Environmental monitoring

Hydrogen purity analysis

Providing traceable gas measurements to industry

As the UK's National Metrology Institute, NPL provides traceability to the International System of Units for gas measurements performed by industry. Furthermore, NPL works in collaboration with National Measurement Institutes around the world to ensure that these measurements are comparable wherever and whenever they are made (this can be confirmed by key comparisons).

We produce a range of reference gas standards for the hydrogen industry including Primary Reference Gas Mixtures (PRGM); these mixtures are primary realisations of the mole as gas mixtures at the top of the traceability hierarchy and are provided with some of the lowest uncertainties available worldwide.

Hydrogen Purity Laboratory Overview

Hydrogen purity analysis

NPL's hydrogen purity laboratory can offer purity analysis of hydrogen, fuel cell or other types, for quality assurance purposes. Our laboratory provides analysis using a range of state-of-the-art gas chromatography and spectroscopic techniques which are capable of performing the most challenging measurements.

The hydrogen purity laboratory was established specifically to support the growing hydrogen economy by providing quality assurance for fuel cell hydrogen against ISO 14687-2. We perform all measurements against high accuracy PRGMs containing the analytes of interest in a matrix of hydrogen. Indicative limits of detections for our hydrogen purity measurements are shown below. For any impurity measured higher than the limit of detection, we would provide a certified amount fraction of the impurity with an assigned measurement uncertainty based on our best measurement capability.

Limit of detection / µmol mol -1 (ppm)
Total hydrocarbons*
Carbon dioxide*
Carbon monoxide*
Total sulphur compounds*
Formic acid
Halogenated compounds (only organic halogenated compounds excluding HCl and Cl2)
Other compounds
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* UKAS accreditation available for these components
** Lower amount fractions can be detected upon request

Reference methods and gas standards are currently being developed for the measurement of formic acid and total halogenated compounds in hydrogen.


Hydrogen samples that are sent to NPL for purity analysis must contain enough gas (at suitably high pressure) to perform all measurements. Samples can be provided in your own vessels, or we may be able to provide cylinders with volumes 500 mL to 10L. For measurements of total sulphur or 'sticky' compounds, it is recommended to use cylinders with suitable passivation such as Sulfinert®. Please contact us if you need advice on how to take your samples before using our hydrogen purity laboratory.

What you get

When purchasing a purity measurement service from NPL, you will benefit from:

  • Advice on how to ensure effective sampling
  • Evacuated (1 x 10-7 mbar) sampling vessels with suitable passivation ranging from 500 mL to 10 L cylinders (available upon request)
  • A tailored measurement service based on your requirements
  • Traceable measurements performed directly against PRGMs using state-of-the-art gas analysers
  • An NPL report (UKAS accreditation is available for several of the impurities as highlighted in the above table)

Requesting hydrogen purity analysis from NPL

To obtain a quotation for hydrogen purity analysis, please contact us with the following information:

  • The number of samples (a discount is applied for more samples in a batch)
  • Pressure and volume of your hydrogen samples
  • A list of impurities and minimum amount fraction to be measured (we may be able to measure a range of additional impurities which are not listed above).

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Contact our Customer Services team on +44 20 8943 7070