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 LAWBS ISO 15373:2001 This British Standard, having been prepared under the direction of the Sector Policy and Strategy Comm
2、ittee 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 This British Standard reproduces verbatim ISO 15373:2001 and implements it as the UK national standard. The
3、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 can be obtained on request to its secretary. Cross-references The British Standards which implement internati
4、onal 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 the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include
5、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 legal obligations. aid enquirers to understand the text; present to the responsible international/European
6、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 UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page pages i
7、i 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 publication Amd. No. Date CommentsINTERNATIONAL STANDARD ISO 15373 First edition 2001-08-15 Reference number ISO 15373
8、:2001(E) Plastics Polymer dispersions Determination of free formaldehyde Plastiques Dispersions de polymres Dosage du formaldhyde libreISO 15373:2001(E) iiISO 15373:2001(E) iii Contents Page 1 Scope . 1 2 Normative references . 1 3 Principle 1 4 Interference 2 5 Reagents (methods A and B) . 2 6 Appa
9、ratus . 4 7 Procedure . 6 8 Calculation 10 9 Precision for method B . 10 10 Test report 11 Bibliography. 12ISO 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 Internat
10、ional 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 I
11、SO, 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 3. Draft International Standard
12、s 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 International Standard may be
13、 the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 15373 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 9, Thermoplastic materials.INTERNATIONAL STANDARD ISO 15373:2001(E) 1 Plastics Pol
14、ymer 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 responsibility of the user
15、 of this International Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard describes two methods for the determination of free formaldehyde (HCHO) in polymer dispersions. The procedu
16、re 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 dispersions with a free-formaldehyd
17、e 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 properties of polymer dispers
18、ions. There are no known limitations to these methods when used in the manner described. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendment
19、s 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 references, the latest edition
20、 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 Specification and test method
21、s. 3 Principle 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 reagent (Nash reagent)
22、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 applicable to the re
23、sulting aqueous sample solution, formaldehyde is separated from other species by liquid chromatography on an octadecyldimethylsilyl (C 18 ) reversed-phase column using an aqueous mobile phase. 10 mg/kg 410 nmISO 15373:2001(E) 2 The detection system includes a post-column reactor which produces a lut
24、idine 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 the aqueous solution is determined using peak areas from the standard and sample chromatograms (calibration by external standar
25、d). This method is specific for formaldehyde. NOTE To determine free-formaldehyde levels in polymer dispersions, it is necessary to carry out the determination without upsetting any equilibria between the liquid phase and the polymer phase that might generate or deplete formaldehyde. Both test metho
26、ds provide means for determining low levels of free formaldehyde in polymer dispersions without upsetting existing equilibria. 4 Interference 4.1 Method A The following species have been identified as possible interferants in the method: acetaldehyde and glyoxylic acid. However, interference by acet
27、aldehyde 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. 4.2 Method B This method is very selective for formaldehyde because potential interferants such as acetaldehyde, acetone, benza
28、ldehyde, formamide, formic acid, glyoxylic acid and propionaldehyde are either chromatographically separated from formaldehyde or do not react with the post-column reagent. Because polymer dispersions vary in composition, the method run time may need to be extended to allow for late- eluting compoun
29、ds. Compounds which remain on the column after an analysis may interfere with the formaldehyde peak in subsequent runs. 5 Reagents (methods A and B) Unless otherwise stated, use only reagents of recognized analytical grade and only grade 1 water as defined in ISO 3696. 5.1 Acetic acid (CH 3 CO 2 H),
30、 glacial. 5.2 Ammonium acetate (CH 3 CO 2 NH 4 ). 5.3 Formaldehyde (HCHO), solution in water. 5.4 2,4-Pentanedione (acetyl acetone) (CH 3 COCH 2 COCH 3 ). 5.5 Phosphoric acid solution,. Dissolve of phosphoric acid (H 3 PO 4 ) in water and dilute to with water. 5.6 Potassium ferrocyanide trihydrate s
31、olution, (Carrez solution I). Dissolve of potassium ferrocyanide trihydrate (K 4 Fe(CN) 6 3H 2 O) in water and dilute to with water. 5.7 Zinc sulfate heptahydrate solution, (Carrez solution II). Dissolve of zinc sulfate heptahydrate (ZnSO 4 7H 2 O) in water and dilute to with water. 5.8 Sodium hydro
32、xide,. Dissolve of sodium hydroxide in water and dilute to with water. 410 nm 37 % 33 mM 2,3 ml 85 % 1 l 36 g/l 36 g 1l 72 g/l 72 g 1 l 0,1 M 4g 1lISO 15373:2001(E) 3 5.9 Sodium phosphate, dibasic (Na 2 HPO 4 ). 5.10 Nash reagent, post-column reagent, prepared as follows: 5.10.1 Transfer of ammonium
33、 acetate (5.2) to a amber bottle (6.1) that contains a stir bar. Add of water to the bottle and mix on a stir plate until the ammonium acetate has completely dissolved. 5.10.2 Pipette glacial acetic acid (5.1) into the bottle. Pipette of 2,4-pentanedione (5.4) into the bottle. Add of water to the bo
34、ttle and mix thoroughly ( of mixing is suggested). NOTE If necessary, other concentrations of ammonium acetate, glacial acetic acid and 2,4-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
35、weekly. 5.10.3 Transfer the Nash reagent to the post-column reactor reservoir (see 6.6.1.2). The reservoir shall be protected from light. 5.10.4 Degas the Nash reagent with a helium sparge. 5.11 Mobile phase and standard diluent, prepared as follows: 5.11.1 Transfer of dibasic sodium phosphate (5.9)
36、 to a mobile-phase reservoir that contains a stir bar. Add of water and mix on a stir plate until the sodium phosphate has completely dissolved. 5.11.2 Adjust the pH of the solution to with phosphoric acid (5.5). 5.11.3 Prepare the standard diluent in the same manner. 5.11.4 Degas the mobile phase w
37、ith 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 the Carrez reagents are used in the sample preparation (see 7.1.4). 5.12 Sample diluent (method B), prepared as follows: 5.12.1 The sample diluent is pr
38、epared in the same way as the mobile phase described in 5.11.1. 5.12.2 The final step of the diluent preparation requires a pH adjustment. Before this step, measure the pH of the polymer dispersion to units. Dilute the polymer dispersion to with a buffer that is within units of the polymer dispersio
39、n. Adjust the pH of the diluent to within units of the polymer dispersion using either NaOH (5.8) or H 3 PO 4 (5.5). 5.13 Standard reference solution (methods A and B). 5.13.1 Stock standard reference solution Prepare of ( ) stock formaldehyde solution by adding of formaldehyde solution (5.3) to of
40、standard diluent. Assay this formaldehyde solution in accordance with ISO 2227. Calculate the mass fraction of the formaldehyde in the stock solution in . 5.13.2 Series of standard reference solutions Prepare a series of standard reference solutions ranging from to of formaldehyde in standard diluen
41、t. 62,5 g 1 l 600 ml 7,5 ml 5 ml 387,5 ml 45 min 1,78 g 2 l 2l 7,0 33 mM 0,1 pH 1 l 0,1 pH 0,1 pH 25 ml 1,18 % 11 840 mg/kg 0,8 g 37 % 24,2 g mg/kg 1 mg/kg 15 mg/kgISO 15373:2001(E) 4 5.13.3 Frequency of preparation Stock and standard reference solutions shall be stored in a refrigerator when not in
42、 use. Fresh stock and standard reference solutions shall be prepared weekly. 6 Apparatus Ordinary laboratory apparatus and glassware, together with the following: 6.1 Amber bottle, of capacity, capable of filtering out ultraviolet and visible light. 6.2 Sample filter, consisting of a sample syringe
43、and a filter assembly to remove micro-particulate matter from the prepared sample solution. 6.3 High-speed centrifuge, capable of operating at ( ) or greater (see 7.1.3). 6.4 Low-speed centrifuge, capable of operating at (see 7.1.4). 6.5 Method A 6.5.1 Photoelectric colorimeter or spectrophotometer
44、wavelength . 6.5.2 Test tubes, colorimeter tubes or photometric cells(i s s u i t a b l e ) . 6.6 Method B 6.6.1 HPLC system, consisting of the following: 6.6.1.1 Liquid chromatograph, having an injection valve, a post-column reactor, a UV/visible detector operating at and an isocratic solvent-deliv
45、ery system capable of delivering a mobile-phase flow of . The UV/visible detector may incorporate either a tungsten lamp or a deuterium lamp with suitable filters. 6.6.1.2 Post-column reactor, with a reservoir capable of delivering a reagent flow of up to and containing a knitted reaction coil that
46、can be heated to and a suitable static mixing tee. 6.6.1.3 Chromatographic column, in length internal diameter, packed with reversed-phase pH- stable C 18 particles. If necessary, other suitable columns may be used (e.g. fast acid, ). 6.6.1.4 Chromatographic guard column, in length internal diameter
47、, packed with reversed- phase pH-stable C 18 particles. If appropriate, other suitable columns may be used. 6.6.1.5 Data system, capable of collecting data at a rate of 1 point/s from a output detector. 6.6.1.6 Configuration of liquid chromatograph A suitable in-line check valve is placed between th
48、e pump and the injector. The guard and analytical columns are connected to the injector. The outlet of the analytical column is connected to the mixing tee as described in 6.6.1.7. 6.6.1.7 Configuration of post-column reactor (PCR) The post-column reagent passes through a pulse dampener and an in-li
49、ne check valve prior to entering one side of the mixing tee. The outlet of the analytical column is connected to the other side of the mixing tee. The reaction coil is connected to the outlet of the mixing tee. Stainless-steel tubing with inside diameter is used to make the connections. Tubing lengths shall be kept to a minimum. The mixing tee and reaction coil are placed in an oven at . 1l 5ml 0,1 m 50 000 r/min 275g 1 000 r/min (410 5) nm 1cm 410 nm 0,6 ml/min 0,5 ml/min 95 C 250 mm 4,6 mm 5 m 100 mm 7,8 mm 10 mm 4,6 mm 5 m 1V 0,25 mm 95
