Matrix effect based on laser-induced breakdown spectroscopy

To analyze and improve the matrix effect on the quantitative analysis of cadmium (Cd) concentration in soil and rice using laser induced breakdown spectroscopy (LIBS), this article takes the Cd Ⅱ 226.502 nm spectral line as the analysis object, and compares the effects of matrix type, KCl mass concentration, and excitation method on the intensity and quantitative analysis results of Cd Ⅱ 226.502 nm spectral line. The results show that the chemical form of the main components of the matrix and the ionization energy are the main factors that produce the matrix effect. KCl as an additive can significantly improve the spectral line intensity of Cd Ⅱ 226.502 nm in rice. The photoelectric double pulse excitation can significantly enhance the spectral line intensity and stability of Cd Ⅱ 226.502 nm in the matrix, and improve the signal to noise ratio. Compared with the single laser pulse excitation method, the lower detection limit of Cd Ⅱ 226.502 nm in silicon dioxide, soil, and rice matrices decreased from 372, 332 and 2874 mg·kg⁻¹ to 42, 72 and 37 mg·kg⁻¹, respectively, under photoelectric dual pulse excitation. This study has important reference value for the development of LIBS technology and its application and promotion in the field of soil and food pollution detection.