The loading capacity for peptides on Sep-Pak C18 and tC18 is about 0.1% to 0.3% multiplied by the sorbent weight.
This loading capacity is estimated for peptides dissolved in a neat solution with no other matrix components present.
For example, on part number WAT036820 - SEP-PAK TC18 Cart 1CC, 100mg cartridges, calculate estimated loading capacity as follows:
100 mg bed mass X 0.001 = 0.1 mg (100 µg)
100 mg bed mass X 0.003 = 0.3 mg (300 µg)
Note: Additional loading capacity may be observed due to the wide variety of peptide characteristics. A loading capacity study (breakthrough study) should be performed in order to verify true mass load. Loading capacity will be less if other hydrophobic matrix components are present in samples.