Autosampler Vial Screw Caps
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Autosampler vials are a specific type of vial used by autosamplers for automated sample retrieval and injection into HPLC, GC or MS analytical instrumentation. Autosampler vial caps (also known as vial closures or seals), can be screw cap, crimp cap or snap closures, but whatever their type, it is important that they offer a secure, tight seal to prevent sample leakage, evaporation and contamination. Autosampler vial screw caps are a commonly used closure type. They comprise the outer screw cap itself, made of polythene, polypropylene, phenolic resin or aluminium, fitted with inner autosampler vial septa made of softer, flexible materials such as PTFE, natural rubber or silicone, or as multilayers of several of these materials.
Autosampler screw caps have a central hole for autosampler needle insertion and sample retrieval, and the septa may also be pre-slit for easier needle penetration. Screw closures are often supplied as caps complete with pre-bonded septum seals to minimise contamination from handling and minimise leakage, but can also be sold as separate components.
There are a range of cap options available, the choice of which may be dependent on autosampler compatibility and the potentially sensitive or aggressive nature of the sample itself: