Fentanyl-selective polymeric membrane electrode

A poly (vinyl chloride) membrane electrode with dibutyl phthalate as plasti cizer based on a fentinyl-tetrakis(4-chlorophenyl)borate ion-pair complex f or the determination of fentanyl citrate in injections is described. A line ar response over the range 1 x 10(-5) mol (.) dm(-3) to 1 x 10(-2) mol (.) dm(-3) drug with a slope of 59.3 +/-0.6 mV/decade was established. The opti mum pH range was 1 to 6. The lower detection limit was 8 x 10(-6) mol (.) d m(-3) fentanyl citrate (2.7 mug cm(-3) fentanyl). There were negligible int erferences from a number of inorganic cations, structural analogues, and so me common drug additives used in injections. The electrode proposed has bee n successfully applied to determine fentanyl citrate in injections. The res ults correlated well with those obtained by the United States Pharmacopoeia standard procedure.