Potentiometric sensors for the selective determination of sulbutiamine

Five novel polyvinyl chloride (PVC) matrix membrane sensors for the selecti ve determination of sulbutiamine (SBA) cation are described. These sensors are based on molybdate, tetraphenylborate, reineckate, phosphotun gestate a nd phosphomolybdate, as possible ion-pairing agents. These sensors display rapid near-Nernstian stable response over a relatively wide concentration r ange 1 x 10(-2) - 1 x 10(-6) M of sulbutiamine, with calibration slopes 28- 32.6 mV decade(-1) over a reasonable pH range 2-6. The proposed sensors pro ved to have a good selectivity for SEA over some inorganic and organic cati ons. The five potentiometric sensors were applied successfully in the deter mination of SEA in a pharmaceutical preparation (arcalion-200) using both d irect potentiometry and potentiometric titration. Direct potentiometric det ermination of microgram quantities of SEA gave average recoveries of 99.4 a nd 99.3 with mean standard deviation of 0.7 and 0.3 for pure SEA and arcali on-200 formulation respectively. Potentiometric titration of milligram quan tities of SEA gave average recoveries of 99.3 and 98.7% with mean standard deviation of 0.7 and 1.2 for pure SEA and arcalion-200 formulation, respect ively. (C) 1999 Elsevier Science B.V. All rights reserved.