Microfluidic paper-based analytical device for measurement of pH using as sensor red cabbage anthocyanins and gum arabic

The objective of this study was to develop and validate a novel microfluidic paper-based analytical device (mu PADpH) for determining the pH levels in foods. Anthocyanins from red cabbage aqueous extract (RCAE) were used as its analytical sensor. Whatman No. 1 filter paper was the most suitable for the device due to its porosity and fiber organization, which allows for maximum color intensity and minimal color heterogeneity of the RCAE in the detection zone of the mu PADpH. To ensure the color stability of the RCAE for commercial use of the mu PADpH, gum arabic was added. The geometric design of the mu PADpH, including the channel length and separation zone diameter, was systematically optimized using colored food. The validation showed that the mu PADpH did not differ from the pH meter when analyzing natural foods. However, certain additives in processed foods were found to increase the pH values.