Coated Wire Electrodes Sensitive to Local Anesthetic Cations and Their Application to Potentiometric Determination

Abstract

Abstract Coated wire electrodes sensitive to procaine(PC), tetracaine(TC), lidocaine(LC), dibucaine(DC), mepivacaine(MC), and bupivacaine(BC), based on ion-pair formation between tetraphenylborate ions and the corresponding local anesthetic cations in a plasticized poly(vinyl chloride) membrane were prepared. The electrodes showed linear responses with Nernstian slopes (55–58 mV/decade) over concentration ranges of 4×10−5–10−2, 4×10−5–10−2, 10−4–10−−2, 4×10−5–10−2, 5×10−5–10−2, and 2×10−4–10−2 mol dm−3 for PC, TC, LC, DC, MC, and BC, respectively. The change in pH did not affect the electrode performance within ranges of 3.2–7.4, 3.2–7.4, 2.1–7.7, 2.5–7.4, 3.5–7.0, and 2.4–5.6 for PC, TC, LC, DC, MC, and BC, respectively. The reproducibility, stability, response time, and selectivity were also investigated. The electrodes were applied satisfactorily to the determination of local anesthetics by potentiometry.