The purpose of a calibration gas standard is to establish accurate reference points for the verification of an analysis. Static mixtures in gas cylinders are unreliable and inaccurate at the levels (ppm-ppb) that analytical technology now demands. In gas cylinders containing low level mixtures, the trace components adsorb onto the cylinder walls causing the standard to be inaccurate and unreliable. Also, if the analyte is polar or reactive, establishing a reliable reference point using gas cylinder mixture is impossible. The Permeation Tube Method solves these problems.
We can also supply a wide range of Refillable Diffusion Tubes and these can be used for compounds with low vapour pressure and for custom applications.