Abstract
Construction and performance characteristics of a novel ion – selective membrane sensors for determining bromazepam drug are described. The sensor was based on the use of bromazepam – phosphotungestiate ion association complex as an electroactive material in poly (vinyl chloride) membrane plasticized with o-nitrophenyloctyl ether and ( dioctyl sebacate( DBS) as a solvent mediator. In aqueous solution of pH 3, the sensor displayed a stable for 4 weeks with reproducible potential and linear response for drugs over the concentration range 1x 0-2 – 1x10-4 M with Nernstian slope of 52.0 ± 0.1 mV/decade for detection limit of 3x10-5M. The response time was 10 -20 s. The selectivity coefficients indicate excellent selectivity for bromazepam over many common cations (e.g., Na+, K+, Co2+, Sr2+, Ag+1, starch, maltose, glucose and lactose. The sensors are used successfully for the determining of bromazepam in pure form and pharmaceutical preparations with average recoveries of 99.20, 97.80 and 99.64 %.