EN ISO 3924:2019
(Main)Petroleum products - Determination of boiling range distribution - Gas chromatography method (ISO 3924:2019)
Petroleum products - Determination of boiling range distribution - Gas chromatography method (ISO 3924:2019)
This document specifies a method for the determination of the boiling range distribution of petroleum products. The method is applicable to petroleum products and fractions with a final boiling point of 538 °C or lower at atmospheric pressure as determined by this document. This document does not apply to gasoline samples or gasoline components. The method is limited to products having a boiling range greater than 55 °C and having a vapour pressure sufficiently low to permit sampling at ambient temperature.
The document describes two procedures.
a) Procedure A allows a larger selection of columns and analysis conditions, such as packed and capillary columns as well as a thermal conductivity detector in addition to the flame ionization detector. Analysis times range from 14 min to 60 min.
b) Procedure B is restricted to only three capillary columns and requires no sample dilution. The analysis time is reduced to about 8 min.
Both procedures have been successfully applied to samples containing fatty acid methyl esters (FAME) up to 20 % (volume fraction).
NOTE For the purposes of this document, the terms "% (mass fraction)" and "% (volume fraction)" are used to represent the mass fraction (µ), the volume fraction (φ) of a material.
Mineralölerzeugnisse - Bestimmung des Siedeverlaufs - Gaschromatographisches Verfahren (ISO 3924:2019)
Dieses Dokument legt ein Verfahren zur Bestimmung des Siedeverlaufs von Mineralölerzeugnissen fest. Das Verfahren ist anwendbar auf Mineralölerzeugnisse und Fraktionen mit einem nach diesem Dokument bestimmten atmosphärischen Siedeende von 538 °C oder darunter. Dieses Dokument gilt nicht für Ottokraftstoffproben oder Ottokraftstoffkomponenten. Das Verfahren ist beschränkt auf Erzeugnisse mit einem Siedebereich größer als 55 °C und mit einem Dampfdruck, der niedrig genug ist, um eine Probenahme bei Umgebungstemperatur zu ermöglichen.
Dieses Dokument beschreibt zwei Verfahren.
a) Verfahren A bietet eine größere Auswahl von Säulen und Analysenbedingungen, wie z. B. gepackte Säulen und Kapillarsäulen, sowie einen Wärmeleitfähigkeitsdetektor zusätzlich zum Flammen-ionisationsdetektor. Die Analysenzeit liegt zwischen 14 min und 60 min.
b) Verfahren B ist auf nur drei Kapillarsäulen begrenzt und erfordert keine Probenverdünnung. Die Analysenzeit wird auf etwa 8 min verringert.
Beide Verfahren wurden erfolgreich auf Proben mit einem Gehalt von Fettsäuremethylestern (FAME, en: fatty acid methyl ester) bis zu 20 % (Volumenanteil) angewendet
ANMERKUNG Für die Zwecke dieses Dokuments wird zur Angabe des Massenanteils (μ) einer Substanz der Ausdruck „% (Massenanteil)“ und für den Volumenanteil (φ) einer Substanz der Ausdruck „% (Volumenanteil)“ verwendet.
Produits pétroliers - Détermination de la répartition dans l'intervalle de distillation - Méthode par chromatographie en phase gazeuse (ISO 3924:2019)
Le présent document spécifie une méthode pour déterminer la répartition dans l'intervalle de distillation des produits pétroliers. La méthode est applicable aux produits pétroliers et aux fractions pétrolières dont le point final de distillation est inférieur ou égal à 538 °C à la pression atmosphérique quand il est mesuré en appliquant le présent document. Celui-ci ne s'applique pas au cas des essences ou composés à base d'essences. Le domaine d'application de la méthode est limité aux produits dont l'intervalle de distillation est supérieur à 55 °C et dont la pression de vapeur est suffisamment basse pour permettre un échantillonnage à la température ambiante.
Ce document présente deux modes opératoires:
a) Le mode opératoire A propose une sélection élargie de colonnes, telles que des colonnes capillaires ou remplies, et de conditions d'analyse avec aussi bien un catharomètre qu'un détecteur à ionisation de flamme (FID). Les temps d'analyse s'étendent sur un intervalle de 14 à 60 min.
b) Le mode opératoire B ne propose que trois colonnes capillaires et ne nécessite pas de dilution de l'échantillon. Le temps d'analyse se réduit à environ 8 min.
Ces deux modes opératoires ont été appliqués avec succès à des échantillons contenant des esters méthyliques d'acides gras (EMAG) jusqu'à des teneurs de 20% (en fraction volumique).
NOTE Pour les besoins du présent document, les termes "% fraction massique" et "% fraction volumique" sont utilisés pour désigner la fraction massique (µ) d'un produit et sa fraction volumique (φ).
Naftni proizvodi - Določevanje destilacijskega območja - Metoda plinske kromatografije (ISO 3924:2019)
Ta dokument določa metodo za določevanje destilacijskega območja naftnih proizvodov. Metoda se uporablja za naftne proizvode in frakcije z zgornjo točko vretja pri temperaturi 538 °C ali manj pri atmosferskem tlaku, kot je določeno v tem dokumentu. Ta dokument se ne uporablja za vzorce bencina ali sestavine bencina. Metoda je omejena na proizvode z destilacijskim območjem nad 55 °C in dovolj nizkim parnim tlakom, ki zagotavlja vzorčenje pri temperaturi okolja. Dokument opisuje dva postopka. a) Postopek A omogoča večjo izbiro kolon in analiznih pogojev, kot so nasute ali kapilarne kolone ter tudi detektor toplotne prevodnosti poleg plamensko ionizacijskega detektorja. Časi analize zajemajo od 14 min do 60 min. b) Postopek B je omejen na samo tri kapilarne kolone, redčenje vzorca pa ni potrebno. Čas analize je skrajšan na približno 8 min. Oba postopka se uspešno uporabljata pri vzorcih, ki vsebujejo do 20 % (prostorninski delež) metil estrov maščobnih kislin (FAME).
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2019
Nadomešča:
SIST EN ISO 3924:2016
Naftni proizvodi - Določevanje destilacijskega območja - Metoda plinske
kromatografije (ISO 3924:2019)
Petroleum products - Determination of boiling range distribution - Gas chromatography
method (ISO 3924:2019)
Mineralölerzeugnisse - Bestimmung des Siedeverlaufs - Gaschromatographisches
Verfahren (ISO 3924:2019)
Produits pétroliers - Détermination de la répartition dans l'intervalle de distillation -
Méthode par chromatographie en phase gazeuse (ISO 3924:2019)
Ta slovenski standard je istoveten z: EN ISO 3924:2019
ICS:
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
75.080 Naftni proizvodi na splošno Petroleum products in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 3924
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2019
EUROPÄISCHE NORM
ICS 75.080 Supersedes EN ISO 3924:2016
English Version
Petroleum products - Determination of boiling range
distribution - Gas chromatography method (ISO
3924:2019)
Produits pétroliers - Détermination de la répartition Mineralölerzeugnisse - Bestimmung des Siedeverlaufs -
dans l'intervalle de distillation - Méthode par Gaschromatographisches Verfahren (ISO 3924:2019)
chromatographie en phase gazeuse (ISO 3924:2019)
This European Standard was approved by CEN on 30 June 2019.
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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3924:2019 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 3924:2019) has been prepared by Technical Committee ISO/TC 28 "Petroleum
and related products, fuels and lubricants from natural or synthetic sources" in collaboration with
Technical Committee CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of
petroleum, synthetic and biological origin.” 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 March 2020, and conflicting national standards shall
be withdrawn at the latest by March 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 3924:2016.
According to the CEN-CENELEC Internal Regulations, the national standards organizations 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, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 3924:2019 has been approved by CEN as EN ISO 3924:2019 without any modification.
INTERNATIONAL ISO
STANDARD 3924
Fifth edition
2019-07
Petroleum products — Determination
of boiling range distribution — Gas
chromatography method
Produits pétroliers — Détermination de la répartition dans l'intervalle
de distillation — Méthode par chromatographie en phase gazeuse
Reference number
ISO 3924:2019(E)
©
ISO 2019
ISO 3924:2019(E)
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise 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 ISO’s member body in the country of the requester.
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Published in Switzerland
ii © ISO 2019 – All rights reserved
ISO 3924:2019(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents and materials . 2
6 Apparatus . 4
7 Sampling . 7
8 Preparation of apparatus . 7
8.1 Column preparation . 7
8.1.1 General. 7
8.1.2 Packed columns . 7
8.1.3 Capillary columns . 7
8.2 Chromatograph . 8
8.3 Column resolution . 8
8.4 Detector response check . 9
8.5 Peak skewness . 9
9 Calibration .10
9.1 Analysis sequence protocol .10
9.2 Baseline compensation analysis .11
9.3 Retention time versus boiling point calibration .11
9.4 Analysis of reference material .12
10 Procedure.13
10.1 Sample preparation .13
10.2 Sample analysis .14
11 Calculation .14
12 Expression of results .14
13 Precision .15
13.1 General .15
13.2 Repeatability Procedure A .15
13.3 Reproducibility Procedure A .15
13.4 Repeatability Procedure B .16
13.5 Reproducibility Procedure B .16
13.6 Bias .16
14 Test report .17
Annex A (informative) Calculation of ISO 3405 equivalent data .18
Annex B (normative) Reference material specified values and deviation limits .21
Annex C (informative) Boiling points of non-normal n-alkane hydrocarbons .23
Annex D (informative) Boiling point revision .26
Annex E (informative) Alternative hydrogen and nitrogen carrier gases using Procedure B.27
Annex F (informative) Hydrogen and nitrogen carrier gases using Procedure A .34
Bibliography .39
ISO 3924:2019(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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels
and lubricants from natural or synthetic sources.
[3] [4]
This method was originally based on the joined IP 406 and ASTM D2887 methods.
This fifth edition cancels and replaces the fourth edition (ISO 3924:2016), which has been technically
revised. The main changes compared with the previous edition are as follows.
— The accelerated procedure has been moved from Annex B to the main body text. It is described
as Procedure B and has a precision and bias calculation in relation to Procedure A (the original
procedure).
— A new annex has been added with the newly defined boiling points for n-alkanes to keep the method
technically equivalent with IP 406 and ASTM D2887.
— Annexes E and F have been added with information on the use of alternative carrier gases.
— Several safety warnings and editorial updates have been made.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved
INTERNATIONAL STANDARD ISO 3924:2019(E)
Petroleum products — Determination of boiling range
distribution — Gas chromatography method
WARNING — The use of this document can involve hazardous materials, operations and
equipment. This document does not purport to address all the safety problems associated with
its use. It is the responsibility of users of this document to take appropriate measures to ensure
the safety and health of personnel prior to application of the document.
1 Scope
This document specifies a method for the determination of the boiling range distribution of petroleum
products. The method is applicable to petroleum products and fractions with a final boiling point of
538 °C or lower at atmospheric pressure as determined by this document. This document does not
apply to gasoline samples or gasoline components. The method is limited to products having a boiling
range greater than 55 °C and having a vapour pressure sufficiently low to permit sampling at ambient
temperature.
The document describes two procedures.
a) Procedure A allows a larger selection of columns and analysis conditions, such as packed and
capillary columns as well as a thermal conductivity detector in addition to the flame ionization
detector. Analysis times range from 14 min to 60 min.
b) Procedure B is restricted to only three capillary columns and requires no sample dilution. The
analysis time is reduced to about 8 min.
Both procedures have been successfully applied to samples containing fatty acid methyl esters (FAME)
up to 20 % (volume fraction).
NOTE For the purposes of this document, the terms “% (mass fraction)” and “% (volume fraction)” are used
to represent the mass fraction (µ), the volume fraction (φ) of a material.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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, Petroleum liquids — Manual sampling
ISO 3171, Petroleum liquids — Automatic pipeline sampling
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
ISO 3924:2019(E)
3.1
initial boiling point
IBP
temperature corresponding to the retention time at which a net area count equal to 0,5 % of the total
sample area under the chromatogram is obtained
3.2
T10, T30, T50, T70, T90
temperature (T) corresponding to the retention time at which a net area count equal to the 10 %, 30 %,
50 %, 70 % or 90 % of the total sample area under the chromatogram is obtained
3.3
final boiling point
FBP
temperature corresponding to the retention time at which a net area count equal to 99,5 % of the total
sample area under the chromatogram is obtained
3.4
slice rate
number of data slices acquired per unit of time used to integrate the continuous (analogue)
chromatographic detector response during an analysis
Note 1 to entry: The slice rate is expressed in Hz (for example, slices per second).
4 Principle
A sample is introduced into a gas chromatographic column, which separates hydrocarbons in the order
of increasing boiling point. The column temperature is raised at a reproducible rate and the area under
the chromatogram is recorded throughout the analysis. Boiling temperatures are assigned to the time
axis from a calibration curve, obtained under the same conditions by running a known mixture of
hydrocarbons covering the boiling range expected in the sample. From these data, the boiling range
distribution is obtained.
[1][5][6]
Annex A presents a correlation model for the calculation of physical distillation equivalent data
from boiling range distribution analysis by gas chromatography determined following this document.
5 Reagents and materials
5.1 Stationary phase for columns, non-polar, that elutes hydrocarbons in boiling point order.
NOTE The following materials have been used successfully as liquid phases, other stationary phases can be
used, see 6.2.
For packed columns:
— silicone gum rubber UC-W98;
— silicone gum rubber GE-SE-30;
— silicone gum rubber OV-1;
— silicone gum rubber OV-101.
For capillary columns:
— polydimethylsiloxane.
2 © ISO 2019 – All rights reserved
ISO 3924:2019(E)
5.2 Solid support for packed columns, usually consisting of crushed fire brick or chromatographic
diatomaceous earth.
The particle size and support loading shall be such as to give optimum resolution and analysis time.
NOTE In general, support loadings of 3 % to 10 % have been found most satisfactory.
5.3 Carrier gas, with a minimum purity of 99,995 %, constituted of:
a) helium for use with flame ionization detectors (FIDs) or thermal conductivity detectors;
b) for the use of nitrogen or hydrogen as a carrier gas, see Annexes E and F.
CAUTION — Helium and nitrogen are compressed gases under high pressure. Hydrogen is an
extremely flammable gas under high pressure.
5.4 Hydrogen, grade suitable for FIDs.
CAUTION — Hydrogen is an extremely flammable gas under high pressure.
5.5 Compressed air, free of oil and water, regulated for FIDs.
CAUTION — Compressed air is a gas under high pressure and supports combustion.
5.6 Calibration mixture, consisting of an accurately weighed mixture of n-alkanes covering the range
from C to C and dissolved in carbon disulfide (5.8).
5 44
For packed columns, the final concentration in mass should be approximately 10 parts of the n-alkane
mixture to 100 parts of carbon disulfide. For capillary columns, the final concentration in mass should
be approximately 1 part of the n-alkane mixture to 100 parts of carbon disulfide.
The following mixture of n-alkanes has been found to be satisfactory for most samples: C , C , C , C ,
5 6 7 8
C , C , C , C , C , C , C , C , C , C , C , C , C . At least one component of the mixture shall
9 10 12 14 16 18 20 24 28 32 36 40 44
have a boiling point lower than the initial boiling point (IBP) of the sample and at least one component
shall have a boiling point higher than the final boiling point (FBP) of the sample. The boiling points of
n-alkanes are listed in Table 1.
If the test sample contains significant quantities of n-alkanes that can be identified on the chromatogram,
these peaks can be used as internal boiling point calibration points. However, it is advisable to use the
calibration mixture to be sure of peak identifications.
Propane and butane can be added non-quantitatively to the calibration mixture, if necessary, to conform
to 5.6. This can be done by bubbling a small amount of the gaseous hydrocarbon into a septum-sealed
vial of the calibration mixture using a gas syringe.
If stationary phases other than those listed in the note in 5.1 are used, the retention times of a few
alkylbenzenes across the boiling range, such as o-xylene, n-butylbenzene, 1,3,5-tri-isopropylbenzene,
n-decylbenzene and n-tetradecylbenzene, shall also be checked to make certain that the column is
separating according to the boiling point order (see Annex C).
5.7 Reference material, the primary reference material used shall be ASTM reference gas oil no. 1 or
no. 2 (as specified in Annex B).
5.8 Carbon disulfide, reagent grade or better (CAS RN 75-15-0).
CAUTION — Carbon disulfide is extremely volatile flammable and toxic.
ISO 3924:2019(E)
Table 1 — Boiling points of normal n-alkanes
Carbon no. Boiling point Carbon no. Boiling point
°C °C
2 −89 24 391
3 −42 25 402
4 0 26 412
5 36 27 422
6 69 28 431
7 98 29 440
8 126 30 449
9 151 31 458
10 174 32 466
11 196 33 474
12 216 34 481
13 235 35 489
14 254 36 496
15 271 37 503
16 287 38 509
17 302 39 516
18 316 40 522
19 330 41 528
20 344 42 534
21 356 43 540
22 369 44 545
23 380
[5]
NOTE API Project 44 is believed to have provided the original normal paraffin boiling point data that were listed in former
editions of this document. However, over the years, some of the data contained in both API Project 44 (Thermodynamics
Research Center Hydrocarbon Project) and the test methods have changed, and they are no longer equivalent. This table
represents the current normal paraffin boiling point values accepted by ISO, ASTM and the Energy Institute. Annex D
contains information about revised boiling points.
6 Apparatus
6.1 Chromatograph, any gas chromatograph that has the following performance characteristics can
be used.
6.1.1 Detector, of either the flame ionization or thermal conductivity type.
The detector shall have sufficient sensitivity to detect a mass fraction of 1,0 % of dodecane with a peak
height of at least 10 % of full scale under the conditions specified in this document, and without loss of
resolution as defined in 8.3. When operating at this sensitivity level, detector stability shall be such that
a baseline drift of not more than 1 % of full scale per hour is obtained. The detector shall be capable of
operating continuously at a temperature equivalent to the maximum column temperature employed.
The detector shall be connected to the column in such a way that any cold spots between the detector
and the column are avoided.
NOTE It is not desirable to operate thermal conductivity detectors at a temperature higher than the
maximum column temperature employed. Operation at higher temperatures only serves to shorten the useful
life of the detector, and generally contributes to higher noise levels and greater drift.
4 © ISO 2019 – All rights reserved
ISO 3924:2019(E)
6.1.2 Column temperature programmer, capable of programmed temperature operation over a
range sufficient to establish a retention time of at least 1 min for the IBP and to elute the entire sample
within the temperature ramp.
The programming rate shall be sufficiently reproducible to obtain retention time repeatability of 6 s for
each component in the calibration mixture (5.6).
6.1.3 Cryogenic column cooling. Column starting temperatures below ambient will be required if
samples with IBPs of less than 93 are to be analysed. This is typically provided by adding a source of
either liquid carbon dioxide or liquid nitrogen, controlled through the oven temperature circuitry.
However, excessively low initial column temperatures shall be avoided, to ensure that the stationary
phase remains liquid. The initial temperature of the column shall be only low enough to obtain a
calibration curve meeting the requirements of this document.
6.1.4 Sample inlet system. Programmed temperature vaporization (PTV) inlets or cool on-column
inlets shall be used for this method.
The sample inlet system shall be connected to the chromatographic column in such a way that any cold
spots between the inlet system and the column are avoided.
6.2 Column. Any column and conditions can be used, provided that, under the conditions of the test,
separations are in the order of boiling points as given in Table 1, and the column resolution, R , is at
c
least three (see 8.3). Typical column operating conditions are given in Tables 2, 3 and 4.
Table 2 — Typical operating conditions for packed columns — Procedure A
Parameter Column 1
Column length (m) 0,7
Column outside diameter (mm) 3,2
Stationary phase OV-101
Per cent stationary phase 5
a
Support material G
Support mesh size (μm) 80/100
Initial column temperature (°C) −40
Final column temperature (°C) 350
Programming rate (°C/min) 10
Carrier gas Helium
Carrier gas flow (ml/min) 30
Inlet Packed inlet
Detector FID
Detector temperature (°C) 370
Injection-port temperature (°C) 370
Sample size (μl), neat sample volume 0,5
a
Dioxosilane.
ISO 3924:2019(E)
Table 3 — Typical operating conditions for capillary columns — Procedure A
Parameter Column 2 Column 3
Column length (m) 5 10
Column inner diameter (mm) 0,53 0,53
Column PDMS PDMS
Stationary phase thickness (μm) 0,88 2,65
Carrier gas Helium Helium
Carrier gas flow rate (ml/min) 12 20
Initial column temperature (°C) 35 40
Final column temperature (°C) 350 350
Programming rate (°C/min) 10 15
Final time at final column temperature (min) 4 4
Detector FID FID
Detector temperature (°C) 380 350
Programmed temperature
Injector temperature (°C) Cool on-column type
vaporization type
Sample size (μl) 1 0,2
Sample concentration [% (mass fraction)] 10 Neat
Key
PDMS = polydimethylsiloxane.
Table 4 — Typical operating conditions for accelerated analysis — Procedure B
Parameter Column 1 Column 2 Column 3
Column length (m) 10 5 7,5
Column ID (mm) 0,53 0,53 0,53
a a a
Stationary phase PDMS PDMS PDMS
Stationary phase thickness (µm) 0,88 2,65 1,5
Carrier gas Helium Helium Helium
Carrier gas flow rate (ml/min) 26 35 37
Initial column temperature (°C) 60 40 40 (0,5 min)
Final column temperature (°C) 360 350 360
Oven programming rate (°C/min) 35 35 35
Final time at final column temperature (min) 4 4 4
Detector FID FID FID
Detector temperature (°C) 360 360 365
Injector PTV PTV Cool on-column
Injector initial temperature (°C) 100 100 100 (0,5 min)
Injector programming rate (°C/min) 35 35 35
Injector final temperature (°C) 360 350 350
Sample size (µl) 0,1 0,1 0,1
Dilution concentration Neat Neat Neat
Analysis time (min) 8 7,8 8
Key
PDMS = polydimethylsiloxane.
6 © ISO 2019 – All rights reserved
ISO 3924:2019(E)
6.3 Integrator/computer, used for determining the accumulated area under the chromatogram. This
can be achieved by using a computer-based chromatography data system or an electronic integrator. The
integrator/computer system shall have normal chromatographic software for measuring the retention
times and areas of eluting peaks. In addition, the system shall be capable of converting the continuously
integrated detector signal into area slices of fixed duration. These contiguous area slices, collected for
the entire analysis, shall be stored for later processing. The electronic range of the integrator/computer
(e.g. 1 V) shall be within the linear range of the detector/electrometer system used. The system shall be
capable of subtracting the area slice of a blank run from the corresponding area slice of a sample run.
NOTE Some gas chromatographs have an algorithm built into their operating software that allows a
mathematical model of the baseline profile to be stored in the memory. This profile can be automatically
subtracted from the detector signal on subsequent sample analysis to compensate for any baseline offset. Some
integration systems also store and automatically subtract a blank analysis from subsequent sample analysis.
6.4 Flow/pressure controllers.
6.4.1 If a packed column is used, the chromatograph shall be equipped with constant-flow controllers
capable of maintaining the carrier gas flow constant over the full operating temperature range.
6.4.2 If a wide-bore capillary column is used, the chromatograph shall be equipped with a controller of
carrier gas flow or pressure appropriate for the inlet used.
6.5 Micro-syringe, used to introduce the sample into the chromatograph. Sample injection can be
either manual or automatic. Automatic sample injection is preferred because it gives better retention
time precision.
7 Sampling
Unless otherwise specified, samples shall be taken by the procedures described in ISO 3170 or ISO 3171.
8 Preparation of apparatus
8.1 Column preparation
8.1.1 General
Any satisfactory method that will produce a column meeting the requirements of 6.2 can be used. The
column shall be conditioned at the maximum operating temperature to reduce baseline shifts due to
bleeding of the column substrate.
8.1.2 Packed columns
An acceptable method of column conditioning, which has been found effective for columns with an
initial loading of 10 % liquid phase, consists of purging the column with carrier gas at the normal flow
rate while holding the column at the maximum operating temperature for 12 h to 16 h.
8.1.3 Capillary columns
Capillary columns shall be conditioned using the following procedure.
a) Install the column following the manufacturer’s instructions. Set the column and detector gas
flows. Ensure that the system is leak free.
b) Allow the system to purge with carrier gas at ambient temperature for at least 30 min. Then
increase the oven temperature by approximately 5 °C/min to 10 °C/min to the final operating
temperature and hold for approximately 30 min.
ISO 3924:2019(E)
c) Cycle the chromatograph through its temperature programme several times until a stable baseline
is obtained.
NOTE 1 Capillary columns with cross-linked and bonded phases are available from many manufacturers and
are usually preconditioned. These columns have much lower column bleed than packed columns.
NOTE 2 The column is not always connected to the FID when making a first conditioning of the column to
overcome that initial column bleed affects the detector’s sensitivity.
8.2 Chromatograph
Place the chromatograph in service in accordance with the manufacturer’s instructions. Typical
operating conditions are shown in Tables 2 and 3.
If a FID is used, the deposits formed in the detector from combustion of the silicone decomposition
products shall be removed regularly, as they change the response characteristics of the detector.
8.3 Column resolution
Analyse the calibration mixture under the same conditions as those used for the samples. Using the
procedure illustrated in Figure 1, calculate the resolution, R , from the time between the hexadecane
c
and octadecane peaks at the peak maxima t and t and the widths y and y of the peaks at half height,
1 2 1 2
as given by Formula (1).
Key
X time, in s y width of hexadecane peak at half height, in s
Y detector signal y width of octadecane peak at half height, in s
t start analysis time 1 hexadecane
t retention time hexadecane, in s 2 octadecane
t retention time octadecane, in s
Figure 1 — Column resolution parameters
8 © ISO 2019 – All rights reserved
ISO 3924:2019(E)
2 tt−
()
R = (1)
c
1,699 yy+
()
where
t is the retention time, in seconds, for hexadecane peak maximum;
t is the retention time, in seconds, for octadecane peak maximum;
y is the width, in seconds, at half height of hexadecane peak;
y is the width, in seconds, at half height of octadecane peak.
The resolution, R , obtained from Formula (1), shall be at least three.
c
8.4 Detector response check
This method assumes that the detector response to petroleum hydrocarbons is proportional to the
mass of individual components. This shall be verified when the system is put into service and whenever
any changes are made to the system or operational parameters. Analyse the calibration mixture (5.6)
using the same conditions as those used for the samples. Calculate the response factor, F , for each
n
n-alkane relative to decane using Formula (2):
mA/
nn
F = (2)
n
mA/
10 10
where
F is the relative response factor;
n
m is the mass of the n-alkane in the mixture;
n
A is the peak area of the n-alkane;
n
m is the mass of decane in the mixture;
A is the peak area of decane.
The relative response factor, F , of each n-alkane shall not deviate from 1,0 by more than ±0,1.
n
8.5 Peak skewness
Determine the peak skewness (the ratio A/B) of the largest peak in the calibration mixture (5.6) as
shown in Figure 2.
The peak skewness shall be not less than 0,5 and not more than 2,0. If peak skewness is outside these
parameters, reanalyse the calibration mixture using a smaller sample size or a more dilute solution, if
necessary, to avoid peak distortion.
NOTE Skewness is often an indication of overloading the column that results in displacement of the peak
apex relative to non-overloaded peaks. Distortion in retention time measurement and hence errors in boiling
point determination will be likely if column overloading occurs. The column liquid phase loading has a direct
bearing on the acceptable sample size.
ISO 3924:2019(E)
Key
X time, in s
Y detector signal
A width of the leading part of the peak at 5 % of peak height, in s
B width of the trailing part of the peak at 5 % of peak height, in s
Figure 2 — Peak skewness
9 Calibration
9.1 Analysis sequence protocol
9.1.1 Define and use for all runs a predetermined schedule of analysis events to achieve maximum
reproducibility. The schedule shall include cooling the oven to the initial starting temperature,
equilibration time, sample injection and system start, and analysis and final temperature hold time.
9.1.2 After the chromatographic conditions have been set to meet performance requirements,
programme the column temperature upward to the maximum temperature to be used and hold that
temperature for the selected time. Following the analysis sequence protocol, cool the column to the
initial starting temperature.
9.1.3 During the cool down and equilibration time, prepare the integrator/computer system for
data acquisition. If a retention time or detector response calibration is being performed, use the peak
detection mode. For samples and baseline compensation determinations, use the area slice mode of
integration. The recommended slice rate for this method is 1 Hz (one slice per second).
9.1.4 At the exact time set by the schedule, inject either the calibration mixture (5.6) or sample into the
chromatograph, or make no injection (baseline blank). At the time of injection and/or at the start of the
baseline blank, start the chromatograph time cycle and the integrator/computer data acquisition. Follow
this analysis sequence protocol for all subsequent analysis, blanks or calibrations.
10 © ISO 2019 – All rights reserved
ISO 3924:2019(E)
9.2 Baseline compensation analysis
9.2.1 A baseline compensation analysis, or baseline blank, shall be performed at least once each day
that the test is run, using the same technique for a sample analysis except that no injection is made.
NOTE The blank analysis is necessary due to the normal occurrence of chromatographic baseline rise near
the maximum column temperature. Factors that influence baseline stability are column bleed, septum bleed,
detector temperature control, constancy of carrier and detector gas flows, leaks, instrument drift, etc.
9.2.2 Subtract the blank analysis from the sample analysis to remove any non-sample slice area from
the chromatographic data.
The blank analysis is typically performed prior to sample analysis, but can be useful if determined
between samples or at the end of a sample sequence to provide additional data regarding instrument
operation or residual sample carry-over from previous sample analysis.
9.2.3 Carry out periodic baseline blank analysis in accordance with the analysis sequence protocol to
give an indication of baseline stability.
9.3 Retention time versus boiling point calibration
9.3.1 It is highly recommended to perform a retention time versus boiling point calibration
(see Figure 3) at least once each day that the test is run. Inject an appropriate aliquot (0,2 μl to 2,0 μl) of
the calibration mixture (5.6) into the chromatograph following the analysis sequence protocol.
Figure 3 — Typical chromatogram of a retention time versus boiling point sample
9.3.2 Prepare a calibration table based on the results of the analysis of the calibration mixture (5.6)
by recording the retention time and the boiling temperature for each component in the mixture. Boiling
temperatures of n-alkanes are listed in Table 1.
9.3.3 Plot the retention time of each peak versus the corresponding boiling temperature for that
component. A typical calibration curve is shown in Figure 4.
9.3.4 Ensure that calibration points bracket the boiling range of the sample at both the low and high
ends. Ideally, the calibration plot of retention time versus boiling temperature should be linear, but it is
impractical to operate the chromatograph such that curvature is eliminated completely.
ISO 3924:2019(E)
NOTE The greatest potential for deviation from linearity is associated with the lower boiling point n-alkanes,
which elute from the column relatively quickly and have the largest difference in boiling temperatures. In general,
the lower the sample IBP, the lower the starting point of the analysis will be.
9.4 Analysis of reference material
9.4.1 The reference material (5.7) is used to verify both the chromatographic and calculation processes
involved in this method.
A secondary reference material can be used, providing it satisfies the following criteria:
a) it is similar in nature and boiling range to the samples to be analysed;
b) the boiling range distribution values assigned to that obtained by averaging multiple analysis of
the secondary reference material on a system that is first shown to be operating properly with the
primary reference material (5.7).
9.4.2 Analyse the primary reference material (5.7) or a secondary reference material at least once each
day that the test is run. Perform an analysis of the reference material following the analysis sequence
protocol (see 9.1). Collect the area slice data and provide a boiling point distribution report in accordance
with 12.1. See Figure 4 for a typical chromatogram of reference material.
Figure 4 — Typical chromatogram of a reference material
12 © ISO 2019 – All rights reserved
ISO 3924:2019(E)
9.4.3 The results of the analysis of the reference material (either batch 1 or batch 2 can be used)
shall not deviate more from the values for that batch given in Annex B than the range specified by the
reproducibility of this document (see 13.3 or 13.5). See Figure 5 for a typical calibration curve.
Key
X retention time, in min
Y boiling point, in °C
Figure 5 — Typical calibration curve
10 Procedure
10.1 Sample preparation
10.1.1 The
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