Short column lifetime due to sulfuric acid in samples?

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

7 posts Page 1 of 1
Hi all,

at this moment we analyze phenolsulfonic acid (para and ortho) using hplc and a Waters xbridge phenyl column (in a 10 mM ammoniumcarbonate buffered system). At this moment the samples are simply prepared dissolving the samples and neutralizing the remaining sulfuric acid in the samples using sodium hydroxide and filtration of the samples. The column lifetime is very short and I wonder if this could be caused bad sample preparations. Any ideas about this or suggestions?

Regards, Mark
What kind of samples are you analyzing? How many injections does a column last and what is the symptom of the loss of performance.

Any more details about both the sample preparation and the LC method (injection volume, temperature,..) would be helpful.
Loss of performance is shown by extreme peak tailing. The injection volume is 10ul @ 1ml/min and column temp is 30C. Elution program is 100% buffer for 5 minutes and from 5.01-12 minutes 90-10 acn-buffer. Column lasts only about a hundred sample injections (or in that order of magnitude).
I thought you said you neutralized the sulfuric acid in your samples?

Anyway, why not inject like 3µl or 5µl instead if you think your samples are the cause of the short lifetimes; with your stated analytes you should have plenty of sensitivity.
Sounds like your column is being 'fouled' by excipients in the sample. What else are you injecting?
How do you prepare the buffer and what is the final pH ?

Are you sure this buffer is compatible with acetonitrile: could there be precipitation if you mix ~10mL buffer with ~90mL acetonitrile?
I don't think that your problem is related to having sulfuric acid in your sample. Even if you don't neutralize it before injection you are injecting only 10 uL with 1 ml/min buffered mobile phase. May be your pH is too high. There is no reason to run your compound at high pH. You can use pH 2-5 and most likely not lose any retention (you might gain it at lower pH)
Vlad Orlovsky
HELIX Chromatography
My opinions might be bias, but I have about 1000 examples to support them. Check our website for new science and applications
www.helixchrom.com
7 posts Page 1 of 1

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