PVC membrane sensors for potentiometric determination of acebutolol

The construction and general performance characteristics of two novel potentiometric membrane sensors responsive to the acebutolol are described. The sensors are based on the use of ion-association complexes of acebutolol (AC) with tetraphenylborate(TPB) (I) and phosphomolybdate(PM) (II) as exchange sites in a PVC matrix. The sensors show a fast, stable and near-Nernstian for the mono charge cation of AC over the concentration range 1 x 10(-3) - similar to 10(-6) M at 25 degrees C over the pH range 2.0 - 6.0 with cationic slope of 51.5 +/- 0.5 and 53.0 +/- 0.5 per concentration decade for AC-I and AC-II sensors respectively. The lower detection limit is 6 x 10(-6) M and 4 x 0(-6) M with the response time 20-30 s in the same order of both sensors. Selectivity coefficients of AC related to a number of interfering cation and some organic compounds were investigated. There are negligible interferences are caused by most of the investigated species. The direct determination of 3 - 370 mu g/ml of AC shows an average recovery of 99.4 and 99.5% and a mean relative standard deviation of 1.5% at 100.0 mu g/ml for sensor I and II respectively. The results obtained by determination of AC in tablets using the proposed sensors which comparable favorably with those obtained by the British pharmacopoeia method. In the present investigation the electrodes have been utilized as end point indicator for some precipitation titration reactions.