OPTIMIZATION OF CONDITIONS FOR DETERMINATION OF Cr AND Ni IN STEEL BY THE METHOD OF LASER-INDUCED BREAKDOWN SPECTROSCOPY WITH THE USE OF PARTIAL LEAST SQUARES REGRESSION

摘要

The effect of laser energy and acquisition time delay on the overall analytical performance of laser-induced breakdown spectroscopy (LIBS) analyses for Cr and Ni in steel samples is evaluated. The analyses were carried out by using the partial least squares regression (PLSR) algorithm. The optimum analytical condition for analysis based on the signal-to-noise ratio (SNR) was found to be nearly the same for both elements. Five additional experimental conditions using different combinations of laser energy and acquisition time delay were also used for the LIBS studies. The least standard error of prediction was obtained at the optimal experimental conditions based on best SNR (90-95 mJ of laser energy with 1.1-1.3 μs acquisition time delay). With deviation from the optimum condition in either laser energy or acquisition time delay axis, the error in prediction increases, indicating a poorer analytical performance for both Cr and Ni.