Standard Reference Material 672 Nickel Oxide, No. 2 has been discontinued and is no longer being produced. The data is public in the Certificate of Analysis for this material.

Standard Reference Material 673 Nickel Oxide, No. 3 has been discontinued and is no longer being produced. The data is public in the Certificate of Analysis for this material.

SRM 690 Iron Ore (Canada) is for use in checking chemical methods of analysis and in calibration with instrumental methods of analysis. This data is public in the Certificate of Analysis for this material.

SRM 691 Iron Oxide, Reduced is intended primarily for use in evaluating chemical methods and in calibrations associated with optical emission and x-ray spectrometric methods of analysis. This data is public in the Certificate of Analysis for this material.

SRM 692 iron Ore (Labrador) is intended primarily for use in checking chemical methods of analysis and in calibration with instrumental methods of analysis. This data is public in the Certificate of Analysis for this material.

SRM 693 Iron Ore (Nimba) - Standard Reference Material 693 Iron Ore (Nimba) is material in the form of powder (<0.1 mm) for use in checking chemical methods of analysis and in calibration with instrumental methods of analysis. This data is public in the Certificate of Analysis for this material.

This Standard Reference Material (SRM) is in the form of chips sized between 0.50 and 1.18 mm sieve openings (35 and 16 mesh). It is intended for use primarily in chemical methods of analysis. Similar material for use in spectrometric methods of analysis is available as SRM 1297. This data is public in the Certificate of Analysis for this material.

Standard Reference Material SRM 915c Calcium Carbonate - This Standard Reference Material (SRM) is intended for use as an analytical standard of known purity. It is intended primarily for use in the calibration and standardization of procedures for calcium (Ca) determinations employed in clinical analysis and for routine critical evaluation of the daily working standards used in these procedures. This data is public in the Certificate of Analysis for this material.

Standard Reference Material 924a Lithium Carbonate - This Standard Reference Material (SRM) is intended for use as a chemical of known purity. It is intended primarily for use in the calibration and standardization of procedures and for the routine critical evaluation of the daily working standards used in these procedures. 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.