2021/4/8 · Step 3: Determine Vial Material. Glass Autosampler Vials. The most common type of Autosampler vial is the Type 1 Borosilicate Glass, which represents the least reactive glass. Type 1 glass has the least pH shift (lowest leaching characteristics) and a Coefficient of Expansion = 33 for Clear and 51 for Amber. Plastic Autosampler Vials.