A modified colorimetric method for the estimation of ...-cyclodextrin using phenolphthalein.

The binding equilibrium between β-cyclodextrin and phenolphthalein has been used to develop a method for the estimation of β-cyclodextrin in solution. From logarithmic plots of amounts of β-cyclodextrin against absorbance at 554 nm, a relation log X = (log A - log Y)/B was found, which gave an estimate of β-cyclodextrin in the concentration range 0.0045 mg mL-1 (3.96 μm) to 4.7 mg mL-1 (4.14 mm), where X = intercept and B = slope. This method was found to be highly reproducible and reliable. [ABSTRACT FROM AUTHOR]