METHOD FOR IDENTIFICATION OF AZO DYES 227 o.s 0,4 o,3 o,o Number of ,•11o •o 0.9 o• 07 o,6 0 A B C o oo o o o ©o øo©oo iI111• ©© Figure 2. Influence of the degree of sulfonation on migration of tested dyes in monophasic neutral solvents. (The position of sulfo groups and the fundamental molecular structure re- maining constant.) 1. Acid Yellow G 17. Orange RN 2. Resorcine Yellow 18. Orange I 3. Orange III 19. Orange II 4. Metanil Yellow 20. Monosol Orange O 5. Orange IV 21. Xylidine Orange 6. Orange G 22. Neptune Brown RX 7. Scarlet GN 23. Ponceau 6R 8. Orange GGN 24. Ponceau 4R 9. Sunset Yellow FCF 25. Amaranth 10. Yellow 27.175N 26. Crystal Ponceau 11. Red 2G 27. Carmoisine 12. Red 10B 28. Fast Red E 13. Victoria Violet 4BS 29. Benzyl Bordeaux B 14. Ponceau MX and 3R 30. Acid Bordeaux 15. Azogrenadine S 31. Roccelline 16. Red 6B Solvent: 1% lithium chloride. 1 per cent lithium chloride was used in these experiments, practically all the saline single-phase solvents showed similar results. C. Other Subslituents: Generally, other substituents are of secondary importance in migration however, they may become significant in a few cases. Hydrophilic substituents (additional auxochromes) do not appear to influence migration, although more complicated groups (as in Lana- fuc/•sin 6B) seem to increase the Rs value. The presence of lipophilic groups has no effect in some cases ($car/et GN, Ponceau MX, Ponceau 3R), but in many others may result in decreased Rs values (Monoso/ Orange O, Xy/idine Orange, Orange Ill), especially if the

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