Direct Mass Spectrometric Analysis of Solid Coal Samples Using Laser Desorption/Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Abstract

The direct analysis of complex organic solid samples, such as coal, still represents a challenge for mass spectrometric researchers. In this work, we present an approach to analyze various carbonaceous samples with different degrees of coalification (one peat and five coals) using laser desorption/ionization in negative ion mode (LDI(−)) and ultrahigh resolving Fourier transform ion cyclotron resonance mass spectrometry. This preparation and analysis method enables a characterization of reactive organic molecules in their native state, without a need for excessive sample preparation or processing. By combining ultrahigh resolving mass spectrometry with different chemometric analyses, an in-depth characterization of the analyzed peat and coal samples was possible, and a correlation between the mass spectra and the degree of coalification of each sample could be verified. As a proof of concept, various analytical standard molecules were analyzed at increasing laser powers to demonstrate that the detected coal-related molecules are actually contained in the samples and were not simply formed by fragmentation reactions during the LDI process. Overall, the direct analysis method presented is a time-saving alternative to analyze complex organic solid samples of all kinds by mass spectrometry.

Analytics Driving Kinetics: Advanced Mass Spectrometric Characterization of Petroleum Products

“…536 It may resolve the ionized analytes according to their individual cyclotron frequencies, which are inversely related to the mass-to-charge ratios (m/z) of the analyte ions. 37 FT-ICR-MS can be utilized for very high-boiling and non-boiling petroleum fractions beyond the reach of GC/GC × GC through direct insertion or infusion. FT-ICR measures the motion of ion orbiting trapped in a magnetic field of an analyzer cell.…”

“…592,593 It is known that direct ionization sources may exhibit drawbacks in comparison to classical ionization methods such as ESI, due to pronounced signal suppression and low detection selectivity. 37 Therefore, coupling LDI source with FT-ICR-MS seems to have a high potential for direct analysis of the volatile and reactive part of a complex solid sample. LDI-FT-ICR-MS 73,[594][595][596] can offer a higher mass resolution, mass resolving power, and mass accuracy, enabling the analysis of complex petroleum mixtures on a molecular level.…”

“…In a recent work of Zuber et al 37 the application of a direct preparation and analysis method for LDI(-)-FT-ICR-MS analysis of organic solid samples was demonstrated. The researchers analyzed six carbonaceous samples with different degrees of coalification -one peat (PECZ), three brown coals (BCSO, BCSL, BCHA), one hard coal (HCPO), and an anthracite (ANIB).…”

“…19 To be able to achieve this from compounds with high sensitivity, the expansion of MS has initiated. The key factor that makes the application of MS possible, is the methods of ionization such as electron ionization (EI), chemical ionization (CI), electrospray ionization (ESI), [20][21][22][23] atmospheric pressure photoionization (APPI), [24][25][26][27][28][29] atmospheric pressure chemical ionization (APCI), [29][30][31][32] atmospheric pressure laser ionization (APLI) [33][34][35] , and laser desorption/ionization including matrix-assisted laser desorption/ionization (LDI 7,[36][37][38][39][40][41] and MALDI, [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] respectively), and field desorption ionization (FDI). [59][60][61][62] For example, the use of field desorption ioniza...…”

Laser Ionization Mass Spectrometry at 55: Quo Vadis?

“…This study served as a proof-of-principle that high quality analysis of NOM samples can be performed with minimal sample preparation and miniscule sample amount (several μg), nevertheless affording the same level of sensitivity and accuracy as specially prepared samples used with other ionization techniques. LI analysis of several coal samples has demonstrated a correlation between the mass spectral data and the degree of coalification using several different types of data evaluation methods (Zuber et al, 2020).…”