ISO/TS 17073:2013

TECHNICAL ISO/TS
SPECIFICATION 17073
First edition
2013-10-15
Soil quality — Determination of trace
elements in aqua regia and nitric
acid digests — Graphite furnace
atomic absorption spectrometry
method (GFAAS)
Qualité du sol — Détermination des éléments en traces solubles
dans l’eau régale et l’acide nitrique — Spectrométrie d’absorption
atomique avec four graphite
Reference number
ISO/TS 17073:2013(E)
©
ISO 2013

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ISO/TS 17073:2013(E)

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© ISO 2013
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ISO/TS 17073:2013(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Principle . 1
4 Interferences 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 solution . 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
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ISO/TS 17073:2013(E)

Foreword
ISO (the International Organization for Standardization) 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 be 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 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 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 during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s 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/TC 190, Soil quality, Subcommittee SC 3, Chemical
methods and soil characteristics.
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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 spectrometry (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 is applicable and validated
Matrix Materials used for validation
Sludge Municipal sludge
Biowaste Compost
Fresh compost
Soil Agricultural soil
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TECHNICAL SPECIFICATION ISO/TS 17073:2013(E)
Soil quality — Determination of trace elements in aqua
regia and nitric acid digests — Graphite furnace atomic
absorption spectrometry 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 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 determination 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 (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 whole 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 laboratory 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 (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 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 certain 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 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 in solution. The measurements are
made at the wavelengths given in Table 2.
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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
Thallium 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 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, because 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. Matrix 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 analytical 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 concentration to be determined.
5.1 Hydrochloric acid, HCl, ρ(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 , ρ(HNO ) ~ 1,4 g/ml, c(HNO ) ~ 15 mol/l, w(HNO ) ~ 650 g/kg.
3 3 3 3
The same batch of nitric acid shall 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 ml of nitric acid (5.2) with about 500 ml of water in a
1 000 ml volumetric flask, and dilute to the mark.
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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 1 000 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 solutions 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 1 000 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 n
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