Impedimetric and stripping voltammetric determination of methamphetamine at gold nanoparticles-multiwalled carbon nanotubes modified screen printed electrode

• SPE/MWCNTs-Nf/GNPs was used as a novel electrochemical sensor for quantitative detection of MA in alkaline solutions.
• The MA oxidation has been investigated by SWASV and EIS owning high sensitivity.
• The synergistic effect of MWCNTs and GNPs could greatly improve the electrode performance.
• Wide linear dynamic range, good reproducibility, high stability and fast response were the main advantages of the proposed impedimetric sensor.

A high performance electrochemical sensor for the detection of methamphetamine (MA) at the gold nanoparticle (GNP)/multiwalled carbon nanotube (MWCNT)-Nafion (Nf) modified screen printed electrode (SPE) is reported. Gold nanoparticles were electrodeposited on the substrate using a constant potential. Energy dispersive X-ray (EDX) spectrum and mapping and also scanning electron microscopy (SEM) results showed that GNPs were deposited and dispersed uniformly on the SPE/MWCNTs-Nf-Nf, respectively. The electrochemical behavior of MA was studied by cyclic voltammetry (CV), and modified electrode was used for the determination of sub-nanomolar amounts of MA in samples using square wave stripping voltammetry (SWSV) and electrochemical impedance spectroscopy (EIS). Under the optimized experimental conditions, the modified SPE revealed broad linear ranges of 0.02–0.1 and 3.0–50 μM (LOD = 6 nM) for SWSV and 1.15–26.9 nM (LOD = 0.3 nM) for EIS. Finally, the SPE/MWCNTs-Nf/GNPs showed stable electrochemical cyclic voltammetry responses. The high performances of the novel MA impedimetric sensor are mainly attributed to high surface area-to-volume ratio, excellent conducting capability and interface-dominated properties of GNPs which in combination with special properties of MWCNTs provide an effective modifier for MA oxidation. Moreover, using sensitive methods like impedimetric and stripping results in excellent responses.

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