Preparation and value assignment of standard reference material 968c fat-soluble vitamins, carotenoids, and cholesterol in human serum

Standard Reference Material 968c Fat-Soluble Vitamins, Carotenoids, and Cho lesterol in Human Serum provides certified Values for retinal, delta-. gamm a-, and alpha -tocopherol, trans- and total p-carotene, and cholesterol in human serum. Values are also reported for 16 additional compounds including lutein, zeaxanthin, alpha- and beta -cryptoxanthin, lycopene, cu-carotene, retinyl palmitate, and 25-hydroxyvitamin D. The certified values for the f at-soluble vitamins and carotenoids in SRM 968c were based on the agreement of results from the means of at least two liquid chromatographic methods u sed at the National Institute of Standards and Technology (NIST) and from t he medians from an interlaboratory comparison study among institutions that participate in the NIST Micronutrients Measurement Quality Assurance Progr am. The assigned values for cholesterol in the SRM are the means of results obtained using the NIST definitive method, gas chromatography-isotope dilu tion mass spectrometry. (C) 2001 Elsevier Science B.V. All rights reserved.