82 Biological Stains 



c68 ORANGE IV C. I. NO. 1 43 



Synonyms: Orange N. Acid yellow D. Tropaeolin 00. 



N=N 



NaSOa NH 



CisHiiNaOsSNa; Mol. Wt. 375.373 



{An acid dye; absorption maximum about 527 in acid solution) 



Solubility at 26''C: in water 0,16%; in alcohol 0.2% 



The only biological use of this dye seems to be occasionally as 

 an indicator. 



c7i BRILLIANT YELLOW S C. I. NO. 1 44 



Synonyms: Curcumine. Yellow WR. 



Ci8Hi3N306S2Na2; Mol. Wt. ^77.^22 



{An acid dye) 



This dye is closely related to metanil yellow and orange IV, 

 being manufactured by the sulfonation of the latter and containing 

 one more sulfonic acid group. The exact position of the latter in 

 the molecule is uncertain. 



Margolena (1933b) has employed this dye in the Doglio (1932) 

 technic, in which it is employed as a counterstain to carbol fuchsin 

 in staining acid-fast bacteria. In Doglio's original paper the 

 exact nature of the dye used is not specified, however, and at least 

 two other dyes (C. I. Nos. 146 and 364) have been sold as brilliant 

 yellow. 



c76 ORANGE I C. I. NO. I50 



Synonyms: Naphthol orange. Tropaeolin G or 000 No. 1. 



N = N 



NaSOa 



I 

 OH 



Ci6HiiN204SNa; Mol. Wt. 350.321 



{An acid dye; absorption maximum about ^76) 



Solubility at 26°C: in water 5.17%o; in alcohol 0.64%) 



