When should I use a frit?

Use a frit in any sample that has significant debris in the sample tube after heat-treatment.

High fat and high protein foods may develop debris as they are heated and cooled. It is therefore very important to allow the sample to cool, to allow fats to solidify, before adding a frit to the tube. If a frit is added prior to fats solidifying then the frit will have no filtering effect and clogging may still occur during liquid transfer into the assay plate.