多径腔增强激光诱导击穿光谱用于合金中痕量元素的高灵敏检测

激光诱导击穿光谱(LIBS)在合金表面痕量元素分析领域具有重要的潜在应用价值,尽管LIBS甚至是双脉冲LIBS(DP-LIBS)已具有很高的检测灵敏度,但对部分元素的检出限(LOD)仍无法满足某些应用需求。为了进一步降低DP-LIBS的LOD,提出了一种共心多径腔(CMC)增强DP-LIBS(CMC-DP-LIBS)技术,使双脉冲激光中的再加热激光在CMC腔室内经多次反射和会聚来持续加热等离子体,充分利用再加热激光的能量,最终实现光谱信号和检测灵敏度的提升。对锌样品表面Mn元素检测的实验结果显示,CMC-DP-LIBS较正交再加热DP-LIBS的LOD降低了63%,说明了CMC-DP-LIBS确实大幅提升了LIBS的检测灵敏度,提升了LIBS在合金表面痕量元素分析中的应用价值,特别是对样品烧蚀及损伤有特殊需求的应用领域。

Sensitive trace element analysis of alloys using multipass cell enhanced laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) has great potential in surface trace element analysis of alloys. Although LIBS, even double-pulse LIBS (DP-LIBS) has greatly improved the sensitivity, its limit of detection (LOD) is not sufficient for some applications. To further improve the sensitivity of DP-LIBS, concentric multipass cell (CMC) enhanced DP-LIBS (CMC-DP-LIBS) technique was proposed, which using CMC to reflect and refocus the reheating laser pulse, heating the plasma continuously. The energy of reheating laser was fully used in this way, thus improving the spectral signal and sensitivity. The results based on the detection of Mn on the surface of Zn samples showed that CMC-DP-LIBS lowered the LOD of Mn by 63% compared with orthogonal reheating DP-LIBS, which indicated that CMC-DP-LIBS indeed greatly improved the sensitivity of LIBS, and was able to expand more application in surface trace element analysis of alloys, especially for the field where the ablating and damage of the samples were restricted.