An improved method for the spectrophotometric determination of equilibrium constants

Abstract

An improved spectrophotometric method of determining equilibrium constants is introduced. The advantages offered by photodiode array spectrophotometer are exploited. The most important of these are the ability to precisely measure analyte absorbance at all wavelengths throughout the ultraviolet and visible spectral range and store the data in computer files. A spreadsheet program is used to assemble the spectral data into an organized array and calculate the most probable value of the equilibrium constant for the entire array. Linear least-squares analysis and weighting scheme are employed to calculate the final result. Precision of the equilibrium constant obtained are at least an order of magnitude better than heretofore possible.