Value assignment of nutrient concentrations in five standard reference materials and six reference materials

A number of food-matrix reference materials (RMs) are available from the Na tional Institute of Standards and Technology (NIST) and from Agriculture Ca nada through NIST. Most of these materials were originally value-assigned f or their elemental composition (major, minor, and trace elements), but no a dditional nutritional information was provided. Two of the materials were c ertified for selected organic constituents. Ten of these materials (Standar d Reference Material(R) [SRM] 1563 Cholesterol and Fat-Soluble Vitamins in Coconut Oil [Natural and Fortified], SRM 1566b Oyster Tissue, SRM 1570a Spi nach Leaves, SRM 1974a Organics in Mussel Tissue (Mytilus edulis), RM 8415 Whole Egg Powder, RM 8418 Wheat Gluten, RM 8432 Corn Starch, RM 8433 Corn B ran, RM 8435 Whole Milk Powder, and RM 8436 Durum Wheat Flour) were recentl y distributed by NIST to 4 laboratories with expertise in food analysis for the measurement of proximates (solids, fat, protein, etc.), calories, and total dietary fiber, as appropriate, SRM 1846 Infant Formula was distribute d as a quality control sample for the proximates and for analysis for indiv idual fatty acids. Two of the materials (Whole Egg Powder and Whole Milk Po wder) were distributed in an earlier interlaboratory comparison exercise in which they were analyzed for several vitamins. Value assignment of analyte concentrations in these 11 SRMs and RMs, based on analyses by the collabor ating laboratories, is described in this paper. These materials are intende d primarily for validation of analytical methods for the measurement of nut rients in foods of similar composition (based on AOAC INTERNATIONAL's fat-p rotein-carbohydrate triangle). They may also be used as "primary control ma terials" in the value assignment of in-house control materials of similar c omposition. The addition of proximate information for 10 existing reference materials means that RMs are now available from NIST with assigned values for proximates in 6 of the 9 sectors of the AOAC triangle, Five of these ma terials have values assigned for total dietary fiber-the first such informa tion provided for materials available from NIST.