Abstract
Spectrophotometric measurements were made on to quantitate batch variations of orcein dyes. Three types of spectra were observed among eleven batches tested. Four showed bimodal curves with a peak absorption at 520nm and smaller peak at 595nm (Type A). Five showed a single peak at 520 nm (Type B) and two synthetic orceins gave a single broad peak at 510 nm (Type C) Modified Shikata's orcein stain for hepatitis B surface antigen was tested with these reagents and large variations in staining capacities were noted. An immunoenzyme method was performed for confirmation and comparison of orcein reaction. Type A orcein gave the best results and staining specificity was found to increase in proportion to the amount of absorption at 595 nm. Results of staining with good batches of orcein were equally satisfactory with immuno-peroxidase staining. The latter method being expensive and timeconsuming, orcein staining was found to be method of choice and a spectrophotometric analysis may facilitate choice of the batches.
