Apr 17, 2020 · HAWACH offers 2ml, 10ml, 20ml, and 40ml sample vials, often used with HPLC, GC of Aijiren, Shimadzu, and Aijiren Technology and other autosamplers. Flat-bottom vials are suitable for downward movement when the instrument is running. Flat-mouth vials have a large contact area with the septa and tighter seal.