BS 6068-2 12-1990 Water quality - Physical chemical and biochemical methods - Determination of phenol index 4-aminoantipyrine (4-aminophenazone) spectrometric methods after distill.pdf

1、BRITISH STANDARD BS6068-2.12: 1990 ISO6439:1990 Water quality Part2: Physical, chemical and biochemical methods Section2.12 Determination of phenol index:4-aminoantipyrine (4-aminophenazone) spectrometric methods after distillationBS6068-2.12:1990 This British Standard, havingbeen prepared under the

2、direction of the Environmentand Pollution Standards Policy Committee, waspublished under the authorityof the Board of BSI andcomes into effect on 30 November1990 BSI10-1999 First published December1984 Second edition November1990 The following BSI references relate to the work on this standard: Comm

3、ittee reference EPC/44 Draft announced in BSI News, August1990 ISBN 0 580 19060 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Environment and Pollution Standards Policy Committee (EPC/-) to Technical Committee EPC/44, upon which the

4、following bodies were represented: Association of Consulting Scientists British Association for Chemical Specialities British Gas plc Chemical Industries Association Department of the Environment for Northern Ireland Department of the Environment (Water Directorate) Department of Trade and Industry

5、(Laboratory of the Government Chemist) Electricity Supply Industry in England and Wales Industry Water Society Institute of Gas Engineers Institute of Petroleum Institution of Water and Environmental Management National Rivers Authority Royal Institute of Public Health and Hygiene Royal Society of C

6、hemistry Scottish Association of Directors of Water and Sewerage Services Soap and Detergent Industry Association Water Companies Association Water Research Centre Water Services Association of England and Wales Amendments issued since publication Amd. No. Date CommentsBS6068-2.12:1990 BSI 10-1999 i

7、 Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Method A Direct colorimetric method 1 5 Method B Chloroform extraction method 4 6 Test report 6 Annex A (normative) Checking the concentration of thephenolstocksolution(

8、4.2.9) 7 Publication(s) referred to Inside back coverBS6068-2.12:1990 ii BSI 10-1999 National foreword This Section of BS6068, which has been prepared under the direction of the Environment and Pollution Standards Policy Committee, is identical with ISO6439:1990 “Water quality Determination of pheno

9、l index 4-Aminoantipyrine spectrometric methods after distillation”. The International Standard was prepared by subcommittee2, Physical, chemical and biochemical methods, of Technical Committee147, Water quality, of the International Organization for Standardization (ISO) with the active participati

10、on and approval of the UK. This Section of BS6068 is a revision of the1984 edition of BS6068-2.12, which is withdrawn and which was identical to ISO6439:1984. There are a number of minor technical clarifications and changes between this revision and BS6068-2.12:1984. There are changes to clauses1, 2

11、, 4.2.1, 4.2.16.4, 4.5.3, 4.6.4 and4.8.1. NOTEThe tests described in this Section of BS6068 should only be carried out in laboratories with suitable facilities and by suitably qualified persons with an appropriate level of chemical expertise. Standard chemical procedures should be followed throughou

12、t. BS6068 is being published in a series of Parts subdivided into Sections that will generally correspond to particular International Standards. Sections are being, or will be, published in Parts1 to7, which, together with Part0, are listed below. Part 0: Introduction; Part 1: Glossary; Part 2: Phys

13、ical, chemical and biochemical methods; Part 3: Radiological methods; Part 4: Microbiological methods; Part 5: Biological methods; Part 6: Sampling; Part 7: Precision and accuracy. The introduction to the International Standard reads as follows. The term “phenol index” as used in this International

14、Standard only includes phenols which react with4-aminoantipyrine under the conditions specified to give coloured compounds. In a water containing phenol itself, there will usually be associated with it other phenolic compounds whose sensitivity to the reagents used in the following methods may not n

15、ecessarily be the same. The percentage composition of the various phenolic compounds(3.1) present in a given test sample is unpredictable. It is obvious, therefore, that a standard containing a mixture of phenolic compounds cannot be made applicable to all test samples. For this reason, phenol (C 6

16、H 5 OH) has been selected as a standard, and any colour produced by the reaction of other phenolic compounds is measured as phenol and reported as the phenol index(3.2). Cross-references International Standard Corresponding British Standard BS6068 Water quality ISO5667-1:1980 Section6.1:1981 Guidanc

17、e on the design of sampling programmes (Identical) ISO5667-2:1982 Section6.2:1983 Guidance on sampling techniques (Identical) ISO5667-3:1985 Section6.3:1986 Guidance on the preservation and handling of samples (Identical)BS6068-2.12:1990 BSI 10-1999 iii It is not possible to use the procedures speci

18、fied in this International Standard to differentiate between kinds of phenols. Some phenolic compounds with substituents such as alkyl, aryl and nitro in the para position do not produce colour with4-aminoantipyrine. Phenolic compounds containing para substituents such as a carboxyl, halogen, hydrox

19、yl, methoxyl or sulfonic acid, do produce colour with4-aminoantipyrine. Hence the phenol index includes only those phenolic compounds which can be determined under specified conditions. Textual errors. When adopting the text of the International Standard, the following textual errors were discovered

20、. They have been marked in the text and have been reported to ISO in a proposal to amend the text of the International Standard. In4.5.1, line2, “4.4.2 b)” should be read as “4.4 b)”. In4.7, the second paragraph should be deleted. A British Standard does not purport to include all the necessary prov

21、isions 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. Summary of pages This document comprises a front cover, an inside front cover, pagesi to iv, pages1to8, an ins

22、ide back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.iv blankBS 6068-2.12:1990 BSI 10-1999 1 1 Scope This International Standard specifies methods for det

23、ermining the phenol index(3.2) in drinking waters, surface waters and waste waters. After a preliminary distillation, the test samples are analysed according to specific application as follows: method A (direct colorimetric method): this method is capable of measuring the phenol index in test sample

24、s that contain more than0,10mg/l in the aqueous phase (without chloroform extraction), using phenol as a standard; method B (chloroform extraction method): this method is capable of measuring the phenol index without dilution from about0,002mg/l to about0,10mg/l when the coloured end-product is extr

25、acted and concentrated in chloroform phase, using phenol as a standard. NOTE 1The limits of detection achievable with both methods are insufficient for checking compliance with the limits given in the Directive80/778/EEC for drinking water. NOTE 2According to the results of a German interlaboratory

26、trial using a method almost identical to method B, the lower limit of detection is0,01mg/l. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicate

27、d were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid Intern

28、ational Standards. ISO5667-1:1980, Water quality Sampling Part1: Guidance on the design of sampling programmes. ISO5667-2:1982, Water quality Sampling Part2: Guidance on sampling techniques. ISO5667-3:1985, Water quality Sampling Part3: Guidance on the preservation and handling of samples. 3 Definit

29、ions For the purpose of this International Standard, the following definitions apply: 3.1 phenolic compounds hydroxy derivatives of benzene and its analogues 3.2 phenol index a number giving a concentration, expressed in milligrams of phenol per litre, of different phenolic compounds based on the de

30、gree of colour they produce with4-aminoantipyrine according to the procedure given 4 Method A Direct colorimetric method 4.1 Principle Separation of phenolic compounds from impurities and preservative agents by distillation. The rate of volatilization of the phenolic compounds is gradual, so that th

31、e volume of the distillate must equal that of the test sample being distilled. Reaction of the steam-distillable phenolic compounds with4-aminoantipyrine at a pH of10,0 0,2 in the presence of potassium hexacyanoferrate(III) to form a coloured antipyrine dye. Measurement of the absorbance of the dye

32、at510nm. The phenol index is expressed as milligrams of phenol (C 6 H 5 OH) per litre. The minimum detectable quantity is equivalent to0,01mg of phenol when a50mm cell is used in the spectrometric measurement and100ml of distillate are used in the determination. 4.2 Reagents During the analysis, use

33、 only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.2.1 4-aminoantipyrine, 20g/l solution. Dissolve2,0g of4-aminoantipyrine (C 11 H 13 N 3 O) in water and dilute to100ml. Prepare this reagent just before use. If red particles remain, the solution c

34、annot be used again. 4.2.2 Ammonium chloride, 20g/l solution. Dissolve20g of ammonium chloride (NH 4 Cl) in water and dilute to1000ml. 4.2.3 Ammonium hydroxide, =0,90g/ml. 4.2.4 Potassium sodium tartrate 1) , buffer solution,pH=10. Dissolve34g of ammonium chloride (NH 4 Cl) and200g of potassium sodi

35、um tartrate (NaKC 4 H 4 O 6 ) in700ml of water. Add150ml of ammonium hydroxide(4.2.3) and dilute to1000ml with water. 1) Systematic nomenclature: potassium sodium2,3-dihydroxybutanedioate.BS 6068-2.12:1990 2 BSI 10-1999 4.2.5 Copper(II) sulfate, pentahydrate (CuSO 4 .5H 2 O). 4.2.6 Copper(II) sulfat

36、e, 100g/l solution. Dissolve190g of copper(II) sulfate pentahydrate(4.2.5) in water and dilute to1000ml. 4.2.7 Hydrochloric acid, =1,19g/ml. 4.2.8 Methyl orange, indicator. Dissolve0,5g methyl orange in water and dilute to1000ml. 4.2.9 Phenol, stock solution,1,00g/l. CAUTION Phenol should not be all

37、owed to come into contact with the skin. Dissolve1,00g phenol in freshly boiled and cooled water, in a1000ml volumetric flask and make up to the mark with the same water. This solution is stable for about1 week. IMPORTANT Phenol must not be liquid or discoloured. Checking the phenol concentration by

38、 titration may be necessary according to the procedure described in Annex A. 4.2.10 Phenol, standard solution corresponding to0,01g of C 6 H 5 OH per litre. Dilute10,0ml of the phenol stock solution(4.2.9) to1000ml with freshly boiled and cooled water in a1000ml volumetric flask. 1ml of this standar

39、d solution contains0,01mg of C 6 H 5 OH. Prepare this solution on the day of use. 4.2.11 Phenol, standard solution corresponding to0,001g of C 6 H 5 OH per litre. Dilute50ml of the phenol standard solution(4.2.10) to500ml with freshly boiled and cooled water in a500ml volumetric flask. 1ml of this s

40、tandard solution contains0,001mg of C 6 H 5 OH. Prepare this solution within2h of use. 4.2.12 Phosphoric acid, =1,70g/ml. 4.2.13 Phosphoric acid, solution1+9. Mix1 part by volume of phosphoric acid(4.2.12) with9 parts by volume of water. 4.2.14 Potassium hexacyanoferrate(III), 2) 80g/l solution. Dis

41、solve8,0g of potassium hexacyanoferrate(III) K 3 Fe (CN) 6 in water and dilute to100ml. Filter if necessary. Prepare this solution within1 week of use. 4.2.15 Sodium sulfate, Na 2 SO 4 , anhydrous and granular. 4.2.16 Special reagents for turbid distillates. 4.2.16.1 Sulfuric acid, 0,5mol/l solution

42、. 4.2.16.2 Sodium chloride. 4.2.16.3 Sodium hydroxide, 2,5mol/l solution. Dissolve10g of NaOH in100ml of water. 4.2.16.4 Chloroform. WARNING Chloroform is toxic and a suspected carcinogen. Do not breathe vapour. Avoid contact with skin and eyes. 4.3 Apparatus 4.3.1 Distillation apparatus, all glass,

43、 consisting of a1litre borosilicate glass distilling apparatus with Graham condenser or equivalent. 4.3.2 pH meter, and suitable electrodes. 4.3.3 Spectrometer, with selectors for continuous or discontinuous variation, suitable for use at510nm and accommodating a cell that gives a path length of10mm

44、 to100mm shall be used. The size of the cell used will depend on the absorbance of the coloured solutions being measured and the characteristics of the spectrometer. In general, if the absorbances are greater than1,0 with a certain cell, the next smaller size cell should be used. 4.4 Sampling and sa

45、mples Sampling of different kinds of waters should be carried out in accordance with ISO5667-1, ISO5667-2 and ISO5667-3, observing the following additional precautions. Samples shall be collected in glass bottles. Phenolic compounds in water are subject to both chemical and biochemical oxidation. Th

46、erefore, unless the samples are analysed within4h of collection, they shall be preserved when collected, using the following procedure: a) acidify the samples to a pH of approximately4,0 with phosphoric acid(4.2.13). Use methyl orange(4.2.8) or a pH meter(4.3.2) to check the pH; b) inhibit biochemic

47、al oxidation of phenolic compounds in the sample by adding1,0g of copper(II) sulfate(4.2.5) per litre of the sample; c) store the sample in the cold(5 C to10 C), and analyse the preserved samples within24h of collection. 2) Trivial name: potassium ferricyanide.BS 6068-2.12:1990 BSI 10-1999 3 4.5 Pre

48、liminary distillation The use of copper(II) sulfate, as described in4.5.1 during distillation of an acidic sample, permits the formation of copper(II) sulfide without subsequent decomposition to hydrogen sulfide. The acidic solution also prevents the precipitation of copper(II) hydroxide, which acts

49、 as an oxidizing agent towards phenolic compounds. 4.5.1 Measure500ml of the sample into a beaker. If the sample was not preserved with copper(II) sulfate4.4.2 b), 3)add5ml of copper(II) sulfate solution(4.2.6), and adjust the pH of the solution to between1 and2 with phosphoric acid(4.2.13). Transfer the mixture to the distillation apparatus(4.3.1). Use a500ml graduated cylinder as receiver. Distil400ml of the sample. Stop the distillation and, when boiling ceases, add100ml of water to the distillation flask. Contin