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Certified Reference Standards

CRS tubes – prepared by introducing known concentrations of compounds into individually labelled sorbent tubes – provide a convenient tool for in-house quality assurance of the complete TD–GC(MS) analytical process and associated calibration protocols. Routine use of CRS tubes complies with guidance given in international standard methods and provides continual assurance of system and procedure reliability.

CRS tubes offered by Markes International are:

  • Prepared by an expert national standards laboratory following approved methodology (ISO 6145 parts 4 or 8, accredited to ISO 17025).
  • Certified traceable to primary standards.
  • Contain masses of analytes accurate to ±3% at levels above 100 ng, and ±5% for masses from 10–100 ng.
  • Supplied in packs of 10 standards with an additional shipping blank.
  • Wrapped in aluminium foil and sealed into air-tight boxes prior to shipment.
  • Supplied with a chromatogram of the shipping blank, together with a certificate of standard traceability.

We offer two main types of CRS tubes:

  • BTX CRS tubes are loaded with benzene, toluene and o-xylene, either at 100 ng per component (suitable for the majority of environmental applications) or at 1 μg per component (suitable for many industrial air and material emissions applications). These standards are prepared using conditioned Tenax TA tubes and have a certified shelf-life of 6–12 months.

  • TO-17 CRS tubes are loaded with nine components of varying volatilities and polarities that are typical of the compounds found during air toxics monitoring. The compounds included are benzene, toluene, o-xylene, 1,2,4-trimethylbenzene, dichloromethane, 1,1,1-trichloroethane, methyl tert-butyl ether, methyl ethyl ketone and ethyl acetate. The required concentration of the standard can be specified. These standards are prepared on conditioned Tenax TA tubes to order, and have a certified shelf-life of 6 months.

Custom standards – If you require a special combination of components pre-loaded onto conditioned sorbent tubes, we also offer a custom service. Up to eight components can be specified, with the sorbent typically being Tenax TA (although others are available).

Please contact us to discuss your requirements prior to ordering.

C-BTX100-10 CRS tubes (BTX), 100 ng, pk 10 Call us for pricing or contact your local distributor
C-TO17XX-10 CRS tubes (TO-17 mix), specify concentration, pk 10 Call us for pricing or contact your local distributor

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Markes International Ltd
Gwaun Elai Medi-Science Campus
Tel: +44 (0)1443 230935
Markes International GmbH
Bieberer Straße 1-7
63065 Offenbach am Main
Tel: +49 (0)69 6681089-10
USA (West)
Markes International, Inc.
2355 Gold Meadow Way
Gold River, Sacramento
California 95670
Tel: +1 866-483-5684 (toll-free)
Markes Instruments (Shanghai) Co., Ltd
Unit 1002, Building 1
No.418, Guilin Road
Shanghai 200233
P.R. China
Tel: +86 21 5465 1216
Part of Schauenburg International

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