Characterization of 2-(2-pyridylazo)-5-[ N-(sulphoalkyl)amino]phenol derivatives as the precolumn chelating agent for trace metal determination by ion-pair reversed-phase liquid chromatography with spectrophotometric detection

• Published in: Analytica chimica acta 1992-01, Vol.256 (1), p.91-96
• Main Authors: Ohtsuka, Chizuko, Matsuzawa, Kimiyo, Wada, Hiroko, Nakagawa, Genkichi
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Cobalt; Copper; Exact sciences and technology; Iron; Liquid chromatography; Nickel; Other chromatographic methods; Spectrophotometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/0003-2670(92)85332-Z

Five 2-(2-pyridylazo)-5-[ N-(sulphoalkyl)amino]phenol derivatives were examined as precolumn chelating agents on a Kaseisorb LC ODS-300-5 column for the determination of trace metal ions by ion-pair reversed-phase liquid chromatography with spectrophotometric detection. The resolution among Cu(II), Co(III), Ni(II) and Fe(II) chelates depends significantly on the substituent group of the chelating agent. Four 2-(5-nitro-2-pyridylazo)-5-[ N-propyl- N-(3- sulphopropyl)amino]phenol (Nitro-PAPS) chelates and reagent were completely separated within about 28 min using acetonitrile—water (30 + 70, v/v) containing 0.05 M sodium ion and 0.02 M acetate buffer (pH 5–6). The detection limits of metals with Nitro-PAPS were 0.6 μg 1 −1 (Co and Ni), 3 μg 1 −1 (Fe) and 32 μg 1 −1 (Cu) at 0.02 a.u.f.s.