Step-by-Step Guide: Assembling Chromatography Vials with Screw Caps and PTFE-Silicone Septa

How to Properly Assemble Chromatography Vials with a Screw Cap and PTFE-Silicone Septa

Oct. 5th, 2023
Chromatography, an essential technique in analytical chemistry, requires careful sample handling and preparation in order to produce accurate and reproducible results. An essential step of this process involves assembling vials with screw caps and PTFE-silicone septa for assembly - doing it correctly ensures no contamination, maintains sample integrity and achieves analytical success! In this guide, we'll walk you through how best to assemble vials to meet your analytical needs.

Before Starting, Assemble Materials You Will Require

Prior to commencing work on any task, gather the required materials.

Chromatography Vial: To ensure accurate chromatography results, choose an inert material such as glass or high-grade plastic for your vial.
Screw Cap: Select a screw cap that snugly fits your vial for secure storage. These caps come in various materials such as polypropylene, aluminum or magnetic designs for quick and easy removal.
PTFE and Silicone Septa: To ensure safe operation of your machine, ensure high-quality PTFE (Polytetrafluoroethylene) and silicone septa are used as they provide an inert barrier while simultaneously sealing properly.
Vial Crimper or Decapper: For when your cap requires crimping, have a vial crimper on hand; in certain instances decappers are also useful for cap removal.

Discover the essential steps for crimping or decrimping vials in this informative article:All About Vial Crimpers: A Detailed 13mm & 20mm Guide

Assembly Steps

For proper assembly, follow these steps.
1. Check the Septa
Before assembly, carefully examine the PTFE-silicone septa for any visible defects, cracks or contamination that might compromise sample integrity. Damaged septa should be discarded immediately to prevent sample contamination.
2. Clean Vials and Caps
It is essential that chromatography vials and screw caps are thoroughly rinsed and dried prior to being used for any experiment or analysis. Any residues or contaminants should be thoroughly removed by thoroughly rinsing and drying before proceeding with further use.
3. Attach the Septum
To seal off a vial properly, add a clean PTFE-silicone septum on top of it with its silicone side touching down for contact with the vial neck while its PTFE side faces up forming the sample barrier.
4. Secure the Screw Cap
Screw the cap securely onto the vial while taking care not to overtighten as too much force can damage the septa and cause sample loss and contamination. A well sealed cap can protect samples from evaporation and contamination.
5. Crimp the Cap (if Necessary)
When using crimp caps, use a vial crimper to securely fasten them onto the vial. Be gentle but firm so as to create an airtight seal; improper crimping could cause sample leakage.
6. Label and Store
Once assembled, label the vial with pertinent information including sample name and date as well as any necessary identifiers. Afterward, store in a cool and dry environment away from direct sunlight or any sources of heat.


Correct assembly of chromatography vials with screw caps and PTFE-silicone septa is key to maintaining sample integrity and producing accurate analytical results. When following these steps for assembly of vials for chromatography experiments, make sure all components are clean, and follow these steps for creating a secure seal to reduce contamination risks in your experiments and ensure successful research or quality control processes.

For comprehensive insights on HPLC vials, don't miss this informative article:50 Most Frequently Asked Questions on HPLC Vials


For comprehensive insights on PTFE/Silicone Septa, delve into this informative article:Everything You Need to Know:137 Pre-slit PTFE/Silicone Septa FAQs