PVC-membranes sensitive to chlorphenoxamine based on tetraphenylborate salt and neutral carrier additives

The performance of a chlorphenoxamine membrane based on TpClPB (I) was observed after addition of either dibenzo-18-crown-6 (II), 18-crown-6 (III) or thiophosphates of calix-{[}6]-derivatives (IV). The Nernstian response changed from 48.4 mV/decade for membrane (I) to 54.7, 54.7 and 53.6 mV/decade for membranes containing neutral carriers (II, III and IV) in addition to the TpClPB. Also, a significant improvement was observed for the selectivity coefficient values for monovalent cations whenever the membranes containing neutral carriers (II, III or IV) were used. The lower limit of the linear range was improved a little by immobilization of the neutral carrier with TpClPB from 10(-4) (type-I) to 5 x 10(-5) (types-II, III and IV). The temperature coefficient values are 1.7 x 10(-4), 2.0 x 10(-4), 4.1 x 10(-4) and 2.5 x 10(-4) V/degreesC for electrodes I, II, III and IV, respectively. The determination of chlorphenoxamine HCl in its tablets was applied in the presence of caffeine with a recovery value of 96.9\% and RSD = 2.726\%.