▎ 摘　　要

A novel channel-switch-mode strategy for simultaneous sensing of Fe3+ and Hg2+ is developed with dual-excitation single-emission graphene quantum dots (GQDs). By utilizing the dual-channel fluorescence response performance of GQDs, this strategy achieved a facile, low-cost, masking agent-free, quantitative and selective dual-ion assay even in mixed ion samples and practical water samples.