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Products shown here are concerned with thermal desorption instrument performance.

Focusing traps

Focusing traps (also known as cold traps) are at the heart of all Markes’ thermal desorption instruments and perform a preconcentration function by focusing analytes to achieve maximum sensitivity. They are constructed of quartz for optimum inertness and packed with a sorbent bed up to 60 mm long and a series of sorbents of increasing strength.

The thermal desorption instrument

transfers compounds from a sorbent tube, canister or via on-line sampling to the focusing trap, which is subsequently heated to rapidly transfer compounds to the GC column in a narrow band of carrier gas. Markes instrument's focusing trap module offers super-fast desorption in a reverse (‘backflush’) flow of carrier gas. This optimises transfer/injection of the widest range of analytes, enabling simultaneous analysis of VOCs and SVOCs with market-leading sensitivity.

Focusing traps for the UNITY and TD-100 series are narrower at the GC end to optimise linear gas velocity and minimise band broadening.

Instrument set-up

Ensuring continued high performance from thermal desorption systems starts with correct set up, connection and configuration. Supplies for instrument set-up ensure an engineer or operator has everything they need to connect the instrument to the GC as well as address any areas of concern such as detecting and isolating leaks. Supplies such as helium leak detectors, tubing and connectors are fundamental for instrument set-up, troubleshooting, and optimising performance.

For instrument set-up Markes Instrument Control (MIC) software is designed to get

the most out of your instrument with components such as automated intelligent diagnostics, leak isolation, usage and maintenance counters.

Following best practice in instrument set-up has multiple benefits, including:

  • Preventative maintenance will minimise instrument downtime
  • Save time with specific supplies for your instrument and application
  • Ability to troubleshoot quickly and effectively

Starter kits

Markes’ starter kits are designed to provide the essentials needed to get a thermal desorption system up and running quickly, by providing a single package with items such as tubes, traps, tools and other accessories.

Markes offers a selection of starter kits for a range of standard methods such as

US EPA Method TO-17 and US EPA 325, as well as application-specific starter kits such as the Material emissions starter kit and the Direct desorption starter kit.

Laboratory managers and technicians using the UNITY–ULTRA-xr or TD100-xr systems may also find the popular essential automated TD starter kit and the automated TD booster pack useful.

Other starter kits have been designed to help customers get up and running with tube tracking technology (TubeTAG) or adopting a new approach to sampling, such as HiSorb sorptive extraction.

Standards & calibration

Calibration of the complete analytical process is of paramount importance when conducting quantitative studies. For TD analysis, additional considerations should be made regarding the loading of standards to be representative of samples, with a variety of tools available to support this.

In addition to gas standards for both canister and

tube-based methods, a number of products have been developed to support laboratories with their calibration and validation:

  • The Calibration Solution Loading Rig (CSLR) was developed to optimise the introduction of liquid standards onto sorbent tubes, by transferring the standard in a flow of gas.
  • Check-standards are sorbent tubes pre-loaded with a suite of analytes that can be used to check instrument performance during set-up or troubleshooting.
  • CRS tubes are loaded with a certified level of analytes and are designed to validate calibration for QA, as described in international standards. They are supplied with a shipping blank, and example chromatograms of the sample and shipping blank.
  • Tubes for liquid calibration contain a short bed of sorbent for analysts wishing to inject a liquid standard directly onto the sorbent tube, rather than loading the tube using a flow of gas (e.g. with the CSLR).