Fundamental Technology Labs., Institute for Innovation, Ajinomoto Co. Inc., 1-1, Kawasaki-shi 210-8681, Japan.
J Chromatogr B Analyt Technol Biomed Life Sci. 2011 Nov 1;879(29):3317-25. doi: 10.1016/j.jchromb.2011.07.025. Epub 2011 Aug 17.
A rapid and comprehensive analytical method for D- and L-enantiomers of proteinogenic amino acids was developed using ultra-high performance liquid chromatography (UHPLC) equipped with a circular dichroism (CD) detector. Pre-column derivatization reagents were examined for enhanced sensitivity and selectivity for UV and CD detection: 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was selected. The method, using a CD detector, does not require separation of optical isomers on a column to calculate the enantio ratio (%D) using the g-factor value and produces a simple chromatogram in comparison to other reported methods. Using this advantage, combined with UHPLC technology, analysis time for the derivatized proteinogenic amino acids was within 5.5 min. The UV detection limit was 4.9-23 pmol/injection and the CD detection limit was 11-64 pmol/injection. The method was applied to the analysis of D- and L-amino acids in food samples. D-Ala, D-Asp, D-Glu and D-Ser were detected at high concentrations in some Japanese black vinegars, fermented milks and yogurts. The results were identical to the results determined by the OPA method. We suggest the UHPLC-CD method would be useful in screening the D-amino acid content of foods and in helping to clarify the importance and reason for the presence of D-amino acids in foods.
建立了一种使用超高效液相色谱(UHPLC)和圆二色(CD)检测器快速分析蛋白质氨基酸对映异构体的综合分析方法。研究了柱前衍生试剂对 UV 和 CD 检测的灵敏度和选择性的增强作用:选择了 4-氟-7-硝基-2,1,3-苯并恶二唑(NBD-F)。与其他报道的方法相比,该方法使用 CD 检测器,无需在柱上分离光学异构体即可使用 g 因子值计算对映体比(%D),并产生简单的色谱图。利用这一优势,结合 UHPLC 技术,衍生化蛋白质氨基酸的分析时间在 5.5 分钟内。UV 检测限为 4.9-23 pmol/进样,CD 检测限为 11-64 pmol/进样。该方法应用于食品样品中 D-和 L-氨基酸的分析。在一些日本黑醋、发酵乳和酸奶中,高浓度检测到 D-Ala、D-Asp、D-Glu 和 D-Ser。结果与OPA 方法确定的结果相同。我们建议 UHPLC-CD 方法可用于筛选食品中 D-氨基酸的含量,并有助于阐明食品中 D-氨基酸的重要性和存在原因。