Based On Liquid Metal Ion Of The Saw Sensor Online Real-time Detection Technology

At present, optic analytical instruments (such as atomic emission or absorption spectrometer), liquid chromatogram and electrochemical analysis meter etc. are usual ways to detect metal ions, but these methods need large and complex devices, and last long time to operate; moreover they usually sample online and analyse offline. So they are not fit for fieldwork. Current ISE (Ion Selective Electrode) chemical sensors are applied to realtime aqueous detection. But ISE has some drawbacks: (1) general ISE is too large; (2) with its high output impedance(about 109 Q), only devices with high inputimpedence and low input offset current can be used to match the ionometer; (3) it is difficult to measure weakly direct current or voltage.To solve these problems, this project developed a technology based on SAW (Surface Acoustic Wave) sensor to detect to aqueous metal ion online and real-time. In this system SH-SAW sensor based on 36?rotated Y-cut X-propagating LiTaO3 (36YX.LT) is selected as sensor component to construct a dual-port differential SH-SAW sensor; SH-SAW sensor, electromagnetic valve, peristaltic pump, mixer measure circuit, cymometer (HP5316B), and PCI-GPIB transition card are integrated into Lab View system to develop a dual-port differential liquid-flow system; pattern recognitions by PLS (Partial Least Squares) and ANN (Artificial Neural Networks) are applied on the data of transient responses of metal ionic solutions to detect the kind and concentration of the metal ion.Initial experimental results showed that the transient responses of different solutions represent unique characteristics of the solutions, which make monitor and analysis of aqueous metal ion feasible. Developing a compact type online real-time analytical instrument will take the head in China and filled the blank domestically, and it will benifit ecology environment monitor.