A smart device-based digital image colorimetry for immediate and simultaneous determination of curcumin in turmeric

Abstract

A fast, plausible, and novel analysis using smart device-based digital image colorimetry (smart device-based DIC) method based on color measurements obtained from digital images of curcumin solutions to determine curcumin in turmeric is proposed. Digital images were obtained using a smart device and daylight white light emitting diodes (LED) light source placed in a photography lightbox as the measurement device. Images in red, green, and blue (RGB) color space were processed to extract relevant colors from the image and the color values were used to analyze curcumin concentrations. Curcumin solutions extracted from turmeric samples using a 60:40 (v/v) mixture of ethanol and hydrochloric acid were captured and the concentration was estimated by comparing color values with those collected in a database. The proposed smart device-based DIC is able to provide a limit of detection (LOD) of 0.48 mg L−1 and a limit of quantitation (LOQ) of 1.61 mg L−1. The color values of curcumin were tested for accuracy using turmeric sample solution spiked with 1.00, 5.00, and 7.00 mg L−1 of standard curcumin. The average percentage recoveries were acceptable in all samples and the percentage recoveries of the method were in the range of 98.57–110.0%. The method was validated by comparing the results with measurements performed using Ultra Violet-Visible microplate reader (UV–Vis MR) and high performance liquid chromatography (HPLC). There was no significant difference observed between the three methods. Consequently, smart device-based DIC provided a convenient, easy-to-use, low-cost, accurate, precise, and efficient approach for rapid detection of curcumin in turmeric.