GC-MS with Cold EI - The Ultimate Performance GC-MS

If you are looking for the best GC-MS technology, you are at the right place.

The 5977-SMB GC-MS with Cold EI was developed at Aviv Analytical.

On the right a photo of the Aviv Analytical 5977-SMB in combination with the Agilent 7890 GC + 5977 MSD. On the left a schematic description of the 5977-SMB interface and its fly-through ion source

Agilent 5977 GC-MSD upgraded with Cold EI interface and its fly-through ion source provide:


  • Improved sample identification: Enhanced and trustworthy molecular ions, unique isomer mass spectral information and isotope abundance analysis (IAA) software and full compatibility with NIST identification
  • Significantly extended range of low volatility and thermally labile compounds amenable for analysis (bridging the gap between GC-MS and LC-MS)
  • Superior sensitivity particularly for difficult to analyze sample compounds via improved signal, lower noise and enhanced M+
  • Highest capability fast GC-MS
  • Uniform compound-independent response for the elucidation of chemical reaction yields

The Aviv Analytical 5977-SMB GC-MS with Cold EI is based on a GC and MS interface with a supersonic molecular beam (SMB) and on the electron ionization of sample compounds while they are vibrationally cold in the SMB (hence the name cold EI) in a fly-through ion source.

Supersonic molecular beams are formed by the expansion of gas through a small shaped nozzle into a vacuum chamber. In this expansion, the carrier gas combined with added helium make-up gas and heavier sample molecules obtain the same final velocity, so that sample compounds are accelerated to the helium velocity. This uniform velocity ensures slow intra-beam relative motion and collisions during the supersonic expansion, resulting in vibrational cooling of the sample compounds. As a result, SMB's are characterized by a few features which are important for GC-MS including: a) Vibrational and rotational cooling of the sample molecules; b) Unidirectional molecular motion in space with heavy species concentration along the beam axis (jet separation); c) Sample species kinetic energy in the hyperthermal energy range up to 20 eV; d) High gas flow rate compatibility up to 100 ml/min of the SMB interface; e) Compatibility with a fly-through ion source.

You can watch the following video, showing a live demonstration of GC-MS with Cold EI:

GC-MS with Cold EI is characterized by the following main features and advantages:

Significantly Improved Sample Identification

  • Enhanced and trustworthy molecular ions that are practically always observed
  • Unique isomer and structural mass spectral effects
  • Cold EI and classical EI modes with method based fast switching with the same fly-through ion source
  • Improved library identification
  • Isotope abundance analysis method and software for improved sample identification and provision of elemental formulas
  • Cluster chemical ionization for unambiguous identification of the molecular ions

Extended Range of Compounds Amenable for GC-MS Analysis

  • The range of thermally labile samples that are amenable for analysis is significantly extended
  • The range of low volatility samples that are amenable for analysis is significantly extended (doubled)
  • Polar compounds such as free fatty acids are amenable for analysis without derivatization
  • Cold EI with SMB unlike electrospray or APCI provides uniform, semi quantitative, compound independent ionization yield, without ion suppression effects for many compounds currently analyzed only by LC-MS.

Increased Sensitivity Particularly for Compounds that are Difficult to Analyze

  • Enhanced molecular ions
  • Vacuum background is eliminated resulting in very low noise
  • High ionization efficiency with the fly-through ion source and its high electron emission current
  • Ion source peak tailing is fully eliminated
  • Inherently inert fly-through ion source without any sample degradation
  • Improved sensitivity is experienced particularly for difficult to analyze compounds

Faster Analysis

  • High capability fast GC-MS is enabled
  • Low thermal mass Supersonic Fast GC is available for under one minute analysis cycle time
  • Unlimited column flow rate is enabled without affecting the sensitivity
  • Ultra fast ion source response time (<0.1 ms) is provided

Flexible system

  • Compatible with all columns ID, length and column flow rates for easy method development
  • Robust fly-through ion source that requires minimal maintenance
  • Can accept two columns simultaneously from two separate injectors for quick change from fast screening to standard confirmation mode

Powerful Options

  • ChromatoProbe sample introduction device for MS studies and extract free sampling
  • SnifProbe airborne sample collection
  • Tal-Aviv Molecule Identifier (TAMI) software
  • Unique low thermal mass Supersonic Fast GC inlet
  • Pulsed flow modulation GCxGC-MS with Cold EI
  • Open probe fast GC-MS for fast analysis of pure samples, simple mixtures and surface contaminants
  • Electron ionization LC-MS with SMB, including on the same GC-MS with Cold EI system with method based mode changing 

We feel that these many unique features and advantages bring together the next GC-MS revolution and we hope to convince you to explore the 5977-SMB and find how it can help you to improve your analysis. GC-MS with Cold EI was extensively tested and used, and it generated over 100 publications and application notes as can be viewed in the applications page. Please enter our Advanced GC-MS Blog Journal and look at its 57 detailed application articles.

Our goal is to provide a well working solution for the most challenging analytical problems, which could bring you competitive advantages. Thus, please let us know about your tough GC-MS requirements.

Please share with us your specific needs and let us explore together the optimal Cold EI solution. We shall be happy to discuss how we can demonstrate the 5977-SMB GC-MS with Cold EI for you on your sample.

For more details on the GC-MS with Cold EI please visit the website of Prof. Aviv Amirav or read the review article on this technology written by A. Amirav, A. Gordin, M. Poliak, and A. B. Fialkov "Gas Chromatography Mass Spectrometry with Supersonic Molecular Beams" J. Mass Spectrom. 43, 141-163 (2008). 

For having this article in a pdf file or the recent GC-MS with Cold EI eBook (with 147 pages and 69 figures) or for a power point presentation with 56 slides on the 5977-SMB GC-MS with Cold EI please communicate with us at and let us know what is the focus of your mass spectrometry activity