Construction and analytical application of ion-selective piezoelectric sensor for atropine sulfate

The method describes the use of a piezoelectric quartz crystal (PQC) as a s ubstitute for ion-selective electrodes. The approach is feasible when the m embrane materials are electrically non-conductive and membrane potential me asurements are consequently not possible. An ion-selective piezoelectric se nsor sensitive to atropine sulfate was constructed by coating a PVC membran e containing activant on one side of a PQC. On the basis of selective adsor ption of atropine ions across the modified film and the sensitive mass resp onse of PQC, the method exhibits a sensitive, rapid response and is easy to operate without pretreatment of the sample. The logarithm of the frequency shift gave a linear relationship with the logarithm of atropine sulfate co ncentration in the 1.0 x 10(-8)-1.0 x 10(-3) M range with a detection limit of 5.0 x 10(-9) M at pH 7.0. Recoveries were from 98.7-102.2%. Two activan ts, atropine tetraphenylborate and atropine dipicrylaminate, were synthesiz ed and investigated. Influencing factors were also examined and optimized. The results for real samples obtained by the proposed method agreed with th ose obtained by conventional methods.