Check the lot-specific certificate of analysis. Sartorius purity tested pipette tips are endotoxin free. Endotoxins are a class of pyrogens. The testing is carried out according to Ph.Eur. 2.6.14 Method D using a chromogenic kinetic method with a detection limit of <0.005 IU/ml (EU/ml). Please see below for additional information on endotoxin free testing.