A promethazine hydrochloride and ammonium phosphomolibdtae ion-pair compound was used as electroactive material for selective determination of promethazine in various samples. The electrode of the composition of PVC: PM-PMD: DBP of 33: 3: 64 (%, w/w) has a detection limit of 1.0 x 10^-6 M in a liner concentration range of 1.0 x 10^-6 – 1.0 x 10^-1 M with a slope of 50.5 ± 0.3 (mV/decay of activity). The electrode can be used in a pH range of 2.5 – 6.0 for a period of 4 weeks and has fast response time of about 5 s.

Keywords: Promethazine; Ion-Selective Electrode; Ion-Pair Compound;