1、BRITISH STANDARD BS EN ISO 5961:1995 BS 6068-2.21: 1995 Water quality Determination of cadmium by atomic absorption spectrometry The European Standard EN ISO 5961:1995 has the status of a British StandardBS EN ISO5961:1995 This British Standard, having been prepared under the directionof the Health
2、and Environment Sector Board, waspublished under the authorityof the Standards Boardand comes into effect on 15September1995 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference EPC/44 Draft for public comment 92/56850 DC ISBN 0 580 24116 5 Committees res
3、ponsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee EPC/44, Water quality, upon which the following bodies were represented: Association of Consulting Scientists British Association for Chemical Specialities British Gas plc Chemical Indust
4、ries Association Convention of Scottish Local Authorities Department of Trade and Industry (Laboratory of the Government Chemist) Department of Economic Development (Northern Ireland) Department of the Environment for Northern Ireland Department of the Environment (Water Directorate) Electricity Ass
5、ociation Industrial Water Society Institution 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 of Chemistry Scottish Association of Directors of Water and Sewerage Ser
6、vices Soap and Detergent Industry Association Society of Chemical Industry Water Companies Association Water Research Centre Water Services Association of England and Wales Amendments issued since publication Amd. No. Date CommentsBS EN ISO5961:1995 BSI 08-1999 i Contents Page Committees responsible
7、 Inside front cover National foreword ii Foreword 2 Section 1. General 1.1 Scope 3 1.2 Normative reference 3 Section 2. Determination of cadmium using atomic absorption spectrometry in air-acetylene flame 2.1 Interferences 4 2.2 Principle 4 2.3 Reagents 4 2.4 Apparatus 4 2.5 Sampling and sample pret
8、reatment 5 2.6 Procedure 5 2.7 Evaluation 6 2.8 Test report 6 2.9 Precision 7 Section 3. Determination of cadmium by electrothermal atomization atomic absorption spectrometry 3.1 Interferences 8 3.2 Principle 8 3.3 Reagents 8 3.4 Apparatus 9 3.5 Sampling and sample pretreatment 9 3.6 Procedure 9 3.7
9、 Determination 10 3.8 Expression of results 10 3.9 Test report 10 3.10 Precision 10 Annex A (informative) Bibliography 11 Table 1 Precision data 7 List of references Inside back coverBS EN ISO5961:1995 ii BSI 08-1999 National foreword This British Standard has been prepared by Technical Committee EP
10、C/44, Water quality, and is the English language version of EN ISO5961:1995 Water quality Determination of cadmium by atomic absorption spectrometry, published by the European Committee for Standardization (CEN). It is identical with ISO5961:1994, published by the International Organization for Stan
11、dardization (ISO). This standard supersedes BS6068-2.21:1985, which is withdrawn. 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 Standard does not of itself
12、 confer immunity from legal obligations. Cross-references Publication referred to Corresponding British Standard BS 6068 Water quality Part 6 Sampling ISO 5667-3:1985 Section 6.3:1986 Guidance on the preservation and handling of samples Summary of pages This document comprises a front cover, an insi
13、de front cover, pages i and ii, the EN ISO title page, pages 2 to 12, 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.EUROPEAN STANDARD NORME E
14、UROPENNE EUROPISCHE NORM EN ISO 5961 March 1995 ICS 13.060.40 Descriptors: Water, quality, water tests, chemical analysis, determination of content, cadmium, atomic absorption spectrometric method English version Water quality Determination of cadmium by atomic absorption spectrometry (ISO 5961:1994
15、) Qualit de leau Dosage du cadmium par spectromtrie dabsorption atomique (ISO 5961:1994) Bestimmung von Cadmium durch Atomabsorptionsspektrometrie (ISO 5961:1994) This European Standard was approved by CEN on1994-11-14. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
16、stipulate the conditions for giving this European Standard the 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 Standa
17、rd exists in three official versions (English, French, German). 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 standa
18、rds bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Centr
19、al Secretariat: rue de Stassart 36, B-1050 Brussels 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to CEN and its members. Ref. No. EN ISO 5961:1995 EEN ISO5961:1995 BSI 08-1999 2 Foreword This European Standard has been taken over by the Tec
20、hnical Committee CEN/TC230, Water analysis, from the work of ISO/TC147, Water quality, of the International Organization for Standardization (ISO). This European Standard shall be given the status of a national standard, either by publication of an identical text or by endoresement, at the latest by
21、 September and conflicting national standards shall be withdrawn at the latest by September. According to the CEN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,
22、 Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EN ISO5961:1995 BSI 08-1999 3 Section 1. General 1.1 Scope This International Standard specifies two methods for the determination of cadmium: flame atomic absorption spectrometry (AAS) (Section2) and electroth
23、ermal atomization (AAS) (Section3). 1.1.1 Determination of cadmium using AAS in an air-acetylene flame The method is applicable to the analysis of water and waste water when the concentration of cadmium is between0,05mg/l and1mg/l. Highest concentrations can be determined after dilution of the sampl
24、e. The range of application of the method can be extended to lower concentrations by carefully evaporating the water sample, previously acidified with nitric acid. Cadmium can be determined in sludges and sediments after an appropriate digestion procedure avoiding the formation of a precipitate. 1.1
25、.2 Determination of cadmium by electrothermal atomization AAS The method is suitable for.the determination of cadmium in water when, with a dosing volume of104l, the concentration range is0,34g/l to34g/l. The range of application of the method can be extended to higher concentrations by diluting the
26、 water sample or by the use of smaller dosing volumes. Cadmium can be determined in sludges and sediments after an appropriate digestion procedure. 1.2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this International St
27、andard. At the time of publication, the edition indicated was 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 edition of the standard indicated below. Members of IEC
28、 and ISO maintain registers of currently valid International Standards. ISO 5667-3:, Water quality Sampling Part3:Guidance on the preservation and handling of samples 1) . 1) To be published. (Revision of ISO5667-3:1985)EN ISO5961:1995 4 BSI 08-1999 Section 2. Determination of cadmium using atomic a
29、bsorption spectrometry in an air-acetylene flame 2.1 Interferences The following ions will not interfere with the method as long as the mass concentrations specified below are not exceeded: The total salt content of the measuring solution shall be less than15g/l and the electrical conductivity shall
30、 be lower than20000mS/m. Samples of unpredictable matrix effects shall be examined appropriately. This influence shall be compensated for either by diluting the sample or by applying the method of standard additions (see3.6.2.2). 2.2 Principle Aspiration of the acidified sample into the air-acetylen
31、e flame of an atomic absorption spectrometer. Measurement of the cadmium concentration at a wavelength of228,8nm. 2.3 Reagents Use only reagents of recognized analytical grade and only distilled water or water of equivalent purity. The cadmium content of water used for blank determinations and for t
32、he preparation of standard solutions shall be negligibly low compared with the lowest mass concentration to be determined in the sample. 2.3.1 Nitric acid, = 1,40 g/ml. 2.3.2 Hydrogen peroxide, w(H 2 O 2 ) = 30% (m/m). 2.3.3 Cadmium stock solution l, (Cd) = 1000 mg/l. Dissolve 1,000g 0,002g of cadmi
33、um in10ml of nitric acid (2.3.1) and10ml of water (see2.3) in a1000ml one-mark volumetric flask. Dilute to volume with water. Store the solution in polyethylene or borosilicate glass containers. The solution is stable for1 year. Alternatively, use any commercially available stock solution containing
34、1,000g/l 0,002g/l of cadmium. 2.3.4 Cadmium standard solution l, (Cd) = 10mg/l. Pipette 10ml of the cadmium stock solution (2.3.3) into a1000ml one-mark volumetric flask, add10ml of nitric acid (2.3.1) and dilute to volume with water. Store the solution in polyethylene or borosilicate glass containe
35、rs. The solution is stable for at least one month if stored at room temperature. NOTE 1The use of a microlitre pipette permits a standard solution of100ml to be prepared. 2.3.5 Cadmium calibration solutions Prepare a minimum of five calibration solutions in accordance with the expected cadmium conce
36、ntrations. As an example, proceed as follows for the range from0,05mg/l to1,0mg/l: Pipette 0,5ml; 2,0ml; 4,0ml; 6,0ml; 8,0ml and10,0ml respectively of the cadmium standard solution (2.3.4) into100ml one-mark volumetric flasks. Add 1ml of nitric acid (2.3.1) to each of these solutions. Dilute to volu
37、me with water and mix. The calibration solutions contain0,05mg/l; 0,2mg/l; 0,4mg/l; 0,6mg/l; 0,8mg/l and1,0mg/l of cadmium respectively. 2.3.6 Blank test solution Pipette 1ml of nitric acid (2.3.1) into a100ml one-mark volumetric flask, and dilute to volume with water (2.3.4). If the sample requires
38、 a pretreatment by digestion, the blank shall be given the same pretreatment (see2.5.2). 2.3.7 Solution for zero-setting the instrument Use water (2.3.4) as a zero-setting solution. The blank solution (2.3.6) may also serve for zero-setting provided its cadmium concentration is negligibly low. 2.4 A
39、pparatus Immediately before use, clean the glassware with warm, dilute nitric acid, approximately2mol/l (e.g. by soaking for24h), followed by a thorough rinsing with water (2.3). Verify that each lot of pipette tips and single-use plastics vessels is free from potential cadmium contamination by carr
40、ying out blank measurements (see2.6.1). Usual laboratory apparatus and Sulfate 10 000 mg/l Chloride 10 000 mg/l Phosphate 10 000 mg/l Sodium 10 000 mg/l Potassium 10 000 mg/l Magnesium 10 000 mg/l Calcium 3 000 mg/l Iron 3 000 mg/l Copper 10 000 mg/l Nickel 3 000 mg/l Cobalt 10 000 mg/l Lead 10 000
41、mg/l Silicon 1 000 mg/l Titanium 3 000 mg/lEN ISO5961:1995 BSI 08-1999 5 2.4.1 Atomic absorption spectrometer, equipped with background correction and a radiation source for the determination of cadmium, operated according to the manufacturers instructions. 2.4.2 Gas supply for air and acetylene. It
42、 is essential that the manufacturers safety instructions be observed. The residual gas pressure for acetylene cylinders shall be at least5 10 5 Pa. 2.4.3 Air-acetylene burner 2.4.4 One-mark volumetric flasks of capacity10ml, 100ml and1000ml. 2.4.5 One-mark pipettes, of nominal capacity1ml,2ml, 3ml,
43、4ml, 5ml, 6ml, 8ml, 10ml, 20ml, 30ml and 40ml. 2.4.6 Microlitre pipettes or diluters 2.4.7 Beakers, of capacity 250 ml. 2.4.8 Heating device, for example a hotplate. 2.4.9 Membrane filtration device with filters, of pore size0,454m, washed thoroughly with dilute nitric acid and rinsed with water. 2.
44、5 Sampling and sample pretreatment See ISO 5667-3. 2.5.1 Sampling Collect the samples in polyethylene or borosilicate glass containers which have previously been cleaned with nitric acid and water. 2.5.2 Pretreatment and preparation of the sample solutions 2.5.2.1 Pretreatment for the determination
45、of the content of dissolved cadmium Filter the water sample as soon as possible after sampling (2.5.1) through a membrane filter of pore size0,454m. To stabilize the filtrate, add, for example,10ml of nitric acid (2.3.1) per litre of water sample to achieve a pH of less than2; add more acid, if nece
46、ssary, to ensure a pH of less than2. 2.5.2.2 Pretreatment for the determination of cadmium after mineralization Acidify the water sample as soon as possible after sampling by adding1ml of nitric acid (2.3.1) per litre of sample; add more acid, if necessary, to ensure a pH of less than2. Completely m
47、ix the sample, for example by thorough shaking. Place 100ml of the homogenized sample in a250ml beaker. Add1ml of nitric acid (2.3.1) and1ml of hydrogen peroxide (2.3.2). Heat the beaker on a hotplate until about0,5ml remains. It is essential that the sample is not reduced to dryness. If there is he
48、avy organic contamination of the water sample, consider a repeated addition of hydrogen peroxide (Caution). Dissolve the residue in1ml of nitric acid (2.3.1) and some water, transfer quantitatively to a100ml one-mark volumetric flask and dilute to volume with water. If sample volumes other than thos
49、e specified are used, the apparatus and reagents shall be adjusted to the respective ratio of volumes. It is not necessary to carry out a digestion in cases where cadmium is quantitatively determinable without this treatment. In such circumstances, only acidify the water sample. 2.6 Procedure Prior to measurement, adjust the instrumental parameters of the spectrometer (2.4.1) in accordance with the manufacturers operating instructions. Optimize flame conditions. Zero the spectrometer by aspirating the zero-setting solution (2.3.7) into the
