Investigating the metabolic profiles of solid sample materials with solution nuclear magnetic resonance (NMR) spectroscopy requires the extraction of these metabolites. This is commonly done by using two immiscible solvents such as water and chloroform for extraction. Subsequent solvent removal makes these extraction procedures very time-consuming. To shorten the preparation time of the NMR sample, the following protocol is proposed: the metabolites from a solid or liquid sample are extracted directly in the NMR tube, the NMR tube is centrifuged, and the metabolite profiles in the aqueous and organic phases are determined by using slice-selective proton NMR experiments. This protocol was tested with 11 black teas and 11 green teas, which can be easily distinguished by their metabolic profiles in the aqueous phase. As a test case for liquid samples, 29 milk samples were investigated. The geographical origin of the diaries where the milk was processed could not be determined unequivocally from the metabolic profiles of the hydrophilic metabolites; however, this was easily seen in the lipid profiles. As shown for the different test samples, the extraction protocol in combination with slice-selection NMR experiments is suitable for metabolic investigations. Because samples are rapidly processed, this approach can be used to explore different extraction strategies for metabolite isolation.

中文翻译：

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NMR代谢组学的简单快速（提取）方案—使用切片选择直接测量亲水和疏水代谢物

用溶液核磁共振（NMR）光谱法研究固体样品材料的代谢特征需要提取这些代谢物。通常通过使用两种不混溶的溶剂（例如水和氯仿）进行萃取来完成。随后的溶剂去除使这些提取过程非常耗时。为了缩短NMR样品的制备时间，提出了以下方案：将固体或液体样品中的代谢物直接在NMR管中提取，将NMR管离心，并确定水相和有机相中的代谢物谱通过使用切片选择性质子NMR实验。用11种红茶和11种绿茶测试了该方案，可以很容易地通过它们在水相中的代谢曲线来区分它们。作为液体样品的测试用例，调查了29个牛奶样品。从亲水性代谢产物的代谢谱不能明确地确定加工牛奶的日记的地理起源；然而，这在血脂谱中很容易看出。如图所示，对于不同的测试样品，将提取方案与切片选择NMR实验结合起来适用于代谢研究。因为样品被快速处理，所以该方法可用于探索用于代谢物分离的不同提取策略。提取方案结合切片选择NMR实验适用于代谢研究。因为样品被快速处理，所以该方法可用于探索用于代谢物分离的不同提取策略。提取方案结合切片选择NMR实验适用于代谢研究。因为样品被快速处理，所以该方法可用于探索用于代谢物分离的不同提取策略。