Determination of Boron in Liquid Nutritional Foods by ICP-AES

Endogenous concentrations of boron in liquid nutritional foods were determined by inductively coupled plasma-atomic emission spectrometry preceded by acid decomposition of samples in closed lined digestion vessels heated by microwave radiation. Both temperature and pressure within a reference vessel were monitored by an on-board computer that switched power (off or on) in concert with preset limits for a programmed sequence of heating events. Concentrations of 1.2 to 1.6 μg/g and <0.6 μg/g were determined for 3.5-g samples of liquid nutritional foods made with and without dietary fiber, respectively. Accuracy of the method was demonstrated by spike recoveries and by successful measurements of boron concentrations in botanical standard reference materials from the National Institute of Standards and Technology. Precision of the method was 4 to 6% relative standard deviation.