Waters Spherisorb

[Chris]

Has anybody got any idea of the pH stability of waters speherisorb C8 columns. I am using 0.1%TFA in water as solvent A and acetonitrile as solvent B (50/50 ratio). The pH of the 0.1% TFA is 2.0 so just wanted to check that this would not damage the column.

[sball]

Hi Chris,

Spherisorb columns, as with most other silica based mateials, should be stable in the pH range 2-8. The higher the proportion of the pH adjusted aqueous component in the mobile phase, the more likely the stationary phase is to become degraded slighty with continued use (particularly if running at "extremes" of pH), however running at 50:50 0.1% TFA in water/MeCN should be fine.

So, it should be ok to use your Spherisorb under these conditions without damaging the column. Make sure you flush the TFA out of the column before storing it for extended periods of time. For your information, some of the newer (silica based) columns on the market which are based on higher purity silica's may be able to withstand extremes of pH for longer.

Hope this help!

Steve.

[pharmason]

your column is suitable for your buffer:organic(1:1) ratio, no problem,just wash with 50:50 (water:acetonitrile) after your each run.