How create the custom fields formula ?

I would like to create a custom field to calculate the assay of two API in the same analysis, can someone help me? 
if I write you the formula, can you help me create a formula step by step?


  • Whats the formula? There are several custom field options for assay so I'm sure there is a way to do this.
  • are CF required here ? can assay of 2 APIs not been completed in processing method with dilutions, purity component table ?
  • These are the formula: 1 = (area sample average 2 replicates* weight std * purity std in % * 100)/(area std average 6 replicates * 50000*0,05).

    2= (area sample average 2 replicates* weight std * purity std in % * 100)/(area std average 6 replicates * 20000*0,20).

    How Can i create the custom fields formula?
    The chromatogram is the same for Boh API .
    Can Young help me ?
    Many thanks
  • Can someone help me?
  • You need to use the component editor to enter you standard amounts. You need to use the sample weights and dilutions field within the sample set method to accommodate your standard weight and dilutions.

    Empower will then calculate the concentration of your analytes in the amount field.

    To average the two replicates you can most easily generate an average by using the same sample label in the sample set for replicate one and two. You can then setup a report to group samples by label and give you an average for each group.

    If you want to use the average value for a calculation down stream, then you will need the following custom field:


  • Many thanks,
    But if i have two api in the same analysis and in the same chromatogram, How can i use sample weight and dilution etc.? I ma obliged To ceate A formula in the empower project.

  • First row - Values for API1
    Second row - Values for API2

  • Can you describe me step by step?
  • @egio : What are you getting stuck on exactly?  Can you also describe where the 50,000, 0.05, 20,000 and 0.20 come from in those two formulas?  Are those related to the dilution schemes of the two different APIs, and if so, what is your typical prep (e.g. 20 mg/100 mL, diluted 1 mL in 50 mL)?  Also in your original formula, why the *100 if your purity is already in % (like 99.2% purity value used) that for unit conversion of some sort?
  • egio said:
    Can you describe me step by step?
    In the Processing Method (PM), you enter names and retention times for both APIs. Pull APIs into Component editor in Sample Set Method editor by clicking on the PM button (the left hand of the 2 buttons w/ yellow on them) once you open the Component editor (Amounts button). Both components will show up. Enter concentrations, purity, etc. for each (taking into account their dilutions makes it all a bit simpler). Do the couple of clicks so you can see samples as well. Enter your Label Claim values for each component there. Enter Sample dilutions in the first table. Process and you should be there.
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