Development of reverse flow injection analysis for determination of iron (II)

A reverse flow injection analysis spectrophotometric procedure for the determination of iron (II) has been developed. The method is based on the injection of 200 µl of tetracycline reagent solution into the flowing stream of an iron (II) standard or sample solution with the optimum flow rate of 3.0 ml min -1 . The absorption of iron (II) - tetracycline complex is monitored at a wavelength of 440 nm. The flow injection system and the experimental conditions were optimized by means of the univariate method. Under the optimum conditions, linear calibration graphs over the concentration range of 25.0 - 500.0 µg ml -1 were obtained with the correlation coefficient of 0.9984. The detection limit (s/n=3) was 2.31 µg ml-1 for iron (II). The method was successfully applied to the determination of iron (II) in water samples with a sample throughput of 70 h -1 .