USP Suitability in Empower

<p>Hi everyone. Did a quick search and didn’t find anything on this – hopefully I didn’t miss anything. I was curious when Empower (in my case Empower 2) was going to update the suitability module to match the recent (well some back to 2009) changes to the USP. In particular this is in regards to the new USP signal to noise calculations. I realize that since USP has harmonized with EP, that EP s/n is the same as USP. However there are issues, such as selecting USP as the compendia in the suitability tab prevents EP s/n from calculating.</p><p></p><p>My suggestion is to realign the compendia calculations to match the most recent changes in all compendia. I would also suggest adding the option to use Average P2P Noise for the noise value, of course requiring the user to set the minimum <span style="text-decoration: underline;">Segment</span>length to 5x 50% peak width (just like they do for start stop times now). I would also suggest adding the option to say “Ignore Integrated Peaks” contained within the Start / Stop region. Something like a simple checkbox in the Noise and Drift tab would work. That way you could actual use the noise “situated equally around the peak of interest”, well when possible that is.</p><p></p><p>Anyway I hope this is something already in the works, as the compendia calculations really need to be updated. Please let me know the timeline for this much needed correction.</p>


  • Hi

    The noise and drift and S/N calculations that you are looking for has been implemented in Empower3. In Empower2 you can do the USP and EP S/N calculations by using custom fields. How to do this is described in the attached technical notes.

    I hope this will help you.

    best regards


  • Good to know there’s some additional options available in Empower 3, however many of us will be using Empower 2 for the foreseeable future. So I do hope a fix is in the works for Empower 2 as well.

    To help achieve this (in both Empower 2&3) I would suggest the following…

    1) Custom calculations, while nice, can be difficult to implement in some cases. And since these are compendia defined values required as part of suitability, they should be available within the software directly. Accordingly the software should also have a mechanism for implementing these types of changes when they occur.

    2) Since USP & EP have mostly harmonized (not sure about JP) the EP S/N result is the same as USP. Still there are two problems:  1) selecting USP prevents the calculation of EP S/N, 2) the EP S/N result says “EP” not “USP”. So it would be nice if the result either included USP (e.g., “USP S/N”, or “USP&EP S/N”, etc.), or was generic ally named (e.g., “S/N-2”, or “2x S/N”, etc.).

    3) On the subject of harmonization, has Empower 3 been updated to reflect the most recent changes? As shown in “What’s New in Empower 3” Revision A, these equations may not be current. First there is still mention of EP requiring 20x peak width, and USP has defined the height from the center of noise like EP (i.e., USP also needs to subtract ½ noise from the height).

    4) I like the peak related blank injection option in Empower 3; however blank injections are not always available. That is why I suggested the ability to exclude integrated peaks from the noise region. The algorithm would be to simply ignore any data points between the peak’s start and stop markers when calculating noise. This would even allow for noise to be “situated equally around the peak of interest”.

    5) Personally I would also like to see an option for using Average Peak to Peak Noise, just like the standard S/N result in Empower 2. In that case the minimum segment width, not start/stop time, would be set to the required compendia peak width. Noise after all is random (well maybe in this case you can also include cyclic). Any oddball, one time, or single point disturbances are not noise. So averaging can be a useful tool when attempting to determine the “true” noise of a system.

    6) In Empower 2, the minimum segment width is 10 second. So that also means that the minimum start / stop range for the noise region is 10 second. With UPLC and other fast chromatographic techniques, even 10 seconds can sometimes be larger than needed. So the minimum has to be reduced in Empower 2 (maybe Empower 3?).

    Anyway I hope that helps clarify my original request. I realize that some of this may be difficult to implement, still we do need to meet changes to compendia requirements as they occur. Any assistance in complying with those changes would be greatly appreciated.

  • Hi Can i have the ,

    PDF or PPT  for All system suitability parameters calculations .

    Thanks in advance



  • Hi Satya

    Attached you will find the System Suitability Quick Reference Guide.

    best regards


  • Thank you for your prompt reply.

    Waters community is really great in solving problems and helping on empower related doubts.

    Great .



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