Rapid determination of Se(IV) and tSe in fungal samples by foam electrode-based electrolytic hydride generation coupled atomic fluorescence spectrometry

The key to accurately identifying trace heavy metal elements is to achieve efficient sample introduction while shielding the interference of matrix components. Taking the electrolytic hydride generation (EHG) technology as an example, this paper explored the effects of cathode materials and structural factors on the electrosynthesis of hydrogen selenide (H₂Se), particularly on suppressing interference from coexisting components. Systematic electrochemical and spectroscopic tests show that the nickel-based electrode can promote the generation of H₂Se, while the multi-layer foam structure with large specific surface area, rich pores and weak gas evolution effect improves the yield and stability of electrosynthesis reaction. Even if the surface state of the electrode changes due to the electrodeposition of high concentration interference ion, the electrochemical behavior of selenium (Se) is basically not affected. After coupling with an atomic fluorescence spectrometer detector, this method has a low detection limit (0.13 μg L⁻¹), a wide linear range (2–100 μg L⁻¹), and stable signal output (RSD, 3.3%, n = 11). With the assistance of high-frequency ultrasound sample extraction and pre-reduction measures, Se(IV) and total Se (tSe) in fungal samples such as mushrooms can be quickly quantified without pre-separation of the matrix. The contribution of this study is to provide an economical and sustainable electrochemical gas separation strategy for spectroscopic quantification of trace and even ultra-trace heavy metal elements in complex matrices.