EN ISO 12782-5:2012

Soil quality - Parameters for geochemical modelling of leaching and speciation of constituents in soils and materials - Part 5: Extraction of humic substances from aqueous samples (ISO 12782-5:2012)

ISO 12782-5:2012 specifies a procedure to determine the concentration of humic substances in aqueous samples. These samples may be obtained as such or as eluates from leaching procedures applied to soil or other materials. Other materials also include waste.The content of humic substances can be used as input in geochemical models.

Bodenbeschaffenheit - Parameter zur geochemischen Modellierung der Elution und Speziation von Bestandteilen in Böden und Materialien - Teil 5: Extraktion von Huminstoffen aus wässrigen Proben (ISO 12782-5:2012)

Der vorliegende Teil der ISO 12782 legt ein Verfahren zur Bestimmung der Konzentration von Huminstoffen in
wässrigen Proben fest. Diese Proben können als solche oder als Eluate aus den für Böden und andere
Materialien geltenden Elutionsverfahren erhalten werden. Andere Materialien schließen ebenfalls Abfall ein.
Der Gehalt an Huminstoffen kann als Vorgabe in geochemischen Modellen verwendet werden.

Qualité du sol - Paramètres pour la modélisation géochimique de la lixiviation et de la spéciation des constituants des sols et des matériaux - Partie 5: Extraction des substances humiques des échantillons aqueux (ISO 12782-5:2012)

L'ISO 12782-5:2012 spécifie un mode opératoire pour déterminer la concentration des substances humiques dans les échantillons aqueux. Ces échantillons peuvent être obtenus en l'état ou sous forme d'éluats par des modes opératoires de lixiviation appliqués au sol ou aux autres matériaux. Les autres matériaux incluent également les déchets. La teneur en substances humiques peut être utilisée comme une donnée d'entrée dans les modèles géochimiques.

Kakovost tal - Parametri geokemijskega modeliranja izpiranja in speciacija sestavin v tleh in talnih materialih - 5. del: Ekstrakcija huminskih snovi iz vodnih vzorcev (ISO 12782-5:2012)

Ta del standarda ISO 12782 opisuje postopek za določevanje koncentracije huminskih snovi v vodnih vzorcih. Te vzorce je mogoče pridobiti kot take ali kot izlužke iz postopkov izpiranja, ki se uporabljajo za tla ali talne materiale. Med materiale spadajo tudi odpadki, opisani v uvodu.

General Information

• Status: Published
• Publication Date: 31-May-2012
• Withdrawal Date: 30-Dec-2012
• ICS: 13.080.05 - Examination of soils in general
• ICS: 13.080.10 - Chemical characteristics of soils
• Technical Committee: CEN/TC 444 - Environmental characterization
• Drafting Committee: CEN/TC 444/WG 1 - Leaching tests
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 01-Jun-2012
• Completion Date: 01-Jun-2012
• Ref Project: SIST EN ISO 12782-5:2013 - Soil quality - Parameters for geochemical modelling of leaching and speciation of constituents in soils and materials - Part 5: Extraction of humic substances from aqueous samples (ISO 12782-5:2012)

Overview

EN ISO 12782-5:2012 (ISO 12782-5:2012) is part of the ISO 12782 series on soil quality - parameters for geochemical modelling of leaching and speciation. This part specifies a validated laboratory procedure to extract and determine the concentration of humic substances (humic acid, fulvic acid and related fractions) from aqueous samples - including direct water samples and eluates produced by leaching tests on soils, wastes and other materials. The extracted humic substances are intended as input parameters for geochemical speciation and leaching models used in environmental risk assessment.

Key topics and technical requirements

• Scope and purpose: Quantification of dissolved humic substances in eluates/aqueous samples to support geochemical modelling (mobility and bioavailability of trace constituents).
• Principle: Isolation and fractionation of dissolved organic matter following conventional IHSS-type methods adapted for aqueous samples.
• Apparatus and reagents: Lists of required analytical equipment, resins (e.g., DAX-8 resin preparation is described), centrifugation and storage conditions.
• Sampling and sample handling: Requirements for laboratory and test samples, test portion selection, and eluate treatment/storage prior to analysis.
• Procedure steps: Preparation of resin, fractionation to obtain humic acid (HA), fulvic acid (FA), hydrophilic organic carbon (Hy) and hydrophobic neutral (HON) fractions, plus blank tests.
• Analytical determination and calculation: Methods to quantify carbon in each fraction, correction factors, concentration calculations and expression of results.
• Quality and performance: Blank tests, performance characteristics, validation guidance and informative annexes (schematic procedure, validation, centrifugation conditions).

Applications

• Geochemical speciation modelling of metals and contaminants in soils, sludges, ashes, construction materials and wastes.
• Translating laboratory leaching test results (pH-dependent, percolation) into field-relevant predictions of mobility and bioavailability.
• Supporting environmental risk assessment, regulatory compliance, waste characterization and remediation planning.
• Providing input parameters (dissolved organic ligand concentrations) for thermodynamic models used by environmental consultants and researchers.

Who should use this standard

• Environmental and soil testing laboratories performing leachate characterization.
• Geochemists and modellers needing reliable humic/fulvic input data for speciation models.
• Consultants, waste managers and regulators involved in leaching assessments and risk evaluation.
• Research groups studying dissolved organic matter interactions with trace elements.

Related standards

• Other parts of ISO 12782 series (Parts 1–4 cover reactive mineral surfaces and humic extraction from solids).
• Characterization leaching standards (e.g., pH-dependent and percolation tests) that produce eluates used as input for this method.

Keywords: EN ISO 12782-5:2012, ISO 12782-5, soil quality, humic substances extraction, humic acid, fulvic acid, geochemical modelling, leaching, eluates, dissolved organic carbon, DAX-8 resin.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2013
Kakovost tal - Parametri geokemijskega modeliranja izpiranja in speciacija
sestavin v tleh in talnih materialih - 5. del: Ekstrakcija huminskih snovi iz vodnih
vzorcev (ISO 12782-5:2012)
Soil quality - Parameters for geochemical modelling of leaching and speciation of
constituents in soils and materials - Part 5: Extraction of humic substances from aqueous
samples (ISO 12782-5:2012)
Bodenbeschaffenheit - Parameter zur geochemischen Modellierung der Elution und
Speziation von Bestandteilen in Böden und Materialien - Teil 5: Extraktion von
Huminstoffen aus wässrigen Proben (ISO 12782-5:2012)
Qualité du sol - Paramètres pour la modélisation géochimique de la lixiviation et de la
spéciation des constituants des sols et des matériaux - Partie 5: Extraction des
substances humiques des échantillons aqueux (ISO 12782-5:2012)
Ta slovenski standard je istoveten z: EN ISO 12782-5:2012
ICS:
13.080.10 .HPLMVNH]QDþLOQRVWLWDO Chemical characteristics of
soils
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 12782-5
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2012
ICS 13.080.05
English Version
Soil quality - Parameters for geochemical modelling of leaching
and speciation of constituents in soils and materials - Part 5:
Extraction of humic substances from aqueous samples (ISO
12782-5:2012)
Qualité du sol - Paramètres pour la modélisation
Bodenbeschaffenheit - Parameter zur geochemischen
géochimique de la lixiviation et de la spéciation des Modellierung der Elution und Speziation von Bestandteilen
constituants des sols et des matériaux - Partie 5: Extraction in Böden und Materialien - Teil 5: Extraktion von
des substances humiques des échantillons aqueux (ISO Huminstoffen aus wässrigen Proben (ISO 12782-5:2012)
12782-5:2012)
This European Standard was approved by CEN on 31 May 2012.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which 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
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists 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 CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12782-5:2012: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 12782-5:2012) has been prepared by Technical Committee ISO/TC 190 "Soil quality"
in collaboration with Technical Committee CEN/TC 345 “Characterization of soils” the secretariat of which is
held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by December 2012, and conflicting national standards shall be withdrawn
at the latest by December 2012.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 12782-5:2012 has been approved by CEN as a EN ISO 12782-5:2012 without any
modification.
INTERNATIONAL ISO
STANDARD 12782-5
First edition
2012-06-01
Soil quality — Parameters for geochemical
modelling of leaching and speciation of
constituents in soils and materials —
Part 5:
Extraction of humic substances from
aqueous samples
Qualité du sol — Paramètres pour la modélisation géochimique de la
lixiviation et de la spéciation des constituants des sols et des matériaux —
Partie 5: Extraction des substances humiques des échantillons aqueux
Reference number
ISO 12782-5:2012(E)
©
ISO 2012
ISO 12782-5:2012(E)
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved

ISO 12782-5:2012(E)
Contents Page
Foreword .iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Apparatus . 3
6 Reagents . 3
7 Sampling . 4
7.1 Laboratory sample . 4
7.2 Test sample . 4
7.3 Test portion . 4
8 Procedure . 4
8.1 Preparation of DAX-8 resin . 4
8.2 Determination of total humic acid (HA), fulvic acid (FA) and hydrophilic organic carbon (Hy)
content in aqueous samples . 5
9 Eluate treatment and storage . 5
10 Analytical determination . 5
11 Blank test . 5
12 Calculation . 6
12.1 General correction factors for the calculation of humic acid (HA), fulvic acid (FA), hydrophilic
organic carbon (Hy) and hydrophobic neutral organic carbon (HON) in aqueous samples . 6
12.2 Concentration of total humic acid (HA), fulvic acid (FA), hydrophilic organic carbon (Hy) and
hydrophobic neutral organic carbon (HON) concentrations in aqueous samples . 7
13 Expression of results . 8
14 Test report . 8
15 Performance characteristics . 8
Annex A (informative) Schematic representation of the fractionation procedure . 9
Annex B (informative) Validation of procedure . 11
Annex C (informative) Conditions regarding centrifugation .16
Bibliography .19
ISO 12782-5:2012(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 12782-5 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 7, Soil and
site assessment.
ISO 12782 consists of the following parts, under the general title Soil quality — Parameters for geochemical
modelling of leaching and speciation of constituents in soils and materials:
— Part 1: Extraction of amorphous iron oxides and hydroxides with ascorbic acid
— Part 2: Extraction of crystalline iron oxides and hydroxides with dithionite
— Part 3: Extraction of aluminium oxides and hydroxides with ammonium oxalate/oxalic acid
— Part 4: Extraction of humic substances from solid samples
— Part 5: Extraction of humic substances from aqueous samples
iv © ISO 2012 – All rights reserved

ISO 12782-5:2012(E)
Introduction
In addition to leaching procedures for subsequent chemical and ecotoxicological testing of soil and other
materials including waste, predictive models are becoming indispensable tools in the environmental risk
assessment of these materials. Models are particularly required when the results of laboratory leaching tests
are to be translated to specific scenarios in the field, with regard to assessing the risks of both contaminant
migration and bioavailability.
In the past few years, geochemical models have been shown to be valuable tools to be combined with the
data obtained from characterization leaching standards, such as pH-dependence and percolation tests. These
models have the advantage of being based on fundamental thermodynamic parameters that have a general
validity. In order to enable extrapolation of laboratory leaching data to the mobility and/or bioavailability of
a constituent in a specific field scenario, these models require additional input parameters for specific soil
properties (see Figure 1).
Key
1 experiment
2 geochemical speciation modelling
3 available metal concentration
4 dissolved humic substances
5 reactive (solid) surfaces
6 database with stability constants
7 computer program
8 assumptions
Figure 1 — Relationships between experimental data, as obtained from laboratory
leaching/extraction tests, and geochemical modelling of the speciation of a heavy metal
in the environment (modified after M. Gfeller & R. Schulin, ETH, Zürich)
Characterization leaching standards provide information on the concentrations of the contaminant of interest as
a function of, in particular, pH and liquid/solid (L/S) ratio. In addition, a more complete analysis of the leachates
also provides information on the major ion composition and dissolved organic carbon (DOC), parameters that
are particularly important for the chemical speciation of constituents through processes such as precipitation,
complexation and competition for adsorption on reactive mineral and organic surfaces in the soil. As illustrated
ISO 12782-5:2012(E)
in Figure 1, for the example of copper, geochemical modelling enables calculation of the metal distribution
among these different chemical species in the system of interest. This provides necessary information for risk-
assessment purposes, as these different chemical forms play distinct roles in the mobility and bioavailability
of the metal in the soil. In addition to information obtained from the leaching standards (in their current state of
development/definition), two additional types of information are required.
a) The “available” (sometimes also referred to as “active” or “exchangeable”) concentration of the constituent
in the solid phase, as opposed to the total concentration determined by acid destruction of the solid matrix.
This “available” concentration can be obtained by leaching at low pH, a condition that can be obtained by
extending the pH range in the pH-dependent leaching test (ISO/TS 21268-4) down to pH ≈ 0,5 to pH ≈ 1.
b) The concentration of reactive organic and mineral surfaces in the soil, which constitute the major binding
(adsorption) sites for most constituents in the soil matrix.
The major reactive surfaces that control the binding of constituents by sorption processes to the soil matrix
are particulate organic matter and iron and aluminium (hydr)oxides. It is generally accepted that the reactivity
of these mineral and organic surfaces can strongly vary as a function of their specific surface area/crystallinity
[iron and aluminium (hydr)oxides] and composition (organic matter). When the results are intended to be used
for the above-described purposes of geochemical modelling in conjunction with leaching tests, it is important
that the methods be selective for reactive surfaces for which generic thermodynamic adsorption parameters
are also available for the most important major and trace elements.
These reactive surfaces have been identified in soils, as well as in a variety of other materials for which the
leaching of constituents is of relevance. It has been shown that the binding properties of these surfaces play
a generic role in the speciation and leaching of constituents among these different materials. As an example,
a similar geochemical modelling approach, using model input from the partial or complete ISO 12782 series,
[4] [5][6] [7]
has been successfully applied to different soils , amended soils , municipal incinerator bottom ash , steel
[8][9] [10] [11]
slag , bauxite residues , and recycled concrete aggregate . Hence, the scope of the ISO 12782 series
extends from soils to materials including soil amendments and waste materials.
This part of ISO 12782 aims to determine important reactive organic surfaces in soil and materials, for which
generic thermodynamic adsorption parameters exist, i.e., humic and fulvic acids. The procedure is based on
Reference [12], while generic thermodynamic adsorption parameters for humic and fulvic acids are available
in References [13] and [14].
Thermodynamic parameters for adsorption models other than those used in References [13] and [14] are also
available in the literature and may also be used to model the binding of constituents to humic and fulvic acids.
[15] [12]
The method is based on a conventional isolation and purification method that is also used by the
International Humic Substances Society (IHSS).
vi © ISO 2012 – All rights reserved

INTERNATIONAL STANDARD ISO 12782-5:2012(E)
Soil quality — Parameters for geochemical modelling of
leaching and speciation of constituents in soils and materials —
Part 5:
Extraction of humic substances from aqueous samples
1 Scope
This part of ISO 12782 specifies a procedure to determine the concentration of humic substances in aqueous
samples. These samples may be obtained as such or as eluates from leaching procedures applied to soil or
other materials. Other materials also include waste. The content of humic substances can be used as input in
geochemical models.
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 references, the latest edition of the referenced document
(including any amendments) applies.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5667-3, Water quality — Sampling — Part 3: Preservation and handling of water samples
ISO 8245, Water quality — Guidelines for the determination of total organic carbon (TOC) and dissolved
organic carbon (DOC)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
dissolved organic carbon
DOC
sum of organically bound carbon present in water originating from compounds (including cyanate and
thiocyanate) which will pass a membrane filter of pore size 0,45 µm
3.2
humic substance
HS
(partial) decomposition product from plant and animal tissue
NOTE 1 Humic substances form a series of relatively high-molecular-weight, brown-to-black-coloured substances
formed by secondary synthesis reactions.
NOTE 2 The term is used as a generic name to describe coloured material or its fractions (e.g. humic and fulvic acids)
obtained on the basis of solubility characteristics.
3.3
humic acid
HA
fraction of a humic substance that is not soluble in water under acidic conditions (pH <1 to 2) but is soluble at
higher pH values
NOTE Humic acids are dark brown to black in colour.
ISO 12782-5:2012(E)
3.4
fulvic acid
FA
fraction of a humic substance that is soluble in water under all pH conditions
NOTE 1 Fulvic acids remain in solution after removal of humic acid by acidification.
NOTE 2 Fulvic acids are light yellow to yellow-brown in colour.
3.5
hydrophilic organic carbon
Hy
organic carbon compound consisting of non-humic and humic-like substances
NOTE In this part of ISO 12782, Hy is essentially regarded as the extractable organic carbon fraction that is not
identified as humic acid, fulvic acid or hydrophobic neutral organic carbon in accordance with the procedure specified in
Clause 8. Hydrophilic organic carbon generally consists of molecules with a lower molecular weight and higher COOH/C
ratios than humic acids and fulvic acids. Examples of compounds are: oxidized carbohydrates with carboxylic acid groups,
low-molecular-weight carboxylic acids, and sugar phosphates.
3.6
hydrophobic neutral organic carbon
HON
difference between the amount of adsorbed fulvic acid and hydrophilic organic carbon and the amount of
desorbed fulvic acid
NOTE Hydrophobic neutral organic carbon can include non-humic and humic-like compounds.
3.7
laboratory sample
sample intended for laboratory inspection or testing
[ISO 11074:2005]
3.8
test sample
sample, prepared from the laboratory sample, from which the test portions are removed for testing or for
analysis; this portion of material, resulting from the laboratory sample by means of an appropriate method of
sample pretreatment, and having the size (volume/mass) necessary for the desired testing or analysis
NOTE Adapted from ISO 11074:2005.
3.9
test portion
analytical portion
quantity of material, of proper size, for measurement of the concentration or other property of interest, removed
from the test sample
NOTE 1 The test portion may be taken from the primary sample or from the laboratory sample directly if no preparation
of sample is required (e.g. with liquids), but usually it is taken from the prepared test sample.
NOTE 2 A unit or increment of proper homogeneity, size, and fineness, needing no further preparation, may be a test portion.
[ISO 11074:2005]
3.10
soil material
excavated soil, dredged material, manufactured soil, treated soil and fill material and other relevant materials,
including soil amendments and waste materials
2 © ISO 2012 – All rights reserved

ISO 12782-5:2012(E)
4 Principle
Specific dissolved organic carbon species are isolated based on defined operational conditions. Humic acids
are precipitated at pH 1 and fulvic acids (and the hydrophobic organic neutral fraction) are adsorbed onto DAX-
8 resin. The organics remaining in solution after resin addition are classified as hydrophilic organic substances.
The DOC concentrations are measured after every step, from which the individual concentrations of humic and
fulvic acids, hydrophobic organic neutrals, and hydrophilic organic substances, are calculated.
5 Apparatus
The following apparatus shall be used. All materials that come in contact with the sample (material or reagents)
should not contaminate the compounds to be determined or adsorb the compounds of interest.
5.1 Balance, with an accuracy of 0,1 g.
5.2 Usual laboratory glass or plastic ware, rinsed in accordance with ISO 5667-3.
5.3 pH-meter, with a measurement accuracy of at least ±0,05 pH units.
-1 -1
5.4 End-over-end shaking machine (5 min to 10 min ).
NOTE Other shaking methods can be used, provided that they can be shown to provide equivalent results.
5.5 Filtration apparatus, either a vacuum filtration device (between 2,5 kPa and 4,0 kPa) or a high-pressure
filtration apparatus (<0,5 MPa). Cleaning is compulsory.
5.6 Filters, pore size 20 µm, for use in the Büchner-funnel filtration device (5.7).
5.7 Büchner-funnel filtration device.
5.8 Membrane filters, for the filtration device, fabricated from inert material with a pore size of 0,45 µm.
Filters shall be pre-washed with demineralized water in order to remove DOC.
5.9 Soxhlet extraction device.
5.10 Soxhlet extraction thimbles, glass-fibre extraction thimbles for Soxhlet extraction device (5.9).
5.11 Centrifuge, preferably at 3 000g. For other appropriate conditions, see Annex C.
5.12 Centrifuge bottles, e.g. polycarbonate, of capacity 250 ml, cleaned with distilled and demineralized
water and diluted acid (HNO ) before use.
5.13 Crushing equipment: jaw crusher or cutting device.
5.14 Sieving equipment, with a nominal screen size of 2 mm or 4 mm.
6 Reagents
The reagents used shall be of analytical grade and the water used shall comply with grade 3 in accordance
with ISO 3696.
6.1 Demineralized water, deionized water or water of equivalent purity (5 < pH < 7,5) with a conductivity
< 0,5 mS/m according to grade 3 specified in ISO 3696.
ISO 12782-5:2012(E)
6.2 Potassium hydroxide, c(KOH) = 0,1 mol/l and 1 mol/l.
6.3 Hydrochloric acid, c(HCl) = 0,1 mol/l to 6 mol/l.
6.4 Sodium hydroxide, c(NaOH) = 0,1 mol/l to 5 mol/l.
6.5 Acetonitrile, (CH CN), suitable for liquid chromatography.
6.6 Methanol, (CH OH), suitable for liquid chromatography.
1)
6.7 DAX-8 resin, e.g. Sigma-Aldrich .
NOTE Various documented methods for HS isolation and purification make use of XAD-8 resin to adsorb HA and/or
FA. This resin is no longer commercially available; therefore, the comparability of the substitute resin DAX-8 was tested.
See Annex B for information.
6.8 Nitric acid, c(HNO ) = 0,1 mol/l.
7 Sampling
7.1 Laboratory sample
The laboratory sample shall consist of a volume to at least 50 ml.
7.2 Test sample
The samples shall be tested on filtered (0,45 µm) liquids. The test samples can be of diverse origins and should be
stored in a refrigerator. To avoid changes in the samples during storage, NaN (0,1 % in solution) can be added.
Sampl
...