MICROWAVE DIGESTION OF MULTICOMPONENT FOODS FOR SODIUM ANALYSIS BY ATOMIC-ABSORPTION SPECTROMETRY

Microwave digestion of a variety of low-sodium dinners was evaluated for determining sodium content. Dinners containing a meat, vegetable and dessert portion were blended, digested with strong acid in the microwave oven, and read by atomic absorption. Sodium values were compared with those obtained by an FDA method. Also, a sodium standard of known concentration was added to some samples, and the recoveries measured for two different amounts added. Reproducibility of microwave digestion was tested on replicates analyzed on the same day, on consecutive days and on consecutive weeks. Of the ten dinner types tested no matrix effects or interferences were noted, and we concluded that microwave digestion is a rapid means of preparing a complex matrix such as a frozen dinner for sodium analysis.