Congo Red, III

Pipette 25 mL iron(III) solution (0.05M) into a conical flask and dilute to 100 mL with de-ionised water. Adjust the pH to 2-3 Congo red paper may be used — to the first perceptible colour change. Add 5 drops of the indicator solution, warm the contents of the flask to 40 °C, and titrate with standard (0.05M) EDTA solution until the initial blue colour of the solution turns grey just before the end point, and with the final drop of reagent changes to yellow. 

Hexacyanoferrate(II) and (III). Employ the original solution from 1 or, if sulphide, cyanide, and sulphite are absent, use 10 ml of the soda extract made acid (to Congo red) with dilute acetic acid. Add 0 5m zinc nitrate solution until precipitation ceases, introduce a Whatman filtration accelerator, stir, and filter the zinc and hexacyanoferrate(II) and (III) in the cold wash with a little O 1m zinc nitrate solution. 

Recently, PHEMA microspheres have been more and more extensively used for IMAC. Separon-IDA-Fe(III) or Cu(II) was prepared. It was found that Cu(II) interacted preferentially with histidine and tryptophan residues, while Fe(III) preferred phosphate residues, as demonstrated by the separation of lysozyme, ribonuclease A, myoglobin, and transferrin on the Cu(II) column and ovalbumin on the Ee(III) column, respectively.The PHEMA-Congo Red-Cu(II) and PHEMA-Cibacron Blue E3GA-Zn(II) microspheres were applied for adsorption of BSA. Without incorporating the metal ions, the dyed sorbents were already good stationary phases for affinity chromatography. As shown in Fig. 2, the addi-... 

Namasivayam, C. and Ranganathan, K. 1993. Waste Fe(III)/Cr(ni) sludge as adsorbent for the removal of Cr(VI) from aqueous solution and chromium plating industry wastewater. Environ. Pollut. 82 255-261. Namasivayam, C. and Arasi, D. 1997. Removal of Congo red from wastewater by adsorption onto waste red mud. Chemosphere 34 401-417. 

Thus, for case (i) the molecular weight of congo red comes to be 5897. In a similar way, for cases (ii) and (iii). the molecular weight was found to be approximately 5930 each. 

III. Ester-type anionics from other anionic surfactants Dowex 1-X4 Saponify by refluxing the resin from II with 5% aqueous KOH. Filter and wash with water, ethanol, and hexane. The filtrate contains the alcohols from the original esters. Stir the resin with acidified (to Congo red) 50 50 Et0H/H20. Filter and wa.sh with ethanol and hexane to remove the acids from the esters. 42... 

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