1、CEN EN*IS0*5763 95 3404587 0304335 657 M Water quality - Determination of cadmium by atomic absorption spectrometry The European Standard EN IS0 5961 : 1995 has the status of a British Standard BS EN IS0 5961 : 1995 BS 6068 : Section 2.21 : 1995 u- CEN EN*IS0*59bL 95 M 3404589 0104336 595 Amd. No. B
2、S EN IS0 5961 : 1995 Date Ext affected 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 September 1995 0 BSI 1995 Committees responsible for this British St
3、andard 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 Industries Association Convention
4、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 Association Industrial Water So
5、ciety 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 Services Soap and Detergent Ind
6、ustry Association Society of Chemical Industry Water Companies Association Water Research Centre Water Services Association of England and Wales The following BSI references relate to the work on this standard: Committee reference EPC/44 Draft for public comment 92/56850 DC ISBN O 580 24116 5 CEN EN
7、*ISO*59bL 75 H 3404589 0304337 421 W BS EN IS0 5961 : 1995 Contents Committees responsible Page Inside front cover National foreword ll Foreword 2 Method Section 1. General 1.1 Scope 1.2 Normative reference Section 2. Determination of cadmium using atomic absorption spectrometry in air-acetylene fla
8、me 2.1 Interferences 2.2 Principle 2.3 Reagents 2.4 Apparatus 2.5 Sampling and sample pretreatment 2.6 Procedure 2.7 Evaluation 3 3 2.8 Test report 2.9 Precision Section 3. Determination of cadmium by electrothermal atomization atomic absorption spectrometry 3.1 Interferences 8 3.2 Principle 8 3.3 R
9、eagents 8 3.4 Apparatus 9 3.5 Sampling and sample pretreatment 3.6 Procedure 3.7 Determination 3.8 Expression of results 3.9 Test report 3.10 Precision 9 9 10 11 11 11 Annex A (informative) Bibliography 12 Ible 1 Precision data 7 i CEN EN*ISO*59bL 95 W 3404589 0304338 3b8 BS EN IS0 5961 : 1995 Natio
10、nal foreword This British Standard has been prepared by Technical Committee EPC/44, Water quality, and is the English language version of EN IS0 5961 : 1995 Water quality - Determination of cadmium by atomic absorption spectrmtry, published by the European Committee for Standardization (CEN). It is
11、identical with IS0 5961 : 1994, published by the International Organization for Standardization (ISO). This standard supersedes BS 6068 : Section 2.21 : 1985, which is withdrawn. Cross-references Publication referred to Corresponding British Standard BS 6068 Water quality Part 6 Sampling Section 6.3
12、 : 1986 Guidance on the pramation and handling of samples IS0 5667-3 : 1985 Compliance with a British Standard does not of itself confer immunity from legai obligations. ii CEN EN*IS0*59bL 95 3404589 0104339 2T4 H EUROPEAN STANDARD EN IS0 5961 NORME EUROPENNE EUROPISCHE NORM March 1995 ICs 13.060.40
13、 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 (IS0 5961 : 1994) Qualit de l?eau - Dosage du cadmium par spectromtrie d?
14、absorption atomique Atomabsorptionsspektrometrie (IS0 5961 : 1994) Bestimmung von Cadmium durch (IS0 5961 : 1994) This European Standard was approved by CEN on 1994-11-14. CEN members are bound to comply with the CENCENELEC Internal Regulations which stipulate the conditions for giving this European
15、 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 Standard exists in three official versions (English, Fr
16、ench, 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 standards bodies of Austria, Belgium, Denmark, Finland,
17、 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 Centrai Secretariat: rue de Stassart 36, B-1050 Brusse
18、ls O 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 IS0 5961 : 1995 E CEN EN*IS0*5961 95 3404589 0104340 TLb Foreword This European Standard has been taken over by the Rchnical Committee CEN/IY= 230, Water
19、analysis, from the work of ISO/lT 147, Water quality, of the International Organization for Standardization 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 September and conflicting national stan
20、dards shall be withdrawn at the latest by September. According to the CENICENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portug
21、al, Spain, Sweden, Switzerland and United Kingdom. (ISO) . CEN EN*ISO*59bL 95 = 3404589 OLO434L 952 Page 3 EN IS0 5961 : 1995 Water quality - Determination of cadmium by atomic absorption spectrometry Section 1: General 1.1 Scope the concentration range is 0,3 pg/i to 3 pg/I. The range of applicatio
22、n of the method can be extended to This International Standard specifies two methods for higher concentrations by diluting the water sample or the determination of cadmium: flame atomic absorp- by the use of smaller dosing volumes. Cadmium can tion spectrometry (AAS) (Section 2) and be determined in
23、 sludges and sediments after an ap- electrothermal atomization (AAS) (Section 3). propriate digestion procedure. 1.1.1 in an air-acetylene flame Determination of cadmium using AAS 1.2 Normative reference The method is applicable to the analysis of water and waste water when the concentration of cadm
24、ium is between 0,05 mg/l and 1 mg/l. Higher concentrations can be determined after dilution of the sample. 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 slu
25、dges and sediments after an appropriate digestion procedure avoiding the formation of a precipitate. The following standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the edition indicated was valid.
26、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 re- cent edition of the standard indicated below. Mem- bers of IEC and IS0 maintain registers of currently valid International Stan
27、dards. IS0 5667-3:-), Water quality - Sampling - Part 3: Guidance on the preservation and handling of samples. 1.1.2 Determination of cadmium by electrothermal atomization AAS The method is suitable for the determination of cad- mium in water when, with a dosing volume of 10 pl, 1) To be published.
28、(Revision of IS0 5667-3:1985) CEN EN*IS0*5963 95 3404589 0304342 879 Page 4 EN IS0 5961 : 1995 Section 2: Determination of cadmium using atomic absorption spectrometry in an air-acetylene flame 2.1 Interferences The following ions will not interfere with the method as long as the mass concentrations
29、 specified below are not exceeded: Sulfate Chloride Phosphate Sodium Potassium Magnesium Calcium Iron Copper Nickel Cobalt Lead Silicon Titanium 10 O00 mg/l 10 O00 mg/l 10 O00 mg/l 10 O00 mg/l 10 O00 mg/l 10 O00 mg/l 3 O00 mg/l 3 O00 mg/l 10 O00 mg/l 3 O00 mg/l 10 O00 mg/l 10 O00 mg/l 1 O00 mg/l 3 O
30、00 mg/i The total salt content of the measuring solution shall be less than 15 g/l and the electrical conductivity shall be lower than 20 O00 mS/m. Samples of unpredict- able matrix effects shall be examined appropriately. This influence shall be compensated for either by di- luting the sample or by
31、 applying the method of stan- dard additions (see 3.6.2.2). 2.2 Principle Aspiration of the acidified sample into the air- acetylene flame of an atomic absorption spectrometer. Measurement of the cadmium con- centration at a wavelength of 228,8 nm. 2.3 Reagents Use only reagents of recognized analyt
32、ical grade and only distilled water or water of equivalent purity. The cadmium content of water used for blank determi- nations and for the 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, p = 1.4
33、0 g/ml. 2.3.2 Hydrogen peroxide, w(H202) = 30 % (mim). 2.3.3 Cadmium stock solution I, p(Cd) = 1 O00 mg/l. Dissolve 1,000 g f 0,002 g of cadmium in 10 ml of nitric acid (2.3.1) and 10 ml of water (see 2.3) in a 1 O00 ml onedark volumetric flask. Dilute to volume with water. Store the solution in pol
34、yethylene or borosilicate glass containers. The solution is stable for 1 year. Alternatively, use any commercially available stock solution containing 1,000 g/i f 0,002 g/i of cadmium. 2.3.4 Cadmium standard solution I, p(Cd) = 10 mg/l. Pipette 10 ml of the cadmium stock solution (2.3.3) into a 1 O0
35、0 ml one-mark volumetric flask, add 10 ml of nitric acid (2.3.1) and dilute to volume with water. Store the solution in polyethylene or borosilicate glass containers. The solution is stable for at least one month if stored at room temperature. NOTE 1 dard solution of 100 ml to be prepared. The use o
36、f a microlitre pipette permits a stan- 2.3.5 Cadmium calibration solutions Prepare a minimum of five calibration solutions in ac- cordance with the expected cadmium concentrations. As an example, proceed as follows for the range from 0,05 mg/l to 1.0 mg/l: Pipette 0,5 ml; 2,O ml; 4,O ml; 6,O mi; 8,O
37、 ml and 10,O ml respectively of the cadmium standard sol- ution (2.3.4) into l O0 ml one-mark volumetric flasks. Add 1 ml of nitric acid (2.3.1) to each of these sol- utions. Dilute to volume with water and mix. The calibration solutions contain 0,05 mg/l; 0,2 mg/l; 0,4 mg/l; 0,6 mg/l; 0,8 mg/l and
38、1,0 mg/l of cadmium respectively. 2.3.6 Blank test solution Pipette 1 ml of nitric acid (2.3.1) into a 100 ml one mark volumetric flask, and dilute to volume with water (2.3.4). If the sample requires a pretreatment by digestion, the blank shall be given the same pretreatment (see 2.5.21. 2.3.7 Solu
39、tion for zero-setting the instrument Use water (2.3.41 as a zero-setting solution. The blank solution (2.3.61 may also serve for zero-setting pro- vided its cadmium concentration is negligibly low. 2.4 Apparatus Immediately before use, clean the glassware with warm, dilute nitric acid, approximately
40、 2 moll1 (e.g. by soaking for 24 h), followed by a thorough rinsing with water (2.3). Verify that each lot of pipette tips and singleuse plastics vessels is free from potential cad- mium contamination by carrying out blank measure- ments (see 2.6.1). Usual laboratory apparatus and 2.4.1 Atomic absor
41、ption 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 is es- sential that the manufacturers safety instructions be observed. The residual gas pr
42、essure for acetylene cylinders shall be at least 5 x lo5 Pa. 2.4.3 Air-acetylene burner. 2.4.4 One-mark volumetric flasks of capacity 10 ml, 100 ml and 1 O00 ml. 2.4.5 Onsmark pipettes, of nominal capacity 1 ml, 2ml, 3ml. 4ml, 5ml, 6ml, 8ml, lOml, 20ml, 30 ml and 40 ml. 2.4.6 Microlitre pipettes or
43、diluters. 2.4.7 Beakers, of capacity 250 ml. Page 5 EN IS0 5961 : 1995 2.4.8 Heating device, for example a hotplate. 2.4.9 Membrane filtration device with filters, of pore size 0,45 pm, washed thoroughly with dilute nitric acid and rinsed with water. 2.5 Sampling and sample pretreatment See IS0 5667
44、-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 of the content of dissolved cadmium Filter the
45、water sample as soon as possible after sampling (2.5.1 1 through a membrane filter of pore size 0,45 pm. To stabilize the filtrate, add, for example, 10 ml of nitric acid (2.3.1) per litre of water sample to achieve a pH of less than 2; add more acid, if necessary, to ensure a pH of less than 2. 2.5
46、.2.2 Pretreatment for the determination of cadmium after mineralization Acidify the water sample as soon as possible after sampling by adding 1 ml of nitric acid (2.3.1) per litre of sample; add more acid, if necessary, to ensure a pH of less than 2. Completely mix the sample, for example by thoroug
47、h shaking. Place 100 ml of the homogenized sample in a 250 ml beaker. Add 1 ml of nitric acid (2.3.1) and 1 ml of hydrogen peroxide (2.3.2). Heat the beaker on a hotplate until about 0,5 ml re- mains. It is essential that the sample is not reduced to dryness. Page 6 EN IS0 5961 : 1995 If there is he
48、avy organic contamination of the water sample, consider a repeated addition of hydrogen peroxide (Caution). Dissolve the residue in 1 ml of nitric acid (2.3.1) and some water, transfer quantitatively to a 100 ml one- mark volumetric flask and dilute to volume with water. If sample volumes other than
49、 those 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 with- out this treatment. In such circumstances, only acidify the water sample. 2.6 Procedure Prior to measurement, adjust the instrumental par- ameters 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 flame. 2.6.1 Blank
