Mineral oil extraction of light filth from rubbed sage: collaborative study

An improved method has been developed for extracting light filth in rubbed sage. The method is similar to 44.A04 and 44.A05, except the light filth is isolated by using 20% isopropanol with mineral oil. Collaborative results show that the proposed method yielded better recoveries than the present official first action method. The method has been adopted as official first action.