Eriochrome Blue Black

Eriochrome Blue Black R (Palatine Chrome Black 6BN, Calcon, 3-hydroxy-4-(2-hydroxy-l-naphthylazo)naphthalene-l-sulfonic acid Na salt] [2538-85-4] M 416.4, pK2 7.0, pKj 13,5. Freed from metallic impurities by three pptns from aqueous soln by addn of HCl. The ppted dye was dried at 60° under vacuum. Indicator for complexometry of Al, Fe and 7i. 

Solochrome dark blue or calcon ( C.1.15705). This is sometimes referred to as eriochrome blue black RC it is in fact sodium l-(2-hydroxy-l-naphthylazo)-2-naphthol-4-sulphonate. The dyestuff has two ionisable phenolic hydrogen atoms the protons ionise stepwise with pK values of 7.4 and 13.5 respectively. An important application of the indicator is in the complexometric titration of calcium in the presence of magnesium this must be carried out at a pH of about 12.3 (obtained, for example, with a diethylamine buffer 5 mL for every 100 mL of solution) in order to avoid the interference of magnesium. Under these conditions magnesium is precipitated quantitatively as the hydroxide. The colour change is from pink to pure blue. 

Fluorimetry is generally used if there is no colorimetric method sufficiently sensitive or selective for the substance to be determined. In inorganic analysis the most frequent applications are for the determination of metal ions as fluorescent organic complexes. Many of the complexes of oxine fluoresce strongly aluminium, zinc, magnesium, and gallium are sometimes determined at low concentrations by this method. Aluminium forms fluorescent complexes with the dyestuff eriochrome blue black RC (pontachrome blue black R), whilst beryllium forms a fluorescent complex with quinizarin. 

The procedure utilises eriochrome blue black RC (also called pontachrome blue black R Colour Index No. 15705) at a pH of 4,8 in a buffer solution. Beryllium gives no fluorescence and does not interfere iron, chromium, copper, nickel, and cobalt mask the fluorescence fluoride must be removed if present. The method may be adapted for the determination of aluminium in steel. 

Eriochrome blue black RC, 0.1 per cent. Prepare a 0.1 per cent solution in 90 per cent ethanol. 

Procedure. Into lOOmL graduated flasks, each containing lOmL of the ammonium acetate solution, 1 mL of the dilute sulphuric acid, and 3 mL of the eriochrome blue black RC solution, run in from a burette 15.0, 20.0, 25.0, 30.0, 35.0, 40.0, 45.0, and 50.0 mL of the standard aluminium solution. Dilute each of the above solutions with distilled water, and adjust to a pH of 4.6 0.2 if necessary before making up to the 100 mL mark. Allow the solutions to stand for at least 1 hour. 

Erbium, tris(2,2,6,6-tetrametbyl-3,5-hep tanedione) structure, 1, 65, 66 Erbium complexes acetylacetone, 2, 374 Erhium(ill) complexes glycolic acid, 2, 472 Eriochalcite, 6, 855 Eriochrome black T metallochromic indicators, 1, 555 Eriochrome blue black R metallochromic indicators, I, 556 Eriochrome cyanine R metallochromic indicator, 1, 556 Erythrocruorin, 6, 689 dioxygen transport, 6,683 stability... 

Willie et al. [508] used Unear sweep voltammetry for the determination of molybdenum. The molybdenum was adsorbed as the Eriochrome Blue Black R complex on a static mercury drop electrode. The method was reported to have a limit of detection of 0.50 xg/l and the results agreed well with certified values for two reference seawater samples. 

Eriochrome Blue Black R [2538-85-4] M 416.4. Freed from metallic impurities by three pptns from aqueous soln by addn of HCI. The ppted dye was dried at 60° under vacuum. 

More than 50 such dyestuffs have been proposed as indicators,8 but they have in common at least one o-hydroxy group from which the titratable metal displaces a hydrogen atom and forms a five-membered chelate ring with the azo nitrogens (cf 51) most have two o-hydroxy groups and can form two chelate rings. Of the few that are still used calcon (eriochrome blue black R ... 

Murexide, or Eriochrome blue-black R are suitable indicators for this analysis. A number of other metal ions may also be determined by related com-plexometric titrations. 

Pirillo, S., Ferreira, M.L., and Rueda, E.H., Adsorption of alizarin, eriochrome blue black R, and fluorescein using different iron oxides as adsorbents, Ind. Eng. Chem. Res., 46, 8255, 2007. 

Eriochrome Blue Black B (Mordant Black 3, 3-hydroxy-4-(l-hydroxy-2-naphthylazo)-naphthalene-l-sulfonic acid Na salt] [3564-14-5] M 416.4, pK 7.0, pK 13,5. Free it from... 

Eriochrome Blue Black B (Mordant Black, 3,3-hydroxy-4-(l-hydroxy-2-naphthylazo)-naphthalene-l-... 

A nanohltrahon membrane with PMIA, poly(vinyl pyrrolidone), and LiCl has been fabricated by a phase inversion technique [93]. The rejechon of the PMIA nanohltrahon membrane for the dyes Eriochrome black T, Eriochrome blue black B, and Alizarin red was all found to be more than 98% at 0.4 MPa. However, the rejection for NaCl was only around 5.5%. The hux increases largely with an increase of pressure and temperature, but the rejection for the dyes remains... 

Carmoisine A Chrysoine S Cochineal red A Cresyl fast violet Crystal violet Direct red 83 Eriochrome blue SE Eriochrome black T Eriochrome blue black B Eriochrome black T Eriochrome blue SE Erythrosine FD C red dye No. 2 FD C red dye No. 4 FD C red dye No. 40 Lyrazol fast red Methyl orange Methyl orange Methyl red Methyl red Orange II Orange GGN Quinolidine yellow Para red Phloxine B Ponceau 6R Procion Red Saffron Scarlet GN... 

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