Sensitive Chemiluminescent Sensing Method for Mercury(II) Ions Based on Monolayer Molybdenum Disulfide

A simple and sensitive chemiluminescent (CL) sensing platform for mercury(II) ions (Hg2+) in water was developed based on monolayer molybdenum disulfide (MoS2). The layered MoS2 can catalyze the oxidation of luminol by H2O2, producing an enhanced CL signal because of the peroxidase-like activity of the layered MoS2. In addition, MoS2 has a good adsorption ability to Hg2+ because of the inherent affinity of Hg2+ to sulfur contained in MoS2. Interestingly, the pre-incubation of Hg2+ with layered MoS2 inhibited the catalytic activity of MoS2 on the luminol-H2O2-MoS2 CL reaction, leading to CL quenching. The CL intensity decreased linearly with increasing concentration of Hg2+ from 0.005 - 40 mu M. The limit of detection (LOD) was estimated to be 1 nM. The relative standard deviation (RSD) was found to be 3.71%, indicating good reproducibility. The recoveries of Hg2+ spiked in tap water were from 100.0 to 116.0% with RSD from 2.7 to 5.6%, detected by the standard addition method, and demonstrated good applicability.