BEH column stability in basic condition

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TCheng
TCheng
in Instrumentation and Mass Spectrometry
<p>I am wondering if some one can pass me some information on BEH column stability in basic condition.</p><p></p><p>I have a method using 10mM ammonia or TEA as mobile phase A (ACN as mobile phase B, ambient temperature, gradient from 95% A to 5% A in 10 minutes) .The pH will be either 11 for ammonia or 12 for TEA.</p><p></p><p>Waters catalog says BEH columns are good for pH 1-12. Do it mean BEH column can operate at pH 12 for months without any significant degradation?</p>

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  • dougm
    dougm
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    Hello,

    This is a commonly-asked (and very good) question.

    Operating pH ranges for columns are not absolute, black/white values. In other words, one cannot achieve the same column lifetime at pH 11.9 as one can at pH 3, despite having a recommended pH range of 1 to 12. Column lifetimes at the extremes of pH, temperature and pressure will vary depending upon the exact operating conditions.

    In the ACQUITY UPLC BEH Columns Care & Use Manual we provide some guidelines. Please take a look. The fact of the matter is that the only way you can truly determine the lifetime of any LC column is to test it under your conditions. That said, BEH columns will outlast any other LC column on the market under basic-pH conditions. Many methods have been developed at high pH since 2004.

    Rules of thumb: all things being equal, lower pH will provide longer column lifetimes than a higher pH value (e.g., pH 11 vs. pH 12). If you combine increased temperatures with increased pressures (at high pH) you may see shorter column lifetimes.

    I am not sure if this helps. I invite others on the eCommunity to reply with their UPLC column lifetime experience(s) under high pH conditions.

    Thanks,

    --Doug       

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