FLOW-INJECTION CHEMILUMINOMETRIC DETERMINATION OF CITRATE BASED ON A PHOTOCHEMICAL-REACTION

A flow injection configuration for the chemiluminometric determination of citrate is proposed. The procedure is based on the photochemical d ecomposition of the iron(III)-citrate complex. Iron(II) formed in the photochemical reaction was measured by its catalysis of the chemilumin escent luminol reaction in the absence of added oxidant. Linear calibr ation graphs were obtained between 2.0 x 10(-7) and 1.0 x 10(-4) mol l (-1) citrate, with a throughput of 30 samples h(-1) and relative stand ard deviations between 0.45 and 1.5%. The applicability of the method to the determination of citrate in pharmaceutical preparations and sof t drinks was demonstrated by investigating the effect of potential int erferences and by the analysis of commercial preparations.