Duplication of periodic micro-structure on the surface of a nickel substrate and its application in surface-enhanced laser-induced breakdown spectroscopy

In order to improve the analytical performance of surface-enhanced laser-induced breakdown spectroscopy (SENLIBS) on the elemental analysis of liquid samples, a 20 μm cylindric rod periodic micro-structure with 20 μm rod diameter, 15 μm rod height and 40 μm periodic length was successfully duplicated on the surface of a nickel substrate using electroplating method. The presence of periodic micro-structure on nickel surface changes the interaction of the laser and substrate; thus, plasma with higher temperature and higher electron density can be generated. The atomic emissions of both analytes and substrates' elements can be significantly enhanced in SENLIBS analysis if compared with that of using a flat substrate without any micro-structures. Mn, Pb, and Cr in aqueous solution samples were quantitatively analyzed by SENLIBS using these surface micro-structured nickel substrates. The detection limit of Mn, Pb, and Cr reached to 107.9 ng/mL, 76.0 ng/mL and 70.5 ng/mL under current experimental condition, respectively. In comparison with that obtained in similar analysis using flat nickel substrates, 4.2–5.1 folds improvement factors on the analytical sensitivity were achieved. This approach demonstrates a cost-effective and convenient method for the substrate preparation and provides a more sensitive elemental analysis of liquid samples by SENLIBS.