A laser ablation millisecond-pulsed glow discharge time-of flightmass spectrometer (LA-GD-TOFMS) for quasi-simultaneous elemental and molecular analysis

Abstract

Elemental and molecular detection capabilities of an in-house built Laser Ablation ms-pulsed Glow Discharge Time-Of-Flight Mass Spectrometer (LA-GD-TOFMS) were investigated using different organic materials and polymers. Benzoic acid, vanillic acid, polytetrafluoroethylene and polyvinyl chloride powders were pressed into pellets for analysis. The benzoic and vanillic acid were prepared both with and without added elements (Al, Cu and Pb). Analyses of these compounds were accomplished by introducing the laser ablated material into two different temporal regimes of the pulsed glow discharge (plateau and afterglow). Complementary elemental, structural, and molecular information was acquired within a single discharge pulse. While elemental ions and fragments of the analyte were detected during the plateau time regime, intact parent molecular ions M⁺ and protonated molecular ions [M + H]⁺ were recorded in the afterglow. The intermediate ionization during the plateau and the soft ionization in the afterglow provided chemical speciation of the analyte. Furthermore, all doped elements to the samples were successfully identified in the collected LAGD spectra with limits of detection in the μg g⁻¹ range. To demonstrate the analytical potential of LA-GD-TOFMS, analysis on commercially available pharmaceutical tablets was carried out.