Abstract: Based on their inherent features and various light-material interactions, the lasers are capable of atomizing and ionizing almost all known materials, therefore, empower tremendous opportunities in advancing mass spectrometry (MS) and significantly expanded its application scopes. By utilizing laser ablation, atomizing, ionizing, and sampling hard materials in open air are made possible. However, due to multiple matrix effects in open air, including ablated-matter-air reactions, rapid ion dissociation, and low ionization efficiency in open air, corresponding performances of the open-air MS (OA-MS) are far from satisfactory. In this study, we explored approaches,

1) laser-induced thermal desorption,

2) magnetic-field-assisted plasma confinement, and 3) direct plasma sampling, to address the

challenges. By thermally desorbing analytes without disrupting their wholeness, it is possible to

detect the analyte molecules directly rather than molecular fragments. Detection sensitivity can

be obviously improved by resonantly activating corresponding reactive species. External

magnetic fields were deployed to assist the confinement and propagation of the laser-ablated

plasma plumes, therefore, elongated the lifetime of the plasma and drove the movement of the

plasma towards the MS orifice. To minimize the open-air matrix effects, direct plasms sampling

was realized for accurate analysis.

Keywords: laser ablation, mass spectrometry, open air, magnetic field, plasma.

Biography: Dr. Yun Shen Zhou is currently a Research Associate Professor in the Department

of Electrical and Computer Engineering at the University of Nebraska-Lincoln. He obtained his

B.Sc. (Material Science and Engineering) and Ph.D. (Condensed Matter Physics) degrees from

the University of Science and Technology of China. His current research interests include laserassisted

material synthesis, micro/nano-fabrication, open-air mass spectrometry, et al.