Why do I get unexpected high values when I hydrolyze my fat samples?

You can see unexpectedly high values when hydrolyzing fat samples if the samples are not adequately dried after the hydrolysis step. 
 
Possible reasons for insufficient drying include: 
 
(1) Dryer is not working properly 
       - Filter needs to be replaced 
       - Dryer is not heating up to the correct temperature (the dryer controller should be set at 110°C) 
 
(2) Samples are not being dried for a long enough time 
       - All samples should be dried for three hours 
 
(3) Contaminated rinse water 
       - The water used for rinsing the sample must be free of contaminants (e.g., salt) 
 
Place a strip of litmus paper in the desiccant pouch (as noted in the procedure). If the paper shows the presence of acid when the dried XT4 bags are placed inside the pouch, dry the samples for an additional 30 minutes. Repeat this procedure until the acid is gone.