A magnet-renewable electroanalysis strategy for hydrogen sulfide in aquaculture freshwater using magnetic silver metal-organic frameworks

A magnet-renewable electroanalytical strategy has been initially developed for monitoring hydrogen sulfide (H2S) in aquaculture freshwater systems using magnetic Fe3O4-loaded silver metal-organic framework (Fe3O4@Ag-MOF). The magnetic composites were synthesized by a hydrothermal route and further attached onto the magnetic electrodes. It was discovered that the Fe3O4@Ag-MOF-based electrochemical sensors could exhibit the extremely sharp and steady signals of solid-state Ag/AgCl electrochemistry at a lower potential. Furthermore, the highly specific and irreversible S-Cl replacement reactions could occur in the presence of H2S, so as to induce the conversion of AgCl into non-electroactive Ag2S with the rational decline of Ag/AgCl signals. Importantly, theFe(3)O(4)@Ag-MOF-modified electrodes could be renewed simply by the removal of the magnet after each of the detection cycles for the next immobilization of Fe3O4@Ag-MOF probes. The developed electroanalytical method could facilitate the detection of H2S in the linear range from 4.0 to 1400 nM, with a limit of detection down to 2.0 nM. Besides, it was employed to detect H2S in aquaculture freshwater samples of fish, crab, and shrimp, showing the satisfactory results. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

A magnet-renewable electroanalytical strategy has been developed for monitoring hydrogen sulfide (H2S) in aquaculture freshwater systems using magnetic Fe3O4-loaded silver metal-organic framework (Fe3O4@Ag-MOF). The method exhibits sensitive and stable signals with rational signal decline in the presence of H2S. The electrodes can be easily renewed for immobilization of Fe3O4@Ag-MOF probes, facilitating detection in aquaculture freshwater samples.