Sigma headspace vials and caps for gas chromatography 2021 - 12 - 22 Sigma headspace vials and caps for gas chromatography Greyhound Chromatography Q-Fil Syringe Filters 14/12/2020 · Q-Fil Syringe Filters are available in 0.22µm and 0.45µm pore sizes, (other pore sizes are available on request).