Should You Acid Wash Autosampler Vials?
Understanding the Risks and Limitations of Acid Washing
Acid washing is sometimes used to reduce surface activity in standard borosilicate autosampler vials by attempting to remove surface silanols (Si–OH groups). However, this practice has both limited benefits and notable drawbacks, particularly when using high-sensitivity techniques like LC-MS.
Why Acid Washing Is Unnecessary for RSA™ Vials
RSA™ (Reduced Surface Activity) vials are manufactured using a proprietary process that eliminates surface silanols and avoids the formation of sodium borate or silicate residues. As a result:
- No acid washing is required
- Surface activity is already minimized
- Vials are LC-MS ready out of the box
Potential Disadvantages of Acid Washing Standard Vials
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Contamination Risk
Acid washing can introduce trace contaminants such as:- Chloride and sodium ions
- Residual acids or surfactants
- Trace metals from reagents or containers
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Inconsistent Results
Manual washing procedures can vary in effectiveness, leading to:- Vial-to-vial variability
- Incomplete removal of reactive sites
- Unpredictable adsorption behavior
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Time and Resource Intensive
Acid washing requires:- Specialized reagents and safety protocols
- Additional rinsing and drying steps
- Cleanroom or low-contamination environments to avoid recontamination
Conclusion
For laboratories requiring high reproducibility, low background contamination, and minimal sample interaction—particularly in LC-MS workflows—RSA™ vials offer a superior alternative to acid-washed standard vials. They eliminate the need for post-processing and reduce the risk of introducing new contaminants.
Click HERE for RSA Vials ordering information.
