title: Non-extractive derivative spectrophotometric determination of cobalt in neutral micellar medium.
abstract: A sensitive derivative spectrophotometric method using 1-nitroso-2-naphthol has been developed for determination of trace amounts of cobalt in the presence of a neutral surfactant. Photometric parameters, viz., lambda(max), molar absorption coefficient and analytical sensitivity of the complex formed in micellar media are 420 nm, 3.18x10(4) l mol(-1) cm(-1) and 2.05 ng ml(-1), respectively. Beer's law holds from 0.20 to 3.0 mug ml(-1) of the analyte concentration. The method has a high sensitivity with a detection limit of 1.68 ng ml(-1). A selective determination of cobalt in presence of copper(II) or iron(III) using derivative spectral profiles and without any masking or pre-separation is also reported. Samples of drugs and standard alloys analysed by the proposed method yielded results comparable to those obtained using recommended procedures.
authors.affiliation: Department of Chemistry, University of Delhi, Delhi 110007, India.
authors.forename: H B
authors.initials: HB
authors.lastname: Singh
authors.forename: N K
authors.initials: NK
authors.lastname: Agnihotri
authors.forename: V K
authors.initials: VK
authors.lastname: Singh