Multicomponent analysis by flow injection using a partial least-squares calibration method. Simultaneous spectrophotometric determination of iron, cobalt and nickel at sub-ppm levels

Abstract

A partial least-squares multivariate calibration method for the analysis of binary and ternary mixtures of Fe, Co and Ni, based on their reaction with 2,2′-dipyridyl ketone picolinoylhydrazone in a flow injection manifold was developed. The parameters controlling the behaviour of the system were investigated. For individual determinations, molar absorptivities of 6.64 × 10³(Fe, 367 nm), 3.89 × 10³(Co, 410 nm) and 5.17 × 10³ l mol^–1 cm^–1(Ni, 385 nm), were obtained, the limits of detection being 1.062, 1.489 and 0.685 µmol l^–1, for Fe, Co and Ni, respectively. The optimized method was applied to the analysis of two samples with complex matrices (a washing solution used in an automotive factory and a waste acidic mine effluent).