Choosing the right Screw Neck Sample Storage Vials is critical to maintaining the integrity of your critical analytical samples. Whether you’re working with volatile organic compounds (VOCs), total organic carbon (TOC) or other sensitive analytes, the quality and characteristics of your sample vials can make all the difference. Consider these five key factors when selecting the ideal screw-neck sample vials for your laboratory:
The material used to manufacture the vials and caps/septa can have a significant impact on sample compatibility and preservation. Common materials include borosilicate glass, amber glass and various polymers such as polypropylene. Borosilicate glass is a popular choice due to its chemical inertness, thermal stability and ability to withstand high temperatures and pressures. Amber glass provides additional protection from light exposure, which can degrade photosensitive analytes. Polymer materials such as polypropylene offer advantages such as break resistance and cost effectiveness, but may have limited chemical compatibility compared to glass. Carefully evaluate the chemical resistance, inertness and thermal stability of materials to ensure they won’t interact with or adsorb your target analytes.
Proper sealing is essential to prevent sample contamination or loss of volatile components. Choose high quality screw caps or crimp tops with PTFE-lined silicone septa that provide a secure, air-tight seal. Evaluate cap and septa materials for compatibility with your samples and test sealing performance under expected storage conditions. Silicone-lined caps may provide a more effective seal than unlined caps, reducing the risk of analyte loss or contaminant ingress. In addition, consider the ease of opening and closing the vials as this can affect workflow efficiency and prevent accidental sample spillage.
Ensure that the screw-cap vials you purchase have undergone rigorous cleaning and decontamination processes. Look for vials that are certified as pre-cleaned and meet specific cleanliness standards, such as those set by the US EPA or ASTM. This helps to minimise the risk of introducing unwanted background contaminants into your samples. Vials may be subjected to various cleaning protocols including detergent washes, acid rinses and solvent rinses to remove trace contaminants. Certification provides assurance that the vials have been thoroughly cleaned and are suitable for use with even the most sensitive analytical methods.
The available headspace volume within the vial can affect sample preservation, especially for volatile analytes. Select vials with the appropriate size and headspace ratio to accommodate your sample volume and avoid excessive headspace that could lead to analyte loss or degradation. Smaller headspace volumes can help minimise sample exposure to ambient air, reducing the potential for evaporation or oxidation. However, ensure that there is enough headspace to allow for sample expansion and gas generation during storage without compromising seal integrity.
Reliable sample tracking and identification is essential for data integrity. Choose vials with clear, solvent-resistant labelling and/or engraving that allows you to easily and permanently mark the vials with sample information. Choose vials with unique identifiers or barcodes to improve traceability throughout your analytical workflow. This can simplify sample management, reduce the risk of mix-ups and ensure accurate data attribution. Consider the compatibility of labelling materials with the solvents or reagents used in your analytical methods to prevent smearing or fading of identification markings.
By carefully considering these five key factors, you can ensure that the screw-top sample storage vials you choose will properly contain, preserve and protect the integrity of your valuable analytical samples. Investing in high quality vials up front can save you time, money and headaches down the line by delivering accurate, reproducible results.