摘要

C-13 isotopic abundance of intracellular free amino acid with a characteristic of fast-turnover can quickly reflect the changes in intracellular metabolic state. However, the concentration of intracellular free amino acid was low and the existed C-13 isotope detection method based on GC-MS could not satisfy the requirement with full scan mode. In this study, selected ion monitoring method with theoretically higher detection accuracy was used for the analysis of C-13 isotopic abundance of free intracellular amino acid. The fracture law of different amino acids was investigated by full scan mode, and also a characteristic fragment library for the 16 kinds of free intracellular amino acids was established. According to this characteristic fragment library, only the specific m/z signal was detected in the sample analysis, which realized the selected ion monitoring and improved the quality of signal. The results of amino acid standards indicated that, in comparison with the full scan mode, the signal-to-noise ratio (S/N), measurement precision and accuracy were improved by 17, 2 and 3.8 times, respectively. In the analysis of coenzyme Q(10) producing strains of samples, C-13 isotopic abundance of 8 kinds of free intracellular amino acids were successfully detected. This method was quite feasible for the detection of C-13 isotopic abundance of the intracellular free amino acids in cell metabolism research.