carbon paste (CP) electrode modified with gold nanoparticles (GNMCPE) was
introduced. The advantages of the gold nanoparticles enhanced the sensitivity of
the CP-electrode significantly. In a mixture of DA, AA and UA the sensor shows
high selective response towards DA and no response for AA or UA. The effect of
various experimental parameters including time of deposition of gold
nanoparticles on CP-electrode, pH, scan rate, accumulation time and types of
electrolytes were studied to find the highest sensitivity for the determination of
DA. Another promising electrochemical sensor was developed using carbon paste
electrode, gold nanoparticles and Nafion (CP-electrode/Nafion modified with gold
nanoparticles-[electrode (2)]). This sensor is sensitive for the determination of
catecholamine compounds, in the presence of interference molecules.
Simultaneous determinations of DA with 5-TH and ACOP with L-DOPA in binary
mixtures were achieved with good separation. Also a highly sensitive and simple
method was investigated for the determination of acetaminophen and morphine
using both electrodes. Under optimized experimental conditions, their sensitivities
were improved greatly. Moreover, the present method was also applied for their
determination in the presence of common interferents and in binary mixture with
dopamine (DA). Also the effect of various experimental parameters on the
voltammetric response of TR and GSH were investigated using [electrode (2)]. At
the optimum conditions, the concentration of TR and GSH was determined and the
effects of common interferences on the current responses were studied. The results
showed that the method was simple and sensitive enough for their determination in
clinical preparations and in commercial tablet under physiological conditions with
good precision.