Quantification of the Trace Metal Element Cr in Stainless Steel Using Picosecond Laser-Induced Breakdown Spectroscopy at Atmospheric Pressure

In the metal sector, the trace elemental analysis of stainless steel is required to regulate product quality. In this work, such analysis was carried out using laser-induced breakdown spectroscopy (LIBS) with a picosecond Nd:YAG laser in a He gas environment and ambient air. The results confirm the enhancement in LIBS emission signals in He gas compared to ambient air, which was achieved by increasing the plasma temperature and electron density. The quantification of the trace element Cr in steel samples was conducted herein. Excellent linear calibration curves of Cr I 425.4 nm with a zero intercept were successfully produced, using Fe I 426.0 nm as an internal standard. The detection limit of Cr was approximately 2 and 3 ppm for picosecond LIBS in He gas and ambient air, respectively. Current LIBS technology is notably helpful in identifying trace elements in the metal industry.