Development of PVC membrane potentiometric sensor for determination of dopamine

Dopamine, a neurotransmitter, is one of the naturally occurring catecholamines and its hydrochloride salt is used in the treatment of acute congestive failure and renal failure. Abnormal dopamine levels play a major role in many medical conditions such as addiction, schizophrenia, and Parkinson's disease. Dopamine determination is very important because dopamine overdose causes side effects such as increased feelings of stress, insomnia, aggression, hallucinations, addiction, vomiting, and depression. For this reason, many methods have been developed for the determination of dopamine. These methods are expensive, require pre-processing and expertise. The potentiometric method has the advantages of short response time, economy and ease. In this study, a PVC membrane dopamine-selective potentiometric sensor (electrode) was developed using dopamine-FM (dopamine-phosphomolybdate) as the ionophore. The optimum membrane composition was determined as 3% dopamine-FM, 64% NPOE (nitrophenyloctylether), 32% PVC (polyvinyl chloride), 1% KTpClPB (potassium tetrakis(4-chlorophenyl)borate). The sensor prepared with the optimum membrane composition exhibited a linear response in the concentration range of 1.0×10−7 molL-1 to 1.0×10−2 molL-1 with a concentration change of 50.3 mV/decade and a detection limit of 1.0×10−7 molL-1 for dopamine hydrochloride. The pH working range of the sensor was determined as 1.95-7.32. The response time of the sensor was determined as 10 seconds. Sample analysis with the dopamine-selective sensor was successfully performed.