CHEMISTRY AND ANALYSIS OF THE PERMITTED 
COAL-TAR FOOD DYES 
By 
JOSEPH A. AMBLER, Chemist, W. F. CLARKE, Assistant Chemist, 0. L. EVENSON, Assistant Chemist, 
H. WALES, Associate Chemist, Color Laboratory, Bureau of Chemistry 
~ CONTENTS 
Page Page 
Te a 1 | Methods of Analysis of Permitted Coal-Tar Food 
Chemistry of Permitted Coal-Tar Food Dyes_________- 2 Dyes—Continned. 
So. gat ee ee ee ee ee 2 Iron, Aluminium, Calcium, and Magnesium________- 19 
lhaeraatk 4 VA ee Se eee 4 Arseme: of 4. bie OG 3s Nas A eee De 20 
to te ee Ae ee Set ee 5 Ether Estracivés. 8 > ti ees ee 23 
TL ag ee eee ee te 6 Salgbur tn’ Celera: £3552 fog Se ees 24 
Naphthol 2 ESS Neue ree ee 7 Wolo: Aegis oe 28 VO cara a) a ee) Ee 24 
as SE ee ee eee 8 Pure Ceal-Tar Dye f 2. 25-2. ee. ee 26 
i 4) a a ae 9 Matter {nsoluble in Carbon Tetrachloride___________ 27 
jy ES a a ae 19 Water. Extrarives>s(2 005) 2 5 oe eee ot 27 
eS a oe ee ee - 10 Melis Pomi: 2 ook ee eee 27 
on Green $ F Yellowish __.._..._.._...---_._.- 11 Lower Sulphonated Dyes__________._.___________- 28 
, Ramee ep ss B58 A 12 Boiling Point of ¥-Cumidine from Ponceau 3R _____- 29 
Methods of Analysis of Permitted Coal-Tar Food Dyes_ 13 Isomeric and Similar Dyes in Amaranth __________ 30 
4 we 3 EN i ee 13 aemiue oda. © 02. Fe ea 30 
Shasta 7) EE Eee a 14 Iodine Organically Combined____._____.__._._____- 30 
_ OS 9 ee es ee 14 ‘Total Halosens 20 ut Lai Fae Se 31 
Total Water-lasoluble Mailers? i OO 14 Sodium Carbonate in Erythrosine_________________ 31 
Nonvolatile Water-Insoluble Matter_____.__________ 15 Orange I] and Other Subsidiary Dyes in Orange I___ 33 
enemnnen ates. Coke er tia ORs 15 Martius Yellow in Naphthol Yellow S____..-.--____- 33 
meen Saipnaies es ee Se 17 Total; Nitresem (392.2 ah Syne ee ny 2 33 
; a a es es eee. 18 Color by Spectrophotometer______...-..----__.___- 34 
( PhS oS) Egle Re eee ieee crane 15 X]" Eteratewe, Gated)! 3. 2. a a 35 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1926 
