Novel affinity monolithic column modified with cuprous sulfide nanoparticles for the selective enrichment of low‐molecular‐weight electron‐rich analytes

A novel monolithic column modified with cuprous sulfide nanoparticles was developed and its affinity characteristics towards low‐molecular‐weight electron‐rich analytes were investigated. In the synthesis process, home‐made cuprous oxide nanocubes were immobilized on the surface of monolithic skeleton with the moderate thickness based on the strong interaction between imidazole groups and cuprous oxide, then the cuprous oxide layer was transformed into the more stable cuprous sulfide layer through the treatment by sodium sulfide. The resulting cuprous sulfide modified monolithic column presented good permeability and stability in a wide pH range from 2 to 10. Two kinds of typical electron‐rich analytes, kanamycin A and purine, were chosen to assess its affinity characteristics. Compared with the commercial Cu²⁺‐ and Ni²⁺‐based affinity sorbents, a larger binding capacity of cuprous sulfide modified column toward kanamycin A was obtained under basic condition and the recovery of kanamycin A in a milk sample was over 70%. Moreover, the binding capacity of cuprous sulfide modified column for purine was up to 5.57 mg/mL in frontal elution mode. These results suggested that the Cu₂S column has a promising application for the enrichment of electron‐rich analytes.