Application of Impedance Measurement Technology in Distinguishing Different Tea Samples with Ppy/SWCNT Composite Sensing Material

Abstract

A six 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 Electron Microscope. 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.

Uncertainty evaluation of multivariate quantities: A case study on electrical impedance

“…In fact, because the electrical impedance allows the quantification of the behaviour of a conducting medium to an electric current, the impedance measurement is used in the determination of the electromagnetic properties of materials and is the basis of various methods of electrical transduction with applications in fields such as chemistry [22,23] and biomedicine [24][25][26][27]. Electrical impedance measurement is important not only in the analysis of electric circuits but also for other purposes.…”