1、DEUTSCHE NORM Julv 2000 Water quality Determination of calcium and magnesium - Atomic absorption spectrometric method (IS0 7980 : 1986) English version of DIN EN IS0 7980 DIN EN IS0 7980 - ICs 13.060.50 Supersedes DIN 38406-3, September 1982 edition. Wasserbeschaffenheit - Bestimmung von Calcium und
2、 Magnesium - Verfahren mittels Absorptionsspektrometrie (IS0 7980 : 1986) European Standard EN IS0 7980 : 2000 has the status of a DIN Standard. A comma is used as the decimal marker. This standard is part of the series Deutsche Einheitsvetfahren zur Wasser-, Abwasser- und Schlamm- untersuchung - Su
3、mmarische Wirkungs- und Stoffkenngren (Gruppe H) (German standard methods for the examination of water, waste water and sludge - Parameters characterizing effects and substances (group HI. National foreword This standard has been published in accordance with a decision taken by CEN/TC 230 to adopt,
4、without alteration, International Standard IS0 7980 as a European Standard. The responsible German body involved in its preparation was the Normenausschuss Wasserwesen (Water Practice Standards Committee). Expert assistance and specialized laboratories will be required to perform the analysis descri
5、bed in this standard. Depending on the objective of the analysis, a check shall be made in each individual case on whether and to what extent additional boundary conditions will have to be specified. Standard methods published as DIN Standards are obtainable from Beuth Verlag GmbH, either individual
6、ly or grouped in volumes. The standard methods included in the loose-leaf publication entitled Deutsche Einheitsvetfahrenzur Wasser-, Abwasser- undSchlammuntersuchung will continue to be published by Wiley- VCH Verlag and Beuth Verlag GmbH. Standard methods or draft standards bearing the group title
7、 German standard methods for the examination of water, waste water and sludge are classified under the following categories (main titles): General information (group A) Sensory analysis (group B) Physical and physicochemical parameters (group C) Anions (group D) Cations (group E) Substance group ana
8、lysis (group F) Gaseous constituents (group G) Parameters characterizing effects and substances (group H) Biological-ecological methods of analysis (group M) Microbiological methods (group K) Test methods using water organisms (group L) Individual constituents (group P) Sludge and sediments (group S
9、) Bio-assays with microorganisms (group T) (DIN 38402) (DIN 38403) (DIN 38404) (DIN 38405) (DIN 38406) (DIN 38407) (DIN 38408) (DIN 38409) (DIN 3841 O) (DIN 3841 1) (DIN 3841 2) (DIN 38413) (DIN 3841 4) (DIN 3841 5) Continued overleaf. EN comprises 4 pages. No pari of this standard may be reproduced
10、 without the prior permission of Ref. No. DIN EN IS0 7980 : 2000-0 Y Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany, s the exclusive right of sale for German Standards (DIN-Normen). English price group 06 Sales No. 1106 11 .o0 Page 2 DIN EN IS0 7980 : 2000 In a
11、ddition to the methods described in the DIN 38402 to DIN 38415 series of standards, there are a number of European Standards available, which also form part of the collection of German standard methods. Information on Parts of these series of standards that have already been published can be obtaine
12、d from the offices of the Normenausschuss Wasserwesen, telephone (030) 26 O1 -24 23, or from Beuth Verlag GmbH, Burggrafenstrae 6, 10787 Berlin, Germany. Amendments DIN 38406-3, September 1982 edition, has been superseded by the specifications of EN ISO, which is identical to IS0 7980. Previous edit
13、ion DIN 38406-3: 1982-09. EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 7980 January 2000 ICs 13.060.50 English version Water quality Determination of calcium and magnesium - Atomic absorption spectrometric method Qualit de leau - Dosage du calcium et du magnsium - Mthode par spectromtrie
14、 dabsorption atomique (IS0 7980 : 1986) Wasserbeschaffenheit - Bestimmung von Calcium und Magnesium - Verfahren mittels Absorptions- Spektrometrie (IS0 7980 : 1986) This European Standard was approved by CEN on 2000-01 -20. CEN members are bound to comply with the CENKENELEC Internal Regulations whi
15、ch 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 stand- ards may be obtained on application to the Central Secretariat or to any CEN member. The European St
16、andards exist 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 st
17、andards bodies of Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Eur
18、opisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 2000. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN IS0 7980 : 2000 E Page 2 EN IS0 7980 : 2000 Foreword International Standard IS0 7980 : 1
19、986 Determination of calcium and magnesium -Atomic absorption spectrometric method, which was prepared by ISO/TC 147 Water quality of the International Organization for Standardization, has been adopted by Technical Committee CEN/TC 230 Water analysis, the Secretariat of which is held by DIN, as a E
20、uropean Standard. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, and conflicting national standards withdrawn, by July 2000 at the latest. In accordance with the CENKENELEC Internal Regulations, the national stan
21、dards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. E
22、ndorsement notice The text of the International Standard IS0 7980 : 1986 was approved by CEN as a European Standard without any modification. 1 Scope and field of application This International Standard specifies a method for the deter- mination of dissolved calcium and magnesium by flame atomic abs
23、orption spectrometry. It is intended for the analysis of raw and drinking waters and can be used for waters having a calcium content of up to 50 mg/i and a magnesium content of up to 5 mg/l. For samples containing higher concentrations of calcium or magnesium a smaller volume of the sample must be t
24、aken for the analysis. When using the air/acetylene flame and the dilution factor 1 in 10, as described in 6.1, the optimum range is 3 to 50 mg/l for calcium and 0,9 to 5 mg/l for magnesium. 2 Principle Measurement by flame atomic absorption spectrometry after adding lanthanum chloride (if an air/ac
25、etylene flame is used) or caesium chloride (if a nitrous oxide/acetylene flame is used) to reduce interferences. For calcium the absorbance is measured at 422,7 nm and for magnesium at 285,2 nm. 3 Reagents and materials During the analysis, use only reagents of recognized analytical grade and only d
26、istilled water or water of equivalent purity. (Commercially available, ready-made solutions may by used. i 3.1 Hydrochloric acid (HCI), e = 1.18 g/ml. 3.2 Dilute 8 ml of hydrochloric acid (3.1) to 1 litre. Hydrochloric acid (HCI), 0,l mol/l. 3.3 of La per litre. Lanthanum chloride (LaCl,) solution,
27、containing 20 g To a 1 litre one-mark volumetric flask add 24 g of lanthanum oxide ( La203) (atomic absorption spectrometry grade). Slowly and cautiously add 50 ml of hydrochloric acid (3.1) while stirring to dissolve the lanthanum oxide. Make up to the mark with water. 3.4 per litre. Dissolve 25 g
28、of caesium chloride in 1 litre of hydrochloric acid (3.2). Caesium chloride (CSCI) solution, containing 20 g of Cs 3.5 Dry a portion of calcium carbonate (CaCO,) at 180 OC for 1 h and allow it to cool in a desiccator. Weigh 2,50 f 0,Ol g of the dried material and suspend this in 100 ml of water. Add
29、 slowly the minimum amount of hydrochloric acid (3.2) necessary to dissolve the calcium carbonate (approximately 250 ml). Boil briefly to expel dissolved carbon dioxide, then cool. Transfer the solution quantitatively to a 1 o00 ml one-mark volumetric flask and make up to the mark with hydrochloric
30、acid (3.2). Calcium, stock solution, 1 O00 mgil. Store the solution in a polyethylene or polypropylene bottle. 3.6 Magnesium, stock solution, 1 O00 mg/l. Dry a portion of magnesium oxide (MgO) at 180 OC for 1 h. Weigh 1,fX i. 0,Ol g and dissolve in hydrochloric acid (3.2). Dilute with the same acid
31、to 1 o00 ml in a one-mark volumetric flask. Store the solution in a polyethylene bottle. 3.7 Calcium-magnesium, standard solution corresponding to 20 mg of Ca and 2 mg of Mg per litre. With pipettes, transfer 20.0 ml of the calcium stock solution (3.5) and 2,O ml of the magnesium stock solution (3.6
32、1 to a 1 O00 ml one-mark volumetric flask. Make up to the mark with hydrochloric acid (3.2). Page 3 EN IS0 7980 : 2000 Volume of Ca-Mg standard solution Iml) 4 Apparatus Usual laboratory equipment, and Atomic absorption spectrometer, set up and operated according to the manufacturers instructions, e
33、quipped with an appropriate burner for airiacetylene flame or nitrous oxide/acetylene flame and a hollow cathode lamp for calcium and magnesium determination. O 23 5 10 15 20 25 NOTES 1 Clean all glassware with warm, dilute Il + 1) hydrochloric acid and rinse with water. 2 The choice of flame to be
34、used is left to the user of this International Standard. It has been claimed that the nitrous oxide/acetylene flame is to be preferred for samples with a high content of dissolved matter, or which contain phosphate, sulfate, aluminium or silica. In general the nitrous oxide/acetylene flame should be
35、 used if the composition of the sample is complex or unknown. Wavelength (nrn) Analyte Air/acetylene flame Nitrous oxide/acetylene flame content mgl) 5 Sampling Calcium Magnesium 422,7 285.2 3 to 50 I 0,9 to 5 i 2 to 20 0.2 to 2 Samples shall be collected in clean polyethylene or polypropylene bottl
36、es. As soon as possible after collection, acidify them with 8 ml of hydrochloric acid (3.1) per litre of sample, in order to reduce their pH value and prevent precipita- tion of calcium carbonate. Samples shall be analysed as soon as possible after collection. 6 Procedure 6.1 to instrument Preparati
37、on of test solution for presentation Samples containing particulate material after acidification shall be filtered to prevent clogging of the nebulizer and burner systems. Prepare a relevant number of 100 ml one-mark volumetric flasks. To each of these add 10 ml of the lanthanum chloride solution (3
38、.3) if an air/acetylene flame is to be used, or 10 ml of the caesium chloride solution (3.4) if a nitrous oxide/acetylene flame is to be used. With a pipette, add 10,O ml of the sample, and make up to the mark with hydrochloric acid (3.2). If the concentrations of calcium or magnesium in the origina
39、l sample are above the ranges listed in table 2 then an ap- propriately smaller volume of the sample shall be used. 6.2 Blank test Carry out a blank test simultaneously with the determination, using the same reagents in the same quantities and following the same procedure, but replacing the volume o
40、f the test sample used in 6.1 by an identical volume of water. 6.3 Preparation of the set of calibration solutions To a series of seven 100 ml one-mark volumetric flasks, add to each either 10 ml of the lanthanum chloride solution (3.3) if an air/acetylene flame is to be used, or 10 ml of the caesiu
41、m chloride solution (3.4) if a nitrous oxide/acetylene flame is to be used. With the aid of pipettes add O; 2.5; 5; IO; 15; 20 and 25 ml of the calcium-magnesium standard solution (3.7) and make up to the mark with hydrochloric acid (3.2). The calibration solutions will have the concentrations shown
42、 in table 1. Table 1 - Concentration of calibration solutions NOTE - These concentrations apply when using the air/acetylene flame. When the nitrous oxide/acetylene flame is used, it may be appropriate to use other concentrations. Page 4 EN IS0 7980 : 2000 6.4 Calibration and determination Carry out
43、 the measurements at the wavelengths shown in table 2. Aspirate the calibration and blank solutions in random order and aspirate hydrochloric acid (3.2) between each. Prepare calibration graphs for calcium and magnesium by plotting the appropriate absorbance readings against the calcium and magnesiu
44、m contents. It is essential that the calibration graph be linear for the concentration ranges given above. If it is not linear, check for and eliminate sources of error and repeat the calibration. Aspirate the test solutions, with an aspiration of hydrochioric acid (3.2) between each, and determine
45、the absorbances. NOTES 1 It is good practice to check the slope of the calibration graphs at regular intervals (for example every 10 samples). 2 When using an air/acetylene flame, interference from refractory compounds containing phosphate, sulfate, aluminium or silica is minimized by the addition o
46、f lanthanum chloride. When using a nitrous oxide/acetylene flame ionization effects are minimized by the addition of caesium chloride. 7 Expression of results 7.1 Calculation Read from the calibration graph the actual concentrations of calcium and magnesium in the test solutions and in the blank. Fr
47、om these values, calculate the calcium and magnesium con- tents of the test sample, taking into account the volume of hydrochloric acid used for acidification, the volume of test sample taken (normally 10 ml), the total volume of the volumetric flask (100 ml), and the blank value as follows. The mas
48、s concentrations of calcium, ea,l, and of magnesium, eMg,l, expressed in milligrams per litre, are given by the equations eMg.2 is the concentration, expressed in milligrams per litre, of magnesium calculated from the calibration graph, having taken into account the blank value; .f is the dilution f
49、actor resulting from the addition of hydrochloric acid (3.11 to the test sample (normally 1,008: see clause 5); Vo is the volume, in millilitres, of the original sample (nor- mally 10 ml) taken for analysis; VI is the volurne, in millilitres, of the volumetric flask referred to in 6.1 (100 ml). If required, the amount of substance concentrations of calcium, cCa, and magnesium, cMg, expressed in millimoles per litre, may be obtained from the equations Express the results to the nearest milligram per litre or to the nearest 0,02 millimole per litre. 7.2 Precision In a si
