Formation of a Specific DMPO-OH Adduct Signal Related to Hydroxy Radical Generation in a Long Term Stored Improved Iodide Formulation.

A specific DMPO-OH adduct signal (1:2:2:1)related to hydroxyl radical generation in a longterm stored improved iodide formulation, tentatively designated as the distilled KMT reagent which prepared from a pH 0.3 solution containing FeCl₃, EDTA, KI and ethanol termed the KMT reagent, was detected by electron spin resonance (ESR) spectroscopy.Although the color intensities of N,N,N,N-tetramethyl-p-phenylenediamine (TMPD) and N,N-diethyl-p-phenylenediamine (DPD) differ, the mixture of the long-term stored distilled KMT reagent and TMPD exhibited a purple color similar to Wurster's blue, and the mixture of the long-term stored distilled KMT reagent and DPD exhibited a pink color similar to Wurster's red. There is a possibility that the long-term stored distilled KMT reagent may possess with the ability to generate a hydroxyl radical.