Aims and Scope

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<table class="tg"><thead>
<tr>
<th class="tg-fymr">Component</th>
<th class="tg-0pky"><span style="font-weight:bold">Range (mol mol^-1)</span></th>
<th class="tg-0pky"><span style="font-weight:bold">Uncertainty (k=2)</span></th>
</tr></thead>
<tbody>
<tr>
<td class="tg-0pky">Benzene</td>
<td class="tg-0pky">5 - 200 x 10^-9</td>
<td class="tg-0pky">3.0 % rel. - 2.0 % rel.</td>
</tr>
<tr>
<td class="tg-0pky">Toluene</td>
<td class="tg-0pky">5 - 200 x 10^-9</td>
<td class="tg-0pky">3.0 % rel. - 2.0 % rel.</td>
</tr>
<tr>
<td class="tg-0pky">Ethylbenzene</td>
<td class="tg-0pky">5 - 200 x 10^-9</td>
<td class="tg-0pky">5.0 % rel. - 3.0 % rel.</td>
</tr>
<tr>
<td class="tg-0pky">o-Xylene</td>
<td class="tg-0pky">5 - 200 x 10^-9</td>
<td class="tg-0pky">5.0 % rel. - 4.0 % rel.</td>
</tr>
<tr>
<td class="tg-0pky">m-Xylene</td>
<td class="tg-0pky">5 - 200 x 10^-9</td>
<td class="tg-0pky">5.0 % rel. - 4.0 % rel.</td>
</tr>
<tr>
<td class="tg-0pky">p-Xylene</td>
<td class="tg-0pky">5 - 200 x 10^-9</td>
<td class="tg-0pky">5.0 % rel. - 4.0 % rel.</td>
</tr>
<tr>
<td class="tg-0pky">Nitrogen</td>
<td class="tg-0pky">Balance</td>
<td class="tg-0pky">-</td>
</tr>
</tbody>
</table>

Criteria of Participation

This PT scheme is open for all laboratories performing the analysis of BTEX (benzene, toluene, ethylbenzene, xylenes) in nitrogen. It is presumed that laboratories are familiar with the safety issues and have experience in handling compressed gases in cylinders.

Quantities to be Measured

Travelling Standard

Each participant will receive a gas mixture in a 5 L aluminium cylinder with appropriate passivation. The cylinder has a DIN-1 outlet. Participants should use their own suitable regulator with the correct connection.

Method and Equipment

Participants are advised to use their routine methods for sampling and analysis and the equipment that is used in routine measurement for this purpose. Laboratories should calibrate their equipment in accordance with their usual practices.

Instructions and Protocol

VSL will provide the protocol before shipping the cylinders. Each participant will have at least 3 weeks to perform the measurements and report the result. VSL will provide a report form for collecting the results.

Schedule

The schedule of this PT can be found on our website. VSL aims to make the PT items available within approximately 4 months or less after registration closes. The aim is to release the PT report no later than six weeks after the deadline for submitting the results by the participants.

Assigned Value

The result from VSL will be used as assigned value. The expected uncertainty is in accordance with the specification but may be increased depending on the stability assessment.

Performance Evaluation

The results will be evaluated using the normalized error (En-score).

Interpretation of the En-score is as follows:

|En| < 1 Satisfactory performance

|En| ≥ 1 Unsatisfactory performance

The final report presents results anonymously. Each laboratory can identify its own performance via a unique code. VSL guarantees full confidentiality and does not share individual data with third parties.

Deliverables

Upon completion of the PT, each participant will receive:
- An anonymised evaluation of your performance;
- A comprehensive PT-report.

This report may serve as supporting evidence for audits and internal reviews.

Confidentiality Statement

The identity of the participant is confidential, and so is the relationship between any participant, its submitted results and the performance evaluation. Results in the PT scheme will be collated, processed, reported and released in anonymised form. The PT reports are provided to the participants only. PT reports and calibration certificates are subject to copyright. You will receive the reference material certificates after the PT evaluation has been carried out.

Want to learn more?

Our experts are ready to help.

Jaïr Blom

PT Coordinator

compass@vsl.nl

Payment Terms

Payment in advance, at least one month before the start.

Failure to pay on time may result in exclusion from participation, without any right to refund or compensation.

Participants

The PT is open to 5-15 participants. If fewer than 5 laboratories register, VSL may cancel or postpone the PT. In such cases, all registered participants will be notified and offered alternative options.