Standard Reference Material 2691 Coal Fly Ash - This Standard Reference Material (SRM) is intended for use in the evaluation of analytical methods used for the classification of coal fly ash and for the determination of constituent elements in coal fly ash or materials of a similar matrix. A unit of SRM 2691 consists of three 10 g hermetically sealed glass vials of fly ash pulverized to less than 150 ?m particle size and blended to a high degree of homogeneity. This data is public in the Certificate of Analysis for this material.

SRM 2692c Bituminous Coal (Nominal Mass Fraction 1 % Sulfur) - This Standard Reference Material (SRM) is intended primarily for use in the evaluation of techniques employed in the determination of sulfur, mercury, chlorine, and ash content in coal and materials of a similar matrix. A unit of SRM 2692c consists of 50 g of bituminous coal ground to pass a 250 µm (60 mesh) sieve, homogenized, and packaged in an amber glass bottle. This data is public in the Certificate of Analysis for this material.

Standard Reference Material 2693 Bituminous Coal (Nominal Mass Fraction 0.5 % Sulfur) - This Standard Reference Material (SRM) is intended primarily for use in the evaluation of techniques employed in the determination of sulfur, mercury, chlorine, and ash content in coal and materials of a similar matrix. A unit of SRM 2693 consists of 50 g of bituminous coal ground to pass a 250 µm (60 mesh) sieve, homogenized, and packaged in an amber glass bottle and then sealed in an aluminized bag. This data is public in the Certificate of Analysis for this material.

Standard Reference Material 2719 Calcined Petroleum Coke - This Standard Reference Material (SRM) is intended primarily for use in the calibration of apparatus and the evaluation of techniques employed in the analysis of calcined petroleum coke and other materials with a similar matrix. SRM 2719 consists of 50 g of calcined petroleum coke ground to pass a 250 µm (60 mesh) sieve, homogenized, and bottled under an argon atmosphere. This data is public in the Certificate of Analysis for this material.

Standard Reference Material 2775 Sulfur in Foundry Coke - This Standard Reference Material (SRM) is intended primarily for use in the evaluation of test methods and for the calibration of instruments used to determine sulfur in foundry (metallurgical) coke. Each unit of SRM 2775 consists of 50 g of foundry coke that was ground to pass a 60 mesh (250 ?m) sieve, homogenized, and bottled under an argon atmosphere. This data is public in the Certificate of Analysis for this material.

Standard Reference Material 2776 Sulfur in Furnace Coke - This Standard Reference Material (SRM) is intended primarily for use in the evaluation of test methods and for the calibration of instruments used to determine sulfur in furnace (metallurgical) coke. Each unit of SRM 2776 consists of 50 g of furnace coke that was ground to pass a 250 ?m (60 mesh) sieve, homogenized, and bottled under an argon atmosphere. This data is public in the Certificate of Analysis for this material.

SRM 2973 Vitamin D Metabolites in Frozen Human Serum (High Level) - 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.

This Standard Reference Material (SRM) is intended for use as a primary calibration standard for the quantitative determination of tellurium. A unit of SRM 3156 consists of five 10 mL sealed borosilicate glass ampoules of an acidified aqueous solution prepared gravimetrically to contain a known mass fraction of tellurium. The solution contains hydrochloric acid at a volume fraction of approximately 10 %, which is equivalent to an amount of substance concentration (molarity) of approximately 1.2 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 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.

SRM 3239 Isoflavones Calibration Solution - This Standard Reference Material (SRM) is intended primarily for use in calibration of instruments and techniques used for the determination of isoflavones. SRM 3239 consists of two solutions containing isoflavones at levels that reflect the mass fraction ratios found in soy products. This data is public in the Certificate of Analysis for this material.