Extending the Range of Compounds and Applications Amenable for GC-MS Analysis with Cold EI

Aviv Amirav, Tel Aviv University, Tel Aviv, Israel
Alexander Fialkov, Tel Aviv University, Tel Aviv, Israel
Uri Keshet, Tel Aviv University, Tel Aviv, Israel
Tal Alon, Tel Aviv University, Tel Aviv, Israel

The most significant shortcoming and Achilles Heel of GC-MS is its inability to analyze low volatility and thermally labile compounds. GC-MS with Cold EI is based on electron ionization of vibrationally cold molecules in supersonic molecular beams (SMB) (hence the name Cold EI) and on interfacing the GC and MS with SMB while replacing the EI ion source with Cold EI contact-free fly-through ion source.

In GC-MS with Cold EI the GC elution temperatures can be significantly lowered upon the reduction of the column length and increase of carrier gas flow rate and over 200ºC lower elution temperatures were demonstrated. Furthermore, via using high column flow rate, lower injector temperatures can be used and sample degradation at the Cold EI fly-through ion source is inherently eliminated. Thus, extended range of thermally labile, polar and low volatility compounds are amenable for analysis. Furthermore, the ionization of cold molecules results in enhancement of the molecular ions and GC-MS with Cold EI further facilitates much shorter analysis times.

Several examples of extended range of GC-MS with Cold EI applications will be demonstrated in the analysis of large hydrocarbons (all with molecular ions), full range of all the organic explosives from TATP to HMX, large polar drugs, thermally labile "LC-MS" pesticides, lipidomics analysis including free fatty acids, cholesterol diglycerides and triglycerides and service GC-MS for the analysis of synthetic organic compounds including the provision of their elemental formula for publications.    

Consequently, GC-MS with Cold EI bridges the gap with LC-MS.