(Histo)chemical aspects of Sudan Black B in various solvents

The spectral properties, chemical composition and practical use in histochemistry of Sudan Black B (SBB) dissolved in pure dimethylsulphoxide (DMSO) have been investigated, in view of favourable characteristics of this solvent observed in previous work. The composition of SBB dissolved in DMSO, as determined with thin layer chromatography, appeared to be similar to that of SBB dissolved in aceton or 70% ethanol. The spectral properties of the two main components of SBB (SBBI and SBBII) also were the same in different solvents. A freshly made solution of SBB in DMSO proved to give good results in staining neutral lipids and phospholipids in frozen sections of rat liver and adrenal cortex, as well as with smears of isolated liver cell nuclei; during aging of such staining solution, however, a new secondary product is formed which greatly reduces the specificity of the staining.