Flow-injection chemiluminometric determination of citrate based on a photochemical reaction

Abstract

A flow injection configuration for the chemiluminometric determination of citrate is proposed. The procedure is based on the photochemical decomposition of the iron(III)–citrate complex. Iron(II) formed in the photochemical reaction was measured by its catalysis of the chemiluminescent luminol reaction in the absence of added oxidant. Linear calibration graphs were obtained between 2.0 × 10^–7 and 1.0 × 10^–4 mol l^–1 citrate, with a throughput of 30 samples h^–1 and relative standard deviations between 0.45 and 1.5%. The applicability of the method to the determination of citrate in pharmaceutical preparations and soft drinks was demonstrated by investigating the effect of potential interferences and by the analysis of commercial preparations.