Pico Molar Sensing of Dopamine in Presence of Serotonin Using BaMnO3/Carbon Nanostructures

Abstract

A novel electrochemical sensor for dopamine (DA) in the presence of serotonin (ST) was fabricated by modifying a glassy carbon electrode with BaMnO3 and super P carbon black. The modifier, BaMnO3 was synthesized by a co-precipitation method and subsequent calcination. The formation of a pure crystalline form of BaMnO3 was ensured during synthesis and verified by characterization techniques such as powder X-ray diffraction, infrared spectroscopy, Raman, thermogravimetry, Ultraviolet–visible spectroscopy, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray analysis. 5 mg of BaMnO3 was sufficient to allow sensor development. The sensor was characterized by electrochemical impedance spectra and cyclic voltammetry studies. The mechanism of oxidation of DA and ST at the sensor is proposed based on experimental findings. Trace level determination of DA and ST was successfully carried out using the sensor. The electrochemical oxidation of DA and ST are completely independent. The limit of detection of DA and ST are 50 pM and 5 nM respectively. The DA has a linear dynamic range (LDR) of 0.1 to 300 nM and ST has a LDR of 10 to 2300 nM. The practical utility of the sensor was demonstrated by calculating the recovery of DA in human blood serum and urine.