Dual-ratiometric electrochemical sensor for propyl gallate detection

A dual-ratiometric electrochemical sensor was constructed for propyl gallate (PG) detection based on anthraquinone/multi-walled carbon nanotube/chitosan modified glassy carbon electrode (AQ/MWCNT/CS/GCE). In the presence of the analyte PG, the AQ/MWCNT/CS/GCE displays three current peaks at different potentials, which are respectively related to the electro-oxidation of PG, AQ, and MWCNT. Anthraquinone and multi-walled carbon nanotube can be then used as inner reference electroactive probes. It was demonstrated that the modification of the GCE with AQ, MWCNT and chitosan can enhance the electrochemical signal of PG, leading to the improvement in the sensitivity of PG detection. Two ratiometric signals, namely, IPG/IAQ and IPG/IMWCNT, linearly increase with the increasing concentration of PG over the range of 1.0 to 30.0 μM, and the detection limit for PG detection are respectively estimated to be 0.67 μM and 0.76 μM. The electrochemical sensor can be applied for PG detection in edible oil samples with satisfactory results.