1、BRITISH STANDARD BSENISO 120:1998 Implementing Amendment No.1 to BS2782-4:Method 451D:1978/ISO 120:1977 (renumbersthe BS as BS EN ISO120: 1998), not published separately Plastics Phenol-formaldehyde mouldings Determination of free ammonia and ammonium compounds Colorimetric comparison method (ISO120
2、:1977) ICS 83.140.99BSENISO 120:1998 BSI05-1999 ISBN 0 580 10187 8 Foreword This British Standard is technically identical to International Standard ISO 120:1977 Plastics Phenol-formaldehyde mouldings Determination of free ammonia and ammonium compounds Colorimetric method. In1998 the European Commi
3、ttee for Standardization (CEN) accepted ISO120:1977 as European Standard EN ISO120:1998. 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
4、 itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, the EN ISO title page, pages2to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorp
5、orated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date Comments 10254 October1998 Implementing European StandardBSENISO 120:1998 BSI 05-1999 i Contents Page Foreword Inside front cover Foreword 2 Text of EN ISO120 3 List of
6、references Inside back coverii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO120 July 1998 ICS 83.080.10 Descriptors: See ISO document English version Plastics Phenol-formaldehyde mouldings Determination of free ammonia and ammonium compounds Colorimetric comparison method (ISO120:197
7、7) Plastiques Pices moules base de phnoplastes Dosage de lammoniac libre et des composs ammoniacaux Mthode par comparaison colorimtrique (ISO120:1977) Kunststoffe Phenoplast-Formteile Bestimmung von freiem Ammoniak und Ammoniumverbindungen Colorimetrisches Vergleichsverfahren (ISO120:1977) This Euro
8、pean Standard was approved by CEN on12 June1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concer
9、ning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own l
10、anguage and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Swede
11、n, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Me
12、mbers Ref. No. EN ISO120:1998 EENISO120:1998 BSI 05-1999 2 Foreword The text of the International Standard from Technical Committee ISO/TC61, Plastics, of the International Organization for Standardization (ISO) has been taken over as a European Standard by Technical Committee CEN/TC249, Plastics, t
13、he secretariat of which is held by IBN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January1999, and conflicting national standards shall be withdrawn at the latest by January1999. According t
14、o CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdo
15、m. Endorsement notice The text of the International Standard ISO 120:1977 has been approved by CEN as a European Standard without any modification. Contents Page Foreword 2 1 Scope and field of application 3 2 References 3 3 Principle 3 4 Reagents 3 5 Apparatus 3 6 Preparation of test sample 3 7 Pro
16、cedure 3 8 Expression of results 4 9 Test report 4ENISO120:1998 BSI 05-1999 3 1 Scope and field of application This International Standard specifies a colorimetric comparison method for the semi-quantitative determination of the amount of ammonia in phenol-formaldehyde mouldings. NOTEThis Internatio
17、nal Standard does not provide an absolute measure of the ammonia present. The amount of ammonia in a moulded article is of importance when corrosion of metal inserts or contamination of foodstuffs in contact with the article has to be considered. 2 References ISO565, Test sieves Woven metal wire clo
18、th and perforated plate Nominal sizes of apertures. ISO648, Laboratory glassware One-mark pipettes 1) . 3 Principle Hot aqueous extraction of free ammonia from a powdered test portion. Distillation of the aqueous extract in the presence of potassium permanganate and sodium hydroxide solution. Colora
19、tion of the distillate by reaction with Nessler reagent and comparison of the colour with that obtained in each of a series of standard matching solutions. 4 Reagents During the analysis, use only ammonia-free reagents of recognized analytical grade, and only ammonia-free distilled water or water of
20、 equivalent purity. 4.1 Potassium permanganate 4.2 Sodium hydroxide,2% (m/m) solution. 4.3 Standard matching stock solution, containing10mg of NH 3per litre. Dissolve31,5mg of ammonium chloride in1000ml of water. 4.4 Nessler reagent 5 Apparatus Ordinary laboratory apparatus, and 5.1 Means for reduci
21、ng the mouldings to a powder. 5.2 Sieve, with nominal apertures of250mm, conforming to ISO565. 5.3 Balance,accurate to0,01g. 5.4 Glass-stoppered flask, 250ml capacity. 5.5 Distillation apparatus, comprising a flask of250ml capacity, splash head and a condenser. 5.6 Filter funnel, with hardened mediu
22、m speed filter paper. 5.7 Pipettes, capacities2 and10ml, complying with the requirements of ISO648. 5.8 Nessler cylinders, 50ml capacity. 6 Preparation of test sample Reduce a fully representative sample of the mouldings to powder by filing, milling, grinding, turning or drilling, taking care that n
23、o undue heating of the material occurs. Sieve this powder, using the sieve (5.2), and use for the test that portion passing through the sieve. Keep the sample in a tightly stoppered flask until required. The extraction with water (see7.2) shall begin within1h of grinding the moulding. NOTEThe method
24、 of reduction to powder can affect the results. In cases of dispute, or for referee purposes, the method should be agreed between the interested parties. 7 Procedure 7.1 Test portion Weigh, to the nearest0,01g,5 0,1g of the sieved material (see clause6). 7.2 Preparation of the test solution Place th
25、e test portion (7.1) in the flask (5.4) and cover it with ten times its mass of water at a temperature of90 to100C. Stopper the flask and shake it so that the powder is thoroughly wetted. Allow it to cool at room temperature, for1h, with occasional shaking. Then filter the contents of the flask, wit
26、hout suction, through the filter funnel(5.6). Transfer, with a pipette (5.7), 10ml of the filtered extract, corresponding to1g of the powder, into the flask of the distillation apparatus(5.5). NOTEBefore using the distillation apparatus, it is recommended that it should be freed from any ammonia whi
27、ch may be present by distilling a quantity of distilled water in it until the addition of2ml of Nessler reagent(4.4) to50ml of distillate does not give rise to any colour. Add to the flask0,1g of potassium permanganate(4.1) and10ml of the sodium hydroxide solution (4.2). Slowly distil the mixture; c
28、ollect the first15ml of the distillate in a Nessler cylinder (5.8) and dilute to50ml with water. 1) At present at the stage of draft. (Revision of ISO/R648.)ENISO120:1998 4 BSI 05-1999 7.3 Determination Transfer, with a pipette (5.7),2ml of the Nessler reagent (4.4) into the Nessler cylinder and det
29、ermine the ammonia content by matching the colour of the test solution (7.2) with that of one of a series of standard matching solutions to which Nessler reagent has been added at the same time as to the test solution. To make the standard matching solutions transfer, with a pipette,1,2,3,4,5 and6ml
30、 portions of standard matching stock solution (4.3) into each of a series of six Nessler cylinders (5.8) and dilute to50ml with water. These correspond to0,01,0,02,0,03,0,04,0,05 and0,06mg of ammonia. NOTEIf the15ml of distillate is found to contain more than0,06mg of ammonia, a10ml portion of the f
31、iltered extract shall be suitably diluted and a10ml portion of this diluted solution used in the distillation. An appropriate dilution factor should be used in the calculation. 8 Expression of results The amount of free ammonia and ammonium compounds, expressed as a percentage by mass of ammonia (NH
32、 3 ), is given by the formula where m is the mass, in milligrams, of ammonia contained in the appropriate standard matching solution from the series (see7.3); D is the dilution factor in the case where the flitrate is diluted before distillation: where V 1is the volume in millilitres of the portion
33、of the filtered extract before dilution (V 1 =10ml); V 2is the volume in millilitres of this10ml portion of the filtered extract after dilution. 9 Test report The test report shall include the following particulars: a) reference to this International Standard; b) full details necessary for the ident
34、ification of the sample; c) the method used for reducing the mouldings to powder; d) amount of free ammonia; e) date of the test. mD 10 - D V 2 V 1 - =BSENISO 120:1998 BSI 05-1999 List of references See national foreword.BS EN ISO 120:1998 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandards
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