Evaluation of Monier-Williams and Committee methods for bisulfite determination as used by the potato processing industry.

The Monier-Williams and the iodometric Committee methods were evaluated for the determination of bisulfite in potato products. Both methods showed critical problems in accuracy and precision at concentrations below 60 ppm. Sensitivity levels of 25 ppm are possible with the Monier-Williams method. However, accuracy problems reflected by the coefficients of variation (Monier-Williams, 47.4%; Committee, 78.2%) as well as variability in recoveries and blank values for both methods produce qualitative rather than quantitative analytical data at low SO2 concentrations.