Electrochemical Methods’ Explorations In Tea Classification And The Detection Of Heavy Metal Contents

Compared with other testing methods, the electrochemical analysis method is fast, accurate, and of high sensitivity, thus it has broad implications in the field of food analysis. Considering these advantages from electrochemical analysis methods, we focus on voltammetry data mining and the development of portable intelligent instruments. In this work, electrochemical methods are explored in tea classification and the detection of heavy metal contents, the main work is organized as follows:1) First, an electronic tongue was designed for classification of green and black teas, with multivariate data analysis of cyclic voltammogram of a homemade metallic oxide (SnO2, ZnO, TiO2, Bi2O3) modified nickel foam electrode. Several different combinations of sensors, were compared in their classification ability in this system. Using the electrochemical responses obtained from cyclic voltammetry as input information, supervised and unsupervised chemometric analysis methods, principal component analysis (PCA) was performed as the exploratory method and support vectors machine (SVM) as the classification method.2) Combining bismuth film electrode with square wave stripping voltammetry, the contents of lead and cadmium were detected. A series of experiments are designed to optimize conditions, and mainly the effects of enrichment parameters and square wave parameters were considered.3) On the basis of the above electrochemical analysis, a portable smart style heavy metal electrochemical analyzer was under research and development. In the terms of hardware, excellent design of integrated circuits and electromagnetic compatibility were adopted, thus to ensure the analyzer’s small systematic error and superior performance; On the software side, incorporated advanced chemometric algorithms were making data processing more accurate and efficient. Finally, the portable intelligent heavy metal analyzer was successfully made and applied to the related solution measurements.Finally, since chemometrics could definitely drag the mathematical meaning of electrochemical signals, part of the hardware performance could be replaced by software, thus there would be a good promotion of smart portable electrochemical analyzer and electrochemical sensors.