864 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Formation of Bandrowski Base 0.6 0.5 0.4 •o X (m•) • •o Figure 3. Bandrowski base in oxidation mixtures. Sprectra in 0.05 21//titrate buffer, pH 2.3. -- BB standard, 1.06 X 10 -• g/ml. ß ß ß PPD oxidized, 1.08 g in 100 ml Na2CO3 at pH 9.5, with 3% H202 diluted 250-fold in buffer. - - - PPD-resorcinol, 1:1, same conditions diluted 500-fold in buffer Standard Absorption Spectrum of BB The spectrum of purified BB was obtained in 0.05 214r titrate buffer of pH 2.3 using a Bausch and Lomb Spectronic 505 spectrophotometer absorption maximum, 400 mu (very broad) molar extinction coefficient, 1(5,200 (Fig. 3). Formation of BB in Oxidation 21•ixtures PPD Alone Present.--.A 1% solution of PPD in water containing Na2COa, at pH 9.5, and H202 at 3% concentration, was stirred at room temperature for one hour. Aliquots at various time intervals were removed, diluted with 0.05 M citrate buffer (pH 2.3), and examined spectrophotometrically for the presence of BB. The absorption of these solutions exhibited a shifting maximum, closer to 380 m/•. The readings were taken at the maximum. Other Dye Intermediates Present.--Mixtures containing 1% PPD and varying amounts of a second component were allowed to react as before,

REACTIONS OF OXIDATION DYE INTERMEDIATES 365 with peroxide at pH 9.5 for one hour. Aliquots were diluted in pH 2.3 buffer and their absorption examined in the 380-400 m/• region (Fig. 3 and Table I). Chromatographic Method for BB In a second method, the above oxidation mixtures were spotted on thin-layer chromatographic plates and developed in two dimensions. TLC plates, 500 /• thick, were made using a 1:2 slurry of Silica Gel G and water. Development was effected by using the upper layer of n-BuOH: HOAc: H20 = 40:10:50. The chromatography tank was equilibrated at 38øC before insertion of the thin-layer plate. The solvent was allowed to ascend 10 cm in one dimension, the plate was removed and air-dried (oven-drying caused BB to be immobile in the second dimension), and then developed 10 cm in the second dimension. Approximately 0.1 3' BB is the limit of detection. Spotting load for a reaction solution was 4 X (Table I). Ouinonediimine Synthesis of ODI QDI was prepared by the method of Willstatter (6). It was used immediately. Table I OCCURRENCE OF BANDROWSKI BASE Dye Intermediates Molar TLC Evidence Spectral Is BB Present Ratio of BB Evidence of BB Present PPD + + Yes PPD: Resorcinol 4:1 + + Yes PPD: Resorcinol 1 '. 1 + -- Trace? PPD: Resorcinol 1: 4 -- -- No PPD: Hydroquinone I: 1 -- -- No PPD: Pyrogallol I: 1 -- -- No PPD: p-Arninophenol 1:1 -- -- No PPD: m-Aminophenol 1:1 -- ? Trace? PPD: Picramic acid 1:1 + ? Trace?