JOURNAL 3596
Journal of Chemical Metrology
Available Online: October 27,2025
p.1 - 5
http://doi.org/10.25135/jcm.121.2507.3596 (DOI number will be activated after the manuscript has been available in an issue.)
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GRAPHICAL ABSTRACT
ABSTRACT
Reference materials (RMs) are essential for ensuring metrological traceability in various fields, including environmental monitoring, chemical analysis, and the verification of alcohol breath analyzers. One critical property of RMs is their long-term stability, particularly for gas mixtures such as ethanol in nitrogen, which are stored in pressurized aluminum cylinders. This paper describes the preparation of such gas mixtures according to ISO 6142-1, utilizing differential weighing to minimize the influence of ambient conditions and ensure accurate composition. The effects of adsorption of ethanol on the internal surfaces of aluminum cylinders were experimentally investigated. Results indicate that ethanol can remain adsorbed on the cylinder walls even after evacuation, leading to measurable ethanol concentrations upon subsequent refilling with nitrogen. Repeated fillings demonstrated a decrease in ethanol levels, confirming the saturation and gradual desorption behavior. These findings underscore the necessity to consider adsorption effects in the uncertainty budget and composition calculations for low-concentration ethanol-in-nitrogen RMs.
KEYWORDS- Stability
- reference materials
- ethanol
- pressurized cylinders
- das chromatography
- desorption
