Caps must tightly seal the vial while remaining compatible with injection systems. Screw caps and crimp caps are the most common options, often paired with septa made from silicone, PTFE, or bonded multi-layer materials. The septum provides a resealable surface for autosamplers and manual syringe injections.

2. Septa and Liners

The septum serves as the point of injection in both GC and LC workflows. Selecting the appropriate septum material depends on the sample matrix, injection method, and temperature range. PTFE/silicone septa, for example, offer chemical inertness and re-sealability, making them ideal for repeated use or high-temperature applications.

In gas chromatography, inlet liners are used to help vaporize the sample and protect the injector. The shape and deactivation of the liner must match the sample type and injection method to prevent adsorption or decomposition of analytes.

3. Columns

The chromatography column is where separation occurs. In LC, columns are typically packed with silica or polymer-based particles and vary in size, pore structure, and stationary phase chemistry. GC columns are often made from fused silica capillaries and coated with various stationary phases to separate volatile compounds.

Column selection depends on the analytical goal — whether resolving closely related compounds, achieving fast run times, or optimizing peak shape.

Supporting Accessories and Tools

Beyond vials, caps, septa, and columns, chromatography workflows require a variety of supporting accessories that contribute to system stability and accuracy.

• Fittings and Ferrules: These small components maintain leak-free connections in tubing systems, particularly in HPLC and GC setups.
• Solvent Filters and Reservoirs: Filtering solvents before introduction into the system helps reduce particulate buildup and protect sensitive components like pump seals and injector valves.
• Syringes and Sample Loops: For manual injections, precision syringes and loops are used to deliver consistent sample volumes.

These tools support reproducibility and reduce the potential for system downtime due to contamination or wear.

Choosing the Right Chromatography Supplies

Several factors influence supply selection, including:

• Compatibility: Materials must be chemically compatible with both the sample and mobile phase.
• Temperature and Pressure Tolerance: Supplies should be rated for the system’s operating conditions, especially in high-temperature GC or high-pressure LC.
• Cleanliness: Particularly in trace analysis, contamination from improperly manufactured supplies can interfere with detection limits.

Many labs also consider pre-cleaned and certified supplies for highly sensitive applications like pharmaceutical residue testing or environmental pollutant analysis.