Determination of ultra-trace selenium in water via preconcentration on MIL-125-NH2 and direct Slurry-HG AFS

Abstract

The content of selenium in environmental water directly affects the metabolism of organisms. In this work, the metal organic framework (MIL-125-NH₂, MOF) was synthesized by microwave, and used as an adsorbent for the determination of selenium in water by direct slurry sampling hydride generation atomic fluorescence spectrometry (Slurry-HG AFS). By controlling a single variable, the pH, kinetics, thermodynamic and isothermal adsorption curves of selenium adsorption by the material were investigated. When pH = 6 and temperature = 298 K, the adsorption performance of the material was the best, and the maximum adsorption capacity of Langmuir was 78.77 mg g⁻¹. Slurry-HG AFS for the determination of selenium exhibited good linearity (R = 0.9972), low detection limit (LOD = 0.92 ng L⁻¹) and high accuracy (recovery rate: 90.0–106.2%), and high precision (RSD: 1.4–6.5%). The results indicated that this method has the advantages of reducing target loss, simple operation, high sensitivity and strong anti-interference ability, and was of great significance for the preconcentration and detection of ultra-trace selenium in water.