Calculate mass balance

[mojo]

When calculating mass balance as area %, should one reject all areas below the LOD, then calculate the % area of each peak greater than the LOD based on the sum of all areas greater than or equal to the LOD?

[Bruce Hamilton]

Neither, for most HPLC detectors.

Calibrate the analyte peak against known purity external standards, thus ignoring other peaks in the chromatogram - unless using an Internal Standard.

If you want to report normalised area % you should report as that, not as mass.

Whether you include peaks below the detection limit depends on you SOP and/or any regulatory guidances you may be following, but I suspect most people would exclude peaks below the LOD. If they are real, then the LOD may be suspect.

Consistent peaks between the LLOQ and LOD are more likely to be included, but it very much depends on the SOPs you are following.

Please keep having fun,

Bruce Hamilton