Construction of a new functional platform by grafting poly(4-vinylpyridine) in multi-walled carbon nanotubes for complexing copper ions aiming the amperometric detection of l-cysteine

This work describes the preparation of an amperometric sensor for electrocatalytical detection of l-cysteine (Cys). The developed sensor is based on a functional platform to complex copper ions on multi-walled carbon nanotubes (MWCNTs) modified with poly-4-vinylpyridine (PVP) through an in situ polymerization. The obtained values for the kinetic constants of heterogeneous electron transfer rate (ks) and for chemical reaction (kobs) between Cu2+ and cysteine were 5.78 s−1 and 6.96 L mol−1 s−1, respectively. The analytical curve showed a linear response range for detecting l-cysteine in concentrations from 5 to 60 μmol L−1. The detection and quantification limits obtained were 1.50 and 5.00 μmol L−1, respectively with a response time of 0.10 s at an applied potential of 150 mV vs SCE.

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► Construction of new nanostructured platform based on MWCNTs–PVP to complex copper(II) ions.
► Development of an amperometric sensor for highly selective determination of Cys in food supplement samples.
► Combination of nanocomposite and the copper(II) ions causes a dramatic enhancement in the sensitivity of Cys quantification at low overpotential.