1、CEN ENxISO88467 95 3404589 009b780 355 I BRITISH STANDARD Water quality BS EN IS0 Determination of permanganate index The European Standard EN IS0 8467 : 1995 has the status of a British Standard 8467 : 1995 BS 6068 : Section 2.32 : 1995 - CEN EN*ISO*8467 75 3404587 0096781 291 m Amd. No. First publ
2、ished as BS 6068 : Section 2.32 July 1987 BS EN IS0 8467 : 1995 Date Ext affected Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austri
3、a Belgium Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Net herlands Norway Portugal Spain Sweden Switzerland United Kingdom Oesterreichisches Normungsinstitut Institut belge de normalisation Dansk Standard Suomen Standardisoimisliito, r. y. Association fransaise de normalis
4、ation Deutsches Institut fr Normung e.V. Hellenic Organization for Standardization Technological Institute of Iceland National Standards Authority of Ireland Ente Nazionale Italiano di Unificazione Inspection du Travail et des Mines Nederlands Normalisatie-instituut Norges Standardiseringsforbund In
5、stituto Portugus da Qualidade Asociacin Espaola de Normalizacin y Certificacin Standardiseringskommissionen i Sverige Association suisse de normalisation British Standards Institution This British Standard, having been prepared under the direction of the Environment and Pollution Standards Policy Co
6、mmittee, was published under the authority of the Standards Board and comes into effect on 15 May 1995 Amendments issued since publication 0 BSI 1995 Second edition for this purpose the chemical oxygen demand should be deter- mined as described in IS0 6060:1989, Water quality - Determination of the
7、chemical oxygen demand. The method is simple and convenient for surveying the quality of a large number of water samples. CEN EN*ISO*8467 95 3404589 0096766 873 E Page 4 EN IS0 8467 : 1995 Water quality - Determination of permanganate index 1 Scope This International Standard specifies a method for
8、the determination of the permanganate index of water. It is primarily intended for water for human consumption and domestic use, drinking water, natural mineral water, well and table water, as well as water from swimming pools. It is used for the determination of the parameter “oxidizability“. It is
9、 applicable to waters having a chloride ion concentration of less than 300 mg/l. Samples having a permanganate index over 10 mg/l should be diluted before analysis. The lower limit of the optimum range of the test is 0,5 mg/l. 2 Normative reference The following standard contains provisions which, t
10、hrough reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of a
11、pplying the most re- cent edition of the standard indicated below. Mem- bers of IEC and IS0 maintain registers of currently valid International Standards. IS0 385-1 : 1 984, Laboratory glassware - Burettes - Part i: General requirements. 3 Definition 3.1 permanganate index (of water): The mass conce
12、ntration of oxygen equivalent to the amount of permanganate ion consumed when a water sample is treated with that oxidant under defined conditions. 4 Principle Heating of a sample in a boiling water-bath with a known amount of potassium permanganate and sulfuric acid for a fixed period of time (10 m
13、in). Re- duction of part of the permanganate by oxidizable material in the sample and determination of the con- sumed permanganate by addition of an excess of oxalate solution, followed by titration with permanga- nate. NOTE 1 The suggested maximum permanganate index of 10 mg/l is equivalent to a co
14、nsumption of approximately 60 % of the added permanganate by the nondiluted sam- ple. 5 Reagents During the analysis, use only reagents of recognized analytical grade and only distilled water, water from a reverse osmosis or water of equivalent purity. Do not use deionized water from an organic ion
15、exchanger. NOTE 2 Non-reducing water can be prepared as follows. Add10 ml of sulfuric acid (5.3) and a small excess of the potassium permanganate stock solution (5.6) to 1 litre of distilled water. Distil in an all-glass apparatus and discard the first 100 ml of distillate. Store in a glass bottle w
16、ith a glass stopper. The volume of the consumed potassium permanga- nate standard solution Vo (see 8.4) shall not exceed 0,l ml, otherwise the procedure shall be repeated or a water of lower organic content shall be used. 5.1 Sulfuric acid, p(H2S04) = 1,84 g/ml, 18 mol/l. 5.2 Sulfuric acid, c(HZS04)
17、 = 7,5 mol/l. Add slowly, while stirring continuously, 420 ml of sulfuric acid (5.1) to 500 ml of water. Allow to cool and dilute to 1 litre. 5.3 Sulfuric acid, c(H2S04) = 2 mol/l. Add slowly, while stirring continuously, 110 ml of sulfuric acid (5.1) to about 500 ml of water. Slowly add potassium p
18、ermanganate solution (5.7) until a faint pink colour persists. Allow to cool, dilute with water to 1 litre and mix. Page 5 CEN EN+IS0+8467 75 3404587 OOWA OT m EN IS0 8467 : 1995 5.4 Sodium oxalate, stock solution, c(Na,C,O,) = 0,05 mol/l. Dry sodium oxalate at 120 “C for 2 h. Dissolve 6,700 g of th
19、e dried solid in water in a 1 O00 ml one- mark volumetric flask. Make up to the mark with wa- ter and mix. This solution is stable for 6 months if stored in a dark place. 5.5 Sodium oxalate, standard volumetric solution, c(Na,C,O,) = 5 mmol/l. Pipette 100 ml f 0,25 ml of the sodium oxalate stock sol
20、ution (5.4) into a 1 O00 mI one-mark volumetric flask, make up to the mark with water and mix. This standard volumetric solution is stable for 2 weeks. NOTE 3 Commercially available ready-made solutions may be used. 5.6 Potassium permanganate, stock solution, c(KMn0,) = 20 mmol/l. Dissolve about 3,2
21、 g of potassium permanganate in water and make up to 1 O00 ml. Heat the solution to 90 “C to 95 “C for 2 h, cool and store for not less than 2 days. Decant the clear solution and store in a dark bottle. 5.7 Potassium permanganate, volumetric solution, c(KMn0,) = 2 mmol/l. Pipette 100 ml of the potas
22、sium permanganate stock solution (5.6) into a 1 O00 ml, one-mark volumetric flask. Make up to the mark with water and mix. This volumetric solution is relatively stable for several months if it is stored in the dark. The procedure de- scribed in 8.5 automatically al!ows for its exact con- centration
23、 to be included in the calculation in 9.1. 6 Apparatus Usual laboratory apparatus, and the following should be used 6.1 Water-bath, with a rack for test tubes, of suffi- cient capacity and power to ensure that the solutions in all the test tubes quickly reach and are maintained at a temperature betw
24、een 96 “C and 98 “C, during both the initial heating and the reaction stages. 6.2 Test tubes, of length 150 mm to 200 mm, di- ameter 25 mm to 35 mm and wall thickness 0,5 mm to 1 mm. Keep the test tubes exclusively for the de- termination of the permanganate index. Clean all new test tubes by heatin
25、g with acidified permanganate solution. This shall be checked by per- forming blank determinations until the values are ad- equately low and constant. A blank value V, shall typically not exceed 0,l ml. 6.3 Burette, of capacity 10 mi, preferably of the piston type, graduated in divisions of 0,02 ml,
26、 and conforming to the requirements of IS0 385-1. 6.4 Measuring flasks, of capacity 100 ml and 1 O00 ml. 6.5 Volumetric pipettes, of capacity 5 ml, 10 ml, 25 ml, 50 mi, and 100 ml. 7 Sampling and samples immediately after receiving the sample in the labora- tory, add 5 ml of sulfuric acid (5.2) per
27、litre of sample, if this was not done during sampling in the field, re- gardless of whether the sample is to be stored before a na lysis. Analyse the samples as soon as possible and not later than 2 days after sampling. Keep them in the dark at O OC to 5 OC if the storage time exceeds 6 h. Shake the
28、 storage bottles and make sure that their contents are well homogenized when withdrawing a test portion for analysis. 8 Procedure 8.1 Check that all flasks and test tubes (6.2) used during the procedure are perfectly clean (see 6.2). 8.2 Dilute samples having a high permanganate index, so that the r
29、esults for the diluted samples fall within the range 0,5 mgll to 10 mg/l. 8.3 Pipette 25,O ml f 0,25 ml of the test sample (or the diluted test sample) into a test tube. Add 5 ml f 0,5 mI of sulfuric acid (5.3) and mix by swirling gently . Place the test tube in the boiling water-bath (6.1) for 10 m
30、in f 2 min. Add 5 ml f 0,05 ml of potassium permanganate volumetric solution (5.7) and commence timing. After 10 min f 15 s, add 5 ml f 0,05 ml of the sodium oxalate standard volumetric solution (5.5) and wait until the solution is colourless. Titrate, whilst hot, with potassium permanganate volumet
31、ric solution (5.7) to a faint pink colour which persists for about CEN EN*ISO*84b 95 3404589 0096788 b4b E Page 6 EN IS0 84.67 : 1995 9,32 to 10,28 I ResorcinoP (6,O mg/U 30 s. Note the volume V, of permanganate solution consumed. 0,07 o,27 to 8.4 Carry out a blank test in parallel with the deter- m
32、ination, using the same procedure, but replacing the test portion with 25 ml of water. Note the volume Vo of permanganate solution consumed. Retain the titrated solution for standardization of the potassium permanganate volumetric solution (5.71, as described in 8.5. 8.5 To the titrated solution ret
33、ained from the blank test (8.41, add 5,OO ml f 0,05 ml of the sodium oxa- late standard volumetric solution (5.5). Reheat the solution, if necessary, to about 80 OC and titrate with potassium permanganate volumetric solution (5.7) until the appearance of a pink colour which persists for about 30 s.
34、Note the volume V, of permanganate solution consumed. NOTE 4 It is good practice to leave the titrated solutions in the test tubes until they are required for the next deter- mination of permanganate index. 9 Expression of results 9.1 Calculation Calculate the permanganate index, iMn, expressed in m
35、illigrams of oxygen per litre, using the expression . . . (1) where VO Vl v2 f is the volume, in millilitres, of permanga- nate solution consumed in the blank titration (8.4); is the volume, in millilitres, of permanga- nate solution consumed in the titration of the test portion (8.3); is the volume
36、, in millilitres, of permanga- nate solution consumed in the standardi- zation titration (8.5); is the factor, in milligrams per litre, for re- calculation to oxygen and allowing for the sample volume used; f is calculated as follows: f= V,-c(Na2C20J-Mo-1 O00 1 ooo*v, where V4 is the volume, in mill
37、ilitres, of the sodium oxalate standard volumetric solution (5.5) used for the determination according to 8.5 (here: 5); c(Na2C,04) is the amount-of- substance concentration, in millimoles per litre, of the sodium oxalate standard volumetric solution (5.5) (here: 5); 1 O00 (numerator) is the factor
38、for re- calculation of c(Na,C,04), from mmol/l to mmol/ml, in millilitres per litre; is the molar mass, in milligrams of oxygen per millimole, for the recalculation to oxygen (here: 16); V, is the sample volume used, in millilitres (here: 25); 1 O00 (denominator) is the factor for recalculation of t
39、he measured value to 1 litre of sample vol- ume, in millilitres per litre. Mo 9.2 Precision 9.2.1 Within-laboratory standard deviation Table 1 Sample Tap water) 0,06 to r),2, I 128 to 1,94 I darious raw and I o,23 to potable waters31 0,60 I 0,05 to Number of degrees of freedom 10 10 10 Various up to
40、 10 1) Range of results obtained for a distributed tap water ana- lysed in six laboratories. N.B. The range of values found should not be taken to indicate the presence of interlaboratory bias, because of possible sample instability. 2) Range of results obtained by seven laboratories for a resorcino
41、l solution made up by the individual laboratories from a distributed resorcinol sample. 3) Range of standard deviations for a variety of raw and potable waters; data obtained from five laboratories. CEN EN*IS0*8467 95 3404589 O096789 582 Sample 9.2.2 Total standard deviation Table 2 Permanganate ind
42、ex found mgll 1,83 9,95 Standard deviation Number of degrees of freedom mg/l 0,lO 20 0,12 23 I 1) Total standard deviations obtained by a single laboratory for several batches. I 1 I Page 7 EN IS0 8467 : 1995 10 Test report The test report shall include the following information: a) reference to thi
43、s International Standard; b) precise identification of the sample; c) any pretreatment, such, as filtration or sedimentation, which may have influenced the re- sults; dl the results, to two significant figures and ex- pressed in milligrams per litre; e) any departure from the procedure specified, an
44、y operations regarded as optional, or any other cir- cumstances that may have affected the results. CEN EN*IS0*84b? 95 3404589 009b790 2T4 BS EN IS0 8467 : 1995 National annex NA (informative) Committees responsible The United Kingdom participation in the preparation of this European Standard was en
45、trusted by the Environment and Pollution Standards Policy Committee (EPC/-) to Technical Committee EPC/44 upon which the following bodies were represented: Association of Consulting Engineers British Association for Chemical Specialities British Gas plc Chemical Industries Association Department of
46、the Environment for Northern Ireland Department of the Environment (Water Directorate) Department of Trade and Industry (Laboratory of the Government Chemist) Industrial Water Society Institute of Petroleum Institution of Water Officers Institution of Gas Engineers Institution of Water and Environme
47、ntal Management National Rivers Authority Royal Institute of Public Health and Hygiene Royal Society of Chemistry Scottish Association of Directors of Water and Sewerage Services Soap and Detergent Industry Association Water Companies Association Water Research Centre Water Services Association of E
48、ngland and Wales The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Agrochemicals Association Ltd. British Ceramic Research Ltd. British Laboratory Ware Association Ltd. British Soft Drinks Association Ltd. Convention of Scottish Loc
49、al Authorities Department of Trade and Industry (Warren Spring Laboratory) GAMBICA (BEAMA) Ltd. Swimming Pool and Allied Trades Association Ltd. CEN EN*ISO*84b7 95 lM 3404589 009b793 L30 BS EN IS0 8467 : 1995 BS 6068 : Section 2.32 : 1995 EIS1 389 Chiswick High Road London W4 4AL 95 05-5-0.5 k-SP BSI - British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Contract requirements A British Standard
