Investigation on the downregulation of dopamine by acetaminophen administration based on their simultaneous determination in urine.

A highly sensitive and selective method is developed for the simultaneous detection of dopamine (DA) and acetaminophen (AP) by reactive blue-4 (RB4) dye entrapped poly1,5-diaminonaphthalne (polyDAN) composite film layer. The polyDAN-RB4 composite is electrochemically developed at glassy carbon electrode. The polymeric film, characterized by XPS and SEM is able to catalyze the oxidation of DA and AP. Two well-defined oxidation peaks are observed in the differential pulse voltammogram (DPV). The experimental parameters affecting the analytical performance are optimized in terms of RB4 concentration, temperature, and pH. The dynamic range for DA and AP analysis is between 0.1-150 and 0.2-164μM with a detection limit of 0.061±0.002 and 0.083±0.003μM, respectively. The anionic form of the polyDAN-RB4 composite repels common metabolites present in serum and urine, and hence no interference is observed. The effect of AP on the DA concentrations in urine is also studied after the oral administration of a single as well as multiple doses. The DA concentrations have been found to decrease nearly 50±3% after prolonged AP administration.