LABORATORY VIALS

Laboratory vials

Vials are small containers, usually cylindrical, designed to hold, transport and preserve sample volumes of just a few millilitres. They are indispensable in chromatography, biological sample storage and pharmaceutical research, where the amount of sample available is limited and any loss or contamination compromises the analysis. Unlike flasks or beakers, which are designed for preparing and handling larger volumes, vials are built around a single purpose: keeping a small sample stable and perfectly identified until the moment it is measured.

Types of vials by application

The working volume is only the starting point. What really determines which vial you need is the instrument and the process it has to withstand:

• Chromatography vials: with a calibrated neck and precise dimensions so that the autosampler needle enters cleanly. The flat or conical bottom lets you recover the last microlitres of sample.
• Lyophilisation vials: wide-mouthed and able to withstand freezing followed by vacuum without cracking, which is essential for freeze-drying cycles.
• Autosampler and storage vials: for sample series that have to remain sealed and traceable for days or weeks before being injected.

Vial materials

The choice of material depends on what the vial has to contain and for how long:

• Borosilicate glass: chemically inert, so it does not release ions into the sample or alter its composition. It withstands sudden temperature changes and is the right choice for organic solvents, acids and reagents intended for long storage. The amber version blocks ultraviolet light and protects photosensitive substances.
• Plastic (polypropylene or HDPE): lighter and practically unbreakable, which makes it ideal for transport, fieldwork and teaching environments. It is not suitable for strong organic solvents, which can swell or attack the polymer.

The closure system: a key component

The cap is not an accessory, it is part of the vial. A poor seal means evaporation, cross-contamination and unreliable results:

• Screw cap: the most airtight option and the best choice for storing samples over time. Standardised thread sizes such as GL18 guarantee interchangeability between vials and caps.
• Snap cap: fitted by pressure, much faster to handle when you are processing a large number of samples, at the cost of a slightly less reliable seal.
• Septum closures: a PTFE or silicone disc that lets the needle pass through and inject the sample without opening the vial, then reseals itself. Essential in gas and liquid chromatography.

Before ordering, check three things: that the thread or diameter matches your instrument, that the material is compatible with your sample, and whether the substance needs protection from light. Getting these three right avoids most of the problems that show up later in the liquid handling stage.

Do you need high-quality laboratory vials?

At Pobel we manufacture and supply laboratory vials in borosilicate glass and plastic, with the closure systems each technique requires. If you are not sure which format suits your application, tell us what you need to analyse and we will recommend the right option. Contact us and we will get back to you.