SIST ISO 17734-1:2013

INTERNATIONAL ISO
STANDARD 17734-1
First edition
2006-03-01
Determination of organonitrogen
compounds in air using liquid
chromatography and mass
spectrometry —
Part 1:
Isocyanates using dibutylamine
derivatives
Détermination des composés organiques azotés dans l'air par
chromatographie liquide et spectrométrie de masse —
Partie 1: Isocyanates par les dérivés de la dibutylamine

Reference number
©
ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Principle. 1
4 Reagents and materials . 3
5 Preparation of standard solutions . 3
5.1 Reference compounds . 3
5.2 Di-n-butylamine (DBA) derivatives of isocyanates . 4
5.3 DBA derivatives of bulk isocyanates. 5
5.4 DBA derivatives of isocyanates in thermal decomposition products of polyurethane
(PUR) or urea-based resins . 6
5.5 Stability . 6
6 Apparatus . 6
7 Air sampling . 9
7.1 Pre-sampling laboratory preparation. 9
7.2 Pre-sampling field preparations. 9
7.3 Collection of air samples . 9
7.4 Blanks . 10
7.5 Raw material. 11
7.6 Shipment of samples. 11
8 Laboratory sample preparation. 11
8.1 Sample sequence. 11
8.2 Work-up procedure. 11
9 Instrumental settings. 12
9.1 HPLC program (LC-MS). 12
9.2 HPLC program (LC-chemiluminescent nitrogen detector) (LC-CLND) . 12
9.3 Mass spectrometer . 12
10 Data handling . 12
10.1 Identification. 12
10.2 Calibration curves. 13
10.3 Quantification. 13
11 Interferences . 13
12 Determination of performance characteristics. 13
12.1 Introduction . 13
12.2 Relevant uncertainty contributions and criteria. 14
12.3 Assessment of performance characteristics, following the detailed approach in
Reference [18] . 14
Annex A (informative) Performance characteristics. 22
Annex B (informative) Examples . 24
Bibliography . 28

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 17734-1 was prepared by Technical Committee ISO/TC 146, Air Quality, Subcommittee SC 2, Workplace
Atmospheres.
ISO 17734 consists of the following parts, under the general title Determination of organonitrogen compounds
in air using liquid chromatography and mass spectrometry:
⎯ Part 1: Isocyanates using dibutylamine derivatives
⎯ Part 2: Amines and aminoisocyanates using dibutylamine and ethyl chloroformate derivatives
iv © ISO 2006 – All rights reserved

Introduction
Isocyanates have been used in industry for about 50 years. They are commercially important chemicals
mainly used for the production of polyurethane (PUR). In spite of controls to limit exposures, there are adverse
health effects such as asthma, contact dermatitis and hypersensitivity pneumonitis as a consequence of
exposure to isocyanates in some industrial sectors.
The analytical method for the determination of isocyanates in workplace air must be sensitive due to the high
irritation and sensitization properties of isocyanates. Extremely low occupational exposure limits (OELs) exist
in many countries, and concentrations well below the OEL (< 1/100) often must be determined. Isocyanates
are very reactive and therefore cannot be analysed directly. Derivatization during sampling is required in order
to prevent interfering reactions. Hundreds of different isocyanates are used in industry, and many more are
formed during thermal degradation of PUR. Therefore the analytical method must be highly selective.
The determination of isocyanates in the work environment using di-n-butylamine (DBA) as a reagent and
liquid chromatography-mass spectrometric detection (LC-MS) has been demonstrated to be a robust method.
The development of the method was initiated when difficulties using the “older” methods during sampling of
[1], [2], [3]
isocyanates in complex atmospheres were encountered (e.g. thermal decomposition of PUR) . The
reaction rate between DBA and isocyanates was found to be fast, and high concentrations can be used to
[4], [5]
secure instantaneous reactions and eliminate problems with interfering compounds . Using impinger
flasks containing a reagent solution and a filter in series efficiently collects and derivatizes isocyanates in both
[6]
the gas and the particle phase . LC-MS/MS of the isocyanate-DBA derivatives enables highly selective and
–6 [7]
precise determinations down to levels below 10 of the OEL .
Solvent-free sampling can also be performed by using a tube coated with a DBA-impregnated glass fibre filter
followed by an impregnated filter. An impregnation solution containing DBA together with an acid is used, and
[8]
the formed ion pair reduces volatility. DBA remains on the filter even after 8 h of sampling .
Monomeric isocyanates that are formed during thermal decomposition of polymers [typically PUR and
phenol/formaldehyde/urea (PFU)-resins], such as isocyanic acid and methyl isocyanate, can also be
[6], [7], [8], [9], [10]
determined . Volatile isocyanate DBA derivatives can be determined using gas
[9]
chromatography (GC)-MS . Using the DBA-method and derivatization with ethyl chloroformate makes
simultaneous determinations of amine, aminoisocyanates and isocyanates possible, as described in the
companion method ISO 17734-2.
For quantification, reference compounds are necessary but are only available for a few monomeric
isocyanates. Most of the isocyanates that are used in industry for the production of PUR can only be obtained
in technical grade mixtures. Many isocyanates that are formed during thermal degradation are not available
and are not easily synthesized. In this method, a nitrogen sensitive detector has been used for quantifying
isocyanates in reference solutions. This technique has been demonstrated to be a useful tool, together with
[10], [11], [12]
MS characterization, in greatly facilitating the production of reference solutions .
For quantifying isocyanates in complex mixtures, MS detection is necessary and provides a unique possibility
of identifying unknown compounds. This method has enabled assessment of new areas for which exposure to
isocyanates previously was not known and has identified new kinds of isocyanates in the work
[6], [7], [8], [9], [10], [11], [12]
environment .
INTERNATIONAL STANDARD ISO 17734-1:2006(E)

Determination of organonitrogen compounds in air using liquid
chromatography and mass spectrometry —
Part 1:
Isocyanates using dibutylamine derivatives
1 Scope
This part of ISO 17734 gives general guidance for the sampling and analysis of airborne isocyanates in
workplace air. When amines and aminoisocyanates are suspected to be emitted (e.g. from thermal
degradation of PUR), it is recommended that in addition to isocyanates the amines and aminoisocyanates in
air are determined, using DBA and ethyl chloroformate as reagents (ISO 17734-2).
The method is suitable for the determination of a wide range of different isocyanates in both the gas and
particle phases. Typical monofunctional isocyanates that can be determined are isocyanic acid (ICA), methyl
isocyanate (MIC), ethyl isocyanate (EIC), propyl isocyanate (PIC), butyl isocyanate (BIC), and phenyl
isocyanate (PhI). Typical monomeric diisocyanates include 1,6-hexamethylene- (HDI), 2,4-
...