Improving the accuracy of laser-induced breakdown spectroscopy using the single-element standard curve calibration

Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) is a well-known standard-free method for the determination of elements. The accuracy of CF-LIBS is greatly affected by spectral line self-absorption, ambient noise and instrument response. In order to improve the accuracy of CF-LIBS, based on internal reference for self-absorption correction (IRSAC), we propose a single-element standard curve correction (SESCC). In the method, after correcting the self-absorption with IRSAC, we further calibrate the spectral intensities and the intercepts of the Saha-Boltzmann plots with SESCC. The quantitative results of the all elemental contents in the samples can be obtained from the corrected mean intercepts of their Saha-Boltzmann plots. To verify the validity of our method, we experimentally measure the elemental composition of five copper alloys. In the experiment, elemental Cu is used as the standard element of known concentration, while the other elements are considered as unknowns. Compared with the IRSAC, our proposed method reduces the average relative error of elemental content by 71.16%. Therefore, our method can be used to improve the accuracy of CF-LIBS.