Overview

Adsorption of analytes to autosampler vial surfaces can negatively affect quantitative accuracy, reproducibility, and sensitivity in chromatographic analyses. This study evaluated how different chemical functional groups influence analyte loss in autosampler vials and compared the performance of RSA™ Reduced Surface Activity Glass Vials to conventional glass autosampler vials.

A range of test compounds was selected to investigate the relationship between molecular functionality and adsorption behavior. Results showed that analyte loss increased as the number of amine functional groups increased. The greatest losses were observed with permanently cationic compounds such as thiamine and cetylpyridinium chloride.

RSA™ Autosampler Vials exhibited substantially lower analyte adsorption than both standard glass vials and market-leading certified glass vials. These results demonstrate the practical benefits of RSA™ surface chemistry for analytical laboratories working with basic, polar, ionic, and low-concentration analytes.

Why RSA™ Vials Reduce Adsorption

Conventional glass vial surfaces contain numerous hydroxyl groups, commonly referred to as silanol groups. These active surface sites can interact with positively charged or basic compounds, resulting in analyte loss through adsorption.

RSA™ Reduced Surface Activity Glass Vials are manufactured to minimize these active surface sites. By reducing surface silanol interactions, RSA™ vials help maintain sample integrity, improve recovery, and increase confidence in quantitative analytical results.

Method Conditions
Tested Item: RSA™, Glass Vials and AQR™ Screw Caps
Specifications: Reduced Surface Activity Glass, Clear, 2 ml, Write On, Screw Top Vials and Screw Caps
Catalog No.: 9509S-1WCP-RS
Column: Cogent Diamond Hydride™, 4 μm, 100 Å
Catalog No.: 70000-7.5P
Mobile Phase: 50:50 DI Water / Acetonitrile with 0.1% Formic Acid
Flow rate: 1.0 mL / minute
Sample Preparation: 5.0–100ppm cetylpyridinium chloride reference standards in DI water diluent. Portions of the same samples were transferred to the two vial types and injected into an HPLC initially and after four hours. Peak areas were recorded and compared to initial injections to calculate percent recovery.

Note: Concentration studies are important to any laboratory that deals with trace-level compounds. Advances in analytical detection technology can now observe lower levels than ever before, but this capability is useless if the analyte is lost to adsorption with the autosampler vial before it even enters the instrument.

Study Findings

• Analyte loss increased with increasing numbers of amine functional groups.
• Permanently cationic compounds demonstrated the highest adsorption to conventional glass vial surfaces.
• RSA™ vials consistently provided higher analyte recovery than conventional glass vials.
• Reduced surface activity decreased undesirable sample-vial interactions.
• Improved recoveries were observed after extended sample residence times in the autosampler.

Conclusion

The study demonstrates that analyte adsorption is strongly influenced by chemical functionality, particularly for basic and permanently charged compounds. RSA™ Reduced Surface Activity Glass Vials significantly reduced adsorption-related losses compared to conventional glass autosampler vials, resulting in improved analyte recovery and more reliable chromatographic data.