A simple and effective flexible electrochemiluminescence sensor for lidocaine detection

A cost-effective, simple, flexible, reproducible electrochemiluminescence (ECL) sensor is a prerequisite for the development of possible foldable sensing devices. Herein, a three-dimensional (3D) flexible electrochemiluminescence (ECL) sensor was fabricated based on a porous graphene paper electrode (GPE) with high specific surface area, excellent conductivity and a wide electrochemical potential window. The 3D GPE was fabricated by a simple tape stripping method. It keeps its original appearance after stripping five times, and retains good electrochemical characteristics after folding 200 times. Tripropylamine was used as a representative ECL coreactant to evaluate the proposed sensor, which showed a linear relationship in the concentration range between 5 nM and 1 mM and a low detection limit of 2.8 nM (S/N ≥ 3). It also exhibited excellent reproducibility and long-term stability. Importantly, this electrode could also be used for analysis of the drug lidocaine in human serum, achieving a wide detection range of 10 nM–10 mM and a low detection limit of 7.8 nM (S/N ≥ 3). The proposed 3D GPE was thus shown to be advantageous in terms of simple operation, foldability, and applicability compared with most previous ECL sensors.