Spectrofluorimetric determination of sulphate in waters in normal and open/closed flow injection configurations

Abstract

A spectrofluorimetric method for the determination of sulphate, based on the formation of a ternary complex with biacetyl monoxime nicotinylhydrazone and zirconium is described. Two flow injection manifolds [normal (nFl) and open/closed] were optimized and used for the determination of sulphate in various water samples with good selectivity. The repeatability and linear range of the calibration graphs was better for the open/closed than for the nFl system (relative standard deviation 2.33%versus 3.51%, and linearity 1.5–150 µg ml^–1versus two linear portions of 2–30 and 30–150 µg ml^–1), but the sampling rate using the nFl configuration (30 samples h^–1) was at least twice that of the open/closed system.