The System Fabric And Application Of Multifrequency Pulse Electronic Tongue

Electronic tongue is a modern analysis instrument for analysis of the integral quality characteristic of liquors, which consists of a number of low-selective, nonspecific and cross-sensitivity sensors array and uses advanced mathematical procedures for signal processing based on the pattern recognition(PARC)and/or multivariate analysis. The structure of electronic tongue could be divided into three parts: (1) sensors array with low-selective, non-specific and responding reproducibly to the analyzed solutions; (2) the equipment of giving power and sampling response signals; (3) suitable pattern recognition or multivariate analysis method.A novel electrochemical method, multifrequency large amplitude pulse voltammetry was introduced in the paper, which was suitable for voltammetric electronic tongues measurement. The actuator of multifrequency large amplitude pulse voltammetry was developed, based on normal electrocircuit of three-electrode systems, potentiostat and single chip microcomputer systems for giving and sampling signals. A novel voltammetric electronic tongue, multifrequency large amplitude pulse electronic tongue was constructed, which was based on multifrequency large amplitude pulse voltammetry controlled by the developed actuator, sensors array with low-selective metal electrodes with stable characteristic, such as platinum electrode, gold electrode, palladium electrode, nickel electrode, titanium electrode and silver electrode, and a suitable multivariate statistic analysis method [principal component analysis]. Multifrequency large amplitude pulse electronic tongue displayed promising future in discriminating red wines, Chinese liquors and Chinese Longjing teas all with different quality.(1) The proof experiment of multifrequency large amplitude pulse electronic tongue application in discriminating red wines of cabernet sauvignon displayed that the electronic tongue not only separated the six different brands well, but also discriminated the regions of cabernet sauvignon. Also, the result showed that the suitable sensors array in classification of red wines was the array with gold electrode and palladium electrode in 100 Hz frequency segment of multifrequency large amplitude pulse voltammetry, and silver electrode in 10 Hz frequency segment of multifrequency large amplitude pulse voltammetry.(2) The proof experiment of multifrequency large amplitude pulse electronic tongue application in classification of Chinese liquors displayed that the electronic tongue was also suitable for valuating the quality of Chinese liquors and discriminating the products fake or not. The result showed that the suitable sensors array was the array with platinum electrode in 10 Hz frequency segment of multfrequency large amplitude pulse voltammetry and gold electrode in 100 Hz frequency segment of multfrequency large amplitude pulse voltammetry. The six brands were well separated and the first component was positive correlation with ethanol content in the score plot of PC1 vs PC2.(3) The proof experiment of multifrequency large amplitude pulse electronic tongue application in classification of Chinese Longjing tea displayed that the Longjing teas with different quality were separated well in the score plot of PC1 vs PC2, and the electronic tongue was able to be applied in valuating the quality of Longjing tea and discriminating the products fake or not. The suitable sensors array for analysis Longjing tea was the array with platinum electrode, nickel electrode and titanium electrode in 100 Hz frequency segment of multifrequency large amplitude pulse voltammetry, and gold electrode and palladium electrode in 1 Hz frequency segment of multifrequency large amplitude pulse voltammetry.Multifrequency large amplitude pulse electronic tongue showed a well application value in classification of various food samples, based on sensors array with different non-modified metal electrodes and different frequency segment of multifrequency large amplitude pulse voltammetry. Mutifrequency large amplitude pulse voltammetry had promising future in modern rapid analysis instruments for qualitative analysis and quantitative analysis instead of expert panel.