2017/2/5 · HPLC vials and closures. The vials (all USP type 1, 33 expansion) were purchased from different vendors. The glass vials will be described as A, B, C, D, and E (each letter is a distinct part number) for the results section. Waters (Waters, Milford, MA, USA): Certified grade (p/n 600000749cv (vial A)), 2 ml capacity.