Reduction of erythrosin at the dropping mercury electrode

✍ Scribed by P.W. Board; D. Britz; R.V. Holland

• Publisher: Elsevier Science
• Year: 1968
• Tongue: English
• Weight: 298 KB
• Volume: 13
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(68)80142-2

✦ Synopsis

The polarographic reduction of erythrosin, the disodium salt of 2',4',5',7'-tetraiodofluorescein, was examined at pH 4.7. Three reduction steps were found. The first step involves two electrons and the reduction of the quinone group as in fluorescein. The second step results from the removal of the 4',5'-iodo groups and the last step from the removal of the 2",7'-iodo groups; each of these steps involves four electrons. This sequence was elucidated by the identification of the products of the controlled potential electrolysis of erythrosin. The value for the diffusion coefficient of erythrosin was found to be 6"45 × 10 -s cmZ/s at 25°C. R~sum6---Etude de la r6duction polarographique de l'6rythrosine, sel disodique de la 2',4',5',7'-t6tralodofluoresc6ine, it pH 4,7. La r6duction se divise en trois 6tapes. La premiere 6tape implique 2 61ectrons et la r6duction du groupe quinone comme dans la fluoresc6ine. La seconde 6tape r6sulte de l'61imination des groupes 4',5'-iodo et la derni6re 6tape, de l'61imination des groupes 2',7', chacune de ces 6tapes impliquant 4 61ectrons. Cette succession a 6t6 61ucid6e par ridentification des produits de l'61ectrolyse it tension contr616e de l'6rythrosine. La valeur du coefficient de diffusion de l'6rythrosine est 6,45 × 10 -6 cm~/s it 25°C.