1、BRITISH STANDARD BS EN ISO 9963-2:1996 BS 6068-2.52: 1996 Water quality Determination of alkalinity Part 2: Determination of carbonate alkalinity The European Standard EN ISO 9963-2:1995 has the status of a British Standard ICS 13.060.40BSENISO9963-2:1996 This British Standard, having been prepared
2、under the directionof the Health and Environment Sector Board, waspublished under the authorityof the Standards Boardand comes into effect on 15 April1996 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference EH/3/2 Draft for comment 92/53921 ISBN 0 580 25
3、292 2 Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical CommitteeEH/3, Water quality, to Subcommittee EH/3/2, Physical, chemical and biochemical methods, upon which the following bodies were represented: The Association of the Labora
4、tory Supply Industry British Agrochemicals Association Ltd. British Ceramic Research British Gas plc British Soft Drinks Association Ltd. Chemical Industries Association Convention of Scottish Local Authorities Department of the Environment (Water Directorate) Department of Trade and Industry (Labor
5、atory of the Government Chemist) GAMBICA (BEAMA) Ltd. Industrial Water Society Institution of Water and Environmental Management National Rivers Authority Royal Society of Chemistry Soap and Detergent Industry Association Society of Chemical Industry Swimming Pool and Allied Trades Association Ltd.
6、Water Companies Association Water Research Centre Water Services Association of England and Wales Amendments issued since publication Amd. No. Date CommentsBSENISO9963-2:1996 BSI 08-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 1 Scope 3 2 Normative r
7、eferences 3 3 Definition 3 4 Principle 3 5 Reagents 3 6 Apparatus 5 7 Sampling and sample treatment 5 8 Procedure 5 9 Expression of results 6 10 Test report 6 Annex A (informative) Information on factors for the conversion of alkalinity values to alternative units 8 Annex B (informative) Bibliograph
8、y 8 Annex ZA (normative) Normative references to international publications with their relevant European publications 8 Figure 1 Principle for absorption of carbon dioxide from air 4 Table 1 Precision data 6 Table 2 Comparison of results using this method with other methods for the determination of
9、alkalinity 7 Table A.1 8 List of references Inside back coverBSENISO9963-2:1996 ii BSI 08-1999 National foreword This British Standard has been prepared by SubcommitteeEH/3/2 and is the English language version of ENISO9963-2:1995 Water quality Determination of alkalinity Part2: Determination of car
10、bonate alkalinity, published by the European Committee for Standardization (CEN). It is identical with ISO9963-2:1994, published by the International Organization for Standardization (ISO). A British Standard does not purport to include all the necessary provisions of a contract. Users of British St
11、andards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred to Corresponding British Standard ISO 3696:1987 BS 3978:1987 Specification for water for laboratory use BS EN 256
12、67 Water quality Sampling EN 25667-1:1993 (ISO 5667-1:1980) Part 1:1994 Guidance on the design of sampling programmes EN 25667-2:1993 (ISO 5667-2:1991) Part 2:1993 Guidance on sampling techniques BS 6068 Water quality Part 1 Glossary ISO 6107-2:1989 Section 1.2:1990 Additional terms relating to type
13、s of water, and treatment and storage of water and waste water, and terms used in sampling and analysis of water ISO 9963-1:1994 BS EN ISO 9663 Water quality Determination of alkalinity Part 1 Determination of total and composite alkalinity IEC 746-2:1982 BS 6438 Electrochemical analyzers Part 2:198
14、4 Method for specifying performance of pH value analyzers Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN ISOtitle page, pages 2 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amen
15、dments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 9963-2 December 1995 ICS 13.060.40 Descriptors: Water, quality, water tests, chemical analysis, determination, alkalinity, volumetric analysis English
16、 version Water quality Determination of alkalinity Part2: Determination of carbonate alkalinity (ISO 9963-2:1994) Qualit de leau Dtermination de lalcalinit Partie2: Dtermination de lalcalinit carbonate (ISO 9963-2:1994) Wasserbeschaffenheit Bestimmung der Alkalinitt Teil2: Bestimmung der Carbonatalk
17、alinitt (ISO 9963-2:1994) This European Standard was approved by CEN on 1995-10-11. 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 an
18、d bibliographical references concerning 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 responsibi
19、lity of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Por
20、tugal, Spain, Sweden, 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 1995 All rights of reproduction and communication in any form and by any means reser
21、ved in all countries to CEN and its members. Ref. No. EN ISO 9963-2:1995 EENISO9963-2:1995 BSI 08-1999 2 Foreword The text of the International Standard from ISO/TC147, Water quality, of the International Organization for Standardization (ISO) has been taken over as a European Standard by the Techni
22、cal Committee CEN/TC230, Water analysis. This European Standard consists of the following Parts: EN ISO 9963-1, Determination of total and composite alkalinity. EN ISO 9963-2, Determination of carbonate alkalinity. This European Standard shall be given the status of a national standard, either by pu
23、blication of an identical text or by endorsement, at the latest by June1996, and conflicting national standards shall be withdrawn at the latest by June1996. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, De
24、nmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. NOTENormative references to International Standard are listed inAnnex ZA (normative).ENISO9963-2:1995 BSI 08-1999 3 1 Scope This part of ISO9963 sp
25、ecifies a method for the titrimetric determination of carbonate alkalinity in natural and drinking water. Using a higherpH value for the endpoint than the method specified inISO9963-1, the influence of other hydrogen acceptors, such as anions of humic acids, is reduced by the procedure. The method i
26、s intended for samples with a carbonate alkalinity between0,01mmol/l and4mmol/l (as H +equivalents). For samples containing higher concentrations of alkalinity, a smaller test portion can be used for analysis. In this context, carbonate alkalinity is often called total alkalinity and usually has nea
27、rly the same numerical value as methyl orange alkalinity (MO-alkalinity). The endpoint detection, using a pH-meter is less prone to interferences than the use of the indicator. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisi
28、ons of this part of ISO9963. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO9963 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated bel
29、ow. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 385-1:1984, Laboratory glassware Burettes Part 1: General requirements. ISO 3696:1987, Water for analytical laboratory use Specification and test methods. ISO 5667-2:1991, Water quality Sampling Part2: Guid
30、ance on sampling techniques. ISO 6107-2:1989, Water quality Vocabulary Part2. ISO 9963-1:1994, Water quality Determination of alkalinity Part1: Determination of total and composite alkalinity. IEC 746-2:1982, Expression of performance of electrochemical analyzers Part2: pH value. 3 Definition For th
31、e purposes of this part of ISO9963, the following definition applies. 3.1 alkalinity (A) the quantitative capacity of aqueous media to react with hydrogen ions ISO6107-2 in this method, the endpoint is chosen in such a way as to permit the full neutralization of the carbonate system usually proton a
32、cceptors (X) other than the carbonate system are present in low concentrations and can often be disregarded. Examples of such buffering substances are ammonia, phosphate, and anions of humic and other organic acids 4 Principle Alkalinity is determined by titration with hydrochloric acid, with simult
33、aneous removal of carbon dioxide. In this way, a precise endpoint independent of the initial concentration of alkalinity can be used. The endpoint preferably needs to be as close to neutrality as possible but still low enough to allow the removal of carbon dioxide produced. In this part of ISO9963,
34、the endpoint is set at pH5,4, since the pH value can easily be determined with the indicator chosen. The induced systematic error is corrected by titrating a blank. 5 Reagents Use only reagents of recognized analytical grade. Commercially available, ready-made solutions may be used.ENISO9963-2:1995
35、4 BSI 08-1999 5.1 Water, grade2 in accordance with ISO3696, free of interfering concentrations of acid or alkali and with a conductivity of less than0,1mS/m. 5.2 Gas, free from carbon dioxide, nitrogen or alternatively a gas free from carbon dioxide obtained by passing air through a standing tube fi
36、lled with soda lime or another compound that absorbs carbon dioxide. Then pass the gas through a wash bottle containing water and subsequently the gas distribution tube (seeFigure 1). 5.3 Mixed indicator pH 5,4 Dissolve0,040g 0,005g of methyl red and0,060g 0,005g of bromocresol green in100ml of etha
37、nol90%(V/V). Neutralize the solution with about2ml of0,1mol/l sodium hydroxide until a brown colour appears. Check the neutrality of the indicator solution by titration to endpoint of one sample. If the brown colour does not remain after the addition of10more drops of the indicator, adjust the pH of
38、 the indicator solution. Stored in an amber glass bottle, the solution is stable for at least6months. Sodium carbonate solution, c(Na 2 CO 3 ). 0,025mol/l. Dry sodium carbonate (Na 2 CO 3 ) in an oven at250 C 10 C for4h. Allow to cool in a desiccator. Dissolve1,3g 0,1g (weighed to the nearest0,001g)
39、 in water in a500ml volumetric flask. This solution is stable for at least one month if stored in a refrigerator. 5.4 Hydrochloric acid, c(HCl). 0,020mol/l. Dilute1,7ml 0,1ml of concentrated hydrochloric acid ( . 1,18g/ml) to1000ml with water in a volumetric flask. An equivalent, commercially availa
40、ble solution can be used. Standardize this solution at least weekly as follows. Pipette2,00ml 0,02ml of the sodium carbonate solution () into the titration vessel (6.2) and add40ml5ml of water (5.1). Titrate according to the procedure using electrodes (see8.1) or with indicator (8.2) for the endpoin
41、t detection Figure 1 Principle for absorption of carbon dioxide from airENISO9963-2:1995 BSI 08-1999 5 Perform at least three titrations, and record the volumes (V 2 ) of hydrochloric acid consumed. The difference between the highest and lowest volume of hydrochloric acid consumed shall be less than
42、0,05ml. Continue until three consecutive titrations give the required result. Using50ml 5ml of water (5.1), carry out a blank determination in the same manner and note the volume V 3 , in millilitres, of acid consumed. Calculate the concentration of the hydrochloric acid using the equation where 6 A
43、pparatus Usual laboratory equipment and, in particular, the following should be used. 6.1 Burette, preferably of total capacity10ml, graduated in divisions of0,02ml, and conforming to the requirements of ISO385-1. 6.2 Titration vessel, use either a glass filter funnel with a porosity of2-3 and a vol
44、ume of about75ml, or a gas distribution tube for dipping into the titration vessel (an Erlenmeyer flask with a volume of100ml). 6.3 pH-meter, with a compatible electrode system suitable for the measurement of pH to within 0,05pH units over the range3to10, for use when the endpoint determination is t
45、o be made using a pH-meter. The equipment shall be set up, calibrated, and used according to IEC746-2. Alternatively, a titrator fulfilling these specifications can be used. 7 Sampling and sample treatment Collect samples in clean polyethylene or borosilicate glass bottles with a volume of at least1
46、00ml. Fill the bottle completely with the sample and insert the stopper so that no air remains inside the bottle. Analyse the samples immediately after collection. If this is not possible, store the samples at a temperature of4 C to8 C in order to avoid nitrification or scaling. (SeeISO5667-2.) 8 Pr
47、ocedure Mount the components according toFigure 1. NOTE 1Coloured samples interfere with the indicator endpoint determination. Such samples should be analysed using a pH-meter. 8.1 Endpoint detection with a pH-meter Set the gas flow (5.2) to the titration vessel (6.2) at a rate that produces abundan
48、t bubbles and transfer50,0ml 0,1ml of sample (volume V 4 ) to the vessel. Insert the pH electrodes and titrate slowly with hydrochloric acid (5.4) to a pH value of5,4. The pH value has to be stable for at least30s, if not continue the titration. Note the volume V 5 , in millilitres, of acid consumed
49、. If the volume of acid consumed exceeds10ml, take a smaller volume of the sample (V 4 ) and dilute to50ml 5ml with water (5.1). In this case, the volume of acid consumed shall be not less than3ml. 8.2 Endpoint detection with indicator Set the gas flow (5.2) to the titration vessel (6.2) at a rate that produces abundant bubbles and transfer50,0ml 0,1ml of sample (volume V 4 ) to the vessel. Add three drops of indicator and titrate slowly with hydrochloric acid (5.4) until the colour chang
