Journal of Electroanalytical Chemistry 860 (2020): 113881.
Transition metal nanoparticles can be considered as promising low cost materials for insulin oxidation catalysis. Combination of transition metal nanoparticles with multi walled carbon nanotubes (MWCNTs), which enlarges the active surface area of the electrode, can improve the analytical characteristics of electrodes. Two types of screen printed carbon electrodes (SPCEs) modified by the combination of copper (CuNPs) or cobalt (CoNPs) nanoparticles with chitosan and MWCNTs were prepared. In the effort to find the most suitable modification for electrochemical insulin determination, stability, analytical characteristics and selectivity of both electrode types were compared. The results proved better stability and analytical characteristics with no significant influence of interferences on insulin determination at CoNPs/chitosan-MWCNTs/SPCE. These electrodes provided low limit of detection (25 nM), high sensitivity (0.031 mA μM−1) and wide linear range (0.05 μM to 5 μM) for insulin determination. The stability of the CoNPs/chitosan-MWCNTs/SPCE was very high, with only 1.7% decrease of maximal current value after 50 measurements. Therefore, CoNPs/chitosan-MWCNTs/SPCE can be considered as the suitable modification for new electrochemical sensor for insulin determination, with better analytical characteristics in comparison with SPCE modification using MWCNTs, chitosan and CuNPs described in this study.
