Dynamic generation of trace gas standards of oxygen-sensitive VVOCs at below zero temperature using Tracer Cert diffusion tubes Presented by Tracer Measurement Systems Ltd at PEFTEC 2015

ISO 6145-8-2005 "Gas Analysis - Preparation of calibration gas mixtures using dynamic volumetric methods - Part 8: Diffusion method" shows designs of diffusion tubes/cells that are clearly very difficult to fill. Tracer Measurement Systems has developed a new design of uniquely identifiable, laser-engraved, refillable and re-useable diffusion tubes (see Journal of Environmental Monitoring, 2009, 11, 1543-4) which is much easier to fill and use than the design shown in ISO 6145-8-2005. 

A novel method of use of these Tracer Cert® diffusion tubes at -21°C in a new Tracer Cert® Sub-ambient Thermostat™ for the dynamic generation of oxygen-sensitive VVOCs, isoprene and acetaldehyde, in an oxygen-free nitrogen carrier gas flow at ppb(v/v) concentrations is described and the results of the calibrations of the diffusion tubes are shown. This method can be widely applied to the dynamic generation of trace standards of oxygen-sensitive VVOCs in the ppm(v/v) to sub-ppb(v/v) concentration range.