DIN ISO 20280-2010 Soil quality - Determination of arsenic antimony and selenium in aqua regia soil extracts with electrothermal or hydride-generation atomic absorption spectrometr.pdf

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1、May 2010 Translation by DIN-Sprachendienst.English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 13

2、.080.10!$bF;“1633524www.din.deDDIN ISO 20280Soil quality Determination of arsenic, antimony and selenium in aqua regia soilextracts with electrothermal or hydride-generation atomic absorptionspectrometry (ISO 20280:2007)English translation of DIN ISO 20280:2010-05Bodenbeschaffenheit Bestimmung von A

3、rsen, Antimon und Selen in Knigswasser-Bodenextrakten mittelselektrothermischer oder Hydrid-Atomabsorptionsspektrometrie (ISO 20280:2007)Englische bersetzung von DIN ISO 20280:2010-05Qualit du sol Dosage de larsenic, de lantimoine et du slnium dans des extraits du sol leau rgalepar spectromtrie dabs

4、orption atomique avec atomisation lectrothermique ou gnrationdhydrures (ISO 20280:2007)Traduction anglaise de DIN ISO 20280:2010-05www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 18 pages04.10 DIN ISO 20280:2010-05 A comma is used as th

5、e decimal marker. Contents Page National foreword .3 National Annex NA (informative) Bibliography 3 1 Scope 4 2 Normative references 4 3 Principle4 4 Reagents.5 5 Apparatus .7 6 Procedure .8 6.1 Test portion 8 6.2 Aqua regia extraction for arsenic, antimony and selenium 8 6.3 Blank test solution.8 7

6、 Method A Electrothermal atomic absorption spectrometry: Preparation of calibration solutions and measurement8 7.1 General8 7.2 Calibration solutions for arsenic .8 7.3 Calibration solutions for antimony 8 7.4 Calibration solutions for selenium 9 7.5 Calibration and determination with ETAAS measurem

7、ent .9 8 Method B Hydride-generation atomic absorption spectrometry: Preparation of calibration solutions and measurement.10 8.1 Pre-reduction and calibration for the determination of arsenic 10 8.2 Pre-reduction and calibration for the determination of antimony. 10 8.3 Pre-reduction and calibration

8、 for the determination of selenium . 10 8.4 Measurement of calibration and test solutions by hydride-generation atomic absorption spectrometry . 11 9 Plotting the calibration graph 11 10 Calculation. 11 10.1 General. 11 10.2 Calculation according to the method of standard additions . 12 11 Expressio

9、n of results . 12 12 Interferences . 12 13 Precision 13 14 Test report . 17 Bibliography. 18 2 DIN ISO 20280:2010-05 National foreword This standard has been prepared by Technical Committee ISO/TC 190 “Soil quality” (Secretariat: NEN, Netherlands). The responsible German body involved in its prepara

10、tion was the Normenausschuss Wasserwesen (Water Practice Standards Committee), Working Committee NA 119-01-02 AA Abfall- und Bodenuntersuchung. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. DIN shall not be held responsible for

11、identifying any or all such patent rights. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 648 DIN EN ISO 648 ISO 1042 DIN EN ISO 1042 ISO 3696 DIN ISO 3696 ISO 5725-2 DIN ISO 5725-2 ISO 11464 DIN ISO 11464 ISO 11465 DIN ISO 11465 ISO 1

12、1466 DIN ISO 11466 National Annex NA (informative) Bibliography DIN EN ISO 648, Laboratory glassware Single-volume pipettes DIN EN ISO 1042, Laboratory glassware One-mark volumetric flasks DIN ISO 3696, Water for analytical laboratory use Specification and test methods DIN ISO 5725-2, Accuracy (true

13、ness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method DIN ISO 11464, Soil quality Pretreatment of samples for physico-chemical analysis DIN ISO 11465, Soil quality Determination of dry m

14、atter and water content on a mass basis Gravimetric method DIN ISO 11466, Soil quality Extraction of trace elements soluble in aqua regia 3 Soil quality Determination of arsenic, antimony and selenium in aqua regia soil extracts with electrothermal or hydride-generation atomic absorption spectrometr

15、y WARNING Certain procedures, reagents and apparatus used in this International Standard pose hazards, especially in connection with concentrated acids, toxic solutions of arsenic (As), antimony (Sb) and selenium (Se), and high-pressure gases. Users should ensure that they are familiar with the safe

16、ty procedures necessary in such situations, and with any legal requirements (including waste disposal). If in any doubt, seek advice from the competent authorities. 1 Scope This International Standard specifies methods for the determination of arsenic, antimony and selenium, in an aqua regia extract

17、 of soil obtained in accordance with ISO 11466, by electrothermal or hydride-generation atomic absorption spectrometry. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated

18、references, the latest edition of the referenced document (including any amendments) applies. ISO 3696:1987, Water for analytical laboratory use Specification and test methods ISO 11464:2006, Soil quality Pretreatment of samples for physico-chemical analysis ISO 11465:1993, Soil quality Determinatio

19、n of dry matter and water content on a mass basis Gravimetric method ISO 11466:1995, Soil quality Extraction of trace elements soluble in aqua regia 3 Principle Arsenic, antimony and selenium are extracted from soil samples with aqua regia according to ISO 11466. Arsenic, antimony and selenium are d

20、etermined by electrothermal atomic absorption spectrometry (ETAAS), in which discrete volumes of sample solution are dispensed into a graphite tube. By increasing the temperature of this graphite tube stepwise, the processes of drying, thermal decomposition of the matrix and thermal dissociation int

21、o free atoms occur. The resulting absorption signal should (under optimum conditions) be a sharp symmetrical peak proportional to the element concentration in solution. Alternatively, arsenic, antimony and selenium are determined by the hydride-generation technique (HGAAS). Arsenic and antimony are

22、first pre-reduced in the aqua regia extract by a mixture of ascorbic acid and potassium iodide. Selenium is pre-reduced by hydrochloric acid at an elevated temperature. After that, the hydride formation occurs by reaction with a sodium borohydride solution. The hydrides are carried from the solution

23、 by an argon stream into a heated quartz cell and decomposed at 900 C and then the atom concentration for arsenic and antimony is measured by atomic absorption spectrometry. There are several commercial systems available where the reaction of hydride formation occurs continuously (continuous flow or

24、 DIN ISO 20280:2010-05 4 flow injection systems) or stepwise (batch systems). All these techniques can be used, but adaptation of the working steps and reagent concentrations according to the advice of the manufacturer may be necessary. Refer to the manufacturers recommendation for wavelengths and s

25、pectral band widths or see Table 1. Table 1 Measurement conditions for arsenic, antimony and selenium Wavelength Spectral band width Element nm nm Arsenic 193,7 0,7 Antimony 217,6 1,0 Selenium 196,0 1,0 4 Reagents All reagents shall be of recognised analytical grade. Use demineralised water or water

26、 distilled from an all-glass apparatus conforming to Grade 2 of ISO 3696. The water used for blank determinations and for preparing reagents and standard solutions shall have element concentrations that are negligible compared with the lowest concentration to be determined in the sample solutions. 4

27、.1 Hydrochloric acid, w(HCl) = 37 %, (HCl) 1,2 g/ml. The same batch of hydrochloric acid shall be used throughout the procedure. 4.2 Hydrochloric acid, diluted (1 + 9). Pour 500 ml of water into a 1 000 ml volumetric flask. Add 100 ml of hydrochloric acid (4.1) with caution, mix and fill to the mark

28、 with water. 4.3 Nitric acid, w(HNO3) = 65 %, (HNO3) 1,4 g/ml. The same batch of nitric acid shall be used throughout the procedure. 4.4 Nitric acid, c(HNO3) = 0,5 mol/l. Pour 500 ml of water into a 1 000 ml volumetric flask. Add 22 ml of nitric acid (4.3) with caution, mix and fill to the mark with

29、 water. 4.5 Aqua regia solution, diluted (1 + 9). Pour 500 ml of water into a 1 000 ml volumetric flask. Add 75 ml of hydrochloric acid (4.1) and 25 ml of nitric acid (4.3) with caution, mix and fill to the mark with water. 4.6 Palladium/magnesium nitrate modifier solution. Two sources of modifier s

30、olutions can be used: commercially available modifier solutions; modifier element solutions prepared in the laboratory from pure palladium (e.g. powder) or from stochiometrically defined and dried salts. Dissolve 0,30 g of palladium nitrate Pd(NO3)2 and 0,36 g of magnesium nitrate Mg(NO3)26 H2O in a

31、 100 ml volumetric flask, fill to the mark with 0,5 mol/l nitric acid (4.4) and mix. DIN ISO 20280:2010-05 5 Alternatively, prepare the palladium/magnesium nitrate modifier solution as follows: Dissolve, in a 250 ml beaker, 0,14 g of palladium powder in 3,5 ml of nitric acid (4.3) and add 10 l of hy

32、drochloric acid (4.1). Evaporate the solution to near dryness on a water bath or hot plate, then add 0,36 g of magnesium nitrate Mg(NO3)2 6 H2O. Dissolve this solid residue in 50 ml of nitric acid (4.4), transfer the solution into a 100 ml volumetric flask, fill to the mark with nitric acid (4.4) an

33、d mix. 10 l of this solution are equal to 14 g of Pd and 36 g of Mg(NO3)2. NOTE The recommendations of instrument manufacturers may propose different modifier-solution concentrations. Also, recommendations of appropriate modifier-to-analyte ratios may be given depending on the furnace design. 4.7 Pr

34、e-reduction solutions, ascorbic acid and potassium iodide. Dissolve 10 g of potassium iodide (KI) and 10 g of ascorbic acid (C6H8O6) in 200 ml of water. This solution shall be prepared on the day of use. 4.8 Sodium borohydride solution. The composition of this solution depends on the hydride-generat

35、ion system used. Generally, the concentration of sodium borohydride (NaBH4) varies from 0,2 g/l to 10 g/l, and the concentration of sodium hydroxide from 0,5 g/l to 5 g/l. Refer to the manufacturers instruction for further information. Dissolve an appropriate quantity of sodium hydroxide in water, a

36、dd a quantity of sodium borohydride, wait until complete dissolution, filter the solution through a membrane filter of 0,45 m porosity into a 1 000 ml volumetric flask, fill to the mark with water and mix. This solution should be prepared freshly on the day of use. 4.9 Preparation of stock and stand

37、ard solutions of individual elements. Two sources of stock solutions are available: commercially available stock solutions; stock solutions prepared in the laboratory from pure elements or stochiometrically defined dried salts or oxides. NOTE Commercially available stock solutions have the advantage

38、 that they remove the need to handle toxic metals. However, special care needs to be taken that these solutions are supplied with a certified composition from a reputable source and are checked on a regular basis. WARNING Arsenic, antimony and selenium are highly toxic. Take appropriate measures to

39、avoid ingestion. Care should be taken in disposal of such solutions. 4.10 Arsenic, stock solution corresponding to 1 000 mg/l of arsenic. 4.11 Arsenic, standard solution corresponding to 100 mg/l of arsenic. Pipette 10,0 ml of the arsenic stock solution (4.10) into a 100 ml volumetric flask, add 1 m

40、l of nitric acid (4.3), fill to the mark with water and mix well. 4.12 Arsenic, standard solution corresponding to 1 mg/l of arsenic. Pipette 1,00 ml of the 100 mg/l arsenic standard solution (4.11) into a 100 ml volumetric flask, add 2 ml of nitric acid (4.3), fill to the mark with water and mix we

41、ll. Prepare this solution at least weekly. 4.13 Antimony, stock solution corresponding to 1 000 mg/l of antimony. 4.14 Antimony, standard solution corresponding to 100 mg/l of antimony. Pipette 10,0 ml of the antimony stock solution (4.13) into a 100 ml volumetric flask, add 5 ml of nitric acid (4.3

42、) and 10 ml of hydrochloric acid (4.1), fill to the mark with water and mix well. DIN ISO 20280:2010-05 6 4.15 Antimony, standard solution corresponding to 1 mg/l of antimony. Pipette 1,00 ml of the 100 mg/l antimony standard solution (4.14) into a 100 ml volumetric flask, add 2 ml of nitric acid (4

43、.3) and 2 ml hydrochloric acid (4.1), fill to the mark with water and mix well. Prepare this solution at least weekly. 4.16 Selenium, stock solution corresponding to 1 000 mg/l of selenium. 4.17 Selenium, standard solution corresponding to 100 mg/l of selenium. Pipette 10,0 ml of the selenium stock

44、solution (4.16) into a 100 ml volumetric flask, add 1 ml of nitric acid (4.3), fill to the mark with water and mix well. 4.18 Selenium, standard solution corresponding to 1 mg/l of selenium. Pipette 1,00 ml of the 100 mg/l selenium standard solution (4.17) into a 100 ml volumetric flask, add 2 ml of

45、 nitric acid (4.3), fill to the mark with water and mix well. Prepare this solution at least weekly. 4.19 1,10 Phenanthrolin-monohydrate solution. Dissolve 10 g of 1,10 phenanthrolin-monohydrate (C12H8N2H20) in 100 ml of water. The solution shall be prepared on the day of use. 5 Apparatus 5.1 Genera

46、l Usual laboratory apparatus should be used. Quartz vessels should be the preferred material for the whole procedure (especially if lower calibration ranges (0,1 g/l to 1 g/l) are to be used for measurement). NOTE Cleaning of glassware: All glassware used must be cleaned carefully before use, e.g. b

47、y immersion in (HNO3) 50 ml/l aqueous nitric acid solution for a minimum of 6 h, followed by rinsing with water before use. It can be helpful to keep a separate set of glassware exclusively for these determinations. 5.2 Water bath. 5.3 Atomic absorption spectrometer, equipped with a hollow cathode o

48、f the element or, preferably, a high-energy discharge lamp (which gives a greater and more stable light intensity) operated at a current recommended by the lamp and instrument manufacturer, an automatic background-correction device, preferably Zeeman correction for ETAAS-measurement, and a computeri

49、sed readout. 5.4 Electrothermal atomiser, equipped with an automated sample introduction system (sample dispenser), which should be adaptable to the atomic absorption spectrometer (5.3). 5.5 Hydride-generation system, commercially available, where the reaction occurs continuously (continuous flow or flow injection systems) or stepwise (batch systems). It should be adaptable to the atomic absorption spectrometer (5.3). Heat the quartz cell at least to 900 C for complete dissociation of metal hydrid