Comparison of historic Grübler dyes with modern counterparts.

Seventeen Grübler dyes produced in Germany between 1880 and 1939 were examined in this study. These dyes were: fuchsin-bacillus, diamond fuchsin, fuchsin S acid, rubin S, safranin O water soluble, safranin yellowish water soluble, methyl eosin, Sudan III, scarlet R, auramine, orange G, aniline blue, pyronin, carmine, lithium carmine, hematein and aurantia. Spectrophotometry and staining characteristics were used to determine the maximum absorbance and efficacy of each dye in common staining techniques. The spectral curves and staining characteristics of these dyes compared well with modern dyes used as controls. Fuchsin bacillus and diamond fuchsin are synonyms for basic fuchsin. Fuchsin S acid and rubin S are synonyms for acid fuchsin. The scarlet R sample was the same as the Sudan III. The two safranins were the same. The basic fuchsin samples were unsuitable for preparation of Schiff's reagent. Both basic fuchsin and pyronin samples were less concentrated than modern counterparts. It is noteworthy that the dyes worked well after up to 100 years in storage, and this observation indicates that dyes can have a long shelf life when stored in cool, dry, air-tight conditions.