Metal Contamination Prevention

Prevent System Contamination Improve Quality 

Improve Test Quality and Corrosion Resistance

Metal ion leaching is of interest to a variety of industries.  Chemical exposure to solutions, such as, organic solvents, deionized water, acids or bleach, can cause a significant amount of metal ions to dissolve into the liquid, causing product contamination, system corrosion, and test problems in analytical and high purity processes including:

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  • Semiconductor Manufacturing
  • Biopharmaceutical Production
  • Medical Diagnostics
  • Precision Cleaning
  • Food and Beverage Processing
  • HPLC Analytical Flow Paths

SilcoTek® offers CVD coating solutions to make your process, analytical, and sampling systems perform better.  Our chemically inert coatings improve test accuracy and reliability by preventing contamination from metal ion leaching caused by chemical reactions between the sample and flow path surface.  The summary below demonstrates how metal ions can be readily leached into flow path solutions and how coated surfaces (right column, green) prevent contamination under all conditions tested.  

Metal ion data summary

 

SilcoTek's CVD silicon coating process bonds inert, non-reactive coatings like Dursan®, Silcolloy®, and SilcoNert® to the surface.  The chemically inert coatings prevent interaction of the sample with the reactive flow path surface. 

SilcoTek has conducted several studies relating to effectiveness of our CVD coatings in preventing metal ion leaching from various surfaces when exposed to organic solvents and deionized water.  Read the Technical Insights below to further understand how SilcoTek coatings improve product and test quality.

This Technical Insight investigated whether Dursan and other SilcoTek coatings can prevent metal ions from leaching into pure organic solvents. 

Read the Stainless Steel  Ion Leaching in Methanol Technical Insight
 
The study showed that high purity organic solvents like methanol can cause contamination and corrosion in stainless steel flow paths.  Coated stainless steel surfaces prevent ion leaching, corrosion, and contamination of analytical test and process streams.
 
Iron leaching rate 11 15 19

In this study titanium is investigated as a substrate for SilcoTek’s coatings. Titanium is commonly used as an alternative to stainless steel due to it being lighter, strong, and biocompatible.  We find that Silcolloy performs well as a barrier, but Dursan and a test coating,RD5, do not provide adequate protection.

Read the Titanium and Stainless Steel  Leaching Study

Test results showed the Silcolloy coated titanium sample improved the resistance to ion contamination in methanol.

Titanium leaching blog images-1

In this study we find that a bare C-22 sintered disc when exposed to pure methanol can leach over 1 ppm total metal into solution, where the same discs coated with Silcolloy, Dursan, and a test coating, RD5, showed no measurable loss of metal ions, indicating only baseline levels of leaching relative to experimental controls.

Read the Hastelloy Metal Ion Leaching Study

SilcoTek coatings prevent Hastelloy ion contamination when the surface is exposed to organic solvents like methanol.  SilcoTek coated surfaces show a significant improvement in purity, with very low ion contamination.

 

Hastelloy metal ion leaching in methanol 2

 

In this study we investigate DI water’s impact on titanium, Hastelloy, and stainless steel.  Among numerous other uses, DI water is commonly used as
a solvent for HPLC analysis, in food and drug production, in high purity ultrasonic cleaning, and as a precursor in semiconductor applications.

Read The DI Water Ion Leaching Study

Results of the tests show that titanium alloys do not suffer metal ion leaching in DI water, while both stainless steel and Hastelloy show large amounts of metal ion leaching, specifically an abnormally large amount of nickel leached into DI water when compared to the methanol leaching studies.

stainless steel di water metal ion leaching 2

In this study, we investigate acetonitrile’s impact on titanium, Hastelloy, and stainless steel; both with and without our coatings. HPLC systems commonly Methanol and acetonitrile are the two most common organic solvents used in HPLC and other analytical testing.

Read the Acetonitrile Metal Ion Leaching Study
Test results show that acetonitrile is the most benign when compared to methanol and DI water. Aside from showing no impact to titanium (similar to water), there are still trace levels of metal ions that leach into the solution which can impact a variety of analyses. ambient atmosphere.

stainless steel metal ion leaching 1

In this Technical Insight, we investigate MP35N exposed to ultrapure HPLC grade methanol, acetonitrile, and DI water.  MP35N is a nickel-cobalt based alloy which has been growing in popularity among HPLC and medical instrument OEMs.  It is marketed for the alloy’s high strength, corrosion resistance, and biocompatibility.   The study evaluates metal ion leaching in the three most common solvents used in HPLC applications: methanol, acetonitrile, and water.

Read The MP35N Ion Leaching Study

The results of the study indicate acetonitrile is the most benign solvent.  The MP35N alloy seems to follow the trend of another nickel based alloy, Hastelloy, in that water shows the most metal ion leaching of any solvent.

ion leaching mp35N in DI water

 

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