Application of a nickel hydroxide gold nanoparticles screen-printed electrode for impedimetric sensing of glucose in artificial saliva

In this study, a non-enzymatic glucose sensor (NEGs) based on the electrochemical deposition of nickel nano particles on screen-printed electrodes modified with gold nanoparticles, Ni(OH)(2)/AuNp/SPE, is obtained. SEM and XPS measurements, and electrochemical performance reveal synergist effects of gold nanoparticles in the behavior of the catalyst when both Ni(OH)(2)/SPE and Ni(OH)(2)/AuNp/SPE systems were compared. SEM images show a homogeneous distribution of nickel spherical nanoparticles (-85 nm of diameter) in Ni(OH)2/AuNp/ SPE. XPS spectra indicate the presence of nickel(ll), probably as nickel hydroxide catalyst at the surface. The electrochemical response of Ni(OH)(2)/AuNp/SPE toward glucose oxidation and the selectivity of the proposed NEG in the presence of ascorbic acid and dopamine were evaluated by Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). In the single-frequency impedance measurements, the imaginary impedance values (Zb) showed the best linear response with glucose concentration in the range of 0.10 to 2 mM, at 0.1 Hz and + 0.400 V vs Ag/AgCl. The calibration curve for 1/Z(im), as a function of glucose concentration in artificial saliva samples was obtained with a slope of 0.073 K Omega(-1) mM(-1), R-2 = 0.995, and limit of detection of 0.04 mM of glucose. Finally, impedimetric Ni(OH)(2)/AuNp/SPE was proposed for the quantification of glucose in non-blood samples.