title: 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.
abstract: 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 (30 min at 68 degrees C in presence of 0.04 M 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 lambda=280 nm. 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.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Alma Mater Studiorum-Università di Bologna, Via Belmeloro 6, 40126 Bologna, Italy.
authors.forename: M G
authors.initials: MG
authors.lastname: Gioia
authors.forename: B
authors.initials: B
authors.lastname: Cacciari
authors.forename: A
authors.initials: A
authors.lastname: Leoni
authors.forename: R
authors.initials: R
authors.lastname: Gatti