The interference of tetrachloromethane in the measurement of benzene in the air by a gas chromatography–photoionisation detector (GC-PID)
<p>The European Union requires that benzene in the air is continuously measured due to its toxicity and widespread presence in the population nuclei, mainly motivated by vehicle emissions. The reference measuring technique is gas chromatography (GC). Automatic chromatographs used in monitoring...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-03-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://www.atmos-meas-tech.net/12/1685/2019/amt-12-1685-2019.pdf |
| Summary: | <p>The European Union requires that benzene in the air is continuously measured due
to its toxicity and widespread presence in the population nuclei, mainly
motivated by vehicle emissions. The reference measuring technique is gas
chromatography (GC). Automatic chromatographs used in monitoring stations
must verify the operating conditions established in Standard EN 14662 part 3,
which includes a type approval section with a number of tests that analysers
must pass. Among these tests, the potential interference of a number of
compounds is evaluated. The 2005 version of the mentioned standard requires
the evaluation of the potential interference of tetrachloromethane (TCM). The
2015 version eliminates TCM as a potential interferent. Although most
consumer uses of TCM have been banned, recent studies have measured
significant concentrations of TCM in the air. In this paper, the potential
interference of TCM in benzene measurements obtained with gas chromatography
coupled to a photoionisation detector (GC-PID) has been investigated. Our study
shows that the simultaneous presence of benzene and TCM causes a significant
decrease in benzene readings. For TCM concentrations of 0.7 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span>
(typical of urban areas) and 4.5 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span> (detected in the vicinity
of landfills), the relative errors in benzene measurements were 34 % and 70 %, respectively, which are far too high compared to the maximum overall
uncertainty allowed for benzene measurements (25 %). Possible mechanisms
to qualitatively and quantitatively explain the behaviour of the PID when
measuring benzene with and without TCM have been proposed.</p> |
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| ISSN: | 1867-1381 1867-8548 |