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 2™ - A universal Thermal Desorption Platform for tagged and untagged tubes

UNITY 2, Markes' next generation thermal desorption platform, harnesses technical advances. It incorporates every feature required for TD method compliance, every system innovation of the last ten years and the field-demonstrated reliability characteristic of all Markes instrumentation. It provides the platform for a state-of-the-art yet robust range of thermal desorbers-


Building on the field-proven strengths of UNITY, UNITY 2 combines tube desorption with cryogen-free analyte re-focusing and efficient back-flush desorption on the focusing trap. Trap desorption injects analytes (split or splitless) into the GC capillary column in a narrow, focused band of vapour and triggers the GC(MS) run.


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ULTRA 2™ - Multi-function TD autosampler with optional reading/writing of electronic tubes tags

UltrA 2 is an innovative, robust and method-compliant thermal desorption (TD) autosampler for up to a hundred 3.5- or 4.5-inch sample tubes, featuring the

option of integrated reading/writing of RFID tube tags. It adds to any series 1 or series 2 UNITY TD platform to provide unmatched TD-GC(MS) analytical performance and extended unattended operation e.g. through an entire weekend.


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TD-100: Automated Thermal Desorber

For over a decade Markes International has led the way in analytical thermal desorption. TD-100 builds on this pedigree, combining every technological innovation of the last 10 years with field-proven reliability to provide a robust yet high performance solution for any high throughput laboratory.


Key words:

  • Versatility
  • Confidence
  • High throughput
  • Economical
  • Robust
  • Upgradability

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Air Server™ TD options: Automated canister and on-line air/gas analysis

Series 2 Air Server modules add to any series 2 (ULTRA-)UNITY system to allow a controlled flow of whole-air or gas to be introduced directly into the electrically-cooled focusing trap of the desorber. The combined systems operate cryogen-free (to minimise running costs/maintenance) and offer optimum analytical performance/sensitivity.


With 3- and 8-channel options available, method-compliant series 2 (ULTRA-)UNITY-Air Server systems are suitable for both automated analysis of canister/bag samples and round-the-clock unattended monitoring of on-line air/gas streams.


Key Words:

  • Monitoring of ozone precursors
  • On- or off-line odour monitoringpb levels
  • "Air Toxics", method TO-(14)15
  • Industrial process control of gas purity and odour 
  • Atmospheric research

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CIA Advantage: Cryogen-free automation for high-performance analysis of canister air and gas

CIA Advantage is an advanced system for automated analysis of VOCs in canister samples. With capacity for up to 27 canisters and cryogen-free operation, it is the ultimate solution for laboratories wanting a robust, high-throughput system for canister air monitoring.


CIA Advantage offers flexibility and productivity enhancements for air-monitoring laboratories that cannot be obtained with other systems. Electrically-cooled focusing eliminates the expense and inherent problems of using liquid cryogen, while heated internal lines and uniquely efficient purge steps eliminate carryover and optimise productivity.


At the same time, CIA Advantage provides both excellent analytical performance and unmatched application versatility. Gas-loop and MFC-controlled sampling options combined with quantitative sample splitting allow compatibility with the widest possible sample concentration range, and the method-compliant tube desorption capability integral to every CIA Advantage allows compatibility with TO-17 air toxics and SVOCs.


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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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HS5-TD: Headspace-thermal desorption module

Automated equilibrium HS coupled with full-functionality TD


Markes International’s HS5-TD module brings together two of the most powerful GC introduction techniques: headspace (HS) and thermal desorption (TD). The combined HS5-UNITY 2 system offers users optimum sensitivity for trace-level organics in solid, liquid and vapour-phase samples, all on one versatile analytical platform.


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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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