Coating Applications for Liquid Chromatography (HPLC - UHPLC)

Improve Test Consistency, Sensitivity, and Peak Quality 

 

 

 

 

Improve LC Test Consistency, Performance, and Reliability

SilcoTek® chemical vapor deposition technologies create a non-reactive surface that prevent interaction of test analytes with the stainless steel, glass and ceramic flow path surfaces.  Our inert coating, Dursan®, improves peak quality and extends component life by preventing flow path corrosion.  

 

The benefits of an inert flow path in HPLC include:  

  • Coat columns and frits for an inert surface like PEEK, but as robust as stainless steel.  All the inertness and performance of PEEK without swelling, assuring consistent column performance. 
  • Improve peak shape, prevent lost peaks and improve test consistency.  
  • Improved performance with compounds like chelating agents, proteins, and biologics.  Saving time and money getting the right results the first time, every time

Get all the information about the benefits of SilcoTek coated analytical flow paths.

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HPLC Medical Background

Coating Applications for High Performance Liquid Chromatography

SilcoTek coatings are used in HPLC applications to prevent interaction of the test analyte with the flow path surface.  Our inert coating, Dursan, prevents adsorption, reactivity, and flow path corrosion.  Applications include:

 
  • Analysis of chelating agents and other metal interactive compounds
  • Phosphate analysis, prevent iron interaction
  • Antifungal agent analysis
  • Protein analysis
  • PEEK replacement in high durability applications
  • Corrosive applications
HPLC nuts 3  

Apply Dursan® to HPLC flow path surface to assure consistent results.  Apply Dursan to: 

 
  •   Needles
  •   Pump heads
  •   Metal fritted filters
  •   Stainless steel tubing
  •   Ampuoles
  •   HPLC columns
  •   Valves and Fittings
  •   More
   

HPLC Coating Data

Comparison of plates show there are negligible effects on pressure and column packability.  The Dursan® CVD coating process results in a micron thick surface on larger geometries like columns.  On fine geometries, like frits, the coating process results in a 100 nm thick surface.  The table below shows Dursan has no impact on column efficiency. 

Column type

Efficiency (avg of 3)

Asym (avg) of 3

Stainless Steel

15195 plates

1.028

Dursan coated frit and column

15233 plates

1.026

With Dursan coated frit, SS column

15069 plates

1.020

Titanium frit SS column

14263 plates

1.044

PEEK is a highly inert material which has been used in HPLC applications for years.  However PEEK has some limitations:

  • Mechanical strength: PEEK begins to flex at 3000 to 5000 PSI, making it unsuitable for UHPLC and other applications where high pressure is required.
  • Work-ability: Machining of PEEK doesn’t produce consistent IDs, which disrupts flows and can shift retention times.
  • Environmental: PEEK has temperature limitations and solvent related swelling issues which limit solvent and temperature options for the user.

Dursan coated stainless steel offers a robust and inert alternative to PEEK.

Material Temperature Stability Solvent Performance Corrosion Resistance Delamination Issues Mechanical Strength Work-ability
Dursan-coated Stainless Steel 450°C No swelling Resistant to most known HPLC solvents Molecularly bound and will not flake off Limited only by the base material Precision coating does not significantly alter dimensions. 
PEEK 148°C Swells with THF, Acetone & more Some acids, halides, chlorides and buffers Lined tubing can experience delamination issues Begins to flex at 3000 to 5000 PSI Inconsistent machining can disrupt flow and shift retention times

 

Comparative studies with Abbott Laboratories demonstrated the non stick feature of Dursan.  Through our collaborative study with Abbott Laboratories, Dursan was shown to prevent non-specific protein binding and minimize protein fouling.  Studies highlighting separations on HPLC peptide standard mixture, ribonuclease, cytochrome C, bovine serum albumin, and proteins show better response and minimum retention of the analyte on the surface, preventing cross contamination.

QCM-D analysis of coated and uncoated stainless steel surfaces show significant increase in protein mass on the stainless steel surface.  The Dursan coated surface does not retain proteins, showing no increase in mass after washing with a non-ionic surfactant.  This demonstrates the non stick feature of the coating.

Protein-Adsorption-Graph

The comparative chromatograph below tells the story.  The resolution quality of tetracycline on a stainless steel column (A) showed poor peak shape and response.  The Dursan® coated column (B) significantly improved the peak shape and response.

 Tetracycline Broken HPLC Data

Organic molecules like phosphates can perform poorly in stainless steel flow paths.  Phosphates are well known to have severe peak tailing during HPLC analysis due to the phosphate-iron interaction.  We compared the performance of phosphate interaction, adenosine triphosphate (ATP), in stainless and Dursan coated systems.  Results show a significant improvement in performance.

ATP Comparison

Comparison of organic molecule performance

Ciclopirox is an antifungal agent typically used in topical fingernail and toenail infections.  We compared the performance of 2-pyridinol-1-oxide, the chelating part of this antifungal agent, on various coated and uncoated surfaces.  The chromatograms show significant loss of signal due to metal interactions in the separation.  This highlights the interaction that the column wall has with the analyte and the need for column coating. 

HPLC anti fungal agent comparison

Dursan resists corrosive attack and damage to stainless steel flow paths.  Dursan's inert surface creates a thin but robust barrier, preventing interaction of corrosives with the underlying surface.

HPLC Corrosion summary 1

Resources

Presentation: Dursan Coated HPLC Columns

Webinar: LC GC Webinar

If you have a technical question about how our coating technologies will perform in your application, contact our Technical Service Team and ask the experts.

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If you would like to buy a coated product directly from the manufacturer, go to our Buy Coated Products page.

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