BS 6068-2 19-1986 Water quality - Physical chemical and biochemical methods - Method for determination of cyanogen chloride《水质 第2部分 物理、化学和生物化学方法 第19节 氯化氰含量测定方法》.pdf

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1、BRITISH STANDARD BS 6068-2.19: 1986 ISO 6703-3: 1984 Water quality Part 2: Physical, chemical and biochemical methods Section 2.19 Method for determination of cyanogen chloride ISO title: Water quality Determination of cyanide Part3:Determination of cyanogen chloride UDC 556.11+614.777+628.1/.3+663.

2、63:53/54BS6068-2.19:1986 This British Standard, having been prepared under the directionof the Environment andPollution Standards Committee, was published underthe authority of the BoardofBSI and comes into effect on 28 February1986 BSI 10-1999 The following BSI references relate to the work on this

3、 standard: Committee reference EPC/44 Draft for comment 82/56063 DC ISBN 0 580 14989 7 Amendments issued since publication Amd. No. Date of issue CommentsBS6068-2.19:1986 BSI 10-1999 i Contents Page National foreword ii 0 Introduction 1 1 Scope and field of application 1 2 Definition 1 3 Principle 1

4、 4 Reagents 1 5 Apparatus 2 6 Sampling and samples 2 7 Procedure 2 8 Expression of results 6 9 Precision 6 10 Test report 6 Figure 1 Three-necked distillation flask 3 Figure 2 Absorption vessel 4 Figure 3 Separating funnel 5 Figure 4 10ml sampling funnel 5 Figure 5 1 ml sampling funnel 5 Table Inter

5、ferences 1 Bibliography 7 Publication referred to Inside back coverBS6068-2.19:1986 ii BSI 10-1999 National foreword This Section of this British Standard, which has been prepared under the direction of the Environment and Pollution Standards Committee, is identical with ISO6703-3:1984 “Water qualit

6、y Determination of cyanide Part3: Determination of cyanogen chloride”. The International Standard was prepared by subcommittee2, Physical, chemical and biochemical methods, of Technical Committee147, Water quality, of the International Organization for Standardization (ISO) as a result of discussion

7、 in which the UK participated. This British Standard 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 to6, which, together with Part0, are listed below. Part 0: I

8、ntroduction; Part 1: Glossary; Part 2: Physical, chemical and biochemical methods; Part 3: Radiological methods; Part 4: Microbiological methods; Part 5: Biological methods; Part 6: Sampling. Terminology and conventions. The text of the International Standard has been approved as suitable for public

9、ation as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point

10、 on the baseline as the decimal marker. Wherever the words “International Standard” or “part of ISO6703” appear, referring to this standard, they should be read as “British Standard” or “Section of BS6068” respectively. In British Standards it is current practice to use the symbol “L” for litre (and

11、 its submultiples) rather than “l” and to use the spelling “sulphur”, etc., instead of “sulfur”, etc. ISO6703-1:1984 and ISO6703-2:1984 are referred to in clause0 for information only. Accordingly, the validity of this standard is not affected. British Standards related to ISO6703-1 and ISO6703-2 ar

12、e BS6068-2.17 and BS6068-2.18 respectively. Textual errors. When adopting the text of the International Standard, the following textual errors were discovered. They have been marked in the text and have been reported to ISO in a proposal to amend the text of the International Standard. a) In clause6

13、, the beginning of paragraph4 should read as follows “Transfer the collected sample to the separating funnel (5.3) as follows. Rinse the outside of the sampling funnel (5.4 or5.5) with water and place it on .”. b) In7.1, the end of the first sentence should read “ into the vessel above the fritted g

14、lass”. Cross-references International Standard Corresponding British Standard BS 6068 Water quality: Part2 Physical, chemical and biochemical methods ISO 6703-4:1985 a Section 2.20:1986 Method for determination of cyanide by diffusion at pH6 (Identical) a Referred to in the text as at the stage of d

15、raft.BS6068-2.19:1986 BSI 10-1999 iii c) In7.1, paragraph2, the second and third sentences should read as follows “Place the separating funnel (5.3) in one side neck with the open-topped funnel in the second side neck. Pour10ml of the buffer solution (4.9) into the flask via the open-topped funnel.”

16、 d) In clause10 d) line2, delete “sections 1 and 3 of”. Additional information a) Air bubbles through the buffered sample in the flask when the stopcock of the separating funnel is closed in7.1, paragraph3. b) With respect to7.1, paragraph4, to be comparable with the standard matching solutions, it

17、is necessary to transfer the contents of the absorption vessel to a one-mark volumetric flask of25,0ml capacity. c) The standard matching solutions prepared in7.4.1 contain0,0008; 0,002; 0,008 and0,010 of cyanide, in milligrams, respectively. d) Experience may show that the checking of new batches o

18、f chemicals referred to in7.4.3 may be particularly necessary with respect to new batches of barbituric acid. 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

19、 Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorpo

20、rated. This will be indicated in the amendment table on the inside front cover.iv blankBS6068-2.19:1986 BSI 10-1999 1 Attention is drawn to the toxicity of cyanide and to the need to take extreme care when handling cyanides and their solutions. Carry out all operations in a fume cupboard. Avoid cont

21、act with the skin and eyes. When pipetting, always use a safety pipette (pipette by bulb). Detoxify samples and solutions containing cyanides or heavy metals in accordance with local official regulations. Other chemicals specified in this part of ISO6703 are also hazardous, for example pyridine. 0 I

22、ntroduction Cyanides may be present in water as hydrocyanic acid (prussic acid), as cyanide ions and as complex cyanides. They may be determined as total cyanide or as easily liberatable cyanide. If cyanide compounds are chlorinated, cyanogen chloride (CICN) is produced, and this compound has to be

23、determined separately. This International Standard comprises four parts as follows: Part 1: Determination of total cyanide; Part 2: Determination of easily liberatable cyanide; Part 3: Determination of cyanogen chloride; Part 4: Determination of cyanide by diffusion at pH6 1) . The methods described

24、 in parts1, 2 and3 are suitable for controlling the quality of water and for the examination of municipal sewage and industrial effluents. They are appropriate to the technology available for the destruction of cyanides in treatment plants, and are based on the separation of liberated hydrogen cyani

25、de (or in the case of this part of ISO6703, of cyanogen chloride) by stripping with a carrier gas. The method specified in part4 is suitable for the determination of smaller amounts of cyanide, depending on the concentrations of copper and nickel. 1 Scope and field of application This part of ISO670

26、3 specifies a method for the determination of cyanides, as cyanogen chloride (seeclause2) in water. The method is applicable for the determination of cyanogen chloride concentrations in the range0,02 to15mg/l. The ions and compounds listed in the table, if present singly or in combination at concent

27、rations above the specified limiting concentration, interfere with the method (the list is not exhaustive). The presence of aldehydes, e.g.formaldehyde, may give lower cyanide values because of the formation of cyanohydrin. Table Interferences 2 Definition For the purpose of this International Stand

28、ard, the following definition applies: cyanogen chloride the first reaction product when cyanide compounds are chlorinated cyanogen chloride is a gas and is only slightly soluble in water, but is highly toxic even in low concentrations 3 Principle Addition of tin (II) chloride solution to the sample

29、 and entrainment of the cyanogen chloride liberated at pH5,4 and room temperature by means of a current of air into an absorption solution containing pyridine/barbituric acid. Determination of the cyanogen chloride concentration photometrically. 4 Reagents All reagents shall be of recognized analyti

30、cal grade and the water used shall be distilled or deionized water. 4.1 Hydrochloric acid, solution, 1,12g/ml. 4.2 Hydrochloric acid, solution, c(HCl)=1mol/l. 4.3 Tin(II) chloride, solution. Dissolve50g of tin (II) chloride dihydrate (SnCl 2 2H 2 O) in the hydrochloric acid solution (4.2) and dilute

31、 with the same hydrochloric solution to1000ml. Prepare a fresh solution each week. 4.4 Sodium chloride, solution, c(NaCl)=0,5mol/l. 1) At present at the stage of draft. Interference Limiting concentration mg/l Sulfide ion Polysulfide ion Sulfide and polysulfide ion Sulfite ion Thiosulfate ion Thiocy

32、anate ion Chlorine (elemental) 1000 300 1000 500 1000 1000 250BS6068-2.19:1986 2 BSI 10-1999 4.5 Sodium hydroxide, solution, c(NaOH)=0,4 mol/l. 4.6 Pyridine/barbituric acid, solution. Place3 g of barbituric acid (C 4 H 4 N 2 O 3 ) in a50ml one-mark volumetric flask, wash down the walls of the flask

33、with just enough water to moisten the barbituric acid, add15ml of pyridine (C 5 H 5 N), and swirl to mix. Add3ml of the hydrochloric acid solution (4.1) and dilute to the mark with water. Store overnight in a refrigerator and, if necessary, filter to eliminate any undissolved barbituric acid. The so

34、lution is stable for1 day if stored in the dark and for1week if stored in a refrigerator. 4.7 Potassium cyanide, standard solution corresponding to10mg of CN per litre. Dissolve25mg of potassium cyanide in the sodium hydroxide solution (4.5) and dilute with the same sodium hydroxide solution to1000m

35、l in a one-mark volumetric flask. Standardize this solution by titration with the silver nitrate solution (4.8), immediately before use or once each day, if numerous determinations are carried out. 4.8 Silver nitrate, solution, c(AgNO 3 )=0,01mol/l. Store in a dark bottle. 4.9 Buffer solution, of pH

36、5,4. Dissolve6g of sodium hydroxide in approximately50ml of water, add11,8g of succinic acid (C 4 H 6 O 4 ) and dilute with water to100ml. 4.10 Chloramine-T, solution. Dissolve0,5g of chloramine-T trihydrate (C 7 H 7 ClNaNSO 2 3H 2 O) in water in a50ml one-mark volumetric flask and dilute to the mar

37、k with water. Prepare fresh solution each week. Check each batch of chloramine-T against a calibration curve. 5 Apparatus Usual laboratory equipment, and 5.1 Three-necked distillation flask, of capacity500 ml, with standard conical joints (centre neck29/32, side necks14,5/23) and funnel, as shown in

38、 Figure 1). 5.2 Absorption vessel, protected against return, with fritted glass G1 (see Figure 2). 5.3 Separating funnel 2) , of capacity100 ml (seeFigure 3). 5.4 Sampling funnel 2) , of capacity10ml (see Figure 4). 5.5 Sampling funnel 2) , of capacity1ml (seeFigure 5). 5.6 Volumetric flasks, of cap

39、acities25, 50, 250 and1000ml. 5.7 Flowmeter 5.8 Spectrometer, with cells of optical path length10mm. 6 Sampling and samples For expected cyanogen chloride concentrations of less than0,15 mg/l, collect the sample in the separating funnel (5.3). For expected concentrations between0,15 and1,5 mg/l, col

40、lect the sample in the10ml sampling funnel (5.4) and for expected concentrations between1,5 and 15mg/l, collect the sample in the1ml sampling funnel (5.5). Take the samples by immersing the appropriate funnels in the water to be sampled (with the stop-cocks closed below the surface of the water). If

41、 using the separating funnel (5.3), place5ml of the tin (II) chloride solution (4.3) in it before collecting the sample. Stopper the funnel immediately. If one of the sampling funnels (5.4 or5.5) was used to collect the sample, place5ml of the tin(II) chloride solution (4.3) in the separating funnel

42、 (5.3) and dilute with water to100ml. Rinse the sampling funnel (5.4 or5.5) with water and place it on 3)the separating funnel (5.3). Open the stop-cock of the separating funnel first, then the lower, and finally the upper, stop-cock of the sampling funnel. After about20ml have run out of the separa

43、ting funnel, close the stop-cocks of the separating funnel, remove the sampling funnel and stopper the separating funnel immediately. Analyse as soon as possible and in any case within24h. If it is necessary to store the sample keep it cool and in the dark. 7 Procedure 7.1 Separation of cyanogen chl

44、oride Place the absorption vessel (5.2) on the centre neck of the three-necked distillation flask (5.1) and pour2ml of the buffer solution (4.9),3ml of the pyridine/barbituric acid solution (4.6),8ml of the sodium chloride solution (4.4) and about8ml of water 3) into the vessel. (This absorption sol

45、ution may be mixed, before use, in a brown bottle; it is stable for several days at room temperature.) 2) The exact volumes of the separating (5.3) and sampling funnels (5.4 and5.5) should be determined prior to use. 3) See national foreword for details of textual error.BS6068-2.19:1986 BSI 10-1999

46、3 Figure 1 Three-necked distillation flaskBS6068-2.19:1986 4 BSI 10-1999 Figure 2 Absorption vesselBS6068-2.19:1986 BSI 10-1999 5 Connect the absorption vessel to the pump and adjust the air flow to about40l/h. 4) Place the separating funnel (5.3) in one side neck and the other funnel (5.4 or5.5) in

47、 the second side neck. Pour10ml of the buffer solution (4.9) into the flask. Open the stop-cock of the separating funnel and lift the stopper carefully to allow air to enter. When the separating funnel is empty, remove the stopper and rinse the funnel with a small amount of water. After 1min, close

48、the stop-cock of the separating funnel, so that the air stream enters the flask through the other funnel. After20 min, disconnect the air supply. Transfer the contents 5)of the absorption vessel into a volumetric flask, rinse the vessel with a very small amount of water, dilute to the mark and mix.

49、7.2 Blank test Carry out a blank test in parallel with the determination, using the same reagents in the same quantities and following the same procedure, but replacing the test sample with water. Figure 3 Separating funnel Figure 4 10 ml sampling funnel Figure 5 1 ml sampling funnel 4) See national foreword for details of textual error. 5) See national foreword (Additional information).BS6068-2.19:1986 6 BSI 10-1999 7.3 Determination Immediately (not later than10min) after separation of the cyanogen chloride