1、 STD.BS1 BS EN IS0 12020-ENGL 2000 W Lb24669 0835773 T83 BRITISH STANDARD Water quality - Determination of aluminium - Atomic absorption spectrometric methods The European Standard EN 12020:2 has the stahis of a British Standard ICs 13.060.50 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMTED BY CO
2、PYRIGHT LAW BS EN IS0 12020:2000 STD-BSI BS EN IS0 L2020-ENGL 2000 = 3b24669 0835774 9LT m Amd. No. BS EN IS0 12020:2000 Date Comments This British Standard, having been prepared under the direction of the Health and Environment Sector Committee, was published under the authority of the Standards Co
3、mmittee and comes inta effect on 15 April 2000 O BSI 04-Zoo0 National foreword This British standard is the official English language version of EN IS0 12020:2OOO. It is identical with IS0 12020: 1997. The UK participation in its preparation was entrusted by Technical Committee Em, Water quality, to
4、 Subcommittee E“, Physical, chemical and biochemical methods which has the responsibility to: - aid enquirers to understand the tea - present to the responsible internatio - monitor related intedonal and European developments and promulgate them in the UK. A list of organizations represented on this
5、 subcommittee can be obtained on request to its secrem. Cross-references Attention is hwn to the fact that CEN and CENELEC %dards normally include an annex which lists normative references to international pubiidons with their corresponding European publications. The British Stan in clause 3 a graph
6、ite furnace AAS method is described. iii STD-BSI BS EN IS0 L2020-ENGL 2000 Lb24bb7 0835780 123 m EN IS0 120202000 Phosphate Sodium Water quality - Determination of aluminium - Atomic absorption spectrometric met hods 10 O00 mgA 10000rngA 1 Scope Magnesium Calcium This International Standard describe
7、s two atomic absorption spectrometric (AAS) methods for the determination of aluminium in water. 10 O00 mg/i 10 000 mQn 1.1 Flame AAS I ron Nickel The flame AAS method (clause 2) is applicable for the determination of aluminium in water in mass concentrations from 5 mgA to 100 mgA. Higher concentrat
8、ions may be determined after an appropriate dilution of the sample. Careful evaporation of the sample, acidified with nitric acid, may be used to extend the working range of the method to lower concentrations as long as no precipitation is observed. 10 O00 mgil 10 O00 ma/l NOTE - If the linear range
9、 of the instrument is sufficiently large, concentrations e 5 mgn may be determined with this method; otherwise the determination needs to be carried out in the graphite furnace, as described in clause 3. Cadmium Lead If the determination of the total content of aluminium is required, a digestion of
10、the sample according to 2.5.3 is necessary. Silicates and aluminium oxide compounds may, however, not be quantitatively determined with this digestion procedure. 3 o00 mg/l 10000mgA 1.2 Graphite furnace The graphite furnace AAS method (clause 3) is applicable for the determination of aluminium in wa
11、ters and waste waters in mass concentrations from 10 pg/I to 100 pg/l applying a dosing volume of 20 pl. The working range can be shifted to higher concentrations either by dilution of the sample or by using a smaller sample volume. 2 Determination of aluminium by atomic absorption spectrometry in a
12、 nitrous oxide/acetylene flame 2.1 Interferences I Chloride I 10 O00 md I I Potassium I 10000 maA I 1 STD-BSI BS EN IS0 12020-ENGL 2000 EN IS0 12O2O:200O Silicate Fluoroborate 200 mgA 2 O00 mgh Titanium Fluoride I lb24bb9 0835783 05T W 1000mgA 3 O00 mgA1) The total salt content of the measuring solu
13、tion should not exceed 15 gA, or its electrical conductivity should not be higher than 2 000 mS/m. For samples whose matrix influence is unknown, the conductivity should be investigated and compensated for, if possible, for example by dilution of the sample or by application of the method of standar
14、d additions. 2.2 Principle Acid is added to the water sample which is then aspirated into a nitrous oxide/acetylene flame of an atomic absorption spectrometer. The absorbance is measured at a wavelength of 309,3 nm and the aluminium content calculated. 2.3 Reagents 2.3.1 General requirements Use onl
15、y reagents of at least recognized analytical grade quality and double-distilled water or water of equivalent purity. The aluminium content of the water or the reagents used shall be negligibly low, compared with the lowest concentration of aluminium to be determined. 2.3.2 Hydrochloric acid, ficI =
16、1,16 g/mi. 2.3.3 Nitric acid, = 1,40 g/mi. 2.3.4 Hydrogen peroxide (dihydrogen dioxide), who2 = 30 %. 2.3.5 Caesium chloride solution, pcs = 20 . Dissolve 25,3 g of CsCI in 100 ml of HCI (2.3.2) and make up to 1 O00 ml with water (2.3.1). 2.3.6 Aluminium stock solution, pAI = 1 O00 mgA. Dissolve 1,W
17、O g of aluminium, minimum punty 99,9 % or band, in a graduated flask, nominal capacity 1 O00 ml, in approximately 15 ml of hydrochloric acid (2.3.2) and make up to volume with water (2.3.1). Alternatively, prepare the solution with a commercially available aluminium standard which contains (1,000 f
18、0,002) g AI. 2.3.7 Aluminium standard solution, pAI = 100 m. Pipette 100 ml of the aluminium stock solution (2.3.6) into a 1 000-ml graduated flask, add 10 ml of nitric acid (2.3.3), and make up to volume with water (2.3.1). 2.3.8 Aluminium calibration solutions. In accordance with the aluminium con
19、centration expected in the sample, prepare at least five calibration solutions from the aluminium standard solution (2.3.7). For the working range of 5 m to 50 mgA, proceed, for example, as follows. a) 2 Pipette, into a series of 100-ml graduated flasks, 5 ml, 10 ml, 20 ml, 30 ml and 50 ml of the al
20、uminium standard solution (2.3.7); STD.BS1 BS EN IS0 L2020-ENGL 2000 3ib24bb 0835782 Tqb EN IS0 12020:2000 b) add 2 ml of caesium chloride solution (2.3.5); c) acidify each of these solutions with 1 ml of nitric acid (2.3.3); d) make up to volume with water and mix. The calibration solutions contain
21、 5 mgil, 10 mgh, 20 mgil, 30 mgh or 50 mgA of aluminium, respectively. Prepare the calibration solutions on the day of use. NOTE - It is advantageous to use additional calibration solutions in the main part of the working range. 2.3.9 Blank solution. Pipette 1 ml of nitric acid (2.3.3) into a 100-ml
22、 graduated flask, and make up to volume with water. If the sample is to be digested or evaporated to a smaller volume, the blank solution shall be submitted to the same pretreatment (2.5.3). 2.3.10 Zeroing solution. Use water (2.3.1) as zeroing solution. The blank solution (2.3.9) may also be used t
23、o zero the instrument, provided the aluminium content of the blank solution is negligibly low. The zeroing solutions shall not be stored in bottles made of polyolefins (see 2.5.1). 2.4 Apparatus 2.4.1 Atomic absorption spectrometer, with background correction and radiation source for the determinati
24、on of aluminium. 2.4.2 Gas supply with nitrous oxide and acetylene; the residual pressure of the acetylene tanks shall never fall below 500 kPa. The nitrous oxide/acetylene supply should be designed to allow high supply quantities. 2.4.3 Graduated flasks, nominal capacities 10 ml, 100 ml and 1 O00 m
25、l. 2.4.4 One-mark pipettes, nominal capacities 5 ml, 10 ml, 20 ml, 30 ml and 50 ml. 2.4.5 Microlitre pipette or diluter. 2.4.6 Silica glass beaker, nominal capacity 250 ml. 2.4.7 Heating appliance, e.g. electric heating plate. 2.4.8 Membrane filtration device, with membrane filters of pore size 0,45
26、 pm. 2.5 Sampling and sample preparation 2.5.1 General requirements Clean the glassware immediately before use with warm dilute nitric acid, c(HN0,) = 0,2 mol/l, and thoroughly rinse with water (2.3.1). Check incoming batches of pipette tips and one-way vessels for possible aluminium contamination.
27、Collect the samples in bottles made of an appropriate plastics material. Bottles made of polyolefins shall not be used because they may contain traces of aluminium. Clean the sample containers as specified for glassware. 3 STDOBSI BS EN IS0 LZOZO-ENGL 2000 = Lb24bbS 0635783 922 EN IS0 12020:2000 2.5
28、.2 Pretreatment for the determination of dissolved aluminium a) Filter the water sample as soon as possible after sample collection (2.5.1) through a membrane filter, pore size 0,45 pm. b) Acidify the filtrate with 1 ml of nitric acid (2.3.3) per 1 O00 ml of water sample for stabilization. c) The re
29、sulting pH shall be 1 O0 pgil in the spiked sample solutions, use a smaller volume. Take this into account on calculation. 7 b) Make the first flask up to volume with water (2.3.1). c) Into the remaining three flasks pipette 0,l ml, 0,2 ml and 0,3 ml of the aluminium standard solution (3.3.8) and ma
30、ke up to volume with water (2.3.1). NOTE - The addition of 0,l mi of aluminium standard solution (3.3.8) corresponds to 20 pg/l AI, related to the sample and blank volume of 5 ml. The dilution by making up to 10 ml does not enter into the calculation. d) Prepare the blank solution (3.3.10) in the sa
31、me way. e) Prior to each measurement, additionally inject 10 pl of the matrix modifier solution (3.3.4) into the graphite tube. f) 3.7 Calculation of results Measure the absorbances, or the time-integrated absorbances, respectively, as described in 3.6.2. 3.7.1 Direct measurement The calculation is
32、carried out in accordance with 2.7, but the mass concentration here is expressed in micrograms aluminium per litre of water sample. 3.7.2 Standard addition In a graph with concentration as the abscissa and signal obtained as the ordinate, enter the values measured for the measuring solutions and the
33、 values measured for the measuring solutions spiked with ascending aluminium mass concentrations. The regression line drawn through these points will intersect the abscissa on its negative side. This point of intersection is the mass concentration of aluminium in the measuring solution. From this va
34、lue, the mass concentration of aluminium in the blank solution, measured in the same way, is subtracted. The difference is the mass concentration of aluminium in the water sample. NOTE - The evaluation can also be performed using regression calculation. 3.8 Expression of results Values shall be repo
35、rted to the nearest 1 pgA, with 2 significant figures at most. EXAMPLE Aluminium (AI) 48 p 4 Precision Details of an interlaboratory test on the precision of the method are summarized in annex A. The values derived from this interlaboratory test may not be applicable to concentration ranges and matr
36、ices other than those given. 5 Testreport The test report shall contain the following information: a) b) C) sample pretreatment, if applicable; d) results, expressed according to 2.8 or 3.8; e) any deviation from the method specified, and all circumstances which may have influenced the result. a ref
37、erence to the method used; identification of the water sample; 8 STD.BSI BS EN IS0 L2020-ENGL 2000 Lb24bb9 0835788 404 Sample AA AB BA BB EN IS0 12020:2000 - L N Outliers X SR CVR 15 42 O 9,78 0,159 1,6 15 42 7 47,29 2,03 1 ,O 6 13 11,3 0,935 1 83 6 13 51,5 4,152 O 8,1 - - Annex A (informative) Resu
38、lts of an interlaboratory trial An interlaboratory trial, carried out in autumn 1993 in Germany, resulted in the values given in table A.l. Table A.l - Precision data L N - X SR CVR AA AB BA BB number of laboratories; number of values; total mean, in pgA; reproducibility standard deviation, in pgA;
39、reproducibility variation coefficient, in YO; drinking water, flame technique; river water, flame technique; river water, graphite furnace technique; industrial waste water, graphite furnace technique. 9 I STD-BSI BS EN IS0 liZ020-ENGL 2000 W Lb24669 0835789 340 EN IS0 12020:2000 Annex B (informativ
40、e) Bibliography l IS0 5667-1 :1980, Water quality - Sampling - Part 1: Guidance on the design of sampling programmes. 2 IS0 5667-2:1991, Water quality - Sampling - Part 2: Guidance on sampling techniques. 3 IS0 5667-3:1994, Water quality - Sampling - Part 3: Guidance on the preservation and handling
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