Autosampler Vials, Inserts, and Closures

Vials, vial inserts, septa, and caps/closures with or without septa for use with autosamplers and autosampler vials; includes a variety of sizes, configurations, material compositions, and closure types.

Autosampler vials hold samples that will be injected from an autosampler into a chromatograph or similar analyzer. A needle is used to pierce the cap and withdraws the sample from the vials. Some autosamplers can also dilute or otherwise manipulate the contents of the vials.

Vials are chosen by diameter, height, thread finish, and other parameters. Selection also depends on analysis type, analytical platform, and sample availability.

Although 2mL vials are the most common, vials are available with capacities from 15 to 60μL. Autosampler vials are usually made from clear or amber glass, both of which are highly inert. Amber glass helps protect more sensitive samples from exposure to UV light and radiation.

Vial inserts are used to reduce the capacity of the vial to accommodate smaller samples. Typically 150 to 400µL in volume, they may be made of glass, plastic, or a combination of materials.

Closure options include those with and without septa, snap caps, screw caps, and crimp top caps. Vial caps and septa help prevent leakage and sample loss due to evaporation.

Factors that affect the choice of closure include:

1. Septa compatibility with sample ‒ chemical compatibility varies based on the solvent concentration, molecular weight, and temperature
2. Septa and cap compatibility ‒ septa that are too thick may prevent proper cap fitting
3. Crimp vs. screw cap closures
• Screw caps are more often used for LC and LC/MS
• Crimp caps work well for GC and GC/MS applications, help avoid sample tampering, and are recommended for working with volatile compounds