Empower CF - Impurity summary


How best is it do CF for Impurity summary where Amount = ppm and then total imps as % Assay

ie SUM(100-(total degs/10000)

where total degs is not including main peak and internal std amount

My thoughts were :

Result , real , = Same.%.Sum(Amount*NEQ(Name,"Main Peak")+Sum(Amount*NEQ(Name,"Internal Standard"))/10000

Then CF : 100- above

Where unknowns U1 , U2 , U3 and U4 but not getting correct result

or use named group in processing method ?



  • Im not usually a fan of the Impurity tab of Empower 3 but you might benefit from playing around with that option- you can easily exclude certain types of peaks like the active and internal standard etc and perform a sum on the remaining peaks. You might want to rename some of the default identifiers like Above Identification Threshold etc and change to something more user-friendly or more appropriate to your needs. 

    You can also create a group of certain impurities eg "Process Impurities" and add impurities to that group and set specs on all or individual impurities. 
  • Pre-impurity tab Empower...I simply have a formula that takes the total and subtracts the API amount...so something like "Sum(.....)-MAINPEAK[Amount]" where your "sum(....)" is whatever you have for your total degs.  You just can't have any spaces or odd characters in the "MAINPEAK" name (or internal std in your case as well of course) I think for it to properly reference it.
  • Hi ,

    Got this problem sorted by using EQ , RANGE and text strings

    Also with NEQI for peak name and rearranging formula to 100-SUM(Totaldegs/10000)

Sign In or Register to comment.