Continuum removal and self-absorption correction incalibration-free laser-induced breakdownspectroscopy for efficient elemental analysis

Abstract

Even though laser-induced breakdown spectroscopy (LIBS) has emerged as a powerful analytical technique, the broad continuum emission and self-absorption effects in laser-produced plasmas (LPP) limit the accuracy of the LIBS technique in multi-elemental compositional analysis. In this work, we developed an algorithm to detect and remove the broad continuum emission, which usually originates from free-free and free-bound transitions. To eliminate the continuum, the segment-wise background correction method (using identified continuum parts of varied range) was used. The spectral interference of lines is more likely to be found in LIBS spectra, especially with low-resolution spectrometers. A Lorentzian curve fitting method was used to resolve closely spaced emission lines. The ‘internal reference self-absorption correction (IRSAC)’ method was introduced to correct the reabsorption effects in LPPs. When these methods are applied to LIBS data of bronze alloy, more accurate quantitative findings are obtained, with a major component accuracy error of less than 10% when compared to its reference abundance.