Design of a Tea Polyphenols Concentration Detector for Tea Health Food Applications

In this work, a tea polyphenols concentration detector is proposed for tea health food applications innovatively. The proposed detector includes a tea polyphenols sensor and a converter that can convert tea polyphenols concentrations into a linear frequency output. Furthermore, the proposed converter designed as a multistage relaxation oscillator is to provide higher sensitivity for adaptive utilization in different tea polyphenols concentrations. The measured input range of the converter was 0.2–2.2 V, and the corresponding range of the frequency output was 3.639–18.14 MHz. The sensitivity was 7.25 MHz/V. The measured range of tea polyphenols concentrations was 0.6–
$2.8\times 10^{-{3}}$
mol/L, and the frequency output was ranged from 8.79 to 13.11 MHz. A 0.27% of the measured maximum linear error was ensured. Finally, a test of green tea was successfully experimented. Confirmations through results, the tea polyphenols concentration detector could have normal functions for tea health food applications.