K/sup +/ detection using shear horizontal acoustic modes

An acoustic delay line sensor for the detection of potassium ion concentration in water has been implemented and tested. The device uses the propagation of shear horizontal (SH) waves in a piezoelectric plate (Love waves) in order to minimize acoustic energy loss in the liquid. One of the plate surfaces is covered with a polyvinyl-chloride-valinomycin membrane, a well-known ligand for the detection of potassium ions. The devices has shown a fairly good linearity of the response in the analyzed pK/sup +/ range of K/sup +/ concentration between 1.49 and 4. The operation is reversible and the response is highly reproducible. Measurements have demonstrated a high selectivity of the device with respect to exposure to Na/sup +/ solutions.<
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