Glass wool is a fibrous inorganic substance (silicates) made primarily from rock, slag, glass, or other processed minerals. It is widely used as a thermal insulation material.

Glass wool plugs are often used in GC inlet liners to improve sample vaporization and to keep non-volatile material from entering the column. They can also be used in packed GC columns, solvent desorption tubes, thermal desorption tubes, and purge traps to retain adsorbent beds.

Substances soluble in hydrochloric acid: ≤ 1 %

Alcali soluble in water (as Na₂O): ≤ 0.1 %

Heavy metals (as Pb): ≤ 0.005 %

Diameter of fibre (15-25 µm): passes test