The Multi-purpose Direct Inlet Accessory (U-INLET) may be added to any manual UNITY thermal desorption platform to provide a simple and convenient mechanism for direct introduction / 'on-line' sampling of headspace vapours from a wide range of bulk sample containers.  Vapours are either pumped or swept through an inert, heated sampling line directly into the electrically-cooled focusing trap of UNITY.  After sample collection, the focusing trap is thermally desorbed to initiate analysis. 

The entire sampling and analysis process may be carried out on- or at-line and facilitates measurement by real-time detectors (enose sensor arrays, process MS, etc.) as well as laboratory GC(-MS). 

Applications
Key application areas include: 

• Characterisation of VOC profiles from natural products and manufactured goods - food, flavour, fragrance analysis
• Measurement of residual volatiles in materials
• Monitoring emissions from living organisms - plants, microbes, fungi, insects, etc.
• Monitoring trace VOC pollutants in environmental water and soil samples
• Off-odour / shelf-life testing
• Monitoring organic vapour products from gasphase reactions.
  

The UNITY-Direct Inlet system significantly improves the sensitivity of conventional headspace methods because hundreds of millilitres of vapour can be sampled and multiple sample volumes can be introduced to the focusing trap before the trapped vapours are finally desorbed and analysed.  It also extends the applicable volatility range.

Selective elimination of unwanted interferents such as water and ethanol is easily achieved simplifying the chromatographic analysis of complex vapour profiles.  

Versatility
The UNITY-Direct Inlet system is compatible with a wide range of sample vessels.  It may be used for purging of headspace vapours from smaller, sealed containers (such as reaction vessels or headspace vials) or for pumping vapours from open or compressible containers such as bell jars or gas sampling bags. 


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 - Thermal Desorption and Air Monitoring Products
• Brochure - Multi-Purpose Direct Inlet Accessory

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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