Detail of "6293-87-4"

Reference

Colorimetric detection and determination of carboxylic acids with 2-nitrophenylhydrazine hydrochloride

Miwa, Hiroshi; Yamamoto, Magobei; Momose, Tsutomu (Fac. Pharm. Sci., Fukuoka Univ., Fukuoka, Japan). Chem. Pharm. Bull., 28(2), 599-605 (English) 1980. CODEN: CPBTAL. ISSN: 0009-2363. DOCUMENT TYPE: Journal CA Section: 64 (Pharmaceutical Analysis) Aq. or aq. ethanolic samples of aliph. and arom. acids were coupled with 2-nitrophenylhydrazine-HCl [6293-87-4] to give acid hydrazides, which showed intense violet colors in an alk. medium. Dicyclohexylcarbodiimide was used as a coupling agent, and a small amt. of pyridine markedly enhanced the reaction. The brown blank soln. was decolorized to a faint yellow by heating the alk. soln. at 60°. The reaction conditions were investigated in detail with acetic [64-19-7], stearic [57-11-4], benzoic [65-85-0] and citric acid [77-92-9], and sensitive methods for the detection and detn. of carboxylic acids were established. The limits of detection and the absorption max. of the alk. colors obtained with many carboxylic acids were detd. Most amino acids, together with hydroxybenzoic acids and aminobenzoic acids, were detected with reduced sensitivity by this method. Salicylic acid [69-72-7] was shown by high-performance liq. chromatog. and gas chromatog.-mass fragmentog. to form mainly its Et ester in the coupling reaction, whereas benzoic acid, which could be sensitively detected, formed only a small amt. of the ester. p-Aminobenzoic acid [150-13-0] also formed a large amt. of its Et ester.