Depth profiling of nanometer thin layers by laser desorption and laser postionization time-of-flight mass spectrometry

Abstract

A laser desorption and laser postionization time-of-flight mass spectrometer was employed for the depth profiling of nanometer thin-layers.

Spatiotemporal Visualization of Insecticides and Fungicides within Fruits and Vegetables Using Gold Nanoparticle-Immersed Paper Imprinting Mass Spectrometry Imaging

“…Additionally, although higher laser irradiance affords more detectable molecular species, the mass spectral resolution can be compromised because of the high energy dispersal of ions. Therefore, a time-lag focusing technique derived from a multichannel delay pulse generator was adopted for improved spectral resolution [ 38 , 39 ]. The region of interest (ROI) can be clearly observed by a built-in camera.…”

Perspective on Advances in Laser-Based High-Resolution Mass Spectrometry Imaging

“…At present, several effective postionization methods have been developed. As the ions only make up a small fraction of the ablated material relative to the ratio of neutral atoms/molecules, ionizing these original “waste” neutral atoms/molecules has shown a great potential to increase utilization and sensitivity. ,,,− Furthermore, the postionization can separate desorption and ionization processes spatially and temporally, ,, which makes it possible to control and optimize both events, respectively. Some postionization techniques have been applied including EI, ,, ESI, and APCI. − As another postionization technique of great potential, the laser has been a prominent candidate with versatile and competent abilities for postionization processes.…”

“…Some postionization techniques have been applied including EI, ,, ESI, and APCI. − As another postionization technique of great potential, the laser has been a prominent candidate with versatile and competent abilities for postionization processes. Laser postionization often proceeds utilizing single photon ionization (SPI), resonant enhance multiphoton ionization (REMPI) , and nonresonant multiphoton ionization (NRMPI) processes. , REMPI has proven to be a highly sensitive technique in the analysis of ultratrace elements and molecular species with specific electronic states. NRMPI opens the new possibility for nonselective, high-sensitivity detection of all the constituents simultaneously, which is very suitable for unknown samples.…”

“…As the ions only make up a small fraction of the ablated material relative to the ratio of neutral atoms/ molecules, ionizing these original "waste" neutral atoms/ molecules has shown a great potential to increase utilization and sensitivity. 34,35,95,109−113 Furthermore, the postionization can separate desorption and ionization processes spatially and temporally, 109,114,115 which makes it possible to control and optimize both events, respectively. Some postionization techniques have been applied including EI, 37,92,93 ESI, 77 and APCI.…”

“…Laser postionization often proceeds utilizing single photon ionization (SPI), 66 resonant enhance multiphoton ionization (REMPI) 107,116 and nonresonant multiphoton ionization (NRMPI) processes. 109,114 REMPI has proven to be a highly sensitive technique in the analysis of ultratrace elements and molecular species with specific electronic states. NRMPI opens the new possibility for nonselective, high-sensitivity detection of all the constituents simultaneously, which is very suitable for unknown samples.…”