Thermal Desorption from Markes International

Thermal Desorption (TD) is a highly versatile, sensitive and labour-saving sample preparation technique for the measurement of volatile and semi-volatile organic compounds (VOC and SVOC) in air and materials. It provides the ultimate sample introduction technology for GC/GCMS combining selective concentration enhancement with direct extraction into the carrier gas and efficient transfer/injection all in one fully automated and labour saving package.


TD is applicable to GC-compatible organics ranging in volatility from acetylene and freons to high-boilers such as n-C40, phthalate plasticisers and benzo-alpha-pyrene. It also offers quantitative concentration for some inorganic gases, including nitrous oxyde, SF6, CS2 and H2S. Key applications include:


Environmental and workplace air monitoring


Civil defence and forensic analysis


Materials and material emissions testing


Food, flavour and fragrance profilling


Many material samples, such as polymers, paints, drugs, foods, textils, etc., can be directly thermally desorbed. Weighed samples placed at thermal desorption tube are heated in a stream of carrier gas, allowing volatiles to be extracted into the gas flow, refocused and injected into the GC(MS) analyser as a discreet, concentrated band of vapour.


Thermal desorption is now recognised as the technique of choice for air monitoring (workplace and environmental) and is the subject of many international standard methods (EN ISO 16017, ISO 16000-6, US EPA TO-15 & TO-17, NIOSH 2549, etc.)


UNITY-xr Single-tube thermal desorption unit with unmatched upgradability

UNITY-xr™ is an industry-leading analytical TD instrument that provides exceptional performance for VOCs and SVOCs collected onto 3½-inch sorbent tubes, while offering unmatched upgrade flexibility for tube, canister and on-line automation. It’s perfect for laboratories with low throughput requirements that are starting out in TD, or for analysts needing a versatile thermal desorber for all their TD applications (whether tubes, canisters, or on-line). 


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TD100-xr Multi-tube thermal desorber for high-throughput automated analysis

TD100-xr™ is an automated thermal desorption system for the rapid and unattended processing of up to 100 × 3½-inch sorbent tubes in a single sequence. It’s the perfect thermal desorption unit for high-throughput analytical laboratories needing to process large numbers of tube-based samples automatically. 


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UNITY–ULTRA-xr Multi-tube thermal desorber with advanced upgrade options

UNITY–ULTRA-xr™ is an automated thermal desorption system for the rapid and unattended sampling of up to 100 sorbent tubes in a single sequence. Additional options include autosamplers for canister, bag or on-line analysis. The UNITY–ULTRA-xr is the ideal platform for labs requiring the flexibility to expand their capabilities to extended analyte ranges and varied sample types while maximising sample throughput. 


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UNITY–ULTRA-xr Pro Multi-tube thermal desorber with advanced re-collection options

UNITY–ULTRA-xr Pro™ is our highest capacity, automated thermal desorption system for the unattended sampling of up to 199 sample tubes in a single sequence. Its automated re-collection of tube and trap desorption split flows is unique to Markes and provides the most comprehensive re-collection options and enhanced sample security. It is ideal for laboratories needing to rapidly process large numbers of tube-based samples and take full advantage of the options for sample re-collection and automated re-analysis.


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DAAMS instruments Automated thermal desorption for 4½" sorbent tube analysis

Markes’ new TD100-xr DAAMS and UNITY–ULTRA-xr™ DAAMS systems are high-throughput, automated thermal desorption instruments for streamlined analysis of 4½? Depot Area Air Monitoring Systems (DAAMS) tubes.

Markes’ TD100-xr DAAMS and UNITY–ULTRA-xr™ DAAMS are ideal for laboratories needing to analyse chemical agents for homeland security applications using 4½? tubes, with versatile upgrade options, including for regular 3½? tubes.

The new DAAMS systems are based on Markes’ tried-and-tested ‘xr’ systems, which include the latest generation of cryogen-free trapping technology.


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Centri The ultimate automated multi-mode extraction and enrichment platform for GC–MS

Powered by best-in-class robotic automation, and using a modular design, Centri® gives unrivalled flexibility for unattended, rapid and efficient extraction and enrichment of VOCs and SVOCs. With its four sampling modes, Centri offers maximum versatility for liquid, solid and gaseous samples.

Innovation lies at the heart of Centri. Incorporating Markes’ advanced cryogen-free focusing trap technology, Centri optimises analytical sensitivity, and enhances the quality of information obtained from GC–MS.

Whichever major brand of GC–MS you’re using, the Centri sample extraction & enrichment platform lets you Discover more and Deliver more.


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UNITY–Air Server-xr Cryogen-free automated thermal desorption system for unattended on-line air monitoring

UNITY–Air Server-xr™ is an air monitoring system that introduces a controlled flow of sample directly into an integral focusing trap, allowing automated on-line analysis of VVOCs and VOCs in air or gas. It’s ideal for round-the-clock air monitoring of volatiles such as PAMS ozone precursors and odorous species, especially in remote locations where unattended sampling at time specific intervals is necessary. 

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UNITY–CIA Advantage-xr Cryogen-free, automated canister and whole air preconcentration system

UNITY–CIA Advantage-xr™ is an inert, multi-channel system for the automated analysis of VOCs in canisters and bags. It has capacity for up to 27 channels, operates completely without cryogen, and is also compatible with on-line and tube-based sampling. It’s the ultimate system for high-throughput laboratories running the canister-based methods US EPA TO-15/TO-15A and Chinese EPA HJ 759. It is also ideal for analysts needing a versatile TD system able to handle other whole-air samples, as well as sorbent tubes. 


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TT24-7 Series 2: Near real-time monitoring 24 hours per day, 7 days per week

TT24-7 Series 2 – Continuous monitoring of trace chemical vapours


The TT24-7 Series 2 is an advanced thermal desorption (TD) system for continuous near-real-time (NRT) monitoring of volatile and semi-volatile organic vapours in air or gas.


With its high-performance analytical capability, reciprocating dual-trapping functionality and cryogen-free operation, the TT24-7 Series 2 is ideal for continuous unattended monitoring, either in static or mobile laboratories.


The TT24-7 Series 2 offers reliable, near-real-time monitoring of chemical warfare agents in military and government installations. It is also an ideal choice for a wide range of challenging civilian applications: advanced environmental research, monitoring pollution levels, controlling air/gas purity, and continuous odour or fragrance profiling.


The TT24-7 Series 2 is normally used in combination with GC or GC/MS technology, but can also be interfaced to direct read-out instrumentation such as process MS systems.


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u-CTE: Micro-Chamber/Thermal Extractor

Sampling technology for fast screening of toxic organic chemicals from products & raw materials


The Markes Micro-Chamber/Thermal Extractor (μ-CTE™) units are designed to meet the growing demand for fast emissions screening in manufacturing industry and third-party test labs.


The μ-CTE offers a uniquely fast and cost-effective quality control (QC) tool for screening the levels of volatile and semi-volatile organic chemicals (VOCs and SVOCs) coming out of products and raw materials.


Demand for testing hazardous chemicals released (emitted) by construction products and consumer goods has seen rapid growth over recent years. This is driven by regulatory developments in Europe (Construction Product Directive/Regulation [CPD/R], Regulation, Evaluation, Authorisation and restriction of CHemicals [REACH], German and French national laws, etc.), the US (the Ca Air Resources Board [CARB] formaldehyde rule, the international Green Construction Code [IgCC] initiative, etc.) and in the Far East (e.g. Chinese REACH). Some of the latest regulations require both third party certification and in-house product quality control of emissions for full compliance.


Typical sample types include wood-based products, plastic goods, insulation materials, electronics, foods, tobacco, decorative products, flooring materials, textiles and cleaning products. The μ-CTE is used for both characterising overall emission (odour) profiles and for analysing the type and amount of individual chemicals coming out of each sample material. 


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TC-20 Tube conditioner & dry purge rig

The TC-20 tube conditioning/dry purge system saves time and money cleaning/purging up to 20 industry standard 3½-inch x ¼-inch O.D. sorbent tubes SIMULTANEOUSLY.


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MTS-32 Multi-tube sequential sampling

Pumped sampling onto sorbent tubes remains one of the most popular and versatile air monitoring options for trace organics in environmental health and safety applications. It is applicable to vapour-phase organic chemicals ranging in volatility from n-C3 to n-C26 (depending on sorbent selection) and for vapour concentrations from low ppt to high ppm. The MTS-32 is a convenient, fieldportable multi-tube sequential sampler from Markes International Ltd. offering unattended sampling onto multiple tubes over time.


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TD accessories

A range of Thermal Desorption accessories are availables as well such as:

  • ACTI-VOC sampling pump
  • Universal Direct Inlet Accessory
  • Calibration Solution Loading Rig
  • Easy-VOC
  • Bio-VOC
  • FLEC
  • VOC-Mole
  • TubeTAG


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