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 Cholesterol in Human Serum provides certified values for retinal, delta-, gamma-, and alpha-tocopherol, trans- and total beta-carotene, and cholesterol in human serum. Values are also reported for 16 additional compounds including lutein, zeaxanthin, alpha- and beta-cryptoxanthin, lycopene, alpha-carotene, retinyl palmitate, and 25-hydroxyvitamin D. The certified values for the fat-soluble vitamins and carotenoids in SRM 968c were based on the agreement of results from the means of at least two liquid chromatographic methods used at the National Institute of Standards and Technology (NIST) and from the medians from an interlaboratory comparison study among institutions that participate in the NIST Micronutrients Measurement Quality Assurance Program. The assigned values for cholesterol in the SRM are the means of results obtained using the NIST definitive method, gas chromatography-isotope dilution mass spectrometry.