Electropolymerization of molecularly imprinted polypyrrole film on multiwalled carbon nanotube surface for highly selective and stable determination of carcinogenic amaranth

A novel amaranth electrochemical sensor was produced by electrodepositing a molecularly imprinted polypyrrole film in the presence of amaranth on a multi-walled carbon nanotube (MWCNT) surface. Template molecules were completely eluted through an innovative strategy that only requires the application of a fixed electrical potential in a blank phosphate buffer solution. Obviously, this strategy is much faster and more eco-friendly. The molecularly imprinted polymer (MIP)-based electrochemical sensor was systematically investigated by scanning electron microscopy, atomic force microscopy, X-ray diffraction, cyclic voltammetry, and electrochemical impedance spectroscopy. The resultant MIP/MWCNT modified glass carbon electrode (MIP/ MWCNT/GCE) shows satisfactory electroactive surface area and charge transfer resistance. As expected, the electrochemical response signals were significantly amplified at the MIP/MWCNT/GCE. Under optimal conditions, the proposed MIP/MWCNT/GCE exhibits extraordinarily good analytical performance for amaranth detection, with two wide detection ranges (0.007 mu M to 1.0 mu M, and 0.40 mu M to 17 mu M) and detection possible down to 0.4 nM. Moreover, the polypyrrole MIP films show high binding affinity and specifically identifies amaranth molecules, enabling the robust detection of amaranth in a complicated matrix with excellent selectivity, reproducibility, and stability. The proposed sensor achieves accurate detection of amaranth concentration in various fruit drinks with acceptable recovery.

Automated summary

A novel amaranth electrochemical sensor was developed by electrodepositing a molecularly imprinted polypyrrole film on a MWCNT surface, leading to enhanced detection performance and environmental friendliness. The sensor allows fast and accurate detection of amaranth concentration in fruit drinks, exhibiting excellent selectivity and stability.