The cap frit on the Level 1 and Level 3 Trident filter end fitting will catch larger particulates and maximize the life of the guard cartridge. Porosity is chosen based on the nature of the sample matrix and, in some cases, the nature of the mobile phase mixture. A frit with a porosity of 2 µm can be used in most cases and is the standard size when ordered. A 0.5 µm frit offers more protection for samples that are not prefiltered or that lack cleanup during sample preparation. Smaller porosity may also be more beneficial when using a 3 µm particle size analytical column or when using a mobile phase that contains higher levels of buffer salts.

