life of a uplc columne

Dear colleagues,just a silly question, how many injections do you usually perform in a uplc beh c18 column ?In our lab, we have an average of 1500-2000 injections, then pressures are too high or resolution is poor (althought in MS is not a big deal).Ee are considering to use guard columns if we could perform enough injections to increase column life, but if our number of injections is normal, then maybe it would'nt worth it.Thanks.Josep Ma GuiuBarcelona

Comments

  • You are talking about only LC/MS chromatography ?

    In our case , we try to use one column for each pH range; but  we don't obtain the same number of injections like you yet.

    Our "longest life" column has almost 600 injections.

    The " normal  life " of our columns is 500 injections.

    Thanks.

  • The lifetime of a UPLC column is determined by what passes through it and the conditions under which it is used.  As you can see in the "More Like This" part of the forum page this question comes up from time to time.  Unfortunately, there is no one numerical answer to your question. A column can last several hundred injections and/or a column can last tens of thousands of injections.  It really depends on how it is treated. 

    The usual culprit of UPLC column failure is particulate or chemical plugging/fouling of the column. Mechanically voiding a UPLC column is very difficult to do because it is packed so tightly (unless you dissolve the packing material at very high pH & temp).

    Could you describe your operating conditions, samples/sample prep, and lab practices (e.g., water source/quality, solvent quality, mobile phase preparation process, how often mobile phase is changed)? 

  • Hi Josep,

    I have seen up to 5000 injections on our BEH columns. We use LC-MS grade quality on all solvents. If you are not using an In-Line filter I would recommend this. It's basically a frit similar to the one placed in the column. Introducing these filters years ago in our lab, increased column life time dramatically. But of course method conditions play a major role and they differ between labs.

    Best regards

    Rasmus

  • Thank you for all your answers.

    In our lab we use a LC-MS/MS (Acquity UPLC - Xevo TQMS), we also use HPLC grade solvents and milliQ water.

    We also use online in-line -filters, but I admit that we should consider using LC-MS grade solvents.

    Maybe our main limitation is that we analyse human plasma samples, and in other ocasions we analyse cell culture medium as well,

    depending on the drug to determine we perform LL extraction (MTBE), PP (TCA), on SPE (Oasis HLB), but always with samples with lots of proteins.

    We have also thought in using guard-columns, do you know or have any experience on them ?

    Best,

    Josep M

  • I have two UPLCs. One connected to MS second is a standalone machine with UV detection. On both the average lifetime of BEH C18 50x2.1mm column is around 2000 injections (weary from 1500 to 2500). We work with SPE purified DNA hydrolyzates. Solvents are MS grade and water is from Millipore water polisher (0.22um filtration at nozzle).

    Columns are usually replaced when resolution of two peaks presented in our samples is below expected and tolerated threshold. I consider 2000 injections as a good number, taking in account our sample composition.

    We are using on-line filters (PN 700002775). I'm using VanGuard pre-columns (PN 186003977) only for specific samples / assays like direct analysis of urine (no pre-purification).

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