Tramadol selective PVC membrane electrodes and their analytical application

Tramadol ion selective PVC membrane electrodes based on the ion-pair comple xes of tramadol cation with tetrakis-(4chlorophenyl)borate and tetraphenylb orate anions were prepared using bis(2-ethylhexyl)sebacate and 1-isopropyl- 4-nitrobenzene as the membrane solvents. These electrodes gave a linear res ponse with sub-Nernstian response values at different concentration ranges depending on the counter ions and the plasticizers used. The electrode base d on tramadol-tetrakis-(4-chlorophenyl)borate as an ion exchanger and bis(2 -ethylhexyl)sebacate as plasticiser provides a rapid sensitive method for t ramadol determination. The basic analytical parameters of these electrodes were evaluated. The potentiometric titration method was used to determine t ramadol hydrochloride substance and the content of capsules (50 mg) with go od precision and accuracy.