Dual-mode electrochemical and electrochemiluminescence detection of dopamine based on perylene diimide self-assembly material

The self-assembly material N,N-bis-(3-dimethyl aminopropyl)-3,4,9,10-perylene tetracarboxylic acid diimide (PDI) is reported to show electrochemical (EC)/electrochemiluminescence (ECL) property for designing new dual-mode dopamine (DA) sensors. K₂S₂O₈ significantly improved the EC reduction current at -0.346 V and ECL intensity at -0.25 V of the PDI self-assembly material. DA largely decreased the EC reduction current and ECL intensity of this homogeneous EC/ECL material due to the competitive consumption of K₂S₂O₈ in the oxidization process of DA and the low electron conductivity of polyDA formed through the oxidization of DA by K₂S₂O₈. In addition, the ECL quenching mechanism involved an energy-transfer process resulting from the collision between the produced o-benzoquinone species (oxidization of DA) and the excited state of PDI, which decreased the ECL intensity. This homogeneous EC/ECL material showed linear EC current response for DA from 5.0 nM to 50.0 µM with a detection of limit of 2.7 nM and linear ECL response for DA from 1.0 nM to 100.0 µM with a detection of limit of 0.41 nM. The proposed dual-mode EC/ECL sensors also showed good feasibility in urine sample analysis.