Peroxide Value Method
1.
Weigh 0.01 mg oil into test tube and record exact weight.
Solid fat should be melted first.
Samples with high PV may need to be serially diluted in working solvent.
Make sure to record dilution factor if so.
Up to 0.10 g can be used for samples with very low PV.
2.
Immediately add 3 mL working solvent and vortex to dissolve-make sure it is fully dissolved.
3.
Prepare a blank tube (solvent in place of sample).
4.
Add 15 μl ammonium thiocyanate to all tubes, and vortex 2-4 sec.
5.
Add 15 μl ferrous chloride to all tubes, and vortex 2-4 sec.
6.
Let sit at room temperature 20 min.
Keep out of bright light.
7.
Read absorbance on spectrophotometer set to 510 nm.
8.
Determine PV using the following calculations: a.       PV (meq peroxide per kg sample) = (As – Ab) x m /  (55.84 x m0 x 2) As= absorbance of sampleAb= absorbance of blankm = slope of standard curvem0=mass in grams of the sample55.84 =atomic weight of iron.
