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A PET/paper chip platform for high resolution sulphur dioxide detection in foods

Fu, Lung-Ming, Liu, Chan-Chiung, Yang, Chia-En, Wang, Yao-Nan, Ko, Chien-Hsuan
Food chemistry 2019 v.286 pp. 316-321
cameras, color, foods, mobile telephones, paper, sulfur dioxide
A convenient assay platform comprising a PET/paper chip (PP-chip) and a smart analytical device is developed for detection of sulphur dioxide (SO2) concentration. In the presented approach, the distilled SO2 solution is dropped onto the detection region of the PP-chip and undergoes a reaction with an acid-based reagent. The resulting color variation is analyzed through a high-resolution camera (CMOS) and the reacted image is processed by a RGB (red, green and blue) analytical app installed on a smartphone. Results show that the known SO2 concentrations ranging from 10 to 300 ppm indicate that the high linear relationship (R2 = 0.9981) between the (R (red) + G (green) − B (blue)) value and SO2 concentration. Moreover, a high measurement resolution is equal to 1.45 ppm/a.u. The presented assay platform was proved to detect the SO2 concentrations of twenty-five practical food samples. Compared with the developed assay platform and certified inspection technique, the deviation of SO2 measurement does not exceed 3.82%. It was satisfactory to apply this developed assay platform to analyze the SO2 concentration in the practical samples.