Abstract | Electrodeposition of Pt-Pb nanoparticles (PtPbNPs) to multi-walled carbon nanotubes (MWCNTs) resulted in a stable PtPbNP/MWCNT nanocomposite with high electrocatalytic activity to glucose oxidation in either neutral or alkaline medium. More importantly, the nanocomposite electrode with a slight modification exhibited high sensitivity, high selectivity, and low detection limit in amperometric glucose sensing at physiological neutral pH (poised at a negative potential). At +0.30V in neutral solution, the nanocomposite electrode exhibited linearity up to 11mM of glucose with a sensitivity of 17.8muAcm(-2)mM(-1) and a detection limit of 1.8muM (S/N=3). Electroactive ascorbic acid (0.1mM), uric acid (0.1mM) and fructose (0.3mM) invoked only 23%, 14% and 9%, respectively, of the current response obtained for 3mM glucose. At -0.15V in neutral solution, the electrode responded linearly to glucose up to 5mM with a detection limit of 0.16mM (S/N=3) and detection sensitivity of approximately 18muAcm(-2)mM(-1). At this negative potential, ascorbic acid, uric acid, and fructose were not electroactive, therefore, not interfering with glucose sensing. Modification of the nanocomposite electrode with Nafion coating followed by electrodeposition of a second layer of PtPbNPs on the Nafion coated PtPbNP/MWCNT nanocomposite produced a glucose sensor (poised at -0.15V) with a lower detection limit (7.0muM at S/N=3) and comparable sensitivity, selectivity and linearity compared to the PtPbNP/MWCNT nanocomposite. The Nafion coating lowered the detection limit by reducing the background noise, while the second layer of PtPbNPs restored the sensitivity to the level before Nafion coating. |
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