How to Build a Better Analyzer System with Inert Coated Flow Paths

Designing a high-performance analyzer system means accounting for every variable - flow rates, material compatibility, contamination risks, and long-term reliability. Yet one critical element is often overlooked: the surface reactivity of internal flow paths.

Even trace adsorption or corrosion inside tubing, valves, or fittings can skew results, degrade sample integrity, and reduce component life. That’s where inert CVD coatings like SilcoNert^® 2000 and Dursan^® make a measurable difference.

Pictured above is a multi-stream GC sample analyzer system.

 Why Inert Internal Surfaces Matter

Whether you're monitoring stack gases, process streams, ambient air, or ultra-trace contaminants, reactive or “sticky” surfaces can lead to:

• Sample loss or delay: Molecules like H₂S, NH₃, or VOCs adsorb to bare metal, skewing time-response and readings.
• Corrosion and leaching: Aggressive chemicals can attack stainless steel, shortening component life and introducing trace metals.
• Baseline drift: Poorly passivated surfaces can release trapped compounds later - causing signal noise or false positives.

Sulfur compounds are stable in SilcoNert 2000 treated stainless steel systems- 17ppbv hydrogen sulfide in 500ml cylinders.

Ammonia (NH₃) is injected into 3 meters of sampling line. The SilcoNert 2000 coated line responds in seconds while the stainless steel and PTFE line takes significantly longer to reach the baseline response.

What an Optimized Flow Path Looks Like

A well-designed analyzer system doesn’t just rely on good hardware - it incorporates chemically inert, corrosion-resistant surfaces from sample probe to detector.

Key areas to coat include:

• Sample probes and transfer lines
• Regulators, valves, and fittings
• GC columns and injection ports
• Wetted internal surfaces of analyzers

These components benefit from coatings like SilcoNert 2000, which block active sites and provide an ultra-inert barrier for trace-level analysis, especially for sulfur, mercury, or VOC compounds.

An example of a coated sample cylinder in a completely coated analyzer flow path. 

Tips for Engineers and Integrators

When specifying coatings for your analyzer system:

1. Start early in design – Coating tolerance, geometry, and assembly requirements are easier to manage upfront.

2. Don’t forget assemblies – SilcoTek can coat welded components and even long lengths of tubing.

3. Use witness coupons – They help confirm coating integrity and uniformity for quality assurance.

What About Electropolishing?

Electropolishing is a common surface treatment for metal components used in analytical systems. While it can improve smoothness and reduce some active sites, it doesn’t fully eliminate surface reactivity - especially for demanding trace-level applications.

The active compounds, hydrogen sulfide (H₂S), carbonyl sulfide (COS), and methyl mercaptan (MeSH), show slow and immediate loss of signal due to adsorption to the surface of the steel, even with electropolishing. Similar results are shown in our full study on non-electropolished tubing. Only the SilcoNert 2000 coating allows the preservation of the active sulfur compounds.

So while electropolishing can be a useful first step, applying an inert CVD coating like Dursan® or SilcoNert® 2000 provides significantly better protection and consistency - especially when analyte integrity and low detection limits matter.

The Bottom Line

If you're building or upgrading an analyzer system, internal surface coatings offer one of the highest returns on investment in performance and reliability. Coating your flow path protects your data, your equipment, and your bottom line.

Want to learn more about choosing the right coating? Contact our team!