Investigation of the self-absorption effect using spatially resolved laser-induced breakdown spectroscopy

The self-absorption effect will seriously influence the accuracy of quantitative analyses using laser-induced breakdown spectroscopy (LIBS). To reduce the self-absorption effect, elements Na and K (major elements) and Pb and Cu (minor elements) in soil plasmas have been studied by spatially resolved LIBS (SRLIBS). The 2-dimensional distributions of line intensities and self-absorption coefficients of lines in the plasmas were investigated and the influence parameters of the self-absorption effect were also studied. Results have shown that the self-absorption effect could be reduced greatly and the accuracy of quantitative LIBS could be improved obviously by selecting the collecting zones of the plasmas carefully. Meanwhile, a high laser energy and a short delay time could be useful to expand the region which is influenced slightly by the self-absorption effect.