Date: 14-FEBRUARY-2014 Last Updated: 14-AUGUST -2026
Overview
RSA™ (Reduced Surface Activity) autosampler vials are designed to minimize interactions between sample components and glass surfaces. Both clear and amber RSA™ vials are manufactured using the same proprietary RSA™ process, providing identical surface characteristics and chromatographic performance.
From an analytical standpoint, there is no measurable difference in adsorption behavior, sample recovery, or LC-MS compatibility between clear and amber RSA™ vials.
RSA™ Surface Technology
RSA™ vials are produced using a specialized manufacturing process that reduces surface activity and minimizes interactions with analytes that may otherwise adsorb to active glass sites.
Benefits include:
- Reduced adsorption of basic compounds
- Improved sample recovery
- Greater analytical reproducibility
- Consistent performance in LC and LC-MS applications
- Reduced risk of sample loss at low concentrations
These benefits are present in both clear and amber RSA™ vial formats.
Chromatographic Performance Comparison
Extensive quality control and product evaluation testing have shown no meaningful chromatographic differences between clear and amber RSA™ vials.
Observed performance characteristics include:
- Equivalent analyte recovery
- Comparable adsorption behavior
- Similar peak area reproducibility
- Consistent sample stability
- Identical surface activity performance
The color of the glass does not affect the RSA™ surface treatment or the chromatographic behavior of the vial.
Sample Adsorption Performance
One of the primary purposes of RSA™ technology is to reduce analyte interactions with the glass surface.
Testing has demonstrated:
- No significant difference in adsorption of basic compounds
- Comparable recovery performance
- Consistent low surface activity across both vial types
As a result, vial color should not be expected to influence analyte recovery.
pH and Sample Stability Considerations
No measurable differences have been observed between clear and amber RSA™ vials with respect to:
- Sample diluent pH effects
- Surface chemistry characteristics
- General chromatographic performance
Both vial types provide equivalent analytical performance when used under comparable conditions.
When to Select Amber RSA™ Vials
Amber RSA™ vials are recommended when samples are sensitive to light exposure.
Examples include:
- Photolabile pharmaceuticals
- Certain vitamins
- Natural products
- Light-sensitive metabolites
- Environmental analytes subject to photodegradation
The amber glass helps reduce exposure to UV and visible light that may adversely affect sample stability.
Glass Composition
Both vial types are manufactured from high-quality borosilicate glass but utilize different formulations to achieve their appearance.
Clear RSA™ Vials
Manufactured from:
- Type I, Class A
- 33-expansion borosilicate glass
Amber RSA™ Vials
Manufactured from:
- N51A expansion borosilicate glass
- Formulations containing iron and related oxides that provide light-blocking properties
These compositional differences are intended for optical protection rather than chromatographic performance.
Choosing Between Clear and Amber Vials
The selection should be based primarily on sample stability requirements.
Select:
- Clear RSA™ vials for routine applications where light protection is not required.
- Amber RSA™ vials for samples that may degrade when exposed to light.
Both options provide the same RSA™ surface performance characteristics.
Key Takeaways
- Clear and amber RSA™ vials exhibit equivalent chromatographic performance.
- Both vial types use the same RSA™ surface technology.
- No measurable differences in adsorption behavior have been observed.
- Sample recovery performance is comparable between both formats.
- The primary reason to choose amber glass is protection of light-sensitive samples.
- Vial selection should be based on sample stability requirements rather than chromatographic concerns.
