Blank interference calculation

Hi, I'm trying to create a custom field to calculate the interference in a blank injection.  I want to calculate the % area of peaks against the average area of one specific component.

I have created a first CF, which is the average area of my SST injections.  Calculations is ok.

Std_SST_Avg_Area :  S01,%,%,AVE(Area)

The second CF is the area of found peaks in my blank divided by CF#1 of CCalRef1

Area/CCalRef1[Std_SST_Avg_Area]*100.

Calculations is ok for all the  injections where the CCalRef1 is present.  But in my blank, the result is not calculated.

Any ideas how to solve that??

thx
 ;) 

Best Answer

  • Accepted Answer
    If you want the average area of one specific component, you should include the CCalRef1 in your Std_SST_Avg_Area custom field such that:
    S01.%.%.AVE(CCalRef1[Area]). Do you have multiple channels or are you only interested in the peak areas of diluent divided by the average area of standards when both are collected in the same channel? If so you can drop the "%" channel syntax:
    S01.%..AVE(CCalRef1[Area]).

    This will generate a result for the average area of the CCalRef1 peak in the injections of S01 where CCalRef1 is found. To calculate % areas of found peaks in the blank, create another custom field and call it something greater alphabetically than the first letter of your average cf, so for example T_Blank, because summary fields are calculated in alphabetical order so T_Blank will have the relevant value at time of calculation. Your second CF then becomes (Area*100)/Std_SST_Avg_Area. If you are running multiple blanks and you want a value for each blank, label your blanks as B and change the formula to (B.%.(Area)*100)/Std_SST_Avg_Area and that will give a different value for each blank injection. If only running one blank, then only one value will populate for each known (if found). 
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