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Demand (niedriger Gehalt) - WS

Proficiency Testing Material




ampule of 2 × 20 mL


in water




matrix material

Allgemeine Beschreibung

Demand (Low Level) - WS proficiency testing material is produced in accordance with ISO/IEC 17043:2010. The PT portfolio allows our test components to offer significant performance data to monitor and prove competency to customers, accreditation bodies or both.

Supelco® is a global proficiency testing (PT) provider that manufactures best-in-class environmental and pharmaceutical PT products. Most water PT samples are available as concentrates or ready-to-use volumes giving the end-user flexibility in selecting samples that will fit their exact needs. Our WS program is designed to meet the quality assurance requirements in compliance with the Safe Drinking Water Act (SDWA), thereby ensuring the analytical competence of your laboratory or drinking water facility.
These samples are typically provided in duplicate for use in case of lab mishap, for QC purposes or to analyze multiple methods.

Type of PT Scheme: Water analysis - Water Supply (WS)

Matrix: Water Supply/Drinking water

Analyte/s: Values of analytes vary lot to lot.

All information regarding the use of Demand (Low Level) - WS can be found in the reporting packet which will be available to download at PT Portal.


Demand (Low Level) - WS proficiency testing material is suitable for testing the analytes in water supply/drinking water.

Have any questions? Explore our FAQs.
For more information on this product, please contact our PT Service Team.


20 mL

Leistungsmerkmale und Vorteile

We have a vast portfolio of environmental PT schemes with "fit-for-purpose" samples to help you meet the needs of the laboratory.

Our proficiency testing (PT) program is a benchmark to:

  • provide staff with an insight into their laboratory′s performance, to verify the accuracy and reliability of their testing process
  • provide a comparison of performance with that of other laboratories, nationally and internationally
  • test and educate staff, provide a better understanding of the impact of incorrect results and identify areas where there may be problems
  • provide an independent evaluation of laboratory performance
  • demonstrate to clients, colleagues and accreditation bodies that there is a commitment to quality

Angaben zur Herstellung


  • 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.

Sample Preparation

  • To prepare the solution, partially fill a 1 L volumetric flask with reagent-grade water.
  • Open ampule PE1388-20ML (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 °C 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 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.

Lagerung und Haltbarkeit

Please refer to sample label for expiration date, specific storage temperature, and specific storage conditions.

Sonstige Hinweise

Are you new to Supelco® Proficiency Testing? Be sure to register your account details in the PT Portal before placing your order.
This will provide access to data entry, reporting packets and final reports. Registrations will be approved shortly after your order is placed. For further questions, write to us at

When placing your order online, please indicate your study preference under the ′your reference′ column. Available studies can be viewed at the bottom of the page.
Click here to learn more about Quick-Turn Studies (on-demand proficiency tests that are offered depending on lot availability). The Quick-Turn results are released within 48-72 hours whereas scheduled study reports are released within 21 days.

Proficiency testing samples are presented as single blind. No values for the samples are released until the testing period concludes.

Proficiency Testing Schedule (2022-2023)

Drinking Water
WS22-2 March 23 - May 6, 2022
WS22-4 September21 - November 4, 2022

WS23-2 March 22 – May 5, 2023
WS23-4 September20 – November 3, 2023

Quick-Turn Study (on demand proficiency testthat is offered depending on lot availability)

Rechtliche Hinweise

Supelco is a registered trademark of Merck KGaA, Darmstadt, Germany



    5-day BOD 5-100 mg/L
    Carbonaceous BOD (CBOD) 5-100 mg/L
    Chemical oxygen demand (COD) 5-100 mg/L
    Total organic carbon (TOC) 1-50 mg/L


12 - Non Combustible Liquids



Flammpunkt F

Not applicable

Flammpunkt C

Not applicable

Certificate of Analysis

Enter Lot Number to search for Certificate of Analysis (COA).

Certificate of Origin

Enter Lot Number to search for Certificate of Origin (COO).

Our team of scientists has experience in all areas of research including Life Science, Material Science, Chemical Synthesis, Chromatography, Analytical and many others.

Contact Technical Service