Sensitive boron detection with surface-enhanced laser-induced breakdown spectroscopy assisted by a surface micro-structured copper foil.

In order to improve the analytical sensitivity of surface-enhanced laser-induced breakdown spectroscopy (SENLIBS) for the elemental analysis of liquid samples, a 20 µm cylindrical hole periodic micro-structure was efficiently fabricated on the surface of copper foil substrates using an integrated method of electroplating and imprinting. The periodic micro-structured surface decreases the reflectance of the incident laser and changes the interaction of the laser with the substrate. Thus, the spectral intensity of both substrates' elements and samples' elements can be effectively enhanced by SENLIBS analysis. Boron (B) in aqueous solution was quantitatively analyzed by SENLIBS using the copper foil substrate with a periodic micro-structured surface. The limit of detection (LoD) of boron reached 0.22 µg/mL under the current experimental conditions, and 3.1-fold improvement factors on the analytical sensitivity were achieved when compared with a flat copper foil substrate. For boron analysis, the quantitative results analyzed by SENLIBS are in good agreement with those analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). An efficient method for fabricating periodic micro-structure on metal surfaces was demonstrated. This approach is expected to extend the applications of SENLIBS and improve its analytical performance for elemental analysis of liquid samples.