On-spot fixed-charge derivatization has been suggested for the modification of α-amino acids for their analysis by thin layer chromatography/matrix-assisted laser desorption ionization (TLC/MALDI) mass spectrometry. The approach was based on post-chromatographic treatment of separated analytes by tris(2,6-dimethoxyphenyl)methenium salt and triethylamine. The reaction proceeded smoothly in mild conditions and gave rise to pink-red colored derivatives, containing permanent positive charge. Their MALDI mass spectra, recorded directly from TLC plates, revealed intense peaks corresponding to decarboxylated cationic parts. All derivatives are characterized by high ionization efficiency, which indicates the high sensitivity of the developed method for analyzing amino acids. Applicability of the method to analysis of amino acids was demonstrated on artificial mixtures and dietary supplement.

对于薄层色谱/基质辅助激光解吸电离（TLC / MALDI）质谱分析，有人建议采用现场固定电荷衍生化法修饰α-氨基酸。该方法基于三（2,6-二甲氧基苯基）亚甲基盐和三乙胺对分离的分析物进行色谱后处理。反应在温和条件下平稳进行，并产生粉红色的衍生物，其中含有永久性正电荷。直接从TLC板记录的MALDI质谱图显示了与脱羧阳离子部分相对应的强烈峰。所有衍生物均具有高电离效率的特征，这表明所开发的氨基酸分析方法具有很高的灵敏度。