Effects of various treatments on the quantitative recovery of endotoxin from water-soluble metalworking fluids.

Three extraction methods were compared for their effectiveness in the quantitative removal of endotoxin from unused and used bulk water-soluble metalworking fluid (MWF) samples. Soluble, synthetic, and semisynthetic fluids were studied. The three modes of extraction consisted of (1) pyrogen-free water (PFW); (2) PFW and Tween 20 (polyoxyethylene sorbitan monolaurate); and (3) PFW, Tween 20, and sonication. Results suggest that vigorous recovery methods yield higher amounts of endotoxin from MWF samples than mild recovery methods in PFW alone. Additional studies are required to aid in the understanding of the factors that significantly affect endotoxin extraction yields from these fluids.