Environmental Vapor Monitor (EVM II)

The World's First Hand-Portable AVS-TLGC/IMS Detector!

The Environmental Vapor Monitor (EVM II) is the first commercial GC/IMS instrument for process and field applications. The EVM II was developed under Contract DAAA15-94-C-0001 as a Small Business Innovative Research Contract in association with the U.S. Army, Edgewood Research Development Engineering Center (ERDEC). It is based on the proven Ion Mobility Spectrometry (IMS) technology for ultra sensitive detection of gas phase analytes with high speed Automated Vapor Sampling (AVS) - Transfer Line Gas Chromatography (TLGC) sampling and separation capabilities developed by FemtoScan and the University of Utah (www.utah.edu./marc/homepage.htm). The EVM II is a sensitive and selective, near real-time vapor detector. The combination of intelligent AVS injections, rapid TLGC separations and high sensitivity IMS detection leads to the first hand-portable hyphenated analytical instrument. The result is an instrument with unparalleled analytical capability in a hand- portable package that is ready for your most demanding on-line, real-time measurement problems.


  • Real-time (in seconds) Response 
  • Rapid Column Change Smart Sampling Capability 
  • ppb Level Sensitivity (Vapor)
  • Notebook PC Data & Control System
  • Hand-Portable
  • Remote Monitoring Capability
  • Battery or 24 Vdc operation
  • Hyphenated TLGC/IMS Operation
  • Easy Process Interfacing
  • Rapid Clear-down
  • Excellent Interferant Rejection
  • No Carrier Gas Required

Instrument Operation:

The EVM II is a complete detector system for portable applications. The lightweight package operates from a 24 V battery pack or from an external power supply. At power-up, the instrument performs a self-diagnostic, resets the sampling and GC conditions to the previous values, comes up to temperature and is ready for operation within 15 minutes for most applications. Sampling operation is either on-demand or continuous allowing different degrees of operator interaction based on the application. All sampling and GC parameters can be reset via the notebook computer data system. Designed for the constraints of field use, the EVM II allows for the use of multiple AVS-TLGC modules in the field with a rapid change capability for AVS-TLGC "front ends." Responses can be observed via the on-board LCD display or via a portable notebook computer data system. In either case, the system is rugged, reliable and easily maintained for field use. One unique feature of the EVM II is its surprising immunity to water vapor. This immunity allows the EVM II to be a "full range" detector for volatile organic compounds, many of which are not detectable with conventional direct IMS1. The low sampling duty cycle of the AVS system reduces water vapor loading to levels that allow the direct detection of alkanes and other organic species typically not detected by IMS systems. The EVM II is not just a "one problem" instrument. The modularity of the system design, and the power of the new Hyphen PC software, greatly facilitate development of new applications.

AVS-TLGC/IMS detection capabilities have been demonstrated for the following select list of chemical classes in a range of volatile and semi-volatile species:

An additional benefit of AVS-TLGC/IMS is the development of quantitative methods for many applications. The use of AVS Smart Sampling allows the extension of instrument dynamic range via computer controlled feedback control of the sampling volume. Coupled with the selectivity of TLGC, this approach has been demonstrated to provide over three orders of magnitude of linear dynamic range in some applications.

Potential EVM II applications include:

Application development is a FemtoScan speciality!

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Additional links:

  FemtoScan - The Company
  Product - Enviroprobe Module
  Product - HYPHEN Software
  Technology - What is AVS-TLGC?
  Application Note 9701 - Detection of Pesticide Vapors ...
  Application Note 9702 - Examining the Analytical Capabilities...
  Application - University of Utah Roving GC/MS and TG/GC/IR/MS
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Page last updated  on 7/19/99