Abstract:
The aim of this work was to increase sensitivity and selectivity in electroanalysis through surface nanostructuring. Electrode surface nanostructuring was done via electronucleation of gold nanoparticles (AuNPs) on Glassy carbon electrode (GCE). Gold nanoparticles deposited glassy carbon electrode was grafted with organic film using cyclic voltammetry. Three types of organic films were selected for surface modification; P-phenylenediamine (representing electropositive film), 4-aminophenol (representing neutral film) and p-nitroaniline (representing electronegative film). Nanoholes were produced by stripping deposited AuNPs and the fabricated electrodes were characterized using potassium hexacynoferrete (negative redox probe), hydroquinone (neutral redox probe) and ruthenium hexamine chloride (positive redox probe). Sensitivity and selectivity of the modified elctrodes were increased by analyzing electropositive analyte on electronegative film grafted nanostructed electrode and electronegative analyte on electropositive film grafted nanostructed electrode. Electroanalytical application of nanohole 4-aminophenol grafted GCE and nanohole P-phenylenediamine grafted GCE were studied for ascorbic acid (electronegative analyte) determination with their respective Limit of detection ( LOD = 3 /slope) 0.626 µ mol/L and 0.123 µ mol/L respectively. Electroanalytical application of nanohole p-nitroaniline grafted GCE was studied for detection of dopamine hydrochloride (electropositive analyte) with LOD 0.0611 µmol/L. Sensor response of AA and DA was not affected by possible interfering species and the three nanostructured electrodes showed good reproducibility and stability.
