Non-contact multi-sensing technique for the precise measurement of concentration of electrolytic solution

Abstract A new approach for the precise measurement of low concentration of electrolytic solutions using multi-sensing technique is presented in this paper. For achieving this multi-functional sensing function, a novel structure is proposed for the multi-functional sensor. Two sensing functions, namely, the inductive and the capacitive sensing functions, can be realized by this sensor. From the two types of sensing two databases are created and then the unknown concentration is precisely determined by comparing with the two databases. Experimental results using the sensor on various solutions of low concentration of NaCl, K2SO4 and Pb(NO3)2 electrolytes show distinct response to various concentrations as well as to different solutions. A concentration as low as 1 ppm of solution is possible to measure by this sensor.