A validated liquid chromatography–tandem mass spectrometry method was developed for the simultaneous determination of d- and l-amino acids in human serum. Under the optimum conditions, except for dl-proline, l-glutamine, and d-lysine, the enantioseparation of the other 19 enantiomeric pairs of proteinogenic amino acids and nonchiral glycine was achieved with a CROWNPAK CR-I(+) chiral column within 13 min. The lower limits of quantitation for l-amino acids (including glycine) and d-amino acids were 5–56.25 μM and 0.625–500 nM, respectively, in human serum. The intraday precision and interday precision for all the analytes were less than 15%, and the accuracy ranged from −12.84% to 12.37% at three quality control levels. The proposed method, exhibiting high rapidity, enantioresolution, and sensitivity, was successfully applied to the quantification of d- and l-amino acid levels in serum from hepatocellular carcinoma patients and healthy individuals. The serum concentrations of l-arginine, l-isoleucine, l-aspartate, l-tryptophan, l-alanine, l-methionine, l-serine, glycine, l-valine, l-leucine, l-phenylalanine, l-threonine, d-isoleucine, d-alanine, d-glutamate, d-glutamine, d-methionine, and d-threonine were significantly reduced in the hepatocellular carcinoma patients compared with the healthy individuals (P < 0.01). d-Glutamate and d-glutamine were identified as the most downregulated serum markers (fold change greater than 1.5), which deserves further attention in hepatocellular carcinoma research.

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开发了一种经过验证的液相色谱-串联质谱法，用于同时测定人血清中的d-和l-氨基酸。在最佳条件下，除了dl-脯氨酸，l-谷氨酰胺和d-赖氨酸外，其他13个对映异构对的蛋白原氨基酸和非手性甘氨酸的对映体分离均通过CROWNPAK CR-1（+）手性色谱柱在13内完成分钟 l-氨基酸（包括甘氨酸）和d的定量下限人血清中的α-氨基酸分别为5–56.25μM和0.625–500 nM。所有分析物的日内精密度和日间精密度均小于15％，在三个质量控制水平下，准确度范围为-12.84％至12.37％。所提出的方法具有快速，对映体拆分和灵敏度高的特点，已成功地用于肝细胞癌患者和健康个体血清中的d-和l-氨基酸含量的定量分析。的血清浓度升精氨酸，升-异亮氨酸，升-天冬氨酸，升-色氨酸，升丙氨酸，升-甲硫氨酸，升-丝氨酸，甘氨酸，升-缬氨酸，升-亮氨酸，升-苯丙氨酸，升-苏氨酸，d -异亮氨酸，d丙氨酸，d -谷氨酸，d谷氨酰胺，d -甲硫氨酸，和d -苏氨酸在肝细胞癌患者显著降低较健康个体（P <0.01）。d-谷氨酸和d-谷氨酰胺被认为是最下调的血清标志物（倍数变化大于1.5），在肝细胞癌研究中值得进一步关注。

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