The effect of aluminum hydroxide dissolution on the bleeding of aluminum lake dyes.
The effect of pH on the bleeding of FD&C yellow No. 5 aluminum lake and FD&C red No. 40 aluminum lake was investigated. The pH-bleeding profiles corresponded to the pH-solubility profile of aluminum hydroxide. The similarity of the bleeding profiles of both lake dyes and the pH-solubility profile of aluminum hydroxide indicates that pH related bleeding, other than that occurring by competition with anions, is a result of dissolution of the aluminum hydroxide substrate. This dissolution is related to the properties of the substrate rather than to the structure of adsorbed dye.
Desai
A
A
Department of Industrial and Physical Pharmacy, Purdue University, West Lafayette, Indiana 47907.
Peck
G E
GE
Lovell
J E
JE
White
J L
JL
Hem
S L
SL
D000536:Aluminum Hydroxide / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D012995:Solubility; D013645:Tartrazine / Q000737:chemistry*
D001391:Azo Compounds; D004396:Coloring Agents; C005915:Allura Red AC Dye; D000536:Aluminum Hydroxide; D013645:Tartrazine