ABSTRACT
Commercial dyes are rarely pure and are seldom produced primarily for biological staining; most are made for dyeing and printing of textiles. Manufacturers and industrial users of such dyes need cheap products that give reproducible results, and are not interested in chemical purity as such. Electrophoresis is primarily an analytical tool rather than a means of preparing samples, but it has been utilized for purification and separation of water-soluble dyes on the basis of charge and ionic weight. Practical responses to the impurity of dyes are to call for quality control of the manufacturing process of dyes and to introduce a rigorous standardization of reagents and staining procedures. The company bought up large batches that Grubler had previously tested for microscopic use. In that way an empirical standardization of dyes was achieved with surprisingly little batch-to-batch variation. The aim of standardization in cell and tissue preparation is to make this artifact reproducible.
