Proficiency testing scheme for volatile organic compounds (VOC) with thermal desorption

Several participants at IFA's test gas stream

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Test gas stream at the IFA
Source: IFA

Proficiency testing (PT) is offered alternatively with and without own sampling. Participants may choose whether they wish to perform sampling for volatile organic compounds themselves, or to have the self-conditioned loaded sample carriers supplied to them [1].

The PT scheme consists of two runs with different concentrations of the same substances within the test gas. The test gas will contain up to ten different substances (examples see table below). To exclude blank values in the basic gas and the test gas stream a blank value of the basic gas will be taken at the beginning of a test series.*

The substance selection is based on indoor air quality issues and covers hazardous substances typically found in indoor workplaces.The concentrations to be measured will lie within the range between 10 to 200 µg/m3 for each substance. Analysis has to be conducted by gas chromatography by means of thermal desorption according to DIN EN ISO 16017-1 [2], DIN EN ISO 16000-6 [3] or IFA Folder No. 8936 [4].

The quantitative evaluation should be based on the substance, so please do not quote the results as toluene equivalent [5].

*Blank value correction:
According to the experience of the IFA, the system blank value is usually negligible. However, it has been shown that in the case of thermal desorption tubes, that substances are occasionally and non-reproducibly detected which can simulate a blank value. The IFA analyses several blank value samples per test. Should a significant plant blank value occur, the participants are immediately informed by e-mail. A blank value correction based on the own blank value samples should only be carried out after consultation with the IFA and only if the substance concentrations that occurred can be clearly and reproducibly traced back to the own tubes.


Selection of VOC

Substance group Substances
Alkanes n-decane, n-dodecane, n-heptane, n-hexadecane, n-hexane, n-nonane, n-octane, pentadecane, n-tetradecane, n-tridecane, n-undecane
Alcohols butan-1-ol, 2-ethyl-1-hexanol
Aromates benzene, 3-carene, cumene, ethylbenzene, limonene, α-pinene, toluene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, o-, m-, p-xylene
Esters and Ethers n-butyl acetate, 2-butoxyethyl acetate, 2-(2-butoxy ethoxy)-ethyl acetate, 2-ethoxy ethylacetate
Ketones and aldehydes butan-2-one, hexanal, acetophenone, 4-methyl-2-pentanone
Siloxanes hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane

1 Proficiency testing with own sampling

A large-scale dynamic test gas stream can be found at the IFA. It is suitable for parallel sampling by up to 25 participants.

  • When: 12th September 2023
  • Number of test series: 2
    At the beginning a sampling is carried out to exclude blank values in the basic gas and the test gas stream, followed by two test series on one day.
  • Where:
    Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung (IFA)
    Alte Heerstr. 111
    53757 Sankt Augustin
    Germany
  • Concentration range: 10 to 200 µg/m3 per substance
  • Duration per test series: 1.5 hours plus preparation time and run-in period.
  • Accommodations: Hotels at Sankt Augustin (PDF, 105 KB)

The registration for the PT schemes with own sampling is valid for only one person per participating company or institution. If you wish to participate with more than one person, please contact us in advance.

Participants will receive detailed information on the PT, a description of the apparatus and the connections for the sampling devices in particular, and a list of the substances to be analysed in good time.

Covid-19 regulations:

The PT schemes with own sampling are carried out according to the Covid 19 hygiene and behavioural specifications of the DGUV in force at the time of performance. You will be informed in advance about the regulations to be observed.

2 Proficiency testing without own sampling

The production of samples for volatile organic compounds is conducted at the dynamic test gas stream of the IFA. The particular feature of this PT scheme is that thermal desorption tubes (e.g., Tenax-TA) are employed for loading which must be conditioned by the participants prior to the PT. Each participant (analysis laboratory) submits eight thermal desorption tubes to the IFA. The sample tubes and the blank value tubes will be loaded with a sampling volume of 2 L. Only personal air samplers are used at the IFA. The sample carrier should not generate a back pressure exceeding 5.0 kPa under the specified conditions. Where internally fabricated sample carriers are used, please supply an adapter (GL14/GL25 threaded connection) for the test gas stream.

Each participant receives a sample kit comprising:

  • four loaded thermal desorption tubes, two per VOC test gas series - for duplicate determinations
  • two thermal desorption tubes loaded with the basic gas of the test gas stream to exclude blank values, and
  • two unloaded thermal desorption tubes.

Participation

Proficiency testing 2023

Sources

[1] Ringversuch Flüchtige Organische Verbindungen VOC mit Thermodesorption (Kennzahl 1630-3) In: IFA-Arbeitsmappe Messung von Gefahrstoffen.

[2] DIN EN ISO 16017-1: Indoor, ambiant and workplace air - Sampling and analysis of volatile organic compounds by sorbent tube/thermal desorption/capillary gas chromatography - Part 1: Pumped sampling (10.01). Beuth, Berlin 2001

[3] DIN ISO 16000-6: Indoor air - Part 6: Determination of volatile organic compounds in indoor and test chamber air by active sampling on Tenax TA® sorbent, thermal desorption and gas chromatography using MS or MS-FID (ISO 16000-6:2011). Beuth, Berlin 2012

[4] VOC (Volatile Organic Compounds, Flüchtige Organische Substanzen) (Kennzahl 8936). In: IFA-Arbeitsmappe Messung von Gefahrstoffen.

[5] Ermittlung und Beurteilung chemischer Verunreinigungen der Luft von Innenraumarbeitsplätzen. Bundesgesundheitsbl. Gesundheitsforsch. Gesundheitsschutz 57 (2014) Nr. 18, S. 1002-1018

Contact

Department Chemical and Biological Hazards

Krista Gusbeth
Brigitte Maybaum
Franziska Nürnberger
Ronja Schustkowski