Scientific equipment

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.

Markes also offer a custom-packing focusing trap service. Contact  to discuss your application.

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.

Certified Reference Standard tubes

Certified reference standard (CRS) tubes are packed sorbent tubes loaded with certified levels of relevant analytes. Prepared by an expert national standard laboratory to ensure high accuracy in loading levels, they are a convenient tool for in-house quality assurance and auditing of the complete TD–GC(–MS) analytical process, including calibration protocols.

- Supplied with a shipping blank, and example chromatograms of the loaded tubes/shipping blank

- Designed to validate the instrument and analytical process for quality assurance.

- Recommended for routine use at a defined frequency, in line with good laboratory practice

Read more: Calibration and validation tools Infographic

Diffusion-locking caps (DiffLok)

DiffLok™ caps sit on both ends of a sorbent tube throughout the entire analytical sequence, in all Markes’ automated thermal desorption instruments. Their patented design prevents loss of sample and ingress of contaminants onto the tube, and avoids the need for complex robotics to cap and uncap tubes. DiffLok caps are available in stainless and inert-coated stainless steel.

Read the full story behind Diffusion-locking technology in our blog.

- Preserve sample integrity by preventing analyte loss and contamination

- Ensure reproducible results during analysis

- Push-fit for ease of use

Storage caps

For storage and transport of conditioned or sampled tubes, long-term storage caps fitted with PTFE ferrules must be used to ensure an effective seal is achieved and minimise loss of sample/ingress onto the tube. Typically, brass Swagelok style caps are used but aluminium caps are available as an alternative.

- Recommended by international standard methods such as US EPA Method TO-17, ASTM D6196 and EN ISO 16017

- Independently validated for up to 27 months

- Caps meet a stringent cleanliness specification and tight manufacturing tolerances

Diffusion caps

Diffusion caps are used to define the air gap between the sampling environment and sorbent surface during diffusive sampling (also known as axial or passive sampling). Used in combination with a single-bed sorbent tube, penclip and aluminium long-term storage cap (at the other end of the tube), diffusion caps offer a simple to use, lightweight approach to personal monitoring.

- Defines the air gap for diffusive sampling at 15 mm, allowing use of published uptake rates

- Prevents small insects/particulates from entering the tube

- Complies with standard methods such as US EPA Method 325

RFID tags for sorbent tubes (TubeTAG)

Markes’ patented TubeTAG technology is a unique RFID tagging and labelling system for thermal desorption tubes. TubeTAG allows automatic tracking of sample information from sampling through to analysis, and/or tube specific information (such as sorbent type or number of thermal cycles) to be associated with a tube for its lifetime.

- Sophisticated and fail-safe solution for recording tube history and tracking tubes in transit

- Can be written to/read online (on a Markes instrument), and offline using a TAGSCRIBE

- Relevant sample information is recorded in the sequence history when using TubeTAG on an automated Markes instrument

Read more: TubeTAG Instruction for use

4.5 inch DAAMS tubes

Depot Area Air Monitoring Systems (DAAMS) tubes are sorbent tubes used for air sampling in chemical defence and counter-terrorism applications and subsequent analysis by TD–GC–MS.

- Packed to ensure optimum recovery of challenging and toxic analytes such as chemical agents

- Tubes are permanently labelled with a unique serial number, barcode and sampling flow arrow

- Available in inert-coated stainless steel or glass

GC Columns from Markes & SepSolve Analytical

Markes has curated these GC column lines to deliver optimum performance for the most common thermal desorption (TD) applications, including: indoor air monitoring, environmental monitoring, material emissions, and breath analysis.

These column lines are compatible with all leading GC instruments from vendors such as Agilent, Thermo, and Shimadzu. The GC columns are supplied by SepSolve Analytical - a Markes member company specializing in application-led analytical processes using GCxGC techniques.

All products include a Quality Assurance (QA) report and a column service record, featuring detailed recommendations for storage, cleaning, and conditioning.

Centri consumables

Centri offers high-sensitivity unattended extraction and enrichment of VOCs and SVOCs in liquid, solid and gaseous samples. There are a number of user-installable consumables that can be replaced between scheduled service visits to help maintain the system, and racks that can be added to the system after installation for increased on-rail storage.

- User-replaceable/installable parts

- Racks to accommodate 1.5, 2, 10 and 20 mL vials and HiSorb septum plugs

- Other consumables to support each sampling mode on Centri are available

Read more: The sample extraction supplies catalogue

Filters for instruments

Filter disks are used in tube receivers to prevent flow path blockages. Instrument filters should be checked and replaced regularly as part of a routine maintenance plan. Split tubes can be used multiple times, but should be routinely replaced – Markes recommends at least every 12 months. Split filter tubes should never be desorbed.

- User-replaceable

- Common parts for all instrument series

- Refer to instrument manual for guidance, or talk to our technical team

Routine Maintenance Kits

Routine maintenance is essential for all Markes instruments and large sampling accessories. Routine Maintenance Kits (RMKs) contain sufficient spares for approximately 12 months’ use, for an average user, and help ensure your instrument continues to perform to its full potential. Contents include filters, O-rings, ferrules etc.

- Ensures most commonly used spares are available for routine maintenance by the user

- Ensures spares are on-site for on-demand maintenance, maximising system availability

- Available for specific for instruments

Vials & caps

Markes supplies a range of vials and caps to support users undertaking headspace (HS), solid-phase micro-extraction (SPME), thin-film SPME (TF-SPME) and HiSorb sorptive extraction sampling. Vials are available in 1.5, 10 and 20 mL sizes, with crimp-tops or screw-tops. Caps to suit sampling method(s) are provided with the appropriate septum.

- Decapper and crimping tools available for use with crimp-top vials

- 5 mL vials available in clear and amber glass

- Caps for 10/20 mL vials are magnetic, to enable automated handling by the Centri robot

Read more: Sample extraction supplies catalogue