Fabrication of an imprinted electrochemical sensor from l-tyrosine, 3-methyl-4-nitrophenol and gold nanoparticles for quinine determination.

This study employed a molecularly imprinted composite (MIC) to develop a selective and very sensitive sensor for the determination of quinine. To fabricate the MIC sensor, 3-methyl-4-nitrophenol (MNP) and L-tyrosine (Tyr) were simultaneously electrodeposited in acidic media containing HAuCl4 to entrap Au nanoparticles (AuNPs) into the formed composite network. The effect of Tyr on the sensitivity and selectivity of the sensor and its electrochemical performance were evaluated. The signal reduction of the Fe2+ probe during differential pulse voltammetry (DPV) was used to determine the concentration of quinine. The signal was found to be linear over the quinine concentration range of 0.1 to 1000 pM with a detection limit of 0.05 pM. The sensor was used to determine the quinine content of several plasma and urine samples.