A new indicator for use in partition chromatography: 3:6-disulpho-β-naphthalene-azo-N-phenyl-α-naphthylamine

Publisher Website
Google Scholar
Abstract
A new indicator, the ammonium salt of 3:6-disulpho-j3-naphthalene-azo-N-phenyl-[alpha]-naph-thylamine, changing from pale pink to deep blue at pH 5.0-3.8, is prepared by diazotising amino-R-acid ([beta]-naph-thylamine-3:6-disulphonic acid), coupling the resulting diazonium compound with N-phenyl-[alpha]-naphthylamine and neutralising the product with ammonia. The new indicator is superior to others (e.g. methyl orange, anthocyanins) for use in the partition chromatographic separation of acetyl-amino-acids since it is readily available, is not leached from the column by the solvents used, and gives a much more easily seen color change.