Chemical Optimization for Simultaneous Voltammetric Detection of Molybdenum and Silver Nanoparticles in Aqueous Buffer Solutions

What is it about?

Simultaneous acquisition of redox signals from different types of metal nanoparticles (NPs) in a multiplexing system requires a good separation in redox potential from each component for successful identification. The appearance of a single distinct peak for each NP type is also preferred. Here, we report variations in the electrochemical nature of molybdenum (Mo) and silver (Ag) NPs cast on a glassy carbon electrode that are sensitive to various conditions of the measurement solution, such as buffering capacity and electrolyte concentration. A series of experiments allowed us to find optimal conditions, where Mo NPs showed a single oxidation peak with good separation of the redox potential from that of Ag NPs (ΔE≈0.25 V), by using differential-pulse voltammetry (DPV). In the simultaneous monitoring of Mo and Ag NPs under the optimal conditions, the peak currents in DPV were quantitative for the amount of Mo/Ag NPs ranging from 7.8/20 to 500/20 ng ng−1 and from 500/20 to 500/0.31 ng ng−1.

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