4. Recovery Calculation:
a. Determine the SO2 concentration in the recovery (SO2 found). Correct for tissue blank.
b. Determine recovery’s fortified level (SO2 added) using
SO2 added, (ppm) = (CFort)(VFort) / WSample
Where:
CFort = Concentration of fortification Solution (D.3) in μg SO2 /μL
VFort = Volume of fortification solution added, in μL.
WSample = Sample weight, in grams.
c. Calculate % Recovery as:
% Recovery = 100% × (SO2 found / SO2 added).