Interfacing an ion funnel into laser ablation time of flight mass spectrometry

Abstract

In the present work the development and characterization of a novel laser ablation ion source for element mass spectrometry is presented. The concept of Laser Ablation Mass Spectrometry (LAMS) was introduced in the 60s by Honig and Woolston. The at that time presented method showed a strong matrix dependence of the ion yields which made the use of LAMS for quantitative analyses challenging. A major reason for this can be attributed to the nanosecond (ns) lasers pulses used for ablation in high vacuum. In this work, a novel strategy is presented, using laser ablation at elevated pressure in Combination with differential pumping via a convergent divergent (CD) nozzle and an RF only ion funnel to transfer the ions to the mass spectrometer. The CD- nozzle and RF only ion funnel achieve an efficient collisional cooling of laser generated ions and their separation From the buffer gas. This configuration ensures a sufficient pressure difference between ion source (up to 100 mbar) and the mass spectrometer (10E−6 mbar) while allowing for multiple collisions.