Can you calculate amounts for unnamed peaks?

Im trying to calculate amount for peaks that are not named in my comp editor, is this possible? I'm running related impurities samples and I'm trying to quantify the amounts off the bracketing standards but of course the only named component in the standards is the active peak. 
There are up to 50 peaks in the samples (100 min run time) so I don't name all these peaks. Right now I use excel spreadsheets for the calculation but was wondering is there any way Empower can do amounts for the unknown peaks or is this not possible?

Best Answers

  • Accepted Answer
    Couldn't you add all the peaks automatically (the button left of Apply Method Set in the main Review Window)? That way all get names as PeakX (Peak 1, Peak 2, Peak 3) and then you just set the CurveReference to your main peak?
  • Accepted Answer
    I'm quite certain that yes, you need to name a peak. Like Dan said, if you set* the main peak  and then apply your method set all peaks will be named RRT x.xx (regarding the main component). 


    *To get peaks named by RRT go to the Components window, click the dropdown menu of "RT Reference Used To name Unnamed Peaks by RRT" and choose your main peak.
  • Accepted Answer
    To quantify unknown peaks, one just needs to set the main peak as 'default peak' in the PM, (just checkmark it in the column 'default peak'). However, this will not help, if you need to perform any kind of intersample calculation. The "RT Reference Used...." won't help either, because the RRT is calculated for each injection and it is very probable, that the value for the RRT of a component will shift a little, what would in fact mean, that the name for the same component will also be different from injection to injection. Currently, there is no automatism implemented in Empower to take this into account. One would need to assign peak names manually, adjusting the retention times against each chromatogram. (or excel;-)

Answers

  • Hi DavidHPLC, yes I will try that. I presume then you need to have SOME kind of name (Peak1,2 etc) on a peak before Empower can calculate amounts? 
  • If "unknown peaks" is checked in the processing method, Empower will name them according to their relative retention times if a retention reference is found among named components. Otherwise, I think it just goes by RT.
  • Thanks guys for the answers. I will keep that in mind for when we upgrade to Empower 3- we are still on Empower 2!!
  • edited March 2018
    Create a custom field to calculate your amount. Set the custom field to run on unknown peaks (or all). 

    I setup an impurity analysis where there were named and unnamed impurities for a client. We didn't want to deal with the Peak 1, Peak 2, etc for unnamed. So, I just left the unknown peaks unnamed and told the custom fields to run on unknown peaks. 

    The approach worked like a charm. 

    If you want to get really fancy you can then also group those unnamed peaks in a report in accordance with RRT to a defined user tolerance (to account for minor peak shifting).
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