1、BRITISH STANDARDBS ISO 16702:2007Workplace air quality Determination of total organic isocyanate groups in air using 1-(2-methoxyphenyl) piperazine and liquid chromatographyICS 13.040.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g5
2、5g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS ISO 16702:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2008 BSI 2008ISBN 978 0 580 56230 3National forewordThis British Standard is the U
3、K implementation of ISO 16702:2007. It supersedes BS ISO 16702:2001 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee EH/2, Air quality, to Subcommittee EH/2/2, Workplace atmospheres.A list of organizations represented on this committee can be obtained o
4、n request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments/corrigenda issued since publicationDate Co
5、mmentsReference numberISO 16702:2007(E)INTERNATIONAL STANDARD ISO16702Second edition2007-12-15Workplace air quality Determination of total organic isocyanate groups in air using 1-(2-methoxyphenyl)piperazine and liquid chromatography Qualit de lair des lieux de travail Dosage des groupements isocyan
6、ates organiques totaux dans lair par drivatisation avec la 1-(2-mthoxyphnyl)piprazine et par chromatographie en phase liquide BS ISO 16702:2007ii iiiContents Page Foreword. v Introduction . vi 1 Scope . 1 2 Normative references . 2 3 Terms and definitions. 2 4 Principle. 3 5 Reagents and materials .
7、 3 6 Apparatus 6 7 Sampling 7 7.1 Calibration of pump 7 7.2 General. 7 7.3 Preparation of sampling equipment (general) . 8 7.4 Preparation of sampling equipment (filters) 8 7.5 Preparation of sampling equipment (impingers). 8 7.6 Collection of filter samples (vapour phase samples) . 8 7.7 Collection
8、 of impinger backed by filter samples (isocyanate aerosols). 9 7.8 Measurements to be made at the end of the sampling period. 9 7.9 Sample logging and field desorption of samples 9 7.10 Transportation. 9 7.11 Field Blanks. 10 8 Procedure 10 8.1 Safety precautions 10 8.2 Cleaning of glassware 10 8.3
9、Prereaction of impinger samples before HPLC analysis 10 8.4 Prereaction of filter samples before HPLC analysis . 10 8.5 HPLC conditions . 10 8.6 Determination of airborne isocyanate for monomeric isocyanates (UV detection) 11 8.7 Identification of polymeric isocyanates: EC/UV ratio approach 11 8.8 C
10、onfirmation of identification for polymeric isocyanates (prepolymers). 12 8.9 Quantification of airborne isocyanate for polymeric isocyanates (EC detection). 13 8.10 Sampling efficiency 13 9 Calculations. 14 10 Interferences . 14 11 Uncertainty of measurement . 14 11.1 Introduction . 14 11.2 Assessm
11、ent of performance characteristics of the method Sampling considerations (detailed ISO/IEC Guide 98:1995 approach). 16 11.3 Assessment of performance characteristics of the method Other considerations (detailed ISO/IEC Guide 98:1995 approach). 17 11.4 Mass of compound in field sample blank. 21 11.5
12、Between-laboratory uncertainty contributions 22 11.6 Combined uncertainty 22 11.7 Expanded uncertainty 22 12 Stability 22 13 Test report . 22 BS ISO 16702:2007iv 14 Quality control. 23 Annex A (informative) Determination of sampling efficiency 24 Annex B (informative) Data used for uncertainty estim
13、ates 25 Annex C (informative) Combined uncertainties for isocyanate formulations 26 Annex D (informative) Sample chromatograms 28 Bibliography . 34 BS ISO 16702:2007vForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member b
14、odies). 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 a
15、nd 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
16、, 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 ca
17、sting 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 16702 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC
18、2, Workplace atmospheres. This second edition cancels and replaces the first edition (ISO 16702:2001), which has been technically revised. BS ISO 16702:2007vi Introduction Isocyanates (molecules containing the NCO functional group) are highly reactive molecules widely used in industry in paints, pol
19、yurethane foams, plastics, and adhesives. They are known respiratory sensitisers and are the major cause of chemically induced occupational asthma. Exposure to isocyanates can occur by inhalation and possibly by contact. Australia, Ireland, and the United Kingdom have set long-term occupational expo
20、sure limits (8 h time-weighted average) of 20 g/m3total isocyanate (NCO) group and short-term limits (15 min) of 70 g/m3for workplace air. In addition, Finland has set a short term limit (15 min) of 35 g/m3and Sweden has set long-term occupational exposure limits (8 h time-weighted average) of 5 ppb
21、1)total isocyanate (NCO) group and short-term limits (15 min) of 10 ppb for workplace air. These limits are for total isocyanate, i.e. monomeric and all polymeric (also called oligomeric, polyisocyanates, oligo-isocyanates or prepolymeric) isocyanates. Sampling and analysis of airborne isocyanates i
22、s not easy. Isocyanates occur in a variety of chemical forms, such as monomers, oligomers, larger and more structurally complex polymers, and mixtures of all these forms. Isocyanate oligomers and polymers are commonly used in industry as they are less volatile than the monomers and so pose less of a
23、 vapour hazard. Isocyanates occur in a variety of physical forms, e.g. vapours, aerosols, and liquids. A sampling method that is suitable for one physical form of isocyanates is not automatically suitable for another. In the workplace, other substances are also present in the air, such as water vapo
24、ur, dust, amines and alcohols, depending on the product and process that is being used, and these can interfere with the liquid chromatography (LC) analysis. Polymeric isocyanate standards are not available, yet these species must be quantified to give a total isocyanate result. Due to the reactive
25、nature of the isocyanate group, analysis in the workplace is commonly carried out by trapping isocyanates with a derivatisation reagent to produce a stable derivative. This International Standard method is based upon the UK method for isocyanate determination, MDHS25/31. The method traps the isocyan
26、ate with 1-(2-methoxyphenyl)piperazine (MP) to form a stable urea derivative. The urea derivative is analysed by LC with electrochemical (EC) and ultraviolet/visible (UV/vis) detection. Isocyanates for which a standard exists or can be prepared can be quantified using a UV/vis detector. This has the
27、 advantage that a UV/vis detector is more stable than an EC detector. However, for the majority of industrially used polymeric isocyanates, no standards exist and these compounds are quantified using the EC detector, which oxidises the methoxy group on the MP derivatisation reagent. As this group is
28、 common to all MP derivatised isocyanates, the polymeric species can be calibrated using the corresponding isocyanate monomer. The procedure used for sampling of workplace isocyanates depends upon their physical form. Filters have been found to sample vapour effectively. An impinger/filter combinati
29、on is recommended for aerosol sampling. This method has been found to be suitable for the commonly occurring mono- and diisocyanates i.e. methylenebis(phenylisocyanate) (MDI), phenylisocyanate (PI), toluene-2,6-diisocyanate and toluene-2,4-diisocyanate (TDI), 1,6-(diisocyanato)hexane (HDI), isophoro
30、nediisocyanate (IPDI), naphthyldiisocyanate (NDI), methylenebis(cyclohexylisocyanate) (hydrogenated MDI) and butylisocyanate as well as polymeric isocyanates based on these monomers. 1) Parts per billion (thousand million). BS ISO 16702:20071Workplace air quality Determination of total organic isocy
31、anate groups in air using 1-(2-methoxyphenyl)piperazine and liquid chromatography 1 Scope This International Standard gives general guidance for the sampling and analysis of airborne organic isocyanate (NCO) compounds in workplace air. This International Standard is appropriate for a wide range of o
32、rganic compounds containing isocyanate functional groups, including isocyanate monomers and prepolymers. Examples of aromatic monomers include toluene diisocyanate (TDI) (both 2,4- and 2,6-diisocyanatotoluene), naphthyl diisocyanate (NDI) (1,5-diisocyanatonaphthalene) and methylenebis(4-phenylisocya
33、nate) MDI, systematically named as di-(4-isocyanatophenyl)methane. Examples of aliphatic monomers include isophorone diisocyanate (IPDI, systematically named as 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane), methylenebis(cyclohexylisocyanate) (hydrogenated MDI, HMDI) and 1,6-diisocyana
34、tohexane (HDI) (also known as 1,6-hexamethylenediisocyanate). Monomers containing a single isocyanate moiety (e.g. methyl isocyanate, ethyl isocyanate, phenyl isocyanate, hexyl isocyanate) are produced during thermal degradation of polyurethanes, i.e. flame bonding and laser cutting. Isocyanate poly
35、mers, also called polyisocyanates, homopolymers, oligomers or prepolymers, are derived from the diisocyanate monomers by self-condensation or reaction with polyols. Polymeric diisocyanates are widely used in the polyurethanes, paints and coatings, and adhesives industries. This International Standar
36、d is appropriate for measuring any product containing free isocyanate groups. It was developed primarily for the commonly used MDI, HDI, and TDI, and their oligomers and polymers1. It has also been used for IPDI, HMDI, and NDI, and their oligomers and polymers. The exposure limit for isocyanates in
37、the UK requires measurement of total isocyanate groups, i.e. monomeric diisocyanates, oligomeric, prepolymeric and polymeric diisocyanates and monoisocyanates. Because there are a wide range of isocyanate structures and molecular masses, the chromatographic conditions used will need to be varied acc
38、ording to the isocyanate formulation being determined. If both isocyanates and amines are believed to be present, and both need to be determined, a standard which enables the simultaneous determination of both amines and isocyanates may be more appropriate2. This method has also been modified to all
39、ow determination of mono-isocyanates produced during thermal degradation3, the use of mass spectrometric detection4and other sampling equipment, e.g. 37 mm filters and other filter cassettes, but these modifications are not covered in this International Standard. If a modified version of this method
40、 is being used, it is the responsibility of the user to demonstrate that the modifications are valid. The method is used to determine time-weighted average concentrations of organic isocyanates in workplace atmospheres, and is suitable for sampling over periods in the range 0,5 min to 8 h. The metho
41、d is designed for personal monitoring, but can also be used for fixed location monitoring by suitable modification. NOTE The objective of air monitoring is usually to determine worker exposure and, therefore, the procedures described in this method are for personal sampling in the breathing zone. Th
42、e method can be used for background or fixed location sampling. However, it should be recognised that, due to aerodynamic effects, samplers designed for personal sampling do not necessarily exhibit the same collection characteristics when used for other purposes. The method is suitable for the measu
43、rement of airborne organic isocyanates in the concentration range from approximately 0,1 g/m3to 140 g/m3for a 15 l sample volume. The qualitative and quantitative detection limits for isocyanate, defined as three times and 10 times the standard deviation of six blank determinations, have been found
44、to be typically between 0,001 g and 0,004 g of isocyanate per sample, respectively (EC detection). For a 15 l air sample, these values correspond to qualitative and quantitative detection limits of 0,07 g/m3and 0,3 g/m3, respectively. BS ISO 16702:20072 2 Normative references The following reference
45、d documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 5725-2, Accuracy (trueness and precision) of measurement methods and
46、 results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method EN 1232, Workplace atmospheres Pumps for personal sampling of chemical agents Requirements and test methods 3 Terms and definitions For the purposes of this document, the followi
47、ng terms and definitions apply. 3.1 Isocyanate chemical species 3.1.1 isocyanate a chemical compound with one or more isocyanate (nitrogen carbon oxygen) functional groups 3.1.2 monomer a chemical compound that joins with other identical compounds to form dimers, trimers, oligomers or polymers EXAMP
48、LE Classes of isocyanate monomers include: monoisocyanates, containing one isocyanate functional group, e.g. methyl isocyanate; diisocyanates, e.g. di(4-isocyanatophenyl)methane (MDI); and triisocyanates, e.g. tri(4-isocyanatophenyl)methane. 3.1.3 diisocyanate a chemical compound with two isocyanate
49、 functional groups 3.1.4 oligomer a compound of low relative molecular mass with multiple isocyanate functional groups, formed by the combination of isocyanate monomers 3.1.5 polyisocyanate oligo-isocyanate an isocyanate compound with multiple isocyanate functional groups 3.1.6 prepolymer the isocyanato-terminated reaction product of a di- or poly-isocyanate with a stochiometric deficiency for a hydroxyl-terminated polyol; these compounds are then further reacted to form polyurethanes or similar compounds 3.2 Analytical definitions 3.2.1 tim
