2,7-Dimethyl-3,8-dinitrodipyrazolo[1,5-a:1',5'-d]pyrazine-4,9-dione: A new labelling reagent for liquid chromatographic analysis of amino acids [An article from: Analytica Chimica Acta]

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Description:
The use of 2,7-dimethyl-3,8-dinitrodipyrazolo[1,5-a:1',5'-d]pyrazine-4,9-dione as pre-column reagent for LC analysis of amino acids is proposed. The compound reacts (30min at 68^oC in presence of 0.04M triethylamine in a dimethylsulfoxide-water mixture) with primary and secondary amino function and the stable resulting adducts can be chromatographed under reversed-phase conditions and detected at @l=280nm. The derivatization conditions were optimized by a series of experiments. The effect of temperature, triethylamine concentration and reagent on the reaction was investigated. The yield of the glycine derivative was found to be quantitative at a reagent amino acid molar ratio of about 6 by comparison with an authentic specimen of synthesized glycine adduct. Application of the method to quality control of commercially available oral polyaminoacid formulations is described.