Aijiren 2ml HPLC Vials with Caps for Sale. 2ml HPLC Vials with Caps are most often used in the diagnostic, analytical, or pharmaceuticals markets. For many users of 2ml HPLC Vials with Caps, the vial is nothing more than a temporary container to hold a sample until it can be analyzed by gas chromatography (GC) or liquid chromatography (LC).