This Standard Reference Material (SRM) is intended for use as a primary calibration standard for the quantitative determination of tungsten. A unit of SRM 3163 consists of 50 mL of an acidified aqueous solution prepared gravimetrically to contain a known mass fraction of tungsten in a high-density polyethylene bottle sealed in an aluminized bag.

This Standard Reference Material (SRM) is intended for use as a primary calibration standard for the quantitative determination of vanadium. A unit of SRM 3165 consists of five 10 mL sealed borosilicate glass ampoules of an acidified aqueous solution prepared gravimetrically to contain a known mass fraction of vanadium. The solution contains nitric acid at an amount of substance concentration (molarity) of approximately 1.6 mol/L. This data is public in the Certificate of Analysis for this material.

This Standard Reference Material (SRM) is intended for use as a primary calibration standard for the quantitative determination of ytterbium. A unit of SRM 3166a consists of five 10 mL sealed borosilicate glass ampoules of an acidified aqueous solution prepared gravimetrically to contain a known mass fraction of ytterbium. The solution contains nitric acid at a volume fraction of approximately 10 %, equivalent to an amount of substance concentration (molarity) of approximately 1.6 mol/L. This data is public in the Certificate of Analysis for this material.

SRM 3235 Soy Milk - This Standard Reference Material (SRM) is intended primarily for validation of methods for determining vitamins, elements, proximates, fatty acids, and amino acids in soy milk and similar materials. This SRM can also be used for quality assurance when assigning values to in-house reference materials. The SRM is a soy milk prepared by a commercial manufacturer. A unit of SRM 3235 consists of 10 ampoules, each containing approximately 10 mL of material. This data is public in the Certificate of Analysis for this material.

SRM 3252 Protein Drink Mix - This Standard Reference Material (SRM) is intended primarily for validation of methods for determining proximates, fatty acids, cholesterol, vitamins, elements, and amino acids in protein drink mixes and similar materials. This SRM can also be used for quality assurance when assigning values to in-house reference materials. This data is public in the Certificate of Analysis for this material.

SRM 3290 Dry Cat Food - This Standard Reference Material (SRM) is intended primarily for use in validating methods for determining proximates, fatty acids, vitamins, elements, and amino acids in dry cat food and similar matrices. This SRM can also be used for quality assurance when assigning values to in-house control materials. This SRM is a blend of commercially available dry cat foods. A unit of SRM 3290 consists of five heat-sealed, aluminized pouches, each containing approximately 10 g of material. This data is public in the Certificate of Analysis for this material.

Standard Reference Material 3949 Folate Vitamers in Frozen Human Serum

Standard Reference Material 909c Frozen Human Serum - This Standard Reference Material (SRM) is intended primarily for use in validating analytical methods for the determination of specified constituents in human serum. This SRM can also be used for quality assurance when assigning values to in house control materials. A unit of SRM 909c consists of three vials, each containing 2 mL of frozen human serum. This data is public in the Certificate of Analysis for this material.

SRM 972a Vitamin D Metabolites in Frozen Human Serum - This Standard Reference Material (SRM) is intended for use as an accuracy control in the critical evaluation of methods for determining the amount-of-substance concentration of vitamin D metabolites in human serum. This SRM can also be used as a quality assurance tool for assigning values to in-house control materials for these constituents. This data is public in the Certificate of Analysis for this material.

Standard Reference Material-1721: Southern Oceanic Air. Ambient Nominal Amount of Substance Fraction for Carbon Dioxide, Methane & Nitrous Oxide. This Standard Reference Material (SRM) is a primary gas mixture for which the amount-of-substance fraction, expressed as concentration, may be related to secondary working standards. This SRM is intended for the calibration of instruments used for ambient carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) determinations and for other applications. This data is public in the Certificate of Analysis for this material.