Demand - WS

Description

• General description: This Certified Reference Material (CRM) is produced and certified in accordance with ISO 17034 and ISO/IEC 17025. All information regarding the use of this CRM can be found on the certificate of analysis.
• Preparation Note: This PT sample is packaged as a 20 mL concentrate. The solvent for this sample is water. The PT sample has been autoclaved for preservation. To prepare solution, partially fill a 1-L volumetric flask with reagent-grade water. Open ampule PE1388 (be careful to avoid cuts on glass) and transfer 10 mL from the ampule into the flask. Fill the volumetric flask to volume with reagent-grade water and mix well. The sample is now ready for immediate analysis. Analyze the solution to determine BOD or CBOD first. If COD and TOC cannot be determined within two hours after sample preparation, an aliquot should be preserved (pH<2) using 0.2 mL of concentrated sulfuric acid per 100 mL. This aliquot should be stored at 4 degrees Celsius and analyzed as soon as possible within the 28-day maximum holding time. NOTES: For proper oxygen depletion of BOD and CBOD, the sample should be tested in a dilution series. Use a natural surface water or diluted domestic sewage for seeded dilution water and avoid entrainment of air. For analysis of CBOD, the use of a nitrifying inhibitor is recommended. Be sure to determine the "blank" BOD of your seeded dilution water so that the proper seed correction can be made.
• Other Notes: Values of analytes vary lot to lot. Some lots may not contain all analytes.