Silica-gel tube

801 is designed for sampling organic solvents in environmental air, particularly for polar solvents such as Methanol and Acetone which cannot be sufficiently adsorbed onto charcoal.
Organic solvent vapour is adsorbed onto the silica gel while passing through the tube. Adsorbed solvent is recovered with a desorption solvent followed by gaschromatographic analysis. When sample air corresponding to 60 to 80 & of the amount causing breakthrough is passed, the colour begins to change from blue to pink by the moisture from the silica gel side predicting breakthrough.