Dec. 21st, 2023
High performance liquid chromatography (HPLC) serves as the foundation of the modern laboratory and is used for the meticulous separation, identification and quantification of components within a mixture. The effectiveness of HPLC analysis depends on a variety of factors, but the integrity of the sample containment system has emerged as a crucial consideration. Within this complex system, the septum, a seemingly unassuming but essential element of the HPLC vial, plays an important role. This article details the subtle purpose of septums on HPLC vials and their pivotal contribution to ensuring the accuracy and reliability of analytical results.
What is a septum?
Characterised as thin, flexible barriers, septums are responsible for sealing the opening of HPLC vials and establishing a safe environment for the sealed sample. Made from materials such as silicone and polytetrafluoroethylene (PTFE), septums are inert and resistant to chemical reactions and do not introduce contaminants into the sample.
Purpose of septums on HPLC vials
Sample protection:
The main function of septums is to provide an effective seal and stop the twin threats of evaporation and contamination in the vial. As sample volumes are often very small in HPLC analysis, any compromise of the sample can lead to inaccurate results. The septum acts as a vigilant barrier and maintains the integrity of the sample until it is injected into the chromatograph.
Hermetic seals:
Closed-loop designs are commonly employed in the field of HPLC systems, which require hermetically sealed vials to prevent leakage of volatile components. Septums play a crucial role in ensuring an airtight seal and facilitate precise control of the sample environment. This assumes increasing importance when dealing with volatile or reactive compounds, where even the smallest leakage can jeopardise the accuracy of the analysis.
Contamination reduction:
Septums serve to prevent contamination from external sources, forming a secure seal that prevents suspended particles, moisture and other contaminants from entering the vial. This role helps achieve reproducible and reliable chromatographic results.
Injection accuracy:
During the injection phase of HPLC analysis, a needle punctures the septum to access the sample. The design and quality of the septum has a significant impact on the accuracy of this process. A properly designed septum ensures consistent and reproducible injections, ensuring that the same amount of sample is introduced into the chromatograph at each iteration.
Compatibility with analytical conditions:
HPLC analysis involves a wide range of sample types and analytical conditions. The septum must demonstrate compatibility with different solvents, pH levels and temperatures, and remain resilient without degrading or leaching contaminants. This compatibility factor is critical to maintaining the reliability of the analyser system across a range of applications.
Conclusion
In the complexities of high-performance liquid chromatography, all components play an important role in determining the success of an analysis. The septum, although small in size, appears as an integral protector of the HPLC vial, maintaining sample integrity and ensuring the accuracy and reliability of the analytical results. As laboratories seek to push the boundaries of analytical chemistry, the importance of using properly designed, high-quality septums in HPLC vials has become a permanent imperative.