I BULLETIN 13 90, U. S. DEPARTMENT OF AGRICULTURE 
The foundation and supplemental affidavits (12) should contain the 
analytical data for the determinations indicated in Table 1, which 
also gives the purity specifications. 
Table 1. — Specifications for ponceau SX 
Component 
Maxi- 
mum tol- 
erance 
(ratio 
to pure 
coal-tar 
dye) 
imim Method 
ance S1S 
Component 
Maxi- 
mum tol- , ,. 
erance : f JJm- 
< rati0 t™ 
to pure t0 ^ r 
coal-tar ance 
dye) 
Method 
of anal, 
ysis 1 
Per cent 
10.0 
.3 
.2 
5.0 
. 5 
( 2 ) 
( 3 ) 
None . 
.3 
.3 
.1 
P.ct. 
Page 
15 
15 
16 
16,18 
18 
19 
19 
20 
21 
21 
21 
Per cent P. ct. 
0.1 
.00014 
(*) 
( 2 ) 
(2) 
.2 
Page 
21 
Insoluble matter: 
Arsenic as AS2O3 
24 
Total 
Ether extractives: 
24,25 
24, 25 
24,25 
24 95 
Sodium chloride 
Sodium sulphate .. 
Sulphated ash ... 
Total 
Sodium in color, 
(3) 2K 9fi 
Eeavy metals 
74 5 
« 26-28 
» 26-28 
( 5 ) 
Calcium 
82 
Lower sulphonated dyes . 
5.0 
Aluminum 
1 Given in U. S. Dept. Agr. Bui. 1390 (rev.) (£). 
2 Although no limit is defined here, a statement of the percentage found by analysis should be incorpo- 
rated in the foundation and supplemental affidavits. 
3 Theoretical. 
4 As for ponceau 3R, etc. 
5 Special method. 
SUNSET YELLOW FCF 
Sunset yellow FCF, a monazo dye (C^Hu^C^^N^), is the 
disodium salt of the product obtained by coupling diazotized sul- 
phanilic acid with /3-naphthol-6-monosulphonic acid (Schaeffer's 
acid) (B. P. 7,098, 1884 (18), and G. P. 32,964 (9)). m These inter- 
mediates are used singly in numerous dyes listed in the Colour 
Index (11). The intermediates should be of such a state of purity 
and the coupling process and subsequent treatment so regulated 
that a minimum amount of the lower sulphonated dyes or subsidiary 
products is present in the finished dye. 
The ground dye is an orange powder soluble in water and 50 per 
cent alcohol. The dye is slightly soluble in 95 per cent alcohol. 
The neutral solution is yellowish orange. Addition of alkali changes 
the tint to brownish red. Addition of acid produces almost no 
change. The powder dissolves in concentrated sulphuric acid with 
an orange color. This becomes yellow on dilution with water. 
The foundation and supplemental affidavits (12) should contain 
the analytical data for the determinations indicated in Table 2, 
which also shows the purity specifications. 
% 
