Application of impedance measurement technology in distinguishing different tea samples with Ppy/SWCNT composite sensing material

Abstract

Asix sensor electrode system was developed to distinguish three tea extract samples by using impedance measurement technology. Five of the six sensing electrodes were made of different wt% single walled carbon nanotubes (SWCNT) and electropolymerizedpyrrole over the surface of gold electrodes. The sixth electrode was made by electropolymerizedpyrrole doped with Poly (sodium-4-styrenesulfonate). The sensing electrodes were characterized by FT-IR, Cyclic Voltammetry, and Transmission ElectronMicroscope. Various concentrations of six tea leaf extracts (3 types) were made and scanned at different frequencies and the best frequency of 100 kHz was chosen. Principal component analysis (PCA) was performed on the signals to show that the signals vary to distinguish each of the tea samples and lead to subsequent classification.