Proficiency testing (PT): Hydrocarbon Oil Index according to standard ISO 9377-2 in natural waters

Distribution Schedule 2024

Round Registration
Final Report

Round April 2024 01/03/2024 18/03/2024 12/04/2024 30/04/2024
Deadline Reporting Results: 12/04/2024

Round November 2024 18/10/2024 04/11/2024 29/11/2024 16/12/2024
Registration Deadline: 18/10/2024

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Scope of the Interlaboratory Proficiency Testing

The scope of this proficiency testing is the evaluation of the performance of laboratories according to standard ISO 9377-2:2000 in natural waters (ex. groundwater, surface water, etc.).

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.


  • Hydrocarbon Oil Index according to standard ISO 9377-2
    (100 - 2000 microg/L)

Proficiency test item:

  • 1 x 1000 mL of test material to be prepared from a water matrix and a spiking solution containing a mixture of Type A and Type B mineral oil with C10-C40 range.

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 analysis must be performed following the analytical procedure prescribed by the standard EN ISO 9377-2:2000 “Water quality -- Determination of hydrocarbon oil index -- Part 2: Method using solvent extraction and gas chromatography”.

One measurement result shall be reported.

ADDITIONAL RESULTS: Each participant can submit up to 5 results* for the same analyte, thus obtaining an evaluation of laboratory performance for different operators and/or instruments (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.