Key characteristics of different autosampler vial types
When designing autosampler vials, the volume of sample needing to be contained, the sample matrix composition and corresponding vial material compatibility, as well as the top style of the vial need to be considered. These different key characteristics result in a broad range of autosampler vials. Depending on the analytical requirements, different types of autosampler vials are needed.
Sample volume capacity
Sample volume capacity
There are several factors to consider when choosing the sample volume you need, including analysis type, analytical platform, and sample availability. Agilent vials offer the same highly consistent performance across the entire size range, from 15 μL to 60 mL. Once the sample volume is determined, the diagram below can be used as a starting point for choosing the type of vials you need:
High recovery vials for smaller sample volumes
Vial inserts, vials with fixed inserts, and high recovery vials are used to offer customers the ability to contain and extract smaller sample volumes; whether the functionality being part of the vial itself or be a standalone insert which is then added to an existing 2 mL vial. The material selection of these products depends on the sample matrix and analytes of interest as they should be relatively inert allowing for maximum extraction. These products come in the following materials: polypropylene, standard glass or deactivated glass.
Vial inserts also come in various forms which provide different functionalities based on user needs: pulled point (5183-2085), pulled point with polymer feet (5181-1270) and flat bottom (5181-3377). Inserts will require the sourcing of a corresponding 2 mL vial to house the insert when placing in the autosampler.
High recovery vials (HRV) are the ultimate and easiest to use based on form factor as they are a one-piece design that includes the outer diameter of a 2 mL vial while the interior is shaped to allow maximum extraction to within 3 µL sample depending inclusive of a 30 µL well. HRVs are available in crimp and screw styles as well as being deactivated and clear or amber glass types.
Micro-v-vials are a one-piece design shaped like wine glass. This design is great for sample preparation and uses less glass than an HRV, so it is more economical to produce. You should be able to extract to within 3 µL sample depending. Agilent Micro-v-vials are available in crimp and screw styles and clear or amber glass types.
Vials with fixed inserts are a more economical version to the HRV as it is a standard 2 mL vial with a pulled point insert affixed to the interior (250 µL fill volume). The approximate sample extraction can go down to within 3 µL. Vials with fixed inserts are available in crimp, snap and screw styles; clear or amber glass types; polypropylene exterior and glass insert interiors.
Storage vials
Storage vials are essential for various purposes, including sample storage and environmental applications. They are available in both clear and amber options and come in a range of volume sizes: 4 mL, 12 mL, 22 mL, and 40 mL. The vials are paired with caps that come in both open and closed top designs. The open top design has a septum which is pierceable whether it be in an autosampler or by manual injection while the close top is completely covered eliminating access to the sample unless the cap is unscrewed.
The 40 mL vials are most common, especially in environmental applications such as water and soil testing. Storage vial kits, including vials and caps in one box, are ideal for fieldwork, making sample collection, securing, and transport to the lab easy.
Headspace Vials
Headspace vials are crucial for headspace gas chromatography (GC) analysis due to their ability to withstand gas pressure. They are offered in 10 mL and 20 mL sizes, available in both flat and round bottom styles to fit various headspace instruments. They are also offered in both clear and amber versions and are also made from Type 1 Borosilicate glass.
Headspace caps are designed to prevent sample contamination and provide secure seals. Headspace caps are made from materials like aluminum, bimetal, and steel. They can tolerate temperatures up to 300°C, with septa typically made from PTFE/silicone (most common), followed by molded PTFE/butyl (less common), and custom options for very high-temperature applications (very rare).
Sample and material composition
Sample and material composition
The material composition of autosampler vials, caps, and septa is crucial as it directly relates to the sample matrix and its volatility during analytical workflows.
Glass vials
Glass vials are usually composed of borosilicate glass as standard in the industry for analytical testing. Borosilicate glass must contain at least 5% boric oxide. Boric oxide helps make the glass more tolerant of higher temperatures and corrosion. Glass vials that are made from Type 1 borosilicate will provide you with the best overall performance inclusive of lower pH shifts, temperatures above 100 °C, and greater resistance to a range of matrices containing water, acids, and most organic substances.
Type 1 borosilicate glass vial provide:
Visual Identification: Clear surface for easy inspection, ideal for monitoring remaining sample volume after drawing several aliquots.
Material Inertness: Non-reactive, ensuring sample integrity and long shelf life.
Clear and Amber Options: Suitable for various samples, including light-sensitive ones.
Heat Tolerance: Resistant to thermal shock, perfect for chromatography.
Deactivated borosilicate glass vials
Deactivated borosilicate glass vials are the go-to option for pesticides, semi volatiles, and other extremely sensitive samples—as well as samples that are prone to sudden pH shifts—deactivated vials are the best, because their surface is more hydrophobic and inert. We also recommend deactivated vials for exacting applications, such as mass spectrometry, to prevent sample interactions before analysis.
Plastic vials
Plastic vials are typically available in polypropylene, polycarbonate, co-polymer, etc. The most common plastic chromatography vial is polypropylene vial (PP vial) due to it’s easy of manufacturing and material characteristics such as:
Chemical Compatibility: PP vials are compatible with a wide range of solvents.
Reduced Adsorption: PP vials minimize adsorption of compounds like proteins and peptides.
Enhanced Durability: PP vials are safer and more durable, especially in high-throughput environments.
Cost Efficiency: PP vials are generally more economical than borosilicate glass vials.
Lightweight: PP vials are lighter than glass, facilitating easier handling and shipping.
Polypropylene vials are an excellent choice for biological and PFAS applications, and for applications involving samples with high metal content—such as ion chromatography, AA, or ICP-MS. Agilent thoroughly tests and evaluates various polypropylene materials before selecting the grade used in our polypropylene vials. Our vials have the lowest levels of extractables to ensure sample integrity.
Compatibility of septa and sample
Make sure the septa you choose is chemically compatible with your sample and solvent. Chemical compatibility can vary, based on factors such as solvent concentration, molecular weight, and temperature. During manufacture, Agilent septa undergo thermal and chemical conditioning to reduce siloxane bleed, which can occur when the septa material is stressed during heating, solvent interaction, or piercing by the autosampler needle. See table below to review your specific conditions:
Septa Chemical Compatibility
PTFE
PTFE/Silicone
PTFE/Silicone/PTFE*
PTFE/Red Rubber
Fluoroelastomer
PTFE/Butyl
Acetonitrile
√
√
√
√
√
Hydrocarbons
√
√
√
√
Methanol
√
√
√
√
√
Benzene
√
√
√
THF
√
√
Toluene
√
√
DMF
√
√
√
√√ √
DMSO
√
√
√
√ √
Ether
√
√
√
Chlorinated solvents
√
√
√
Alcohols
√
√
√
√
√
√ √
Acetic acid
√
√
√
√
Acetone
√
√
√
Phenol
√
√
√
√
√
Cyclohexane
√
√
√
√
*PTFE/Silicon/PTFE has the same chemical compatibility of PTFE only until punctured
Top style
Top style: crimp cap, screw cap, snap cap
Screw top vials feature a threaded neck, which allows for easy sealing and opening without special tools. They are ideal a wide range of applications, including HPLC and LC/MS. Screw top vials are highly recommended for volatile compounds. They provide a secure seal to prevent leaks and contamination.
Crimp top vials require a crimping tool to secure the cap, providing an exceptionally tight seal that prevents sample evaporation and ensures integrity, which is crucial for GC applications and when tamper-proof sealing is needed. Crimp caps can provide extra security for food, forensics, and other applications where sample tethering needs to be avoided.
Snap top vials offer the quickest and easiest sealing method with a simple press-on cap, suitable for high-throughput environment. Snap top vials allow for rapid sample handling, which makes it the top choice in HPLC, LC/MS and many other applications where frequent access to the vial is necessary, such as sample preparation involving pipetting.
