| 摘要 |
<p>Sodium erythrosine, for use as a colour strengthening agent in foodstuffs, drinks and cosmetics, for mfr. of ortho-chromatic photographic plates and as a sensitiser for silver bromide, is made by (a) dissolving fluorescein and iodine in water, adding, NaOH to give pH 8-10; (b) heating to 90 deg. C and slow addn. of potassium iodate; (c) treatment with reducing agent e.g. acetic acid, until the erythrosine acid is completely pptd.; (d) elimination of the subsidiary colourants formed; (e) sepn. of the erythrosine by filtration, and washing; (f) suspension in water and treatment with Na2CO3 until CO2 evolution ceases, to form the sodium salt.</p> |
