Quantitation of hydroperoxides in the aqueous solutions of non-ionic surfactants using polysorbate 80 as the model surfactant.

The application of coupled oxidation of NADPH to peroxide quantitation in non-ionic surfactant solutions is demonstrated using polysorbate 80 as the model surfactant. The linearity, precision, accuracy, and sensitivity of the method are discussed. The method has the following advantages over the traditional iodimetric method: (1) it is not affected by the non-ionic surfactant present in the solution; (2) it is reactive to less reactive hydroperoxides; (3) it is not light sensitive; and (4) it is carried out at near physiological pH in aqueous solutions. The method was employed to monitor the peroxide concentration of polysorbate 80 solutions stored under three different conditions. The effects of light and heat on peroxide concentration are more pronounced in more dilute solutions (0.1 and 1%). The peroxide concentration determined in the freshly prepared polysorbate 80 solution can be converted to the peroxide number of the raw material, which is not available from the supplier of polysorbate 80.