What are the components of Standards Grade gases?

  • Primary Standard - Highly accurate mixtures prepared gravimetrically on high-precision electronic balances. These standards are analyzed against Linde Primary Laboratory Standards (PPLS) and named to a gravimetrically generated concentration.
  • Certified Standard - These routine calibration mixtures are prepared by either gravimetric, volumetric or partial pressure methods. These standards are analyzed against Linde Primary Laboratory Standards (PPLS).
  • Non-Certified - Mixtures are prepared by the same methods and the same care used for Certified Standard Grades. Analyses are not reported.
  • Custom - Mixtures prepared to the exact blend tolerance and analytical uncertainty requested

ST - Standard Grades

Mixture GradeOrder ReferenceMixture Component Concentration RangeBlend ToleranceAnalytical Uncertainty
Primary Standardp1 ppm - 9.9 ppm
10 ppm - 25 ppm
25.1 ppm - 9999 ppm
1.0% - 49.9%		± 10%
± 10%
± 5%
± 2%		± 0.1 ppm
± 1%
± 1%
± 1% or 0.02% abs*
Certified StandardC1 ppm - 99.9 ppm
100 ppm - 999 ppm
0.1% - 49.9%		± 20%
± 10%
± 5%		± 5%
± 2%
± 2%
Non-Certified StandardU1 ppm - 999 ppm
0.1% - 49.9%		± 20%
± 10%		N/A
Custom StandardZ1 ppm - 49.9%TBDTBD

Note: For all mixtures, blend tolerance and analytical uncertainty specification may vary depending on the chemical characteristics of the component and the cylinder size. For mixtures outside of these ranges, please contact your local Linde representative.