Evaluation of free amino acids (FAAs) and nucleotides in various food matrices has been a widely studied topic in recent years. Here, a fast and efficient strategy for the simultaneous analysis of 20 FAAs and six 5′-nucleotides, using stable isotope labeling-liquid chromatography coupled with tandem mass spectrometry (SIL-LC-MS/MS) is proposed. The method was validated with respect to selectivity, linearity, limits of detection (LOD) and quantification (LOQ), recovery, precision, and stability. LOQs of most FFAs were lower than 1 ng/mL, and 5′-nucleotides were in the range of 5–20 ng/mL. FAAs and 5′-nucleotides in ten shiitake mushrooms from different cultivate areas were further analyzed. Results showed that the contents of cytidine 5′-monophosphate, adenosine 5′-monophosphate, lysine, threonine, arginine were significantly different. Principal component analysis showed clear discrimination of origins, seasons and species. Thus, the proposed method is suitable for the fast discrimination of species and geographical origins of shiitake mushrooms.

近年来，各种食品基质中游离氨基酸（FAA）和核苷酸的评估已成为广泛研究的话题。在此，提出了使用稳定同位素标记液相色谱-串联质谱（SIL-LC-MS / MS）同时分析20种FAA和6种5'-核苷酸的快速有效策略。该方法在选择性，线性，检测限（LOD）和定量（LOQ），回收率，精密度和稳定性方面均得到验证。大多数FFA的LOQ低于1 ng / mL，5'核苷酸的范围为5-20 ng / mL。进一步分析了来自不同栽培区的十个香菇中的FAAs和5'-核苷酸。结果表明，胞苷5'-单磷酸，腺苷5'-单磷酸，赖氨酸，苏氨酸，精氨酸的含量存在显着差异。主成分分析表明对来源，季节和物种有明显的区分。因此，所提出的方法适用于快速区分香菇的种类和地理起源。