How Inert Coatings Improve Metal Capillary Column Analysis

July 06 2018 LC & GC Chromatography


Metal capillary columns offer durability but do they perform?  Are metal columns non reactive and are they up to the task of analysis in the field?  Let's find out.

In this blog you will learn:

  • The benefits of an inert metal capillary column.
  • Data showing the inertness performance of SilcoNert® (Siltek®) deactivation for analytical columns.
  • Sulfur analysis performance of the SilcoNert surface.
  • Inertness performance in simulated distillation.

Want proof on how inert SilcoNert® coated metal tubing is?  Let turn the page of an interesting article we found in American Laboratory.  The article, written by Jaap de Zeeuw of Restek® Corporation, compares the performance of SilcoNert® 2000 (called Siltek® and Sulfinert® in the article) coated metal capillary columns.  The article highlights the benefits of inert surfaces in chromatography, and process separation or process analyzers. Superior inertness of the SilcoNert 2000 (Siltek) coating improves separation and peak resolution.  Separation of Hexanediol and Chlorophenol compounds (below) are improved with SilcoNert 2000.*

 Siltek Deactivation Chromatogram

Primary benefits of a SilcoNert coated metal column are:

  • Allow high temperature analysis in simulated distillation and biodiesel applications
  • Improved sulfur analysis with little to no surface interaction and adsoroption.
  • Precise process analysis.  Repeatable test results without contamination or desorption.
  • Improved separation and column durability
  • Improved direct heating and heat transfer compared to non metal columns.

Learn about all the benefits and applications our coatings offer in analytical sampling applications.  Get our e-book "Ultimate Guide to Reliable Analytical Sampling".  You'll get an easy to read series of books that are full of great tips and comparative data relating to oil and gas, process analytical and laboratory sampling and analysis.

Ultimate Guide to Reliable Analytical Sampling

Sulfur Performance

The article goes on to say: " The Siltek/Sulfinert deactivation has demonstrated efficacy when accurate levels of sulfur need to be monitored. This technique is not only useful for transfer lines, but also for sample loops, liners, MXT columns, flame jets, etc.; thus the entire GC system can be optimized to produce the highest possible signal."  SilcoNert® 2000 (Sulfinert®) is a proven solution to difficult sulfur sampling problems.  After 15 days, the SilcoNert 2000 coated sample cylinders show minimal loss of sulfur compounds, untreated sample cylinders show total adsorption of sulfur compounds.*

Sulfinert sulfur chromatogram

SilcoNert® 2000 improves process analytical efficiency, increases process yields and improves product quality by preventing surface interaction and adsorption of sample or product.

Inertness in Simulated Distillation.  

High temperatures associated with simulated distillation applications will damage fused silica columns and will promote reactivity with metal surfaces.  Reactivity of a metal surface can change the accuracy and repeatability of the boiling point, ultimately causing variation in retention.  That's why minimizing reactivity with a high temperature capable inert coating is key to simulated distillation and surfaces used in refinery or oil and gas related analysis .  The graph below highlights the repeatability and precision of SilcoNert coated metal surfaces, showing consistent peak shapes and elution.*

MXT Sim Dis graph


Learn more about SilcoNert® 2000. 

Have questions about SilcoTek Coatings?  Contact our Technical Service Team.

Contact Our Technical  Service Team *Image courtesy of Restek® Corporation