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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 12338:1998 The Euro
2、pean Standard EN 12338:1998 has the status of a British Standard ICS 13.060.01 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Water quality Determination of mercury Enrichment methods by amalgamation Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 14:51:03 GMT+00:00 20
3、06, Uncontrolled Copy, (c) BSI BS EN 12338:1998 This British Standard, having been prepared under the direction of the Health and Environment Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 December 1998 BSI 1998 ISBN 0 580 30251 2 Amendment
4、s issued since publication Amd. No.DateText affected National foreword This British Standard is the English language version of EN 12338:1998. The UK participation in its preparation was entrusted by Technical Committee EH/3, Water quality, to Subcommittee EH/3/2, Physical, chemical and biochemical
5、analysis, which has the responsibility to: aid enquirers to understand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them
6、 in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. It is essential that users evaluate this standard in their own laboratories and demonstrate its fitness for purpose. The provisions of this standard allow alternative procedures (for exa
7、mple, those described in the annexes) to be carried out in place of those specified in the standard. Alternative procedures should be used only where it can be demonstrated that performance data generated using these procedures is equivalent to, or better than, the performance data given obtained us
8、ing the procedures described in this standard. Appropriate calculations, using procedures given in BS 5497-1, should be used. When comparing the performance data obtained using the alternative procedures with those obtained using procedures given in this standard, appropriate calculations, using pro
9、cedures given in BS 2846-4, should be used. NOTEThe tests described in this British Standard should only be carried out by suitably qualified persons with an appropriate level of chemical expertise. Standard chemical procedures should be followed throughout. Cross-references The British Standards wh
10、ich implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled International Standards Correspondence Index, or by using the Find facility of the BSI Standards Electronic Catalogue. A British Standard does not
11、purport to include all the necessary 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. This document comprises a front cover, an inside front cover, the EN
12、title page, pages 2 to 14, an inside back cover and a back cover. Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 14:51:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI CEN European Committee for Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secreta
13、riat: rue de Stassart 36, B-1050 Brussels 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12338:1998 E EUROPEAN STANDARDEN 12338 NORME EUROPE ENNE EUROPA ISCHE NORM July 1998 ICS 13.060.01 Descriptors: water tests, surface wat
14、er, ground water, sewage, chemical analysis, determination of content, mercury, reduction methods, sodium tetraborate, tin chloride English version Water quality Determination of mercury Enrichment methods by amalgamation Qualite de leau Dosage du mercure Me thodes apre s denrichissement par amalgam
15、e Wasserbeschaffenheit Bestimmung von Quecksilber Verfahren nach Anreicherung durch Amalgamierung This European Standard was approved by CEN on 21 June 1998. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the
16、 status of a national standard without any alteration. Up-to-date lists 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)
17、. A version in any other language made by translation under the responsibility 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, Czech Republic, Denmark, Finla
18、nd, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 14:51:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 2 EN 12338:1998 BSI 1998 Foreword This Europ
19、ean Standard has been prepared by Technical Committee 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 1999, and conflic
20、ting national standards shall be withdrawn at the latest by January 1999. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germ
21、any, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Annexes designated informative are only given for information. In this standard annexes A, B, C and D are informative. Contents Page Foreword2 Introduction3 1Scope3 2No
22、rmative references3 3General interferences3 4Determination of mercury after tin(II) chloride reduction and enrichment by amalgamation4 4.1Working range4 4.2Principle4 4.3Interferences4 4.4Reagents4 4.5Apparatus5 4.6Sampling and sample pretreatment6 4.7Digestion method using permanganate peroxodisulf
23、ate6 4.8Procedure7 4.9Calculation7 4.10 Expression of results8 4.11 Test report8 5Determination of mercury after sodium tetrahydroborate reduction and enrichment by amalgamation8 5.1Working range8 5.2Principle8 5.3Interferences8 5.4Reagents8 5.5Apparatus8 5.6Sampling and sample pretreatment9 5.7Dige
24、stion method9 5.8Procedure9 5.9Calculation9 5.10 Expression of results9 5.11 Test report9 6Precision data11 Annex A (informative) Ultrasonic digestion method13 Annex B (informative) Autoclave digestion method13 Annex C (informative) Microwave digestion method13 Annex D (informative) Bibliography14 L
25、icensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 14:51:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 3 EN 12338:1998 BSI 1998 Introduction It should be investigated whether and to what extent particular problems will require the specification of additional marginal conditions. It is absolu
26、tely essential that tests conducted according to this standard are carried out by suitably qualified staff. In natural water sources, mercury compounds generally occur only in very small concentrations of less than 0,1 mg/l. Higher concentrations may be found, for example, in waste water. Both inorg
27、anic and organic compounds of mercury can be present. Mercury may accumulate in sediment and sludge. WARNING: Mercury and mercury compounds are very toxic. Extreme caution is recommended when handling samples and solutions which contain or may contain mercury. 1 Scope This European Standard specifie
28、s the determination of mercury in two parts which use either tin(II) chloride or sodium tetrahydroborate as reducing agent. The methods described in clauses 4 and 5 are suitable for the determination of mercury in water, for example in ground, surface and waste waters, in the concentration range fro
29、m 0,01 mg/l to 1 mg/l. Higher concentrations may be determined if the water sample is diluted. The total mercury content of water is determined after digestion of the sample. If only soluble mercury compounds are to be determined, a filtration step using a 0,45 mm membrane filter is applied prior to
30、 digestion. Mono- or divalent mercury is reduced to the elemental form by a reducing agent such as tin(II) chloride, SnCl2, or sodium tetrahydroborate, NaBH4, in an acid medium. Elemental mercury is then stripped from the solution with the aid of a stream of inert gas and transported over a noble me
31、tal surface with a large area, such as gold/platinum gauze, on which the mercury is adsorbed. The mercury is released by rapid heating of the adsorbant and further transported in a stream of carrier gas to a suitable cuvette. Absorbances are measured at a wavelength of 253,7 nm in the radiation beam
32、 of an atomic absorption spectrometer. Concentrations are calculated using a calibration curve. In order to fully decompose all of the mercury compounds, a digestion procedure is required. Digestion can be omitted only if it is certain that the mercury concentration may be measured without this pret
33、reatment. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to
34、 or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 25667-1:1993, Water quality Sampling Part 1: Guidance on the design of sampling progr
35、ammes. (ISO 5667-1:1980) EN 25667-2:1993, Water quality Sampling Part 2: Guidance on sampling techniques. (ISO 5667-2:1991) EN ISO 5667-3:1995, Water quality Sampling Part 3: Guidance on the preservation and handling of samples. (ISO 5667-3:1994) 3 General interferences With mercury there is a risk
36、that exchange reactions, that is adsorption and desorption, will occur on the walls of the reaction vessel. The description in 4.6 should therefore be followed exactly. Mercury vapour can diffuse through various plastics, therefore, special consideration should be given to the choice of tubing mater
37、ial. Glass or special plastics tubing, e.g. FEP tubes may be used (FEP = perfluoroethenepropene polymer). Silicone tubing, for example, is unsuitable. Volatile organic substances can absorb in the UV range and be mistaken for mercury. They are in most cases destroyed by adding potassium permanganate
38、 until the solution is permanently coloured red and removed by purging for 10 min with an inert gas, prior to reduction of the mercury compounds. Often, such interference by non-specific absorption can also be eliminated using a background compensation system. All solutions should be brought to the
39、same temperature ( 0,1 mg/l causes interference with the determination due to the formation of mercury complexes. In this case use another method such as reduction with sodium tetrahydroborate (see clause 5). Because of the reduction potential of the tin(II) chloride solution, various inorganic merc
40、ury compounds such as mercury sulfide and organic mercury compounds cannot be fully reduced without digestion. 4.4 Reagents 4.4.1 General requirements At least analytical grade reagents or those with lowest possible mercury content shall be used. Water shall be double distilled or of similar purity.
41、 The mercury content of the water and reagents shall be negligible compared to the lowest analyte concentration. 4.4.2 Nitric acid, r(HNO3) = 1,40 g/ml. 4.4.3 Sulfuric acid, r(H2SO4) = 1,84 g/ml. 4.4.4 Hydrochloric acid, r(HCl) = 1,16 g/ml. 4.4.5 Potassium permanganate solution. Dissolve 50 g of pot
42、assium permanganate, KMnO4, in 1 000 ml of water. 4.4.6 Stabilizer solution. Dissolve 5 g of potassium dichromate, K2Cr207, in 500 ml of nitric acid (see 4.4.2) and dilute to 1 000 ml with water. WARNING: Potassium dichromate is toxic. Caution should be exercised when handling the solid material or
43、its solutions. 4.4.7 Potassium peroxodisulfate solution. Dissolve 40 g of potassium peroxodisulfate, K2S2O8, in 1 000 ml of water. 4.4.8 Hydroxylammonium chloride solution. Dissolve 10 g of hydroxylammonium chloride, H4ClNO, in 100 ml of water. 4.4.9 Tin(II) chloride solution. Dissolve 5 g of tin(II
44、) chloride dihydrate, SnCl2 2 H2O, in 30 ml of hydrochloric acid (see 4.4.4), dilute to 100 ml with water. A solution of smaller concentration, e.g. 0,5 g in 100 ml, may be used with flow systems. Prepare this solution freshly daily from the more concentrated solution by diluting with water. If a hi
45、gh result for the blank is obtained, pass nitrogen through the solution for 30 min in order to remove traces of mercury. 4.4.10 Mercury stock solution I, r(Hg) = 100 mg/l. Dissolve 108,0 mg of mercury(II) oxide, HgO, in 10 ml of the stabilizer (see 4.4.6), dilute to 1 000 ml with water. 1 ml of the
46、solution corresponds to 0,1 mg of mercury. Stock solution I may be prepared from a commercially available mercury standard. The solution is stable for about 1 month. 4.4.11 Mercury stock solution II, r(Hg) = 1 mg/l. Add 10 ml of stabilizer (see 4.4.6) to 10 ml of stock solution I (see 4.4.10) and di
47、lute to 1 000 ml with water. 1 ml of this solution corresponds to 1 mg of mercury. The solution is stable for about 1 week. Licensed Copy: sheffieldun sheffieldun, na, Sat Oct 28 14:51:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Page 5 EN 12338:1998 BSI 1998 4.4.12 Mercury standard solution I, r(H
48、g) = 100 mg/l. Add 10 ml of stabilizer (see 4.4.6) to 100 ml of mercury stock solution II (see 4.4.11) and dilute to 1 000 ml with water. 1 ml of this solution corresponds to 100 ng of mercury. Prepare the solution on the day of use. 4.4.13 Mercury standard solution II, r(Hg) = 10 mg/l. Dilute 1 ml
49、of stabilizer solution (see 4.4.6) and 10 ml of standard solution I (see 4.4.12) to 100 ml with water. 1 ml of this solution corresponds to 10 ng of mercury. The solution is stable only a short time and shall be freshly prepared before use. 4.4.14 Mercury standard solution III, r(Hg) = 1 mg/l. Dilute 1 ml of stabilizer solution (see 4.4.6) and 10 ml of standard solution II (see 4.4.13) to 100 ml with water. 1 ml of this solution corresponds to 1 ng of mercury. The solution shall be freshly prepared before each series of measuremen