Certified Reference Standards (CRS)

CRS tubes are recommended in many key standard methods (e.g. US EPA Method TO-17) for auditing purposes and as a means of establishing analytical quality control.

Markes International CRS tubes are certified traceable to primary standards, have a minimum 6 month shelf life and are available with concentrations varying from 10 ng to 100 µg per component.  Each pack of CRS tubes includes a shipping blank to demonstrate the integrity of the storage and transportation process.  Chromatograms from this shipping blank, and an example analysis of a CRS tube are supplied along with the CRS Certificate. 
CRS tubes are available loaded with:

• Benzene, toluene and xylene at levels of 25 ng or 1 µg per component .
• TO-17 standard at 25 ng per component of benzene, toluene, xylene, dichloromethane, 1,1,1-trichloroethane, 1,2,4-trimethylbenzene, methyl-t-butyl ether, butanol, ethyl acetate, methylethyl ketone).

Custom CRS tubes are also available on a variety of sorbents for a wide range of compounds, contact Markes International directly (enquiries@markes.com) for further information. 

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 Catalogue
• Brochure - Certified reference standards
• TDTS 30 – Certified reference materials for analysis of VOCs in air by thermal desorption
  

Other sorbent tubes and accessories available from Markes include Sorbent tubes, Sorbents, SafeLok tubes, Sorbent tube accessories, Diffusive sampling accessories 

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