Advances in discharge-based microplasmas for the analysis of trace species by atomic spectrometry

Microplasmas have become an actual topic of interest for research in atomic spectrometric systems. Their excellent characteristics including low power consumption and small size and weight make the use of microplasmas a promising technique for developing portable analytical instrumentations for the real-time and on-site measurement of trace species. In this review, the current status of discharge-based microplasmas is presented and discussed from the viewpoint of four typical applications in the field of atomic spectrometry, i.e., excitation source, atomizer, ionization source, and induced vapor generation. Microplasma excitation sources are not only highlighted for the direct detection of trace species by optical emission spectrometry (OES), but also focused on for a series of coupling techniques with gas chromatograph (GC), microelectrodialysis (μED), capillary electrophoresis (CE), chemical vapor generation (CVG), and electrothermal vaporization (ETV). Besides the atomization function, microplasma atomizers could serve as a preconcentration device to achieve the trapping and release of analytes in atomizers. Microplasma ionization sources are used to ablate compounds from sample surfaces for analyte detection and profile analysis. Microplasma-induced vapor generation provides a novel sample introduction approach with the feature of being a green analytical method. The future prospects of microplasma application in the field of atomic spectrometry are also described.