Quantitative analysis of Li, Na and K in single-element standard solutions using portable laser-induced breakdown spectroscopy

Abstract

Laboratory-based laser-induced breakdown spectroscopy (LIBS) instruments have proven themselves for trace element analysis of an extensive range of elements. As portable devices have evolved greatly in recent years, new areas of field application are opening up. However, no portable LIBS (pLIBS) has yet been used for quantitative inorganic water analysis. The aim of this study was to explore whether pLIBS combined with a surface-enhanced liquid-to-solid conversion method can quantify light alkali element concentrations in standard solutions. Multivariate calibrations were performed with single-element standard solutions at detection limits of 0.006, 0.011 and 0.007 mg l −1 for Li, Na and K, respectively. Coefficients of determination ( R 2 ) for the calibration lines from 0.1 to 100 mg l −1 for Li and Na, and 0.1 to160 mg l −1 for K were between 0.96 and 0.99. It has been shown that the surface preparation technique used improves the homogeneity of the spread and shape of the evaporation residue and thus the accuracy and precision of the analysis. Hence, this study demonstrates that it is possible to quantify light alkali metals in single-element standard solutions in the range of 0.1 to 160 mg l −1 using handheld LIBS.