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1、BRITISH STANDARD BS EN ISO 11969:1996 BS 6068-2.55: 1996 Water quality Determination of arsenic Atomic absorption spectrometric method (hydride technique) The European Standard EN ISO 11969:1996 has the status of a British Standard ICS 13.060 Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 01
2、:41:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 11969:1996 This British Standard, having been prepared under the direction of the Health and Environment Sector Board, was published under the authority of the Standards Board and comes into effect on 15 November 1996 BSI 10-1998 The follow
3、ing BSI references relate to the work on this standard: Committee reference EH/3/2 Draft for comment 94/502109 DC ISBN 0 580 26097 6 Committees responsible for this British Standard The preparation of this British Standard was entrusted by Technical Committee EH/3, Water quality, to Subcommittee EH/
4、3/2, Physical, chemical and biochemical methods, upon which the following bodies were represented: British Agrochemicals Association Ltd. British Ceramic Research British Gas plc British Soft Drinks Association Ltd. Chemical Industries Association Convention of Scottish Local Authorities Department
5、of the Environment (Her Majestys Inspectorate of Pollution) Department of the Environment (Water Directorate) Department of Trade and Industry (Laboratory of the Government Chemist) GAMBICA (BEAMA) Ltd. Industrial Water Society National Rivers Authority Royal Society of Chemistry Soap and Detergent
6、Industry Association Society of Chemical Industry Swimming Pool and Allied Trades Association Ltd. Water Companies Association Water Research Centre Water Services Association of England and Wales Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Sa
7、t Nov 18 01:41:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 11969:1996 BSI 10-1998i Contents Page Committees responsibleInside front cover National forewordii Foreword2 1Scope3 2Normative references3 3Principle3 4Reagents3 5Apparatus4 6Sampling4 7Interferences4 8Procedure4 9Calculation of
8、 the results using the standard calibration method5 10Expression of results6 11Precision6 12Test report6 Annex A (informative) Effect of other substances on the determination of arsenic7 Annex B (informative) Precision data8 Figure 1 Example of decomposition apparatus6 List of referencesInside back
9、cover Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 01:41:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 11969:1996 ii BSI 10-1998 National foreword This British Standard has been prepared by Subcommittee EH/3/2. It is the English language version of EN ISO 11969:1996 Water quality
10、 Determination of arsenic Atomic absorption spectrometric method (hydride technique) published by the European Committee for Standardization (CEN). It is identical with ISO 11969:1996 published by the International Organization for Standardization (ISO). NOTEThe tests described in this British Stand
11、ard should only be carried out by suitably qualified persons with an appropriate level of chemical expertise. Standard chemical procedures should be followed throughout. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsi
12、ble for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references Publication referred toCorresponding British Standard BS EN 25667 Water quality. Sampling ISO 5667-1:1980Part 1:1994 Guidance on the design of sampling pr
13、ogrammes ISO 5667-2:1991Part 2:1993 Guidance on sampling techniques ISO 5667-3:1994BS 6068 Water quality Part 6: Sampling Section 6.3:1996 Guidance on the preservation and handling of samples Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN ISO ti
14、tle 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 amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 01:41:16 GMT+00
15、:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 11969 July 1996 ICS: 13.060.00 Descriptors: Water, quality, water pollution, water tests, chemical analysis, determination of content, arsenic, atomic absorption spectrometric method. English version Water
16、quality Determination of arsenic Atomic absorption spectrometric method (hydride technique) (ISO 11969:1996) Qualit de leau Dosage de larsenic Mthode par spectromtrie dabsorption atomique (technique hydrure) (ISO 11969:1996) Wasserbeschaffenheit Bestimmung von Arsen Atomabsorptionspektrometrie (Hydr
17、idverfahren) (ISO 11969:1996) This European Standard was approved by CEN on 1996-06-28. 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 list
18、s and 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 respon
19、sibility 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,
20、 Portugal, 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 1996 Copyright reserved to CEN members Ref. No. EN ISO 11969:1996 E Licensed Cop
21、y: sheffieldun sheffieldun, na, Sat Nov 18 01:41:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 11969:1996 BSI 10-1998 2 Foreword The text of the International Standard ISO 11969:1996 has been prepared by Technical Committee ISO/TC 147, Water quality, in collaboration with Technical Committee
22、CEN/TC 230, Water analysis, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 1997 and conflicting national standards shall be withdrawn at the lates
23、t by January 1997. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway,
24、Portugal, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 01:41:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 11969:1996 BSI 10-19983 WARNING Arsenic and arsenic compounds are toxic and are recognized as human carcinogens. Avoid any exposu
25、re by inhalation. Personal protection must be used in all cases where exposure to arsenic or arsenic compounds is possible. 1 Scope This International Standard specifies a method for the determination of arsenic including organically bound arsenic in drinking waters, ground waters and surface waters
26、, in a concentration range from 1 g/l to 10 g/l. Higher concentrations can be determined by using a suitable dilution of the water sample. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At
27、 the time of publication, the editions indicated 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 I
28、SO maintain registers of currently valid International Standards. ISO 5667-1:1980, Water quality Sampling Part 1: Guidance on the design of sampling programmes. ISO 5667-2:1991, Water quality Sampling Part 2: Guidance on sampling techniques. ISO 5667-3:1994, Water quality Sampling Part 3: Guidance o
29、n the preservation and handling of samples. 3 Principle The method is based on the atomic absorption measurement of arsenic generated by the thermal decomposition of arsenic(III) hydride. Under the conditions of this method, only As(III) is quantitatively converted to the hydride. To avoid errors in
30、 determination, other oxidation states need to be converted to As(III) prior to the determination. As(III) is reduced to gaseous arsenic(III) hydride (AsH3) by reaction with sodium tetrahydroborate in a hydrochloric acid medium. The absorbance is determined at a wavelength of 193,7 nm. 4 Reagents Du
31、ring the analysis, use only reagents of recognized analytical grade. The arsenic content of the water and the reagents shall be negligible, compared with the lowest concentration to be determined. 4.1 Sulfuric acid (H2SO4), r = 1,84 g/ml. 4.2 Hydrochloric acid (HCl), r = 1,15 g/ml. 4.3 Hydrogen pero
32、xide (H2O2), w = 30 % (m/m). 4.4 Sodium hydroxide (NaOH). 4.5 Sodium tetrahydroborate solution Dissolve 1 g of sodium hydroxide (4.4) in about 20 ml of water. Add 3 g of sodium tetrahydroborate (NaBH4). Dilute to 100 ml with water. Prepare the solution on the day of use. NOTE 1For flow-through syste
33、ms, it is recommended to follow the instructions of the manufacturer. A solution containing 0,5 % of sodium tetrahydroborate and 0,5 % of sodium hydroxide is suitable. This solution is stable for at least one week. 4.6 Potassium iodide-ascorbic acid solution Dissolve 3 g of potassium iodide (KI) and
34、 5 g of L(+)ascorbic acid (C6H8O6) in 100 ml of water. Prepare the solution on the day of use. NOTE 2It is unnecessary to use ascorbic acid if a 20 % solution of potassium iodide is used. 4.7 Arsenic stock solution, corresponding to 1 000 mg of As per litre. Place 1,320 g of arsenic(III) oxide (As2O
35、3), in a volumetric flask of nominal capacity 1 000 ml. Add 2 g of sodium hydroxide (4.4) and dissolve in a small quantity of water. Dilute to volume with water. This solution is stable for at least 1 year. Arsenic stock solutions are commercially available. If the stock solution contains As(V), the
36、 standard solutions shall be treated in the same way as the sample for the reduction step (8.3.2). 4.8 Arsenic standard solution 1, corresponding to 10 mg of As per litre. Pipette 10 ml of arsenic stock solution (4.7) into a volumetric flask of nominal capacity 1 000 ml. Add 20 ml of hydrochloric ac
37、id (4.2) and dilute to volume with water. The solution is stable for about 1 month. If a stock solution of arsenic(V) is used, arsenic(V) shall be reduced to arsenic(III) according to 8.3.2, before dilution to 1 000 ml. Licensed Copy: sheffieldun sheffieldun, na, Sat Nov 18 01:41:16 GMT+00:00 2006,
38、Uncontrolled Copy, (c) BSI EN ISO 11969:1996 4 BSI 10-1998 4.9 Arsenic standard solution 2, corresponding to 0,1 mg of As per litre. Pipette 10 ml of arsenic standard solution 1 (4.8) into a volumetric flask of nominal capacity 1 000 ml. Add 20 ml of hydrochloric acid (4.2) and dilute to volume with
39、 water. Prepare the solution on the day of use. 5 Apparatus Usual laboratory apparatus and 5.1 Atomic absorption spectrometer, fitted with a hydride system, and a suitable radiation source for the determination of arsenic, for example electrodeless discharge lamp or a hollow cathode lamp with a back
40、ground correction facility, if necessary. 5.2 Gas supply, with argon or nitrogen. 5.3 Glassware, to be cleaned immediately before use with warm, dilute nitric acid 10 % (V/V) and rinsed with water. 6 Sampling Take samples according to ISO 5667-1 and ISO 5667-2. Collect samples in polyethylene or bor
41、osilicate glass containers which have been previously cleaned with nitric acid e.g. 10 % (V/V) and then rinsed with water. On site, add 20 ml of hydrochloric acid (4.2) to each 1 000 ml of the water sample. If the pH of the sample is still greater than 2, add more hydrochloric acid until the pH is 2
42、 or less. For sample conservation, see ISO 5667-3. 7 Interferences Most organic materials interfere with the arsenic determination. They shall be removed prior to the analysis by the digestion procedure described in 8.3.1. Samples forming foams when tetrahydroborate is added shall be pretreated (e.g
43、. with an anti-foaming agent or by complete digestion). When an anti-foaming agent is added, it is also necessary to add it to the blank and calibration solutions. Annex A gives details of the effect of potential interfering substances on the determination of arsenic. These results were obtained at
44、the Laboratory of the Government Chemist (UK). Of the substances tested, only concentrations of copper greater than 2,0 mg/l, antimony greater than 0,2 mg/l, selenium greater than 0,05 mg/l and nitrate greater than 100 mg/l interfere at arsenic concentration levels of 1,0 g/l. The noble metals, for
45、example platinium and palladium, may supress the response of the arsenic(III) hydride. 8 Procedure 8.1 Blank solution Pipette 2 ml of hydrochloric acid (4.2) into a volumetric flask of nominal capacity 100 ml and dilute to volume with water. Treat the blank in exactly the same way as the sample. 8.2
46、 Calibration solutions Using arsenic standard solution 2 (4.9), prepare at least five calibration solutions covering the expected working range. For example, for the range 1 g/l to 10 g/l, pipette 1 ml, 3 ml, 5 ml, 8 ml and 10 ml of arsenic standard solution 2 into a series of 100 ml volumetric flas
47、ks. To each of these flasks, add 2 ml of hydrochloric acid (4.2) and dilute to volume with water. These solutions correspond to arsenic concentrations of 1 g/l, 3 g/l, 5 g/l, 8 g/l and 10 g/l, respectively. Prepare the calibration solutions daily. Treat the calibration solutions in exactly the same
48、way as the sample. 8.3 Pretreatment Most of the organically bound arsenic compounds are decomposed by the digestion procedure described in 8.3.1. If it is known that the sample to be analysed does not contain organic arsenic compounds, it is permissible to omit the digestion process. In this case, p
49、roceed to 8.3.2. Place 50 ml of the sample (see clause 6) in a round-bottomed flask (see example in Figure 1). 8.3.1 Method of digestion WARNING Fumes produced by heating concentrated sulfuric acid are irritant and this operation must therefore be carried out in a fume chamber. Add 5 ml of sulfuric acid (4.1) and 5 ml of hydrogen peroxide (4.3) to the round-bottomed flask (see 8.3). Add some anti-bumping beads and connect the flask to the apparatus as shown in Figure 1. Heat the contents of the flask to boiling an