Abstract
New modified carbon paste electrodes for determination of ketotifen fumarate in its pure and pharmaceutical preparations were constructed. The used modifiers are ketotifen phosphotungestate(Keto(3)PT), and ketotifen tetraphenylborate (Keto-TPB). Single and mixed ion-associate electrodes were prepared. Both Keto-TPB and mixed (Keto-TPB and Keto3PT) electrodes have a linearity range of 1.00 x 10(-5)-1.00 x 10(-2) mol L-1. The slopes were 58.30 and 54.20 mV/decade for Keto-TPB and mixed chemically modified carbon paste electrodes (CMCPE), respectively. The limits of detection were 1.42 x 10(-6) and 1.00 x 10(-5) mol L-1 for Keto-TPB and mixed CMCPEs, respectively. The potential variation due to pH change is considered acceptable in the pH ranges 4.44-9.11 and 2.50-9.00 for Keto-TPB and mixed ion-exchanger CMCPE, respectively. The response time was <= 10 s for both electrodes. Selectivity coefficients values towards different inorganic cations, sugars, and amino acids reflect high selectivity of the prepared electrodes. Potentiometric titrations and standard addition methods were applied for the determination of ketotifen ion in its pure samples and pharmaceutical formulations (Zaditen tablet and syrup) using proposed electrodes. The electrodes were also tested in flow injection analysis (FIA). The results obtained from both methods were statistically treated by F-and t-tests. The carbon paste electrodes have the advantages of being more easily prepared and longer life span compared to the plastic membrane electrodes previously reported. Copyright (C) 2011 John Wiley & Sons, Ltd.