Rapid Detection of Mercury and Iodine Using Laser Breakdown Time-of-Flight Mass Spectrometry

It has been highly recognized that heavy metals and other trace species pollution concerns the environment, as well as human health. This paper describes the rapid detection of mercury and iodine using laser breakdown time-of-flight mass spectrometry at high sensitivity without partial fragmentation interference from other species. Two irradiation wavelengths 1064 and 532 nm were employed under various experimental conditions. The second harmonic 532 nm performs excellent measurement results. The influence of pressure on signal intensity displays a linear growth when increasing the pressure. The power dependence shows that as the laser power increased, mercury ion and iodine ion signal intensity increased first and then decreased. Experiment with different buffer gases clarified the recombination of mercury ion and iodine ion with electrons when increasing the laser power, resulting in the decrease of mercury ion and iodine ion signal intensity. Mercury ion signal intensity can be enhanced 3.8 times and the signal intensity of iodine ion can be enhanced 1.3 times employing 35 ps 532 nm breakdown. The detection limits (3σ/ms) of mercury ion and iodine ion signal using 35 ps laser breakdown were 0.82 ppb and 6.18 ppb, respectively.