Dispersive liquid-liquid microextraction coupled with digital image colorimetric analysis for detection of total iron in water and food samples

Abstract A simple and low cost assay for total iron in various samples based on dispersive liquid-liquid microextraction (DLLME) coupled with digital scanning image analysis was proposed. Orthogonal experiment design was utilized to optimize the amount of extraction solvent and disperser solvent, O-phenanthroline concentration and buffer pH. Under the optimum conditions, the calibration curve was linear over the range of 0.047–1.0 μg mL −1 (R 2  > 0.99) of iron. The limit of detection (LOD) for iron was 14.1 μg L −1 and limit of quantification (LOQ) was 46.5 μg L −1 . The relative standard deviations for seven replicate determinations of 0.5 μg mL −1 of iron was 3.75%. The method was successfully applied for analysis of total iron in water and food samples without using any spectral instrument and it could have a potential industrial impact in developing fast and portable devices to analyze the iron content in water and certain foods.