UNITY is compatible with true back-pressure-regulated electronic pneumatic control (available from many leading commercial GC providers).  EPC regulation enables complete stabilisation of GC retention times (RTs) even under widely different conditions of split flow or thermal desorption temperature.  It also allows accurate monitoring and closed-loop control of the column head pressure, whatever the stage of thermal desorption operation and whatever the required flow.

Key benefits include:

• Independence of retention times and TD conditions – retention times remain stable even if split flows, desorption temperatures or trap sorbents are changed.
  
• Retention times are stabilised – such that they can be re-established precisely after servicing – e.g. column maintenance / replacement.  This means that compound lists, developed in datahandling software to identify and quantify peaks, never need to be adjusted.  It also allows methods to be transferred between TD-GC systems configured with (nominally) the same column and GC detector, thus simplifying operator training and trouble shooting.
  
• Retention times are sufficiently stable to allow the creation of searchable databases (libraries) of component retention times and, if applicable, these databases can also incorporate mass spectral data (key ions) to confirm peak identities in a fully automatable post-run data processing operation.
  
• Retention time stabilisation via back-pressure-regulated EPC also facilitates use of spectral deconvolution for automated confirmation of the presence / absence of trace target compounds
  

For part numbers and pricing please contact your local Markes distributor or visit our on-line shop

Relevant technical support publications from Markes International can be automatically downloaded from this web site (registration required). Examples include:

• Brochure - UNITY, ULTRA, Air Server thermal desorption systems
• Brochure - Electronic Pneumatic Control (EPC) of Carrier Gas 
• Product Sheet - ULTRA 50:50
  

Other thermal desorption instrumentation available from Markes International includes: 

UNITY platform thermal desorber
ULTRA multi-tube autosampler for UNITY TD 
ULTRA 50:50 Automated TD with single autosampler re-collection
AutoSecure. Fully automated TD system
Mass Flow Control Accessory
Air Server and ASIS 8 Systems for on-line automation
TT24-7 near real time monitoring

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