▎ 摘　　要

A novel and sensitive electrochemiluminescence (ECL) sensor based on poly(5-formylindole)/reduced graphene oxide (P5FIn/erGO) nanocomposite with high conductivity is fabricated for detection of Hg-2(+). Amino modified thymine (T)-riched single-strand (DNA SI) is connected with P5FIn/erGO by covalent coupling of the amino and aldehyde groups. In this sensor, Au nanoparticle (AuNP) linked graphene quantum dots (GQDs)-DNA S3 and DNA S2 is used as ECL signal probe. The presence of AuNP can increase the load of GQDs, and the combination of AuNP and GQDs can achieve signal amplification. The signal probe can be assembled to the modified electrode for hybridizing with DNA SI in the presence of target Hg-2(+) through T-Hg-2(+)-T coordination chemistry. The fabricated ECL sensor exhibits a wide linear response to Hg-2(+) ranging from 0.01 nM to 100 nM, and the detection limit is 2.48 pM. Moreover, this ECL sensor displays good stability, reproducibility and selectivity to Hg-2(+) against other interference ions, and can be utilized to detect Hg-2(+) in tap water and human serum samples with good performance.