Amino compounds having primary groups such as amino acids or aminocyclitol antibiotics lack chromopores or fluorophores in their molecules. Derivatization is required for their detection with high sensitivity using high-performance liquid chromatography or high-performance apillary electrophoresis with photometric and fluorimetric detection. Reagent for the derivatisation of primary amines. The alanine-derivative shows a 3 times stronger fluorescence than o-phthalaldehyde. The reagent has been used in the HPCE-determination of aminoacids.