SIST EN ISO 20847:2004

SLOVENSKI STANDARD
01-september-2004
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Petroleum products - Determination of sulfur content of automotive fuels - Energy-
dispersive X-ray fluorescence spectrometry (ISO 20847:2004)
Mineralölerzeugnisse - Bestimmung des Schwefelgehaltes von Kraftstoffen für
Kraftfahrzeurge - Energiedispersive Röntgenfluoreszenz-Spektrometrie (ISO
20847:2004)
Produits pétroliers - Détermination de la teneur en soufre des carburants pour
automobiles - Spectrométrie de fluorescence de rayons X dispersive en énergie (ISO
20847:2004)
Ta slovenski standard je istoveten z: EN ISO 20847:2004
ICS:
75.160.20 7HNRþDJRULYD Liquid fuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 20847
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2004
ICS 75.080; 75.160.30
English version
Petroleum products - Determination of sulfur content of
automotive fuels - Energy-dispersive X-ray fluorescence
spectrometry (ISO 20847:2004)
Produits pétroliers - Détermination de la teneur en soufre Mineralölerzeugnisse - Bestimmung des Schwefelgehalts
des carburants pour automobiles - Spectrométrie de von Automobilkraftstoffen - Energiedispersive
fluorescence de rayons X dispersive en énergie (ISO Röntgenfluoreszenz-Spektrometrie (ISO 20847:2004)
20847:2004)
This European Standard was approved by CEN on 1 March 2004.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2004 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20847:2004 E
worldwide for CEN national Members.

Foreword
This document (EN ISO 20847:2004) has been prepared by Technical Committee ISO/TC 28
"Petroleum products and lubricants" in collaboration with Technical Committee CEN/TC 19
"Petroleum products, lubricants and related products", 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 September 2004, and conflicting national
standards shall be withdrawn at the latest by September 2004.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Endorsement notice
The text of ISO 20847:2004 has been approved by CEN as EN ISO 20847:2004 without any
modifications.
INTERNATIONAL ISO
STANDARD 20847
First edition
2004-03-15
Petroleum products — Determination of
sulfur content of automotive fuels —
Energy-dispersive X-ray fluorescence
spectrometry
Produits pétroliers — Détermination de la teneur en soufre des
carburants pour automobiles — Spectrométrie de fluorescence de
rayons X dispersive en énergie

Reference number
ISO 20847:2004(E)
©
ISO 2004
ISO 20847:2004(E)
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ii © ISO 2004 – All rights reserved

ISO 20847:2004(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references . 1
3 Principle . 1
4 Reagents and materials. 2
5 Apparatus. 2
6 Sampling and sample handling . 3
7 Apparatus preparation. 3
8 Calibration. 4
9 Procedure. 6
10 Calculation. 6
11 Expression of results. 6
12 Precision . 6
13 Test report. 7
Annex A (informative) Interferences.8
Annex B (informative) Guidelines for measuring low sulfur contents (less than 100 mg/kg). 10
Bibliography . 11

ISO 20847:2004(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 20847 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants.
iv © ISO 2004 – All rights reserved

ISO 20847:2004(E)
Introduction
This International Standard is directed specifically at the lower end of the concentration range covered in
ISO 8754 ([3] in the Bibliography), which covers sulfur contents from 0,01 % (m/m) up to 5,00 % (m/m). By
restriction of instrument type, a better signal to background ratio for sulfur K emission is assured and by the
use of matrix matched calibration standards or other means of matrix corrections (as detailed below), the
precision and accuracy of results for samples having varying C:H mass ratios and oxygen contents are
improved. A knowledge of the general composition of the sample for analysis is advantageous in obtaining the
best test result.
Where matrix matching is not used and where the C:H mass ratio of the test sample is known or can be
determined, accuracy may be improved by the use of the equation given in A.2.2 to correct the result to the
C:H mass ratio of the calibration standards, i.e. the reference diluent oil (4.1).
Some instruments include the capability for the separate measurement of scattered radiation from the X-ray
tube, and notes for information are provided in A.2.3 on the use of this scattered radiation for compensation
for matrix effects in the test sample.
INTERNATIONAL STANDARD ISO 20847:2004(E)

Petroleum products — Determination of sulfur content of
automotive fuels — Energy-dispersive X-ray fluorescence
spectrometry
WARNING — The use of this International Standard may involve hazardous materials, operations and
equipment. This International Standard does not purport to address all of the safety problems
associated with its use. It is the responsibility of the user of this International Standard to establish
appropriate safety and health practices and determine the applicability of regulatory limitations prior
to use.
1 Scope
This International Standard specifies an energy dispersive X-ray fluorescence (EDXRF) test method for the
determination of the sulfur content of motor gasolines, including those containing up to 2,7 % (m/m) oxygen,
and of diesel fuels, including those containing up to 5 % (V/V) fatty acid methyl ester (FAME), having sulfur
contents in the range 30 mg/kg to 500 mg/kg. Other products may be analysed and other sulfur contents may
be determined according to this test method; however, no precision data for products other than automotive
fuels and for results outside the specified range have been established for this International Standard. For
reasons of spectral overlap, this International Standard is not applicable to leaded motor gasolines,
lead-replacement gasolines containing 8 mg/kg potassium to 20 mg/kg potassium, or to products and
feedstocks containing lead, silicon, phosporus, calcium, potassium or halides at concentrations greater than
one-tenth of the concentration of sulfur measured.
NOTE For the purposes of this International Standard, the terms “% (m/m)” and “% (V/V)” are used to represent the
mass fraction and the volume fraction of a material, respectively.
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 3170:2004, Petroleum liquids — Manual sampling
ISO 3171:1988, Petroleum liquids — Automatic pipeline sampling
3 Principle
The test portion, in a cup fitted with an X-ray transparent window, is placed in a beam of exciting radiation
from an X-ray tube. The intensity of the sulfur K characteristic X-radiation is measured, and the number of
accumulated counts is compared with a calibration curve constructed from sulfur standards covering the range
of sulfur contents under examination.
NOTE The exciting radiation may be either direct, or indirect via a secondary target.
ISO 20847:2004(E)
4 Reagents and materials
4.1 Diluent oil
4.1.1 The reference diluent oil is white oil (light paraffin oil) of high purity grade, with a sulfur content of
1 mg/kg maximum. However, if only one type of matrix is to be analysed (e.g. motor gasoline), the accuracy of
results may be improved by using a matrix-matched diluent. These should match approximately the aromatic
and oxygen content of the material to be analysed, and should consist of high purity components of less than
1 mg/kg sulfur content.
NOTE Suitable components for the matched matrix diluent include heptane, 2,2,4-trimethylpentane, toluene, xylenes,
ethanol, methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME) and fatty
acid methyl ester (FAME).
4.1.2 For the analysis of diesel fuels containing FAME at contents greater than 5 % (V/V), a matched matrix
diluent oil of the white oil with FAME shall be used.
4.2 Sulfur compounds
4.2.1 General
Sulfur compounds of known sulfur content shall be used for the preparation of the primary standards. The
compounds given in 4.2.2 to 4.2.5 are suitable, and their nominal sulfur contents are given. Where the purity
of these compounds is less than 99 % (m/m), either the concentrations and nature of all impurities are to be
known or certified reference materials shall be used.
4.2.2 Dibenzothiophene (DBT), with a nominal sulfur content of 17,399 % (m/m).
4.2.3 Dibutylsulfide (DBS), with a nominal sulfur content of 21,915 % (m/m).
4.2.4 Thionaphthene (Benzothiophene) (TNA), with a nominal sulfur content of 23,890 % (m/m).
4.2.5 Dibutyldisulfide (DBDS), with a nominal sulfur content of 35,950 % (m/m).
4.3 Reference materials
Certified reference materials (CRMs) from accredited suppliers, containing a range of sulfur concentrations,
are suitable alternatives to the compounds listed in 4.2 for use as calibration standards.
4.4 Quality control samples
Stable samples representative of the materials being analysed, that have a sulfur content that is known by this
test method over a substantial period of time, or supplied commercially with a certified value. Ensure before
use that the material is within its shelf life.
5 Apparatus
5.1 Energy-dispersive X-ray fluorescence analyser
5.1.1 Energy-dispersive X-ray fluorescence analyser, having facilities for measuring and subtracting the
background to give net sulfur intensities.
The instrument shall be capable of measuring the content of sulfur at 50 mg/kg with an error due to counting
statistics of 3 % relative standard deviation (RSD) maximum.
5.1.2 Source of X-ray excitation, with significant flux at X-ray energies above 2,5 keV.
2 © ISO 2004 – All rights reserved

ISO 20847:2004(E)
5.1.3 Removable sample cup, providing a sample depth of at least 5 mm, and equipped with replaceable
X-ray transparent film.
NOTE The transparent film is normally of polyester or polycarbonate with a thickness between 2 µm and 6 µm.
Polyester film is the preferred choice as samples of very high aromatic content can dissolve polycarbonate film. There are
possibly trace amounts of calcium in polyester film, but any absorption or enhancement effects would be cancelled out
when samples and standards are analysed using the same material. It is important that samples, standards and blanks
are measured using the same batch of film to avoid bias.
5.1.4 X-ray detector, with high sensitivity, and resolution not exceeding 800 eV at 2,3 keV.
5.1.5 Means of discriminating between sulfur K characteristic X-radiation and other X-rays of higher

energy (e.g. filters).
5.1.6 Signal conditioning and data handling electronics, including the functions of pulse counting, and a
minimum of two energy regions (to correct for background X-rays). When matrix matching of samples and
standards is not used, the instrument shall also be able to measure an energy region corresponding to
scattered radiation, and to use this measurement to compensate for matrix effects (see Annex A). The latter
measurement can also be used as the second energy region specified above and used to calculate the
background.
NOTE Differences in carbon/hydrogen ratios, or oxygen contents, between samples and standards can cause matrix
effects which may lead to a bias in the analytical result.
5.2 Analytical balance, single-pan or double-pan, capable of weighing to the nearest 0,1 mg.
5.3 Mixer, magnetic stirrer with PTFE-coated stirring rods.
5.4 Flasks, of 100 ml capacity, narrow-necked, conical, and made of borosilicate glass.
6 Sampling and sample handling
6.1 Unless otherwise spec
...