A new dual-signalling electrochemical sensing strategy based on competitive host-guest interaction of a β-cyclodextrin/poly(N-acetylaniline)/graphene-modified electrode: sensitive electrochemical determination of organic pollutants.

Based on the competitive host-guest interaction between a β-cyclodextrin/poly(N-acetylaniline)/electrogenerated-graphene (β-CD/PNAANI/EG) film and probe or target molecules, a new dual-signalling electrochemical sensing method has been developed for the sensitive and selective determination of organic pollutants. As a model system, rhodamine B (RhB) and 1-aminopyrene (1-AP) were adopted as the probe and target molecules, respectively. Due to the host-guest interaction, RhB molecules can enter into the hydrophobic inner cavity of β-CD, and the β-CD/PNAANI/EG-modified glassy carbon electrode displays a remarkable oxidation peak due to RhB. In the presence of 1-AP, competitive association to β-CD occurs and the RhB molecules are displaced by 1-AP. This results in a decreased oxidation peak current of RhB and the appearance of an oxidation peak current for 1-AP, and the changes of these signals correlate linearly with the concentration of 1-AP. When the value ΔI(1-AP)+∣ΔI(RhB)∣ (ΔI(1-AP) and ΔI(RhB) are the change values of the oxidation peak currents of 1-AP and RhB, respectively) is used as the response signal to quantitatively determine the concentration of 1-AP, the detection limit is much lower than that given by using ΔI(1-AP) or ΔI(RhB) as the response signal. This dual-signalling sensor can provide more sensitive target recognition and will have important applications in the sensitive and selective electrochemical determination of electroactive organic pollutants.