1、 ISO 2013 Soil quality Determination of trace elements in aqua regia and nitric acid digests Graphite furnace atomic absorption spectrometry method (GFAAS) Qualit du sol Dtermination des lments en traces solubles dans leau rgale et lacide nitrique Spectromtrie dabsorption atomique avec four graphite
2、 TECHNICAL SPECIFICATION ISO/TS 17073 First edition 2013-10-15 Reference number ISO/TS 17073:2013(E) ISO/TS 17073:2013(E)ii ISO 2013 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2013 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized ot
3、herwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright offi
4、ce Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ISO/TS 17073:2013(E) ISO 2013 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 Principle 1 4 Inter
5、ferences and sources of errors . 2 5 Reagents 2 6 Apparatus . 4 6.1 Usual laboratory apparatus . 4 6.2 Atomic absorption spectrometer 4 6.3 Automated sample introduction system . 4 6.4 Graphite tubes . 4 6.5 Chemical modification 4 7 Procedure. 5 7.1 Graphite furnace programme . 5 7.2 Test sample so
6、lution 5 7.3 Test blank solution 6 7.4 Determination . 6 7.5 Calibration 6 8 Calculation 7 9 Expression of results 7 10 Test report . 7 Annex A (informative) Examples of instrumental parameter settings . 8 Bibliography 9 ISO/TS 17073:2013(E) Foreword ISO (the International Organization for Standardi
7、zation) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to b
8、e represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. The procedures used
9、to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of
10、the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified
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12、e meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information The committee responsible for this document is ISO/
13、TC 190, Soil quality, Subcommittee SC 3, Chemical methods and soil characteristics.iv ISO 2013 All rights reserved ISO/TS 17073:2013(E) Introduction ISO/TS 17073 is based upon CEN/TS 16172 Sludge, treated biowaste and soil Determination of elements using graphite furnace atomic absorption spectromet
14、ry (GF-AAS), which was developed by CEN/TC 400, Project Committee Horizontal standards in the fields of sludge, biowaste and soil. This Technical Specification is applicable and validated for several types of matrices as indicated in Table 1. Table 1 Matrices for which this Technical Specification i
15、s applicable and validated Matrix Materials used for validation Sludge Municipal sludge Biowaste Compost Fresh compost Soil Agricultural soil ISO 2013 All rights reserved v Soil quality Determination of trace elements in aqua regia and nitric acid digests Graphite furnace atomic absorption spectrome
16、try method (GFAAS) WARNING Persons using this Technical Specification should be familiar with usual laboratory practice. This Technical Specification does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate
17、 safety and health practices and to ensure compliance with any national regulatory conditions. IMPORTANT It is absolutely essential that tests conducted according to this Technical Specification be carried out by suitably trained staff. 1 Scope This Technical Specification specifies the determinatio
18、n of trace elements in aqua regia or nitric acid digests or other extraction procedures of sludge, treated biowaste and soil, using atomic absorption spectrometry with electrothermal atomization in a graphite furnace. The method is applicable for the determination of the following elements: Arsenic
19、(As), cadmium (Cd), cobalt (Co), lead (Pb), antimony (Sb), thallium (Tl), vanadium (V). This method may be applied to other elements. The lower working range is approximately 0,01 mg/kg to 0,001 mg/kg, depending on the element to be determined. 2 Normative references The following documents, in whol
20、e or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3696, Water for analytical laborato
21、ry use Specification and test methods ISO 11466, Soil quality Extraction of trace elements soluble in aqua regia ISO 16729, Soil quality Digestion of nitric acid soluble fractions of elements ISO 16965, Soil quality Determination of trace elements using inductively coupled plasma mass spectrometry (
22、ICP-MS) 3 Principle Graphite furnace atomic absorption spectrometry (GFAAS) (also known as Electrothermal Atomic Absorption Spectrometry (ETAAS), discrete sample aliquots are dispensed into a graphite tube (of which there are several types), which can be heated to over 2 500 C very rapidly and in a
23、controlled manner. By increasing the temperature stepwise, the processes of drying, thermal decomposition of the matrix and thermal dissociation into free atoms occurs. Atomic absorption spectrometry is based on the ability of free atoms to absorb light. A light source emits light specific for a cer
24、tain element (or elements). When the light beam passes through the atom cloud in the heated graphite furnace, the light is selectively absorbed by atoms of the chosen element(s). The decrease in light intensity is measured with a detector at a specific wavelength. The concentration of an element in
25、the sample is determined by comparing the absorbance of the sample with the absorbance of calibration solutions. The signal-peak produced is, under optimum conditions, sharp and symmetrical, and of narrow half-width. The peak area is for most elements proportional to the concentration of the element
26、 in solution. The measurements are made at the wavelengths given in Table 2. TECHNICAL SPECIFICATION ISO/TS 17073:2013(E) ISO 2013 All rights reserved 1 ISO/TS 17073:2013(E) Table 2 Wavelengths of the elements Element Wavelength nm Arsenic 193,7 Cadmium 228,8 Cobalt 240,7 Lead 217,0 Antimony 217,6 T
27、hallium 276,8 Vanadium 318,4 Zeeman background correction and platform use is common practice. If necessary, interferences may be overcome by adding a matrix modifier to the samples before analysis, or by performing the calibration with standard addition technique. The results are given as the mass
28、of analyte (micrograms or milligrams) per kilogram of dried sample materials. 4 Interferences and sources of errors The sample solutions prepared from digestion of samples may contain large amounts of substances that may affect the results. High concentrations of chloride may cause low results, beca
29、use the volatility of many elements is increased and analyte loss may occur during the pyrolysis step. High chloride concentrations interfere with TI determinations and result in severe losses of the analyte, avoid aqua regia digestions and use only nitric acid digestion according to ISO 16729. Matr
30、ix effects may be overcome, partially or completely, by optimization of the temperature programme, the use of pyrolytically coated tubes or platforms, the use of chemical modifiers, the standard addition technique and the use of background correction. 5 Reagents Use only reagents of recognized analy
31、tical grade and water grade 1 as specified in ISO 3696. For the determination of elements at trace and ultra-trace level, the reagents shall be of adequate purity. The concentration of the analyte or interfering substances in the reagents and the water should be negligible compared to the lowest con
32、centration to be determined. 5.1 Hydrochloric acid, HCl, (HCl) 1,17 g/ml. c(HCl) 12 mol/l, w(HCl) 370 g/kg. The same batch of hydrochloric acid shall be used throughout the procedure. 5.2 Nitric acid, HNO 3 , (HNO 3 ) 1,4 g/ml, c(HNO 3 ) 15 mol/l, w(HNO 3 ) 650 g/kg. The same batch of nitric acid sh
33、all be used throughout the procedure. 5.3 Nitric acid, diluted 1 + 3 (volume fraction). Add 250 ml of nitric acid (5.2 ) to 500 ml of water in a 1 000 ml volumetric flask and fill to the mark with water. 5.4 Aqua regia, diluted 1 + 3 (volume fraction). Dilute 210 ml of hydrochloric acid (5.1) and 70
34、 ml of nitric acid (5.2) with about 500 ml of water in a 1 000 ml volumetric flask, and dilute to the mark.2 ISO 2013 All rights reserved ISO/TS 17073:2013(E) 5.5 Standard stock solutions Both single-element standard stock solutions and multi-element standard stock solutions with concentration of 1
35、000 mg/l, stating the acid used and the preparation technique, are commercially available. These solutions are considered to be stable for more than one year, but in reference to guaranteed stability, the recommendations of the manufacturer should be considered. Alternatively, the standard stock sol
36、utions may be prepared as indicated in Table A.1. 5.6 Standard solutions Use the same acid as the digested samples when preparing the standard and the calibration solutions. 5.6.1 Standard solution corresponding to 10 mg/l of element Pipette 10 ml of the actual standard stock solution (5.5) into a 1
37、 000 ml volumetric flask. Add 20 ml of nitric acid (5.3) or 20 ml of aqua regia (5.4), fill to the mark with water and mix well. 5.6.2 Standard solution corresponding to 0,1 mg/l of element Pipette 5 ml of the standard solution (5.6.1) into a 500 ml volumetric flask. Add 10 ml of nitric acid (5.3) o
38、r 10 ml of aqua regia (5.4), fill to the mark with water and mix well. Prepare this solution on the day of use. 5.7 Calibration solutions Before each batch of determinations, prepare, from the standard solutions of each element (5.6.1 or 5.6.2), at least four calibration solutions covering the linea
39、r range of the calibration curve for the element to be determined. Use nitric acid (5.3) or aqua regia (5.4) to adapt the acid concentration in calibration solutions to digest sample solution used. Calibration solutions shall be prepared on the day of use. Use the set of standard solutions containin
40、g the same acid as the digested samples. 5.8 Calibration blank solutions Prepare a calibration blank solution in the same way as the calibration solutions, but add no standard solution. Use a 100 ml volumetric flask. Use nitric acid (5.3) or aqua regia (5.4) to adapt the acid concentration to that i
41、n calibration solutions (5.7). Cool if necessary and dilute to volume with water. 5.9 Palladium nitrate/magnesium nitrate modifier Dissolve 0, 259 g of Mg( NO 3 ) 2 6H 2 O in 100 ml of water. Mix the palladium nitrate solution 10 g/l Pd(NO 3 ) 2 with twice the volume of magnesium nitrate solution. O
42、bserve the manufacturers recommendations. 10 l of the mixed solution is equal to 15 g of Pd and 10 g of Mg(NO 3 ) 2 . Pd(NO 3 ) 2solution is commercially available (10 g/l). Prepare the solution freshly every month. The palladium solution is stable for more than one month. 5.10 Magnesium nitrate mod
43、ifier Dissolve 0,865 g of Mg(NO 3 ) 2 6H 2 O in 100 ml of water. 10 l of this solution is equal to 50 g of Mg(NO 3 ) 2 . Observe the manufacturers recommendations. 5.11 Ammonium dihydrogen phosphate modifier Dissolve 2,0 g of NH 4 H 2 PO 4in 100 ml of water. 10 l of this solution is equal to 200 g o
44、f NH 4 H 2 PO 4 . Observe the manufacturers recommendations. ISO 2013 All rights reserved 3 ISO/TS 17073:2013(E) 5.12 Ammonium dihydrogen phosphate / magnesium nitrate modifier Dissolve 2,0 g of NH 4 H 2 PO 4and 0,1 73 g of Mg(NO 3 ) 2 6H 2 O in 100 ml of water. 10 l of this solution is equal to 200
45、 g of NH 4 H 2 PO 4and 10 g of Mg(NO 3 ) 2 . Observe the manufacturers recommendations. 5.13 Purge gas, argon, Ar ( 99,99 %). 6 Apparatus 6.1 Usual laboratory apparatus All glass or plastic ware shall be cleaned carefully before trace element determinations, e.g. by immersion in 5 % (volume fraction
46、) aqueous nitric acid solution for overnight, followed by rinsing with water before use. The nitric acid shall be replaced each week. NOTE It has been found convenient to keep separate sets of glass or plastics ware for the determinations given in this T echnical Specification, in order to reduce th
47、e possibility of within-laboratory contamination. Similarly, it can be convenient to carry out the acid cleaning step overnight. Certain kinds of plastic are affected by nitric acid, so care should be taken in the choice of plastic. Because of the high sensitivity of electro-thermal atomic absorptio
48、n spectrometry, stringent precautions should be taken to clean all glass or plastic ware and avoid contamination of sample, standard and calibration solutions from foreign material and dust from the laboratory atmosphere. 6.2 Atomic absorption spectrometer The atomic absorption spectrometer shall be
49、 equipped with an electro-thermal atomizer, the necessary hollow cathode lamps or electrodeless dischard lamps appropriate to the element of interest and operated at a current recommended for the lamp by the instrument manufacturer, an automatic background correction device, and a computerized read-out or a high speed chart recorder. Background correction shall be used with electrothermal atomic absorption spectrometry, the minimum acceptable technical specification (below 350 nm wavel
