Store your samples in these vials to eliminate leaching of ions while maintaining a consistent pH for the life of your sample. Storage vials range from 2mL to 40mL. Plastic vial | Sigma-Aldrich Product Description. SDS. 27537. volume 0.7 mL, natural polypropylene vial, vial O.D. × H 8 mm × 40 mm, closure type, starburst conical snap plug