Developing a Mickey-Mouse-Designed Microfluidic Paper-Based Analytical Device (μPAD) to Determine The Antioxidant Activity of Green Tea

Abstract

The determination of the antioxidant activity in green tea using FRAP essays developed in a Microfluidic Paper-Based Analytical Device (μPADs) was observed. μPAD was prepared on the chromatographic paper with a suitable pattern and then printed using a solid ink printer. The solid printing was intended to obtain a hydrophobic barrier and a hydrophilic channel on the chromatographic paper. A preliminary study was done to determine the optimum time and temperature used on the penetration of obtaining the hydrophobic barrier to avoid leakage in the channel. Optimization of temperature and time was calculated by the average velocity, the optimum condition was obtained at 120 °C for 90 seconds with an average speed of 0.1 mm.s−1. The green tea samples were prepared by extracting its active compound using demineralized water at 25 °C and 90 °C with 2 hours of immersion time. For the measurement of antioxidant activities, the analysis was carried out by placing 0.5 μl in the detection zone and 5 μl samples into the sample zone μPAD. Then, the color reaction product, which propagates from the sample zone to the detection zone, is processed by Image J software to measure color intensity in CMYK mode. Extracts of green tea samples at 25 °C and 90 °C has a significant difference in antioxidant activity. These results indicate that the method developed in this work can be used as an alternative method for analyzing antioxidant activity in green tea extract. The results of the average amount of antioxidant activity in green tea samples were shown with Fe2+ concentration. High-speed detection, low cost, high accuracy, and ease of use can be attributed to the advantages of our μPAD method.