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Reagents in DIN EN ISO 11890-2 test method (Paints and varnishes - Determination of VOC and SVOC contents)
Posted Date:2025/7/29
7 Reagents
7.1General
Table 1 shows the surrogate standard as well as a non-exhaustive list of an internal standard, markers,performance criteria compounds and extraction solvents.
Table 1-List of reagents and their function
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Reagent
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CAS-NO.
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Abbreviation
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Function
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n-docosane
|
CAS 629-97-0
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C22
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SVOC marker compound
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|
dibutylsebacate
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CAS 109-43-3
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DBS
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Performance criteria
compound
|
|
n-tetradecane
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CAS 629-59-4
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C14
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|
triethylene glycol
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CAS 112-27-6
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TEG
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|
diethyladipate
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CAS 141-28-6
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DEA
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VOC marker compound internal standard/surro-gate standard
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|
acetonitrile
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CAS 75-05-8
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ACN
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Extraction solvent
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|
methanol
|
CAS 67-56-1
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MEOH
|
|
tetrahydrofuran
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CAS 109-99-9
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THF
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7.2 Internal standard
The internal standard should be a compound which is not present in the sample and is completely separated from the other components in the chromatogram. It shall be inert with respect to the sample constituents, stable in the required temperature range, and of known purity. The preferred internal standard is DEA.
It has been observed that DEA is not chemically stable in alkaline matrices when the solvent methanol is used. If reaction of DEA in a matrix is suspected, choose another suitable solvent or another internal standard.
NOTE 1 The benefit of using DEA as internal standard is that only one compound needs to be added during analysis fulfilling the function as surrogate standard (7.3), marker compound (7.4) and internal standard.
NOTE 2 If DEA is not suitable as internal standard, internal standards such as glycol ethers can be suitable.
7.3 Surrogate standard
The surrogate standard to be used is DEA.
7.4 Marker compound
In case of the need of a classification according to 9.2, marker compounds may be used to classify unidentified components as VOC or SVOC via retention time. If a peak cannot be identified, its boiling point will be unknown. In this case, the marker compound to characterize the upper limit of the VOC range is DEA and the marker compound to characterize the upper limit of the SVOC range is C22, if not otherwise specified by the contractor, i.e. any valid legislation, label or a classification.
7.5 Performance criteria compounds
The performance criteria compounds are used to prove sufficient chromatographic resolution at the retention time of the marker compounds. They are also used to ensure that the analytical system has a sufficient sensitivity.
7.6 Calibration compounds
The compounds used for calibration shall have a purity of at least a 99 % by mass or shall be of known purity. In the latter case, a correction with respect to purity shall be applied.
7.7 Extraction solvent
The extraction solvent should be suitable to completely extract the VOCs and SVOCs from the sample under investigation. Methanol, acetonitrile and THF have been proven to be suitable extraction solvents. The extraction solvent shall be of known purity and it shall not contain any substances which interfere with the determination, e.g. causing overlapping peaks in the chromatogram. Always carry out a separate run injecting the solvent alone in order to observe contaminants and possible interference peaks, especially in trace analysis.
The suitability of a solvent or solvent mixture other than methanol, acetonitrile and THF shall be checked by determining the recovery rates of analytes from the sample under investigation.