BS 6068-2 44-1993 Water quality - Physical chemical and biochemical methods - Determination of sodium and potassium determination of sodium and potassium by flame emission spectrom.pdf

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1、BRITISH STANDARD BS6068-2.44: 1993 ISO9964-3: 1993 Water quality Part2: Physical, chemical and biochemical methods Section2.44 Determination of sodium and potassium: determination of sodium and potassium by flame emission spectrometry UDC 614.777:556.114:543.42:546.32/.33BS6068-2.44:1993 This Britis

2、h Standard, havingbeen prepared under thedirection of the Environment and Pollution Standards Policy Committee, was published underthe authority of the Standards Board and comes intoeffect on 15 September1993 BSI 07-1999 The following BSI references relate to the work on this standard: Committee ref

3、erence EPC/44 Draft for comment89/53615 DC ISBN 0 580 22551 8 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 following bodies wer

4、e represented: Association of Consulting Scientists British Association for Chemical Specialities British Gas plc Chemical Industries Association Convention of Scottish Local Authorities Department of the Environment for Northern Ireland Department of the Environment (Water Directorate) Department o

5、f Trade and Industry (Laboratory of the Government Chemist) Electricity Association Industrial Water Society Institute of Gas Engineers Institution of Water and Environmental Management Institution of Water Officers National Rivers Authority Royal Institute of Public Health and Hygiene Royal Society

6、 of Chemistry Scottish Association of Directors of Water and Sewerage Services Soap and Detergent Industry Association Society of Chemical Industry Water Companies Association Water Research Centre Water Services Association of England and Wales The following bodies were also represented in the draf

7、ting of the standard, through subcommittees and panels: British Agrochemicals Association Ltd. British Ceramic Research Ltd. British Laboratory Ware Association (The Association of the Laboratory Supply Industry) British Soft Drinks Association Ltd. Department of Trade and Industry (Warren Spring La

8、boratory) GAMBICA (BEAMA Ltd.) Ministry of Defence Swimming Pool and Allied Trades Association Ltd. Amendments issued since publication Amd. No. Date CommentsBS6068-2.44:1993 BSI 07-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1

9、 3 Principle 1 4 Reagents 1 5 Apparatus 2 6 Sampling 2 7 Procedure 2 8 Calculation and expression of results 2 9 Test report 3 Annex A (informative) Bibliography 4 Table 1 Precision data 3 List of references Inside back coverBS6068-2.44:1993 ii BSI 07-1999 National foreword This Section of BS6068, w

10、hich has been prepared under the direction of the Environment and Pollution Standards Policy Committee, is identical with ISO9964-3:1993 Water quality Determination of sodium and potassium Part3: Determination of sodium and potassium by flame emission spectrometry. The international standard was pre

11、pared by Technical Committee147, Water quality, of the International Organization for Standardization (ISO) with the active participation and approval of the UK. BS6068 is being published in a series of Parts subdivided into Sections that will generally correspond to particular international standar

12、ds. 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: Physical, chemical and biochemical methods; Part 3: Radiological methods; Part 4: Microbiological methods; Part 5: Biological methods; Part 6: Sa

13、mpling; Part 7: Precision and accuracy. BS6068-2.42:1993 describes a method for determination of sodium by atomic absorption spectrometry and BS6068-2.43:1993 describes a method for determination of potassium by atomic absorption spectrometry. A British Standard does not purport to include all the n

14、ecessary provisions 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. Cross-references International standard Corresponding British Standard BS6068 Water quality ISO56

15、67-1:1980 Section6.1:1981 Guidance on the design of sampling programmes (Identical) ISO5667-2:1991 Section6.2:1991 Guidance on sampling techniques (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cove

16、r. 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.ISO9964-3:1993(E) BSI 07-1999 1 1 Scope 1.1 Field of application This International Standard specifies a method for the determinati

17、on of dissolved sodium and potassium by flame emission spectrometry (FES). Itis intended for the analysis of raw and drinking waters. The method is applicable to water samples with a mass concentration of sodium and potassium of up to10mg/l. For samples containing higher concentrations of sodium and

18、 potassium, a smaller test portion is taken for analysis. The lower limits of determination are less than0,1mg/l for both sodium and potassium. 1.2 Interferences The ions normally present in raw and drinking waters do not interfere with the flame emission spectrometric method for sodium and potassiu

19、m if an ionization suppressant is present. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO9964. At the time of publication, the editions indicated were valid. All standards are subject to revision, and

20、 parties to agreements based on this part of ISO9964 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 International Standards. ISO5667-1:1980, Water quality Sampling Part1

21、: Guidance on the design of sampling programmes. ISO5667-2:1991, Water quality Sampling Part2: Guidance on sampling techniques. 3 Principle Aspiration of the sample into a gas flame of sufficient thermal energy to cause any sodium and potassium present to emit its characteristic radiation. Measureme

22、nt of the intensity at a wavelength of589,0nm for sodium and766,5nm for potassium. When using the air/acetylene flame, the addition of caesium chloride solution as an ionization buffer is necessary. 4 Reagents During the analysis, use only reagents of recognized analytical grade and only deionized w

23、ater or water of equivalent purity. 4.1 Hydrochloric acid, c(HCl) 11mol/l, =1,18 g/ml. 4.2 Nitric acid, c(HNO 3 ) 16 mol/l, =1,41 g/ml. 4.3 Caesium chloride, (CsCl), solution. Dissolve25g of caesium chloride in a solution of50ml of hydrochloric acid (4.1) and450ml of water, and dilute to1 litre with

24、 water in a one-mark volumetric flask. One litre of this solution contains approximately20g of Cs. NOTE 1Nitric acid (4.2) may be used instead of hydrochloric acid (4.1). 4.4 Sodium, stock solution In a 1000ml one-mark volumetric flask, dissolve5,084g 0,005g of sodium chloride (previously dried for

25、at least1 h at140 C 10 C) in water and make up to the mark. Store the solution, which is stable for at least6months, in a polyethylene bottle. One litre of this solution contains2000mg of Na. Alternatively, use a commercially available, readymade solution. 4.5 Potassium, stock solution In a1000ml on

26、e-mark volumetric flask, dissolve3,814g 0,005g of potassium chloride (previously dried for at least1h at140 C 10 C) in water and make up to the mark. Store the solution, which is stable for at least6months, in a polyethylene bottle. One litre of this solution contains2000mg of K. Alternatively, use

27、a commercially available, readymade solution. 4.6 Sodium/potassium, standard solution Pipette10ml of the sodium stock solution (4.4) and the potassium stock solution (4.5) into a1000ml one-mark volumetric flask. Make up to the mark with water. The solution shall be prepared freshly when required. 1m

28、l of this standard solution contains204g of Na and204g of K.ISO9964-3:1993(E) 2 BSI 07-1999 5 Apparatus Ordinary laboratory apparatus and 5.1 Flame photometer, equipped with an appropriate interference filter for the determination of sodium and potassium, or Atomic absorption spectrometer, in the em

29、ission mode, set up and operated according to the manufacturers instructions. 5.2 Glassware and polyethylene ware Clean both glass and polyethylene ware by soaking in an aqueous solution of10% (V/V) of nitric acid (4.2) followed by thorough rinsing with deionized water. The apparatus should only be

30、used for this method. 6 Sampling Collect samples in clean polyethylene bottles (See ISO5667-1 and ISO5667-2). Sample preservation by acidification is not necessary. NOTE 2If other metal analyses are to be carried out on the samples, the sample can be preserved using hydrochloric acid(4.1) or nitric

31、acid (4.2) to give a pH of approximately1. All samples, standards and blanks should contain the same concentration and the same type of acid. 7 Procedure 7.1 Preparation of test samples for presentation to the instrument 7.1.1 Filter samples containing particulate matter through an acid-washed filte

32、r of pore size0,454m. (The acid used for washing the filter should have the same concentration and be of the same type as the acid used in the sample preparation.) NOTE 3Instead of filtration, the particulate matter may be removed from suspension by using a centrifuge. 7.1.2 Take a number of50ml one

33、-mark volumetric flasks according to the number of samples being analysed. To each of these flasks, add up to40ml of the test sample and5ml of the caesium chloride solution (4.3). Make up to the mark with water. 7.2 Preparation of the set of calibration solutions Pipette0ml;1,0ml;2,5ml;5ml;10ml;15ml

34、; 20ml and25ml of the sodium/potassium standard solution (4.6) and5ml of the caesium chloride solution (4.3) into a series of50ml one-mark volumetric flasks and make up each flask to the mark with water. The calibration solutions will have the concentration0mg/l;0,4mg/l;1,0mg/l; 2,0mg/l;4,0mg/l;6,0m

35、g/l;8,0mg/l and 10,0mg/l of Na and K, respectively. NOTE 4Addition of the caesium chloride solution (4.3) can be omitted for the test samples (7.1) and the calibration solutions(7.2) if flames other than an air/acetylene flame are used. 7.3 Calibration and determination 7.3.1 Set up the spectrometer

36、/photometer according to the manufacturers instructions. Fit the appropriate filter for the metal being measured. Aspirate the calibration solution (7.2). Optimize the aspiration and flame conditions (aspiration rate, nature of the flame). 7.3.1.1 For flame photometer. Aspirate water and adjust the

37、scale reading to zero deflection(0%reading). Aspirate the10mg/l calibration solution (see7.2) and adjust the scale reading to full deflection (100%) reading). Repeat the aspiration of water and the10mg/l calibration solution until the0% and100% readings, respectively, are obtained without the need o

38、f further adjustment. 7.3.1.2 For atomic absorption spectrometer in the emission mode. Aspirate water and adjust the response for the instrument to zero absorbance. 7.3.2 Aspirate the calibration solutions (7.2) with an aspiration of water between each. Measure the instrument response of each soluti

39、on (at a wavelength of589,0nm for sodium and at766,5nm for potassium) using the spectrometer. Prepare calibration graphs for sodium and potassium by plotting the appropriate instrument response on the ordinate against the mass concentrations of sodium and potassium on the abscissa. Calculate from th

40、e graph the slope, b, in litres per milligram. NOTE 5The calibration graph is normally linear up to10mg/l but can show a slight curvature, especially when a flame emission spectrometer is used. 7.3.3 Aspirate the test samples (7.1) with an aspiration of water between each, and measure the instrument

41、 response. 7.3.4 Carry out a blank determination with each batch of samples by applying the same procedure and using water instead of the sample. NOTE 6It is good practice to check the slope of calibration graphs at regular intervals (e.g.every10 samples). 8 Calculation and expression of results 8.1

42、 Use of calibration graph Read the concentrations of sodium and potassium in the test solutions from the calibration graph (see7.3.2). From these values, calculate the sodium and potassium concentration of the test sample, taking into account the volume of the test sample taken (normally40ml) and th

43、e total volume of the volumetric flask (50ml).ISO9964-3:1993(E) BSI 07-1999 3 8.2 Method of calculation If the calibration graph is linear, calculate the mass concentrations of sodium, Na , and potassium, K , in the sample, in milligrams per litre, using the equations If required, calculate the amou

44、nt of substance concentrations, c Naand c K , in millimoles per litre, using the equations 8.3 Precision An interlaboratory trial, carried out in spring1992, produced the results given in Table 1. 9 Test report The test report shall include the following information: a) a reference to this Internati

45、onal Standard; b) precise identification of the water sample; c) the results and the method of expression used, in accordance with clause8; d) any deviation from this method or any other circumstances which may have influenced the results. Table 1 Precision data . . . (1) . . . (2) where R is the re

46、sponse of the sample; R 0 is the response of the blank; V m is the volume, in millilitres, of the test portion (normally40ml); V p is the volume, in millilitres, of the volumetric flask (50ml); b is the slope of the calibration graph, in litres per milligram. Na R Na R 0 ()V m V p b - = K R K R 0 ()

47、V m V p b - = . . . (3) . . . (4) c Na Na 23,0 - = c K K 391 , - = Sample a l n n a % mg/l r mg/l VC r % R mg/l VC R % Sodium A B C 7 7 7 21 21 21 0 0 0 4,38 63,1 87,0 0,396 1,539 2,843 9,0 2,4 3,3 0,080 0,568 0,363 1,8 0,9 0,4 Potassium A B C 7 7 7 18 21 18 0 0 14 0,37 5,28 15,1 0,092 0,213 0,296 2

48、4,9 4,0 2,0 0,052 0,040 0,149 14,0 0,8 1,0 lis the number of laboratories nis the number of values n a is the percentage of outliers is the mean value r is the repeatability standard deviation VC r is the repeatability variation coefficient R is the reproducibility standard deviation VC R is the rep

49、roducibility variation coefficient a A: drinking water B: river water C: municipal waste water x xISO9964-3:1993(E) 4 BSI 07-1999 Annex A (informative) Bibliography Standard methods for the examination of water and waste water (1985). American Public Health Association (16th edition), Washington, D.C. Dissolved Sodium in Raw and Potable Waters. Tentative methods. Department of the Environme