I switch to a Premier column and chromatography improves for a while, but then it goes bad again. What could be causing this? - WKB225007

ENVIRONMENT

• Column characteristics
• Premier columns

ANSWER

Over time, more metal ions can be stripped off upstream in non-Premier systems, and these components can accumulate and be detected. The Premier column will not prevent the upstream contamination from occurring or from being detected. The Premier hardware can only minimize the effect of the column hardware. 

If the tubing, sinkers, and other components are typical stainless steel, this could very possibly be a contributing factor. This is why Waters has gone so far as to develop a new system comprising Premier technology.  

Here are some ideas to help manage metal contamination on a non-Premier system:
1. Change the sinkers in your solvent containers regularly; use titanium sinkers rather than glass or stainless steel.
2. Likewise, change your injector needle to titanium.
3. Run a decontamination passivation procedure on the system with a chelating agent. 
4. If you have any very old stainless steel tubing, consider changing it out.

Acids in general, such as phosphoric acid, can be especially bad in terms of extracting iron from stainless steel components in a system. 

ADDITIONAL INFORMATION