How to reject peak areas based on size using custom fields and recalculate the percent area of those remaining - WKB68630

OBJECTIVE or GOAL

Create custom fields to test the % peak area and reject peaks below a threshold, and then recalculate the % peak area of the peaks that remain.

ENVIRONMENT

• Empower
• Custom fields

PROCEDURE

1. This method requires a number of custom fields (CFs).
2. Create a Boolean CF called TestSmallPeaks. This tests for %Area less than the value set and assigns a 1 or 0 for use in the next CF.  The calculation is GT(%Area,1).        Replace the 1 with your desired threshold.
3. Create a Peak CF called AreaAccept. This multiplies each peak area by the result of TestSmallPeaks (1 or 0). The calculation is Area*TestSmallPeaks.   Peaks with a %Area less than the rejection value are 0.
4. Create a Result CF called SumRemainingPeaks. This sums the areas now remaining in the AreaAccept CF (i.e., Total area without those peaks below the %Area threshold set in TestSmallPeaks CF). The calculation is -   SUM(AreaAccept)
5. Create a Peak CF called RemainingAreaPercent. This calculates the new %Area after disregarding the small peaks.  The calculation is -  AreaAccept/SumRemainingPeaks*100
6. The custom fields created can all be displayed in a peak table in a report as required and displayed in the review window. 

ADDITIONAL INFORMATION

Subscribe to the Empower blog for more tips.

More Custom field tips on KCS.