Does the RSA‑Pro X™ Surface Treatment Add Chlorides to Autosampler Vials?

Short Answer

No. The RSA‑Pro X™ deactivation process does not introduce chlorides or chloride‑containing species to the glass surface. 

Detailed Technical Explanation

1. Background: Why Users Ask About Chlorides

Analytical chemists—particularly those operating in LC‑MS, IC, or trace‑level impurity workflows—are understandably cautious about potential contaminants introduced by vial surface treatments. Chlorides, if present, can:

• Participate in ion suppression / ion enhancement effects in electrospray sources
• Produce analytically visible adducts (e.g., [M + Cl]–)
• Contribute to corrosive interactions, especially in high‑temperature GC systems
• Compromise ultra‑low–level quantitation, especially for halogenated species or ion chromatography workflows

Because many vial‑deactivation processes depend on halogenated silanes or other reactive precursors, concern about chloride incorporation is reasonable.

2. RSA‑Pro X™ Surface Engineering Overview

RSA‑Pro X™ is a specialized hydrophobic surface modification applied to RSA™ (Reduced Surface Activity) borosilicate glass. While the precise chemistry is proprietary, the process is engineered to:

• Produce a hydrophobic, non‑adsorptive surface
• Resist hydrolytic degradation
• Maintain inertness even under high‑moisture, high‑water, or aqueous biological conditions
• Support extended autosampler residence times, sample storage, and exposure to –80 °C or autoclaving

The key point is that this process creates an inert, stable surface without introducing ionic chlorides or chloride‑based reagents. According to the official documentation, no chlorides are added at any point during the deactivation treatment. 

3. Why the RSA‑Pro X™ Process Does Not Introduce Chlorides

The treatment chemistry used in RSA‑Pro X™ does not involve chloride‑bearing precursors, reagents, or post‑treatment steps.

This is explicitly stated in the official FAQ: “No, the RSA‑Pro X™ surface treatments used do not add chlorides.”

In contrast to certain silanization techniques that utilize chlorosilanes (which release HCl during hydrolysis), the RSA‑Pro X™ modification uses non‑chlorinated, non‑halogenating chemistries. As a result:

• No residual chloride ions are present on or near the glass surface.
• No chloride‑related byproducts remain because none are generated.
• No risk of chloride‑derived adducts exists for LC‑MS workflows.

This design is particularly beneficial in situations where even trace halogens could compromise analytical specificity.

4. Analytical Implications for LC, LC‑MS, GC, and IC Users

4.1 LC‑MS

• No chloride‑related adduct formation
• No ion suppression from ionic halides
• Cleaner mass spectra and improved detection limits

4.2 Ion Chromatography (particularly anion‑IC)

• No exogenous chloride peaks
• Avoids baseline contamination
• Supports ultra‑trace halogen analysis

4.3 GC / GC‑MS

• No chloride‑driven glass corrosion under high temperatures
• No potential breakdown products from halogenated surface chemistry

5. When to Choose RSA‑Pro X™

RSA‑Pro X™ is recommended when your workflow demands:

• Minimal adsorption of proteins, peptides, hydrophilic species, or charged biomolecules
• Long‑term stability in aqueous media
• Hydrolytically stable, non‑leaching surfaces
• Assurance that no halogen‑based surface residues can interfere with detection

For users who must avoid any halogen artifacts—such as those in environmental analysis, PFAS studies, or trace ionic species quantitation—the confirmation that RSA‑Pro X™ introduces zero chloride contamination makes it a highly reliable choice.