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1、BRITISH STANDARD BS ISO 15373:2001 Plastics Polymer dispersions Determination of free formaldehyde ICS 83.080 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 15373
2、:2001 This British Standard, having been prepared under the direction of the Sector Policy and Strategy Committee for Materials and Chemicals, was published under the authority of the Standards Policy and Strategy Committee on 09 October 2001 BSI 09 October 2001 ISBN 0 580 38544 2 National foreword
3、This British Standard reproduces verbatim ISO 15373:2001 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee PRI/21, Plastics test methods, which has the responsibility to: A list of organizations represented on this committee c
4、an be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using th
5、e “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from
6、 legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the U
7、K. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page pages ii to iv, pages 1 to 12, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publicatio
8、n Amd. No. DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDARD ISO 15373 First edition 2001-08-15 Reference number ISO 15373:2001(E) Plastics Polymer dispersions Determination of free formaldehyde Plastiques D
9、ispersions de polymres Dosage du formaldhyde libre Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 15373:2001(E) ii Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 15373:2001
10、(E) iii ContentsPage 1Scope .1 2Normative references .1 3Principle 1 4Interference 2 5Reagents (methods A and B) .2 6Apparatus .4 7Procedure .6 8Calculation 10 9Precision for method B .10 10Test report 11 Bibliography.12 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:00 2006,
11、 Uncontrolled Copy, (c) BSI ISO 15373:2001(E) iv 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
12、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
13、 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 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for v
14、oting. 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 International Standard may be the subject of patent rights. ISO shall not be held responsible for identifyin
15、g any or all such patent rights. International Standard ISO 15373 was prepared by Technical Committee ISO/TC 61,Plastics, Subcommittee SC 9, Thermoplastic materials. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI INTERNATIONAL STANDARDISO 1
16、5373:2001(E) 1 Plastics Polymer dispersions Determination of free formaldehyde WARNING This International Standard may involve hazardous chemicals, materials and operations. This International Standard does not purport to address all of the safety problems, if any, associated with its use. It is the
17、 responsibility of the user of this International Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1Scope This International Standard describes two methods for the determination of free formaldehyde (HCHO) in polyme
18、r dispersions. The procedure has been evaluated using acrylic, acrylonitrile butadiene, carboxylated styrene- butadiene and vinyl acetate polymer dispersions. Both test methods may also be applicable to polymer dispersions of other compositions. Method A is the preferred method for polymer dispersio
19、ns with a free-formaldehyde content higher than. Method B is recommended if lower formaldehyde contents have to be determined or arbitration analyses have to be carried out. Both methods minimize changes in free-formaldehyde concentration that can result from changes in the physical or chemical prop
20、erties of polymer dispersions. There are no known limitations to these methods when used in the manner described. 2Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated referenc
21、es, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated refere
22、nces, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 2227,Formaldehyde solutions for industrial use Determination of formaldehyde content. ISO 3696,Water for analytical laboratory use Specifi
23、cation and test methods. 3Principle The polymers dispersed in a polymer dispersion are separated from the aqueous phase by filtration, centrifugation or coagulation. The resulting aqueous sample solution may be used to determine formaldehyde directly using method A by addition of 2,4-pentanedione re
24、agent (Nash reagent) and subsequent measurement of the extinction coefficient at . The concentration of formaldehyde is determined using a calibration plot obtained by plotting the extinction coefficients of formaldehyde standards against the corresponding formaldehyde concentrations. If method B is
25、 applicable to the resulting aqueous sample solution, formaldehyde is separated from other species by liquid chromatography on an octadecyldimethylsilyl (C18) reversed-phase column using an aqueous mobile phase. 10 mg/kg 410 nm Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:0
26、0 2006, Uncontrolled Copy, (c) BSI ISO 15373:2001(E) 2 The detection system includes a post-column reactor which produces a lutidine derivative by reaction of formaldehyde with 2,4-pentanedione reagent (Nash reagent) and a UV/visible detector operating at. The concentration of free formaldehyde in t
27、he aqueous solution is determined using peak areas from the standard and sample chromatograms (calibration by external standard). This method is specific for formaldehyde. NOTETo determine free-formaldehyde levels in polymer dispersions, it is necessary to carry out the determination without upsetti
28、ng any equilibria between the liquid phase and the polymer phase that might generate or deplete formaldehyde. Both test methods provide means for determining low levels of free formaldehyde in polymer dispersions without upsetting existing equilibria. 4Interference 4.1Method A The following species
29、have been identified as possible interferants in the method: acetaldehyde and glyoxylic acid. However, interference by acetaldehyde and glyoxylic acid is to be expected only when the species concerned is present in excess amounts (100-fold and more) compared with the formaldehyde concentration. 4.2M
30、ethod B This method is very selective for formaldehyde because potential interferants such as acetaldehyde, acetone, benzaldehyde, formamide, formic acid, glyoxylic acid and propionaldehyde are either chromatographically separated from formaldehyde or do not react with the post-column reagent. Becau
31、se polymer dispersions vary in composition, the method run time may need to be extended to allow for late- eluting compounds. Compounds which remain on the column after an analysis may interfere with the formaldehyde peak in subsequent runs. 5Reagents (methods A and B) Unless otherwise stated, use o
32、nly reagents of recognized analytical grade and only grade 1 water as defined in ISO 3696. 5.1Acetic acid (CH3CO2H), glacial. 5.2Ammonium acetate (CH3CO2NH4). 5.3Formaldehyde (HCHO),solution in water. 5.42,4-Pentanedione (acetyl acetone) (CH3COCH2COCH3). 5.5Phosphoric acid solution,. Dissolveofphosp
33、horic acid (H3PO4) in water and dilute towith water. 5.6Potassium ferrocyanide trihydrate solution,(Carrez solution I). Dissolveof potassium ferrocyanide trihydrate (K4Fe(CN)63H2O) in water and dilute towith water. 5.7Zinc sulfate heptahydrate solution,(Carrez solution II). Dissolveof zinc sulfate h
34、eptahydrate (ZnSO47H2O) in water and dilute towith water. 5.8Sodium hydroxide,. Dissolveof sodium hydroxide in water and dilute towith water. 410 nm 37 % 33 mM 2,3 ml85 %1 l 36 g/l 36 g1 l 72 g/l 72 g1 l 0,1 M 4 g1 l Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:00 2006, Unc
35、ontrolled Copy, (c) BSI ISO 15373:2001(E) 3 5.9Sodium phosphate, dibasic (Na2HPO4). 5.10Nash reagent, post-column reagent, prepared as follows: 5.10.1Transferof ammonium acetate (5.2) to aamber bottle (6.1) that contains a stir bar. Addof water to the bottle and mix on a stir plate until the ammoniu
36、m acetate has completely dissolved. 5.10.2Pipetteglacial acetic acid (5.1) into the bottle. Pipetteof 2,4-pentanedione (5.4) into the bottle. Addof water to the bottle and mix thoroughly (of mixing is suggested). NOTEIf necessary, other concentrations of ammonium acetate, glacial acetic acid and 2,4
37、-pentanedione in the Nash reagents are also possible. 2,4-Pentanedione is light-sensitive. Protect it from light during use. Prepare fresh Nash reagent solution weekly. 5.10.3Transfer the Nash reagent to the post-column reactor reservoir (see 6.6.1.2). The reservoir shall be protected from light. 5.
38、10.4Degas the Nash reagent with a helium sparge. 5.11Mobile phase and standard diluent, prepared as follows: 5.11.1Transferof dibasic sodium phosphate (5.9) to amobile-phase reservoir that contains a stir bar. Add of water and mix on a stir plate until the sodium phosphate has completely dissolved.
39、5.11.2Adjust the pH of the solution towithphosphoric acid (5.5). 5.11.3Prepare the standard diluent in the same manner. 5.11.4Degas the mobile phase with a helium sparge. Water may also be used as the mobile phase without the addition of a buffer. A water mobile phase shall be used, however, when th
40、e Carrez reagents are used in the sample preparation (see 7.1.4). 5.12Sample diluent (method B), prepared as follows: 5.12.1The sample diluent is prepared in the same way as the mobile phase described in 5.11.1. 5.12.2The final step of the diluent preparation requires a pH adjustment. Before this st
41、ep, measure the pH of the polymer dispersion tounits. Dilute the polymer dispersion towith a buffer that is withinunits of the polymer dispersion. Adjust the pH of the diluent to withinunits of the polymer dispersion using either NaOH (5.8) or H3PO4(5.5). 5.13Standard reference solution (methods A a
42、nd B). 5.13.1Stock standard reference solution Prepareof() stock formaldehyde solution by addingofformaldehyde solution (5.3) toof standard diluent. Assay this formaldehyde solution in accordance with ISO 2227. Calculate the mass fraction of the formaldehyde in the stock solution in. 5.13.2Series of
43、 standard reference solutions Prepare a series of standard reference solutions ranging fromtoof formaldehyde in standard diluent. 62,5 g1 l600 ml 7,5 ml5 ml 387,5 ml45 min 1,78 g2 l 2 l 7,033 mM 0,1 pH1 l0,1 pH 0,1 pH 25 ml1,18 % 11 840 mg/kg0,8 g37 % 24,2 g mg/kg 1 mg/kg15 mg/kg Licensed Copy: shef
44、fieldun sheffieldun, na, Mon Nov 27 08:12:49 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 15373:2001(E) 4 5.13.3Frequency of preparation Stock and standard reference solutions shall be stored in a refrigerator when not in use. Fresh stock and standard reference solutions shall be prepared weekly.
45、6Apparatus Ordinary laboratory apparatus and glassware, together with the following: 6.1Amber bottle, ofcapacity, capable of filtering out ultraviolet and visible light. 6.2Sample filter, consisting of asample syringe and afilter assembly to remove micro-particulate matter from the prepared sample s
46、olution. 6.3High-speed centrifuge, capable of operating at() or greater (see 7.1.3). 6.4Low-speed centrifuge, capable of operating at(see 7.1.4). 6.5Method A 6.5.1Photoelectric colorimeter or spectrophotometer wavelength. 6.5.2Test tubes, colorimeter tubes or photometric cells (is suitable). 6.6Meth
47、od B 6.6.1HPLC system, consisting of the following: 6.6.1.1Liquid chromatograph, having an injection valve, a post-column reactor, a UV/visible detector operating at and an isocratic solvent-delivery system capable of delivering a mobile-phase flow of. The UV/visible detector may incorporate either
48、a tungsten lamp or a deuterium lamp with suitable filters. 6.6.1.2Post-column reactor, with a reservoir capable of delivering a reagent flow of up toand containing a knitted reaction coil that can be heated toand a suitable static mixing tee. 6.6.1.3Chromatographic column,in lengthinternal diameter,
49、 packed with reversed-phase pH- stableC18particles. If necessary, other suitable columns may be used (e.g. fast acid,). 6.6.1.4Chromatographic guard column,in lengthinternal diameter, packed with reversed- phase pH-stableC18particles. If appropriate, other suitable columns may be used. 6.6.1.5Data system, capable of collecting data at a rate of 1 point/s from aoutput detector. 6.6.1.6Configuration of liquid chromatograph A suitable in-line check valve is placed between the pump and the injector. The guard and analytical columns are connected to the injector.
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