title: Traceable reference gas mixtures for sulfur-free natural gas odorants.
abstract: The first reference gas mixtures of sulfur-free natural gas odorants that are traceable to the International System of Units (SI) have been produced and their compositions validated. These mixtures, which contain methyl acrylate and ethyl acrylate at amount fractions between 1.1 and 2.1 μmol mol(-1), can be used to underpin measurements of sulfur-free odorants, which are increasingly being used to odorize natural gas in transmission networks as they have less harmful properties than traditional sulfur-containing odorants. The reference gas mixtures produced have been shown to be stable in passivated aluminum cylinders for at least 8 months and have been validated (to within 6% or less) by interlaboratory measurements at three National Measurement Institutes. The stability of methyl acrylate and ethyl acrylate in gas sampling bags has been investigated, and the challenges of analyzing 2-ethyl-3-methylpyrazine, which is used as a stabilizer in sulfur-free odorants, are also briefly discussed.
authors.affiliation: Analytical Science Division, National Physical Laboratory , Teddington, Middlesex TW11 0LW, United Kingdom.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Brown
authors.forename: Adriaan M H
authors.initials: AM
authors.lastname: van der Veen
authors.forename: Karine
authors.initials: K
authors.lastname: Arrhenius
authors.forename: Michael L
authors.initials: ML
authors.lastname: Downey
authors.forename: Daniel
authors.initials: D
authors.lastname: Kühnemuth
authors.forename: Jianrong
authors.initials: J
authors.lastname: Li
authors.forename: Hugo
authors.initials: H
authors.lastname: Ent
authors.forename: Lucy P
authors.initials: LP
authors.lastname: Culleton