Single particle microwave plasma optical emission spectrometry (SP MWP OES) for selenium nanopowder analysis: from size to elemental composition and surface characteristics

Abstract

Single particle microwave plasma optical emission spectrometry (SP MWP OES) was applied for the characterization of selenium nanopowder synthesized via a microwave-assisted green protocol using citrus juice as a reducing and stabilizing agent. The technique enabled real-time, single-particle detection of elemental signals, allowing assessment of particle size distribution and surface composition. The influence of particle size on signal intensity was determined using in-house synthesized quasi-spherical SeNP standards of known sizes. Time-correlated selenium and carbon signals confirmed the presence of surface-bound carbon-containing biomolecules, while co-detection of cadmium indicated potential interactions between SeNPs and cadmium species. These findings highlight the utility of SP MWP OES for probing nanoparticle surface functionalization and compositional variability. Although current calibration focused on spherical SeNPs, further development will address more complex systems. Overall, SP MWP OES proves to be a sensitive and informative tool for the characterization of SeNPs in biologically and environmentally relevant contexts.