Donor serum for SRM 2378 was collected from three groups of individuals: (level 1) three healthy donors who took 1000 mg/day of fish oil supplements for a minimum of one month prior to collection; (level 2) three healthy donors who took 1000 mg/day of flaxseed oil supplements for a minimum of one month prior to collection; and (level 3) three healthy donors who did not take either fish or flaxseed oil supplements for one month prior to collection. Value assignment of the mass fractions of the fatty acids in SRM 2378 was based on the results of one or two analytical methods at NIST and one analytical method at the Centers for Disease Control (CDC) with confirmation by data provided by an interlaboratory comparison. This data is public in the Certificate of Analysis for this material.

SRM 2387 Peanut Butter - This Standard Reference Material (SRM) is intended primarily for use in validating methods for determining proximates, fatty acids, calories, vitamins, elements, amino acids, aflatoxins, and acrylamide in peanut butter and similar matrices. This SRM can also be used for quality assurance when assigning values to in-house reference materials. The SRM is a creamy peanut butter prepared by a manufacturer of peanut butter products. A unit of SRM 2387 consists of three jars of peanut butter containing 170 g each. This data is public in the Certificate of Analysis for this material.

SRM 1950 Metabolites in Frozen Human Plasma - This Standard Reference Material (SRM) is intended primarily for validation of methods for determining metabolites such as fatty acids, electrolytes, vitamins, hormones, and amino acids in human plasma and similar materials. This SRM can also be used for comparison of measurement technologies used in metabolomic studies and for quality assurance when assigning values to in-house reference materials. This SRM is intended to represent "normal" human plasma. A unit of SRM 1950 consists of five vials, each containing approximately 1.0 mL of plasma. This data is public in the Certificate of Analysis for this material.

An implementation of Quantitative Fatty Acid Signature Analysis (QFASA) in R. QFASA is a method of estimating the diet composition of predators. The fundamental unit of information in QFASA is a fatty acid signature (signature), which is a vector of proportions describing the fatty acid composition of adipose tissue. Signature data from at least one predator and from samples of all potential prey types are required. Calibration coefficients, which adjust for the differential metabolism of individual fatty acids by predators, are also required. Given those data inputs, a predator signature is modeled as a mixture of potential prey signatures and its diet estimate is obtained as the mixture that minimizes a measure of distance between the observed and modeled signatures. A variety of estimation options, goodness-of-fit diagnostic procedures to assess the suitability of estimates, and simulation capabilities are implemented. Please refer to the package vignette and the documentation files for individual functions for details and references.

SRM 1849a Infant/Adult Nutritional Formula - This Standard Reference Material (SRM) is intended primarily for validation of methods for determining proximates, fatty acids, cholesterol, vitamins, elements, amino acids, and nucleotides in infant and adult nutritional formulas and similar materials. This SRM can also be used for quality assurance when assigning values to in-house reference materials. The SRM is a milk-based, hybrid infant/adult nutritional powder prepared by a manufacturer of infant formula and adult nutritional products. A unit of SRM 1849a consists of 10 packets, each containing approximately 10 g of material. This data is public in the Certificate of Analysis for this material.

SRM 1958 Organic Contaminants in Fortified Human Serum (Freeze-Dried) - This Standard Reference Material (SRM) is intended for use in evaluating analytical methods for the determination of selected polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, and polybrominated diphenyl ether (PBDE) congeners in human serum and similar matrices. Reference values are provided for selected polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho PCB congeners, perfluorinated compounds (PFCs), and serum lipid. Information values are provided for selected toxaphene congeners and hydroxylated compounds. A unit of SRM 1958 consists of five vials, each containing freeze-dried fortified human serum. Before use, the serum in each bottle must be reconstituted with 10.7 mL of distilled or HPLC-grade water. This data is public in the Certificate of Analysis for this material.

SRM 1957 Organic Contaminants in Non-Fortified Human Serum (Freeze-Dried) - This Standard Reference Material (SRM) is intended for use in evaluating analytical methods for the determination of selected polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, and polybrominated diphenyl ether (PBDE) congeners in human serum and similar matrices. Reference values are provided for selected polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), perflourinated compounds (PFCs), and serum lipid. Information values are provided for selected hydroxylated compounds. All of the constituents for which values are provided in SRM 1957 are naturally present in the freeze-dried human serum. A unit of SRM 1957 consists of five 30 mL vials each containing freeze-dried non-fortified human serum. Before use, the serum in each vial must be reconstituted with 10.7 mL of distilled or HPLC-grade water. This data is public in the Certificate of Analysis for this material.

The data set contains results for nine serum biochemistries in molting Pacific black brant (Branta bernicla nigricans). These data were used to calculate reference intervals (sometimes referred to as normal values) for the nine serum biochemistries. All brant were after-hatch year. All samples were collected in 2006 and 2007 in the Teshekpuk Lake Special Area, Alaska.

SRM 2384 Baking Chocolate - This Standard Reference Material (SRM) is intended primarily for use in validating methods for determining proximates, fatty acids, calories, vitamins, elements, catechins, caffeine, and theobromine in baking chocolate and similar matrices. This SRM can also be used for quality assurance when assigning values to in-house reference materials. The SRM is baking chocolate prepared from 100 % cocoa beans by a manufacturer of baking chocolate and consists of a single production lot. A unit of SRM 2384 consists of five 91 g (3.2 oz) individually wrapped bars of baking chocolate. This data is public in the Certificate of Analysis for this material.