A Simple Spot Test Method with Digital Imaging for Chromium Speciation in Water Samples

چکیده مقاله

Abstract: A simple and environmentally friendly method for the speciation of chromium based on a spot test obtained from digital images has been developed. Due to rapidity and simplicity of the method and portability of the used devices, the proposed method is suitable for in situ determination of chromium. The method employed a smartphone to capture digital images of Cr(VI)-1,5-diphenylcarbazide colored complex in microplate wells which were accommodated in a wooden box. A color digitizer app was used to extract RGB values from captured images. To obtain total chromium content in the sample, Cr(III) was oxidized to Cr(VI) with Ce(IV) prior to analysis. Under the optimum conditions, the calibration curves were linear over the concentration ranges of 20 to 250 and 30 to 250 μg/L with the detection limits of 5 and 7 μg/L and RSD values of 5.8 and 6.3% for Cr(VI) and Cr(III), respectively. The proposed method was successfully applied to the speciation of chromium in spiked water samples. © 2022, Pleiades Publishing, Ltd.