Stability and accuracy improvement of element in water using LIBS with geometric constraint liquid-to-solid conversion

Poor spectral stability and low detection accuracy limit the development of laser-induced breakdown spectroscopy (LIBS) in liquid analysis. A simple and fast new liquid pretreatment method, namely geometric constraint liquid-to-solid conversion (GCLSC), was used in sample pretreatment of LIBS to improve the spectral stability and detection accuracy simultaneously. Aluminum (Al) target was used as a substrate. The boron (B) and chromium (Cr) in aqueous solution were analyzed using LIBS with GCLSC. The results showed that the spectral stability and detection accuracy of LIBS in liquid analysis could be improved by using GCLSC compared with filter paper assisted liquid-to-solid conversion (FPLSC) and unconstrained direct liquid-to-solid conversion (UDLSC). The relative standard deviation (RSD) values of B and Cr for the GCLSC method were 6.8% and 4.6%, respectively. The root-mean-square error of cross validation (RMSECV) values of B and Cr for GCLSC were 2.09 mg/L and 1.63 mg/L, respectively. The experimental results demonstrated that the GCLSC method is a promising method to improve the stability and accuracy of LIBS quantitative analysis in liquids detection.