Determination of Nutrition Labeling Education Act minerals in foods by Inductively Coupled Plasma Optical Emission Spectroscopy

The Nutrition Labeling Education Act of 1990 (NLEA) mandates significant reform of food labels and requires extensive chemical testing and analytical method development to implement. Many minerals and nutrient metals are targeted for labeling. Part of the analytical challenge to be met results from the large numbers of samples to be tested and widely divergent levels of the elements of interest within the samples. Ideally, the new methodology developed for food analysis will be generic and applicable to many elements and matrices simultaneously. This work discusses an Induc tively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) method for the determination of nutrient metals and minerals in juice, corn products, milk, and ice cream. Sample preparation time was the primary limitation to sample throughput and this was minimized using microwave digestion. Due to the wide linear dynamic range of the ICP-OES, trace and macro levels of nutrients were determined simultaneously in samples without multiple dilution/analysis iterations. Quality assurance (QA) was performed by analyzing replicate samples, fortifying and analyzing samples and reagent blanks, and analyzing Standard Reference Materials. Acceptable precisions, recoveries and agreement with authentic values and certified values were obtained.