Potentiometric determination of some 1, 4-benzodiazepines in pharmaceutical preparations and biological samples

New, simple, low cost and sensitive ion selective electrodes aredescribed for the determination of some 1,4-benzodiazepines in theirpharmaceutical preparations as well as in biological fluids. Drug-tetraphenylborate and drug-phosphotungstate ion pairs have beenprepared and used as electroactive materials. Poly (vinyl chloride)(PVC), and poly(ester-urethane)s (UPCLs, UPBA, and UPDEGA)are used as the matrix. The proposed sensors give rapid nernstianresponse for 10-4-10-6 M of the above mentioned drugs in a pHrange of 3-7. The membranes developed have potential stability forup to 4 weeks and show high selectivity for the investigated drugsover many interfering ions. The electrodes are used for determiningtrace amounts of bromazepam, clonazepam and diazepam in theirpharmaceutical preparations as well as in biological fluids. Forpharmaceutical preparations, the relative standard deviation (RSD