Abstract:The electronic tongue has better stability and repeatability than sensory evaluation and it also has the advantages of easy-operated and faster detection speed relative to traditional equipments. At present, the research of electronic tongue is mainly focused on sensor development, and the research on system integration and automation is rare. Thus, a voltammetric electronic tongue was designed, which can automatically adjust the temperature of sample, feed into sample, clean the electrode and detect sample. It included the upper computer, control module, electrode, signal acquisition module, automatic sampling module, thermostatic bath module and display module, etc. The control interface was based on LabVIEW. The upper computer sent commands to control module to drive the automatic sampling module, thermostatic bath module and other modules through the serial port. Signal acquisition module connected the upper computer through USB cable. It contained a three electrodes system, and the signal curve of the sample was obtained by pulse voltammetry. The test results showed that all the modules were stable and reliable and the temperature control accuracy of the sample was (25±1)℃. The area between the signal curve and the X axis was used as the signal characteristic value. The drift of signal characteristic values of 20d was below 5.6%. The characteristic value was affected significantly by the sample temperature. When the sample temperature departure was ±5℃, the error of the characteristic value was 36%. Under the control of temperature bath (25±1)℃, the error of the characteristic value was 5.8%, which indicated that the temperature control can effectively improve the accuracy of electronic tongue detection result. In the detection application，the electronic tongue can distinguish among four different kinds of beer, milk, water and different grades of tea with the principal component analysis (PCA).
