Image based kinetic determination of iron(III) in blood samples using a CCD camera

Abstract

Digital image-based calibration was applied for the determination of iron(III), Fe3+, as a catalyst in the oxidation of indigo carmine (IC) using bromate ion (BrO3−). During the reaction, a colorless product was produced and there was an induction period (IP) before the color of the solution faded. The length of IP depended on the concentration of Fe3+. The color fading of reaction was recorded as a change of red, blue and green colors (%RBG). Kinetic profiles similar to what has been reported in a previous spectrophotometric study were obtained. Fe3+ was determined in the concentration range of 6–16 ppm at pH = 2 and 25 °C. The detection limit of Fe3+ was found to be 1.994 ppm, which is better in comparison with the previous work. Optimum concentrations of IC and BrO3− were obtained as 5.5 × 10−5 and 3 × 10−3 M, respectively, using a one-at-a-time optimization method. The optimum pH value was 2. The interference effect of various cations and anions on the determination of iron is reported. In addition, the application of the method to real samples of human serum was performed. The obtained results from real samples were in accordance with the obtained results using standard methods. The analysis of images (movies) recorded from an evolutionary chemical systems seems to open new, simple and low-cost analytical opportunities.