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

Abstract 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 Δ I 1‐AP +∣Δ I RhB ∣ (Δ I 1‐AP and Δ I 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 Δ I 1‐AP or Δ I 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.