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

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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 μM. 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.