FLOW-ANALYSIS DETERMINATION OF IODIDE AT NANOGRAM LEVELS IN WATER

This paper describes a new method for flow, injection analysis (FIA) d etermination of iodide nt nanogram levels in water based on the cataly tic destruction of the colour of Fe(III)-SCN- -CP+ (cetylpyridinium ch loride) complex. The apparent molar absorptivity of the complex in ter ms of iodide is (6.90) x 10(5) l mole(-1) cm(-1) at a maximum absorpti on of 470 nm. The detection limit of the method is 0.1 ng I-/ml. The F IA variables for the determination of iodide in the water were optimiz ed. Sample throughput was 50 samples/h. The method is particularly use ful for characterization of iodide at lower nanogram levels in rain, s urface and ground water samples.