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

Abstract

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.

Keywords: A smart analytical device; Food; PET/paper chip; Sulphur dioxide.