Redox titration of antioxidant mixtures with N-bromosuccinimide as titrant: analysis by non-linear least-squares with novel weighting function.

Equations are presented by which potential-volume data from redox titrations can be analyzed. Mixtures of analytes as well as of titrants may be analyzed, yielding for each component its concentration, number of electrons, and reduction potential. A novel weighting function ensures endpoint accuracy in fitting. Standard deviation of each parameter is obtained. The equations can be readily implemented in Microsoft Excel. Agreement with true values and good precision of fit parameters is demonstrated for a number of test cases. Use of these exact equations enables analysis of analyte mixtures without prior separation using single titrant or titrant mixtures. The equations were used to demonstrate that N-bromosuccinimide, a useful oxidant for organic analytes, undergoes hydrolysis.