A New Dual-Signalling Electrochemical Sensing Strategy Based on Competitive HostGuest Interaction of a β-Cyclodextrin/Poly(N-acetylaniline)/Graphene-Modified Electrode: Sensitive Electrochemical Determination of Organic Pollutants

Based on the competitive hostguest interaction between a -cyclodextrin/poly(N-acetylaniline)/electrogenerated-graphene (-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, rhodamineB (RhB) and 1-aminopyrene (1-AP) were adopted as the probe and target molecules, respectively. Due to the hostguest interaction, RhB molecules can enter into the hydrophobic inner cavity of -CD, and the -CD/PNAANI/EG-modified glassy carbon electrode displays a remarkable oxidation peak due to RhB. In the presence of 1-AP, competitive association to -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 I1-AP+IRhB (I1-AP and IRhB 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 I1-AP or IRhB 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.