Digital image-based method for iron detection using green tea (Camellia sinensis) extract as natural colorimetric reagent

Abstract

In this study, the widely available green tea (Camellia sinensis) extract was used as a natural colorimetric reagent for digital image-based detection of iron to provide a simple, cost-effective, and environment friendly analytical method. The method was based on the RGB measurement of the violet complex formed by the reaction of iron (III) and the polyphenols present in the green tea extract. Images of the solutions were taken using a digital camera and processed using ImageJ software. Under the optimum conditions, a linear range from 2.5 to 17.5 mg L−1 iron (III) was obtained with a calibration sensitivity of 5.96 a.u. L mg−1. The calculated limit of detection and limit of quantitation were 0.9 mg L−1 and 1.6 mg L−1, respectively. The relative standard deviation for the analysis of 6.0 and 14.0 mg L−1 standard Fe3+ solutions were 1.5% and 0.8%, respectively. The proposed method was applied for the determination of the amount of Fe in dietary supplements producing results that statistically agree with those obtained by FAAS. With its analytical performance, the presented method can be a promising method for the detection of iron.