Photoionization MS

Mass spectrometry (MS) is one of the most exacting methods for identifying and quantifying molecules. Used in identifying a compound or measuring the quantity of a known compound in mixtures such as air or liquid, reliable detection over a wide range of conditions depends critically on the properties of the ionizer.

Threshold photoionization (PI) introduces the ability to choose a narrow band of ionization energy that is sufficiently high to ionize and detect most molecules of interest, yet sufficiently low to avoid detection of the most common constituents of air. The figure illustrates this principle. Photoionization mass spectrometry (PI MS) is capable of rapid analysis of the contents of mixtures due to the properties of PI to provide reasonably
simple molecular ion spectra with minimal fragmentation, minimal fragmentation, and minimal ionization of air and common solvent. The method of electronic ionization (EI) by contrast imparts energy that greatly exceeds the dissociation thresholds leading to extensive fragmentation and ionization of air and solvent matrix compounds.

Schematic shows photoionization vs. electron ionization.

Syagen Technology, Inc., 1411 Warner Avenue, Tustin, CA 92780. Tel: 714-258-4400; Fax: 714-258-4404.