Electrochemiluminescence sensor based on the target recognition-induced aggregation of sensing units for Hg2+ determination

Abstract In this work, the target recognition-induced aggregation of sensing units was initiated on a solid electrode to develop an enhanced surface-tethered electrochemiluminescence (ECL) sensor for Hg2+ analysis. Thymine (T) was assembled on upconversion nanoparticles (UCNP) as sensing units (T-UCNP). In the presence of Hg2+, the T monolayer-modified Au electrode (AuE/T) absorbed Hg2+ and T-UCNP by T-Hg2+-T matching. Surface-tethered T-UCNP further recruited more Hg2+, as well as T-UCNP, thus forming a UCNP-T-Hg2+-T-UCNP reticular architecture on the surface of the electrode. Hg2+ quantification was subsequently conducted by detecting the ECL signal amplified by the captured UCNP. During ECL analysis, target recognition and signal accumulation were simultaneously realized by the target-induced aggregation of T-UCNP. The simple and flexible strategy proposed in this work immobilized ECL emitters efficiently and simplified the preparation procedure of the sensor. The proposed ECL sensor displayed a low limit of detection of 0.38 pmol L−1 and favorable recoveries (84.8%–98.7%) during real-sample analysis.