Morphology and Functionalization Dependent Sensing of Dopamine on L-Arginine Functionalized Hydroxyapatite Nanoparticles

Hydroxyapatite (HA) nanoparticles have been synthesized using L-arginine as an organic growth modifier, in addition to serving as a functionalization agent by ultrasonically assisted chemical precipitation technique. The influence of Ca2+: arginine ratio and pH of the synthetic medium on the morphology and functionalization of L-arginine on HA and their collective role in the selective electrochemical determination of dopamine (DA) has been elucidated. The electrochemical behavior of DA at L-arginine functionalized HA (fHA) containing carbon paste electrodes was investigated using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and differential pulse voltammetry (DPV). fHA containing carbon paste electrode exhibits excellent sensing ability toward DA than their counterparts. The role of the morphology of HA and the nature of functionalization of L-arginine on HA towards sensing DA is related to a plausible mechanism of interaction. The most proficient electrode was found to exhibit a wide linear current response in the concentration range of 5 mu M- 200 mu M, with 0.32 mu M as a limit of detection. The practical application of the fabricated electrode was successfully confirmed by the real sample analyses carried out using DA injection as well as in human urine samples.