Vials are small glass or plastic bottles used for storage. Depending on supplier they can be supplied in amber or clear glass, plastic, with or without markings and in various configurations of features and sizes. Vials can be used for media, diagnostic, storage, display and sample collection applications. Vials have different mouth and cap styles to accommodate different types of applications. The mouth of a vial can either be a standard size or wide mouth for facilitation of adding and dispensing samples. The connection type for vials is typically one of five standard types, screw thread, crimp, snap seal, snap ring and RAM for robotics. A screw thread connection is an external threaded connection. A crimp style connection is not threaded; a cap would "crimp" on. A snap seal connection is a special style of crimp that allows a seal to snap on. A snap ring connection is a special style of crimp that allows a ring to snap on to the vial. RAM for robotics is a special style of thread designed for robotic applications.
Important parameters to consider when specifying vials are volume, drams, outer diameter and height. The volume of the vial is the maximum amount of sample that the vial can hold. A dram is a unit of fluid measurement common to laboratory applications; one dram is about 3.7 mL. The outer diameter of the vial is important in applications where an autosampler would be used. The height of the vial is important in applications where an autosampler would be used.
Features important in specifying vials include limited volume inserts, high recovery, shell vial, marking spots, and self-centering springs. Limited volume inserts are used to limit the volume that the vial can contain. High recovery vials allow for a maximum amount of the sample to be recovered. A shell vial is an inexpensive thin walled cylinder. Marking spots are square or graduated spots to denote volumes. Self-centering springs allow for re-centering when used with an autosampler.