Determination of iodine concentration in human milk, cows' milk and infant formula and estimation of daily iodine intake of infants.

A simple and sensitive kinetic-catalytic method was used for the determination of iodine concentration in human milk, cows' milk and infant formula. The method, based on the catalytic effect of iodine on the redox reaction between CeIV and AsIII, was first described by Sandell and Kolthoff. The calibration curve was constructed by plotting absorbance of CeIV after a known time versus iodine concentration. The precision, accuracy and recovery of the method was determined. After the application of the method to milk and infant formula samples, the daily iodine intake of infants on their first or second day after delivery was estimated at 20.0 +/- 11.9 micrograms d-1 and 13.0 +/- 3.3 micrograms d-1 from human milk and infant formula, respectively.