Rapid Detection of Trace Element Concentrations Using Laser Induced Breakdown Spectroscopy and Laser-Breakdown Time-of-Flight Mass Spectrometry

The rapid and precise measurement of trace species is imperative for various applications such as industrial process, environment and human health issues. The trace species of mercury (Hg), iodine (I), strontium (Sr), cesium (Cs) and arsenic (As) were measured in this study. Hg and iodine were measured employing two detection systems for the comparison of their detection characteristics. A laser beam was introduced to break the samples and then the emission signal and ion signal were detected using laser induced breakdown spectroscopy (LIBS) and laser breakdown time-of-flight mass spectrometry (LB-TOFMS). Multi-photon ionization and electron impact ionization in a plasma generation process were controlled by the reduction of pressure and short pulse laser breakdown. The detection limit in LB-TOFMS was improved using a picosecond laser operated at 532 nm, resulting in the increase of ion signal intensity. The detection limit of trace species was enhanced using LB-TOFMS. Hg and iodine detection limits of 600 laser shots (1 minute) using 35 ps LB-TOFMS were 1.0 ppb and 9.9 ppb (3σ) respectively, which showed better detection sensitivity than those using LIBS.