Interlaboratory Proficiency testing: Chemical & Physical-chemical parameters in wastewater

Distribution Schedule 2024

Round Registration
Final Report

Round February 2024 19/01/2024 05/02/2024 01/03/2024 18/03/2024
Final Reports in the Customer Area

Round May 2024 26/04/2024 13/05/2024 07/06/2024 24/06/2024
Final Reports: 24/06/2024

Round September 2024 06/09/2024 23/09/2024 18/10/2024 05/11/2024
Registration Deadline: 06/09/2024
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Scope of the Interlaboratory Proficiency Testing

The scope of this proficiency testing is the evaluation of the performance of laboratories for the determination of the chemical and physical-chemical parameters in wastewater, eluates and similar matrices.

Interlaboratory proficiency testing organized in accordance with the standard ISO/IEC 17043:2010 - Conformity assessment — General requirements for proficiency testing and accredited by ACCREDIA, Italian accreditation body, with the accreditation number PTP n. 0014 P. Download the Accreditation Certificate.


  • Ammonia Nitrogen
    (1 - 50 mg/L N)
  • Anionic Surfactants (MBAs) (3)[°]
    (100 - 1000 microg/L)
  • Biochemical Oxygen Demand (BOD5) (2)[°]
    (20 - 500 mg/L O2)
  • Chemical Oxygen Demand
    (COD) [°]

    (20 - 1000 mg/L O2)
  • Chloride
    (50 - 2000 mg/L)
  • Conductivity (25 oC)
    (1000 - 10000 microS/cm)
  • Fluoride
    (1 - 50 mg/L)
  • Nitrate Nitrogen
    (5 - 100 mg/L N)
  • Nitrite Nitrogen
    (0.5 - 5.0 mg/L N)
  • pH (20 oC)
    (6.5 - 9.5 U)
  • Sulphate
    (100 - 1000 mg/L SO4)
  • Total Nitrogen (1)
    (5 - 150 mg/L N)
  • Total Organic Carbon (TOC) [°]
    (10-500 mg/L C)
  • Total Phosphorus
    (1 - 20 mg/L P)
  • Total Suspended Solids[°]
    (20 - 200 mg/L)
(1): Determination of the Total Nitrogen (organic and inorganic). Reference methods: ISO 11905-1:1997, ISO 20236:2018 or equivalent methods.
(2): Determination of the Biochemical Oxygen Demand (BOD5) - Procedure with inoculum of the test aliquot must be used.
(3): Parameter included in Round February and Round September.

Proficiency test item

  • 1 x 1000 mL of the test material ready to use for the determination of all parameters except Anionic Surfactants (MBAs), BOD5, COD, TOC and Total Suspended Solids.
  • 1 x 1000 mL of the test material to be prepared from a matrix and a vial of the spiking solution for the determination of Anionic Surfactants (MBAs).
  • 1 x 1000 mL of the test material ready to use for the determination of BOD5, COD and TOC.
  • 1 x 1000 mL of the test material material ready to use for the determination of Total Suspended Solids.

NOTE: All the details for the preparation of the final test sample are included in the Guide Lines of the interlaboratory proficiency testing provided with the test samples.

ADDITIONAL TEST SAMPLES: For costs and availability of additional test samples contact Qualitycheck (e-mail


The test sample should be analysed under the same conditions and with the same procedures used for the routine samples in the laboratory including the quality control procedures.

For each measurand shall be reported one result.

ADDITIONAL RESULTS: Each participant can submit up to 5 results* for the same analyte, thus obtaining an evaluation of laboratory performance for different operators, instruments and/or test methods (e.g. operator 1/operator 2, instrument A/instrument B, etc..).

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    *: Only one result submitted by the laboratory will be included in the statistical treatment of data for the calculation of the Assigned Value and statistics of data of the analyte, to avoid that a single laboratory has a different statistical weight, depending on the number of its submitted results. The additional results are evaluated by assigning z-score values, using the Assigned Value and the Standard Deviation for Proficiency Assessment obtained from statistical treatment.

    [°]: The measurands marked with the symbol [°] are not included in the scope of accreditation of this
    proficiency testing.