Dual detection strategy for electrochemical analysis of glucose and nitrite using a partitionally modified electrode

A dual-region modified electrode was designed and fabricated by means of partitioned electrodeposition of gold and platinum nanoparticles on an indium tin oxide (ITO) conductive glass for dual-component electrochemical detection. The two differently modified regions were assigned to detect two analytes, separately and simultaneously. The gold nanoparticle modified ITO region (AuNPs/ITO) was used for glucose detection while the platinum nanoparticle modified ITO region (PtNPs/ITO) for nitrite detection. The glucose oxidation peak current at 0.10 V on AuNPs/ITO exhibited a linear dependence on the concentration of glucose and was used to determine the concentration of glucose in dual-detection. The nitrite reduction peak current at PtNPs/ITO showed a nonlinear dependence on the concentration of nitrite. A theoretical model combining the adsorption-controlled and the mass-transfer-controlled kinetics was proposed to quantitatively describe the nonlinear behavior. Though the presence of glucose interfered with the electrochemical detection of nitrite, it was demonstrated that the influence of glucose on nitrite detection can be corrected. On the basis of the proposed theoretical model, the simultaneous dual-detection of glucose and nitrite was accomplished at ITO electrodes partitionally modified with AuNPs and PtNPs.