An Ultraviolet-Schiff Reaction for Unsaturated Lipids

Abstract

Tissues are fixed 12-18 hr in cold, neutral, 10% aqueous formalin, sectioned on a freezing microtome and the sections placed in a shallow, open dish of water under an ultraviolet light source. Sections are then treated with Schiff's reagent for 15 min, rinsed in 3 changes of sulfurous acid (3 min in each) and in distilled water and mounted in an aqueous mounting medium. The time of irradiation necessary to produce a maximum reaction is determined empirically. The magenta color indicating the site of unsaturated lipids fades and runs in many preparations in a few days. Evidence is presented that this reaction is most likely the histochemical equivalent of an iodine number determination.