Peroxide value test of oil

Dear sir we are performing peroxide value test. using this method

everything is fine, but in last oil sample was not dissolve after final titration .
there is oil showing, after color change yellow to white.
Is it necessary that oil should be dissolve after titration? why it is not dissolve ? please answer me. Thanks

Please try any one of the following solvent mixtures to dissolve the oil, alternatively please use more volume of solvent mixture to dissolve the oil before determining of peroxide value.

Solvent Mixture
A solvent mixture might be prepared by measuring the volume of glacial acetic acid and organic solvent in separated volumetric flasks prior to be blended. A selection of solvent mixtures is given below.

Solvent Mixture I
Glacial acetic acid: chloroform (3:2)

Solvent Mixture II
Glacial acetic acid: cyclohexane (3:2)

Solvent Mixture III
Glacial acetic acid: isooctane (3:2)