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 quant itative removal of endotoxin from unused and used bulk water-soluble metalw orking fluid (MWF) samples. Soluble, synthetic, and semisynthetic fluids we re studied. The three modes of extraction consisted of (1) pyrogen-free wat er (PFW); (2) PFW and Tween 20 (polyoxyethylene sorbitan monolaurate); and (3) PFW, Tween 20, and sonication. Results suggest that vigorous recovery m ethods yield higher amounts of endotoxin from MWF samples than mild recover y methods in PFW alone. Additional studies are required to aid in the under standing of the factors that significantly affect endotoxin extraction yiel ds from these fluids.