Binding Biochemical buffers

Fig. 2. Binding of ChAc ( ) and protein (o) to membranes from synaptosome fraction at various ionic strengths. A, Gelfiltration of membranes and ChAc on Sephadex columns equilibrated with 1 mmole sodium phosphate buffer plus NaCI to give final ionic strength and pH 7.2 and B, Dilution of sample with water to final ionic strength 0.015 and pH 7.2. (Reproduced from Biochem. J. (1968),...

Speciation of Cr as part of biomolecules consists in applying well known biochemical procedures, such as gel permeation chromatography, anion - cation chromatography, affinity chromatography, capillary electrophoresis, ultrafiltration, to be followed on the one hand by the determination of the exact amount of a specific protein and on the other hand by the quantitative determination of the chromium present in the fractions (Cornells, 1990). This is not an easy task. All the commercially available buffers are unfortunately loaded with Cr. The separation medium (e.g. the gel) may be another possible source of error. The contaminating Cr atoms are liable to form fortuitous bindings with the proteins which possess many free ligands. 

---