Nanochannel-Confined Graphene Quantum Dots for Ultrasensitive Electrochemical Analysis of Complex Samples

Abstract

Herein, we present an electrochemical sensing platform based on nanochannel-confined graphene quantum dots (GQDs), which is able to detect a spectrum of small analytes in complex samples with high sensitivity. Vertically-ordered mesoporous silica-nanochannel film (VMSF) is decorated on the supporting electrode, conferring the electrode with excellent anti-fouling and anti-interference properties through steric exclusion and electrostatic repulsion. The synthesized GQDs with different functionalities are confined in the nanochannels of VMSF through electrophoresis, serving as the recognition element and signal amplifier. Without the usual need of tedious pretreatment, ultrasensitive and fast detection of Hg2+, Cu2+ and Cd2+ (with limit of detection or LOD of 9.8 pM, 8.3 pM and 4.3 nM, respectively) and dopamine (LOD of 120 nM) in complex food (Hg2+-contaminated seafood), environmental (soil leaching solution), and biological (serum) samples are realized as the proof-of-concept demonstrations.