α-Amino acids are present in two opposite configurations due to the presence of a central carbon atom which is a chiral center. While l-amino acids are present in large amount in nature, only tiny quantities of their d-enantiomers exist. For a long time, d-amino acids have been considered of bacterial origin only, but recently we realized that they are present in all living organisms: notably, d-amino acids play specific and relevant functions in the different organisms. Detection and quantification of d-amino acids are mandatory to shed light on their physiological roles, especially related to foods and human health. Chromatographic techniques are among the most commonly used analytical methods for the enantioseparation of amino acids. Here, we revised the latest improvements in chromatographic direct methodologies based on chiral selectors and aimed to improve analytical speed, sensitivity, robustness, and reproducibility. While current methods are well suited for d-amino acid analysis in foodstuffs and pharmaceuticals, further improvements seem required for their simultaneous, fast and sensitive detection in biological fluids, an emerging field since d-amino acids have been proposed as biomarkers of different and relevant human pathologic states.

中文翻译：

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用于氨基酸对映拆分的直接色谱方法：最新进展。

由于存在作为手性中心的中心碳原子，α-氨基酸以两种相反的构型存在。虽然自然界中大量存在1-氨基酸，但仅存在少量的它们的d-对映体。长期以来，d-氨基酸仅被认为是细菌起源的，但是最近我们意识到它们存在于所有活生物体中：值得注意的是，d-氨基酸在不同生物体中发挥特定和相关的功能。d的检测和定量-氨基酸必须阐明其生理作用，尤其是与食品和人类健康有关的生理作用。色谱技术是氨基酸对映体分离最常用的分析方法之一。在此，我们修订了基于手性选择剂的色谱直接方法的最新改进，旨在提高分析速度，灵敏度，鲁棒性和重现性。尽管当前的方法非常适合食品和药品中的d-氨基酸分析，但似乎需要对它们进行同时，快速和灵敏的生物流体检测进行进一步的改进，这是一个新兴的领域，因为d-氨基酸已被提议作为不同和相关的生物标志物人类病理状态。