A SHEAR-HORIZONTAL SAW DEVICE AS A PH MONITOR

A shear horizontal surface acoustic wave (SAW) that propagates on 36-d egrees rot. Y-cut X-propagating LiTaO3 immersed in a liquid is affecte d by an acoustoelectric interaction between the piezoelectric potentia l and the electrical properties of the materials in the liquid. Using the SAW device, pH changes in enzymatic reactions can be detected by t he measurement of the SAW velocity change caused by a pH change associ ated with the reactions. In this paper, preliminary experiments on a u rea-urease reaction and the inhibition effect of the butyrylcholine ch loride-cholinesterase reaction due to a pesticide are reported.