Progress in calibration-free laser-induced breakdown spectroscopy

Direct elemental analysis of materials via modeling of the laser-produced plasma emission attracted great interest since the introduction of calibration-free laser-induced breakdown spectroscopy in 1999. However, the large number of different approaches and their validation in diverse experimental conditions make it difficult to evaluate the achievable performance with this revolutionary type of analytical measurements. The purpose of the present paper is to provide a critical review of the development of calibration-free LIBS, to highlight the progress being achieved until now, and to estimate its available analytical performance. Based on the identification of the principal sources of measurement uncertainty, solutions are proposed to further improve the accuracy in order to bring calibration-free LIBS to the standard of fully recognized analytical methods.