One of the problems present in the application of the Limulus test, for the detection of bacterial endotoxins in pharmaceutical products, is the adjusting of the pH between 6.0 and 7.5. The utilization of strong acids and bases (e.g. NaOH and HCl) bring about chem. interferences with the components of the injectables in the assay. The use of buffers, like TRIS-HCl, does not permit adjusting a pH that is extremely acidic or alk. The present work studies the advantages of utilizing solutions of sodium bicarbonate and acetic acid to obtain the desired pH.