Accurate quantitative analysis of metal oxides by laser-induced breakdown spectroscopy with a fixed plasma temperature calibration method

Abstract

Titanium (Ti) in Al₂O₃ was accurately and quantitatively analyzed by laser-induced breakdown spectroscopy (LIBS) with a fixed plasma temperature calibration method. Two calibration methods with fixed energy of laser pulses and fixed plasma temperature were employed to establish the calibration curves of Ti in the measured samples. Experimental results showed that the calibration method with fixed energy of laser pulses traditionally used in LIBS is not suitable for the analysis of Ti in Al₂O₃ due to the difference of the plasma temperature of samples with different Ti content caused by strong matrix effects. Instead, the calibration method with fixed plasma temperature can minimize the matrix effects and provide a more accurate calibration curve. The correlation coefficients R² of the calibration curve with fixed plasma temperature reaches 0.9938 with a relative standard deviation of 4.3%, which is significantly improved compared with values of 0.9457 and 12.5% for the calibration curve with fixed energy of laser pulses. The results illustrate that the LIBS technique with the fixed plasma temperature calibration method presents great potential for the analysis of metal in metal oxides.