学中的衍生化、汽化、层析和电离，特别是在气相色谱-质谱仪(GC/MS)中。本研究考察了加热对小分子标准品的影响，并分别考察了加热对人血浆代谢产物提取物的影响。这些样品，无论是衍生的还是未衍生的，在三个不同的温度(60,100和250°C)下，在不同的暴露时间(30 S，60 S和300 S)下加热。所有样品均采用高效液相色谱-电喷雾电离质谱仪(LC/MS)联用，用XCMS Online()进行数据处理。结果表明，100℃的升温对未衍生化和衍生的分子都有明显的影响，而250℃的升温会使图谱发生很大的变化。例如，在血浆代谢物分析中，超过40%的分子峰在加热(250°C，300s)后发生变化，并形成显著的降解和转化产物。小分子标准的分析证实了观察到的血浆代谢物随温度的变化，其中大多数小分子在高温下降解，即使在最小暴露时间后(S 30次)。例如，三重和二重有机磷(例如，三磷酸腺苷和二磷酸腺苷)在加热过程中很容易降解为单有机磷(例如，一磷酸腺苷)。核苷和核苷酸(例如肌苷和肌苷一磷酸)也被发现转化为嘌呤衍生物(例如次黄嘌呤)。在血浆提取物和小分子标准混合物的未衍生化和衍生化形式中都发现了新形成的转化产物油酰乙胺，可能是由油酸生成的。总体而言，这些分析表明，小分子和代谢物在暴露于高温下时会发生显著的时间敏感变化，特别是那些模拟GC/MS实验中的样品制备和分析的条件。
Thermal processes are widely used in small molecule chemical analysis and metabolomics for derivatization, vaporization, chromatography, and ionization, especially in gas chromatography mass spectrometry (GC/MS). In this study the effect of heating was examined on a set of 64 small molecule standards and, separately, on human plasma metabolite extracts. The samples, either derivatized or underivatized, were heated at three different temperatures (60, 100, and 250 °C) at different exposure times (30 s, 60 s, and 300 s). All the samples were analyzed by liquid chromatography coupled to electrospray ionization mass spectrometry (LC/MS) and the data processed by XCMS Online (). The results showed that heating at an elevated temperature of 100 °C had an appreciable effect on both the underivatized and derivatized molecules, and heating at 250 °C created substantial changes in the profile. For example, over 40% of the molecular peaks were altered in the plasma metabolite analysis after heating (250 °C, 300s) with a significant formation of degradation and transformation products. The analysis of 64 small molecule standards validated the temperature-induced changes observed on the plasma metabolites, where most of the small molecules degraded at elevated temperatures even after minimal exposure times (30 s). For example, tri- and diorganophosphates (e.g., adenosine triphosphate and adenosine diphosphate) were readily degraded into a mono-organophosphate (e.g., adenosine monophosphate) during heating. Nucleosides and nucleotides (e.g., inosine and inosine monophosphate) were also found to be transformed into purine derivatives (e.g., hypoxanthine). A newly formed transformation product, oleoyl ethyl amide, was identified in both the underivatized and derivatized forms of the plasma extracts and small molecule standard mixture, and was likely generated from oleic acid. Overall these analyses show that small molecules and metabolites undergo significant time-sensitive alterations when exposed to elevated temperatures, especially those conditions that mimic sample preparation and analysis in GC/MS experiments.