Chromatography Forum

Dear all,

Could anyone please help me create a custom field in Empower to calculate the percentage difference between the peak areas of two selected injections?

The percentage difference is calculated as follows:

% Difference = ((Maximum Area − Minimum Area) / Average Area) × 100

Try these search results...
https://www.chromforum.org/search.php?s ... r+%25+diff

Give the two injections the same label in your sample set such as U1 or U2 etc.

Then create a peak, real, calculated custom field with a search order of Result Set Only, Peak and Sample Type of All, the All or Nothing option not ticked and the missing peak not ticked. The formula is:

(SAME.SAME.SAME.MAX(Area)-SAME.SAME.SAME.MIN(Area)/SAME.SAME.SAME.AVE(Area))*100

Make sure the function Summarize Custom Fields is in as the last line of the sample set. Then process a sample set to generate a result set and your answer will be in the result set.

If its 2 injections of the same sample then the formula is edited slightly:

(SAME.%.SAME.MAX(Area)-SAME.%.SAME.MIN(Area)/SAME.SAME.SAME.AVE(Area))*100