Introduction

RSA™ (Reduced Surface Activity) Autosampler Vials have long been recognized for their ability to reduce analyte interactions associated with conventional borosilicate glass surfaces. The original RSA™ glass technology remains a preferred choice for many pharmaceutical, LC-MS, and analytical laboratories because it minimizes adsorption without relying on coatings or surface treatments.  To support a broader range of sample types, the RSA™ family has evolved to include surface-modified vial technologies designed for compounds that benefit from highly hydrophobic sample-contact surfaces.

The Foundation: RSA™ Glass Vials

Standard RSA™ autosampler vials are manufactured using proprietary Reduced Surface Activity glass technology that provides a low-activity surface without applied coatings or surface treatments.  Benefits include:

• Reduced interaction with basic compounds
• Improved recovery of low-level analytes
• Consistent surface chemistry
• Excellent LC-MS compatibility
• Reduced adsorption compared to conventional borosilicate glass

These characteristics make RSA™ vials especially useful for:

• Basic pharmaceutical compounds
• Amines
• Adsorption-sensitive analytes
• Trace-level analyses
• LC-MS and LC-MS/MS applications

RSA-Pro™ Vials

RSA-Pro™ was developed as a hydrophobic surface option within the RSA™ family.  The surface modification provided:

• Increased hydrophobicity
• Reduced adsorption for selected analytes
• Improved recovery in specialized applications

Today, RSA-Pro™ is primarily available as a Special Order Item and has largely been succeeded by RSA-Pro X™ technology.

Why RSA-Pro X™ Was Developed

RSA-Pro X™ was designed to provide the benefits of a hydrophobic surface while offering significantly improved durability and long-term performance.  Compared to earlier surface treatment technologies, RSA-Pro X™ provides:

• Enhanced hydrolytic stability
• Greater resistance to aqueous environments
• Improved durability
• Long-term hydrophobic performance
• Greater versatility for challenging applications

These improvements have made RSA-Pro X™ the preferred hydrophobic vial technology within the RSA™ product family.

Applications for RSA-Pro X™

RSA-Pro X™ is particularly useful for compounds that may adsorb to conventional glass surfaces.  Examples include:

• Proteins
• Peptides
• Enzymes
• Biologics
• Hydrophilic biomolecules
• Adsorption-sensitive pharmaceutical compounds

By reducing surface interactions, RSA-Pro X™ can help improve recovery, precision, and analytical reproducibility.

Performance Advantages

RSA-Pro X™ offers several practical benefits for analytical laboratories:

Enhanced Stability in Aqueous Samples

• The surface maintains its performance characteristics even during prolonged contact with aqueous solutions.

Freeze-Thaw Compatibility

RSA-Pro X™ is suitable for applications involving:

• Freezing
• Thawing
• Long-term sample storage

Autoclave Compatibility

• The surface technology is sufficiently robust to withstand autoclaving without compromising its intended performance characteristics.

Long-Term Surface Performance

• Unlike some traditional hydrophobic treatments, RSA-Pro X™ is designed to maintain its properties during extended laboratory use and storage.

Choosing the Right RSA™ Vial

Choose RSA™ When:

• Analyzing basic compounds
• Performing LC-MS analyses
• Working with low-level analytes
• Seeking a low-activity glass surface without additional treatments

Choose RSA-Pro X™ When:

• Working with proteins or peptides
• Analyzing enzymes or biologics
• Using aqueous sample matrices
• Requiring hydrophobic surface properties
• Conducting long-term storage studies

Both technologies provide advantages, but the optimal choice depends on analyte chemistry and method requirements.

Conclusion

The expansion of the RSA™ family provides chromatographers with multiple surface technologies tailored to different analytical needs. Standard RSA™ vials remain an excellent choice for basic compounds and LC-MS applications, while RSA-Pro X™ delivers advanced hydrophobic performance for proteins, peptides, enzymes, and other biomolecules. By offering specialized surface options, the RSA™ family helps improve sample recovery, analytical reproducibility, and confidence in sensitive analytical workflows.