Soft ionization method for semi-volatile compounds
T11N4
A.N. Verenchikov, A.P. Kolosov
The paper presents an improved сonditioned glow discharge ionization method, based on Penning ionization by аrgon metastable atoms at fore-vacuum gas pressures. The afterglow flow passes through the capillary to remove charged species (so called «conditioning») and then the analyte molecules are mixed with metastable atoms within the throat of the supersonic jet. Method provides exclusively M+• molecular ions accompanied with limited fragmentation, even for alkanes, phthalates and nitro compounds. When inducing in-source fragmentation, spectra appear similar to NIST ones. Signal is linear with concentration within at least four orders of dynamic range and is notably independent on presence of chemical matrix. The sensitivity is uniform within wide range of analyte compounds including alkanes and fatty acids. The simultaneously provided combination of soft ionization, NIST identification of fragment spectra and quantitative analysis presents a novel opportunity in analytical chemistry. The method may be particularly suitable for analysis of crude oils and for quantitative metabolomics measurements.
