SIST EN 12916:2019

Petroleum products - Determination of aromatic hydrocarbon types in middle distillates - High performance liquid chromatography method with refractive index detection

This European Standard specifies a test method for the determination of the content of mono-aromatic, di-aromatic and tri+-aromatic hydrocarbons in diesel fuels that may contain fatty acid methyl esters (FAME) up to 30 % (V/V), in paraffinic diesel fuels that may contain fatty acid methyl esters (FAME) up to 7 % (V/V) and petroleum distillates in the boiling range from 150 °C to 400 °C. The polycyclic aromatic hydrocarbons content is calculated from the sum of di-aromatic and tri+-aromatic hydrocarbons and the total content of aromatic compounds is calculated from the sum of the individual aromatic hydrocarbon types.
Compounds containing sulfur, nitrogen and oxygen can interfere in the determination; mono-alkenes do not interfere, but conjugated di-alkenes and poly-alkenes, if present, may do so.
The precision statement of the procedure A, for regular distillates, has been established for diesel fuels with and without FAME blending components, with a mono-aromatic content in the range from 6 % (m/m) to 30 % (m/m), a di-aromatic content from 1 % (m/m) to 10 % (m/m), a tri+-aromatic content from 0 % (m/m) to 2 % (m/m), a polycyclic aromatic content from 1 % (m/m) to 12 % (m/m), and a total aromatic content from 7 % (m/m) to 42 % (m/m). The precision statement of the procedure B, for non-aromatic distillates, has been established for diesel fuels, with and without FAME blending components, with a mono-aromatic content in the range from 0,2 % (m/m) to 1,8 % (m/m), di-aromatic and polycyclic aromatic contents around 0,1 % (m/m), and a total aromatic content from 0,2 % (m/m) to 2 % (m/m).

Mineralölerzeugnisse - Bestimmung von aromatischen Kohlenwasserstoffgruppen in Mitteldestillaten - Hochleistungsflüssigkeitschromatographie-Verfahren mit Brechzahl-Detektion

Dieses Dokument legt ein Prüfverfahren zur Bestimmung des Gehaltes an monoaromatischen, diaromatischen und tri+-aromatischen Kohlenwasserstoffen in Dieselkraftstoffen, paraffinischen Dieselkraftstoffen und Mineralöldestillaten fest.
Dieses Dokument legt zwei Verfahren fest, A und B.
Verfahren A gilt für Dieselkraftstoffe, die bis zu 30 % (V/V) Fettsäuremethylester (FAME; en: fatty acid methyl ester) (wie in [1], [2] und [3]) sowie Mineralöldestillate im Siedebereich von 150 °C bis 400 °C (wie in [4]) enthalten dürfen.
Verfahren B gilt für paraffinische Dieselkraftstoffe mit bis zu 7 % (V/V) FAME. Dieses Verfahren beinhaltet keine Verdünnung von Proben, damit die geringen Konzentrationen aromatischer Komponenten in diesen Kraftstoffen bestimmt werden können.
Der Gehalt an polyzyklischen aromatischen Kohlenwasserstoffen wird als Summe der Gehalte an diaro-matischen und tri+-aromatischen Kohlenwasserstoffen berechnet; der Gesamtgehalt an aromatischen Kohlenwasserstoffen errechnet sich aus der Summe der individuellen aromatischen Kohlenwasserstofftypen.
Verbindungen, die Schwefel, Stickstoff und Sauerstoff enthalten, können die Bestimmung stören; Mono-alkene stören nicht, während sich vorhandene konjugierte Diene und Polyene störend auswirken können.
ANMERKUNG 1   Für die Zwecke dieser Europäischen Norm wird zur Angabe des Massenanteils, µ, einer Substanz der Ausdruck "% (m/m)" und für den Volumenanteil, φ, einer Substanz der Ausdruck "% (V/V)" verwendet.
ANMERKUNG 2   Vereinbarungsgemäß werden die aromatischen Kohlenwasserstofftypen auf Basis ihrer charakteris-tischen Elution von der angegebenen Säule für Flüssigchromatographie relativ zu aromatischen Modellverbindungen festgelegt. Die Quantifizierung jeder aromatischen Verbindungsklasse erfolgt durch externe Kalibrierung mit einer einzelnen aromatischen Verbindung für jeden Typ, die für die Aromaten in der Probe repräsentativ sein kann oder nicht. Andere Techniken und Prüfverfahren können die verschiedenen aromatischen Kohlenwasserstoffklassen anders klassifizieren und quantifizieren.
ANMERKUNG 3   Rückspülung ist Teil der laborinternen Wartung.
WARNUNG - Die Anwendung dieser Norm kann die Anwendung gefährlicher Stoffe, Arbeitsgänge und Geräte mit sich bringen. Diese Norm beansprucht nicht, alle damit verbundenen Sicherheitsprobleme zu behandeln. Es liegt in der Verantwortung des Anwenders dieser Norm, vor ihrer Anwendung geeignete Maßnahmen für die Sicherheit und den Gesundheitsschutz des Personals zu ergreifen und dafür Sorge zu tragen, dass behördliche und gesetzliche Maßnahmen eingehalten werden.

Produits pétroliers - Détermination des familles d'hydrocarbures dans les distillats moyens - Méthode par chromatographie liquide à haute performance avec détection par réfractométrie différentielle

Le présent document prescrit une méthode pour déterminer la teneur en hydrocarbures mono-aromatiques, di-aromatiques, et tri+-aromatiques des carburants diesel, des carburants diesel paraffiniques et des distillats pétroliers.
Le présent document définit deux modes opératoires, A et B.
La procédure A est applicable aux carburants diesel, qui peuvent contenir des esters méthyliques d’acides gras (EMAG) jusqu’à 30 % (V/V) (comme ceux prescrits dans [1], [2] ou [3]), et distillats pétroliers d'intervalle d'ébullition de 150 °C à 400 °C (comme ceux prescrits dans [4]).
La procédure B est applicable aux carburants diesel paraffiniques qui peuvent contenir jusqu’à 7 % (V/V) d’EMAG. Cette procédure n’implique pas d’étape de dilution de l’échantillon afin de déterminer les faibles teneurs en aromatiques dans ces carburants.
La teneur en hydrocarbures aromatiques polycycliques est calculée à partir de la somme des di-aromatiques, et tri+-aromatiques, et la teneur totale en composés aromatiques est calculée à partir de la somme des teneurs des différentes familles de composés aromatiques.
Les composés soufrés, azotés et oxygénés peuvent interférer dans la mesure. Les mono-oléfines n'interfèrent pas, au contraire des dioléfines conjuguées et des polyoléfines qui peuvent interférer, si elles sont présentes.
NOTE 1   Pour les besoins de la présente Norme européenne, les expressions "% (m/m)" et “% (V/V)” sont utilisées pour désigner respectivement les fractions massiques, µ, et les fractions volumiques, φ, d’un produit.
NOTE 2   Par convention, la présente Norme définit les familles d’hydrocarbures aromatiques à partir de leurs caractéristiques d’élution dans la colonne de chromatographie liquide prescrite, et par comparaison aux temps d'élution des composés aromatiques servant de modèle. La quantification est effectuée par étalonnage externe avec un seul composé aromatique par famille d’hydrocarbures aromatiques, ce composé pouvant être ou non représentatif des aromatiques présents dans l’échantillon. Il est possible que des techniques et méthodes alternatives classent et quantifient différemment les familles d'hydrocarbures aromatiques.
AVERTISSEMENT — L'utilisation de la présente norme peut impliquer la mise en œuvre de produits, d'opérations et d'équipements à caractère dangereux. La présente norme n'est pas censée aborder tous les problèmes de sécurité concernés par son usage. Il est de la responsabilité des utilisateurs de cette norme de prendre les mesures appropriées pour assurer la sécurité et préserver la santé du personnel avant son application, et pour répondre aux exigences réglementaires et statutaires à cette fin.

Naftni proizvodi - Določevanje aromatskih ogljikovodikov v srednjih destilatih - Metoda tekočinske kromatografije visoke ločljivosti z detekcijo lomnega količnika

Ta evropski standard opredeljuje preskusno metodo za določanje vsebnosti monoaromatskih, diaromatskih in tri+-aromatskih ogljikovodikov v dizelskih gorivih, ki lahko vsebujejo do 30-odstotkov (V/V) metilnih estrov maščobnih kislin (FAME), v parafinskih dizelskih gorivih, ki lahko vsebujejo do sedem odstotkov (V/V) metilnih estrov maščobnih kislin, in naftne destilate z območjem vrelišča od 150 °C do 400 °C. Vsebnost policikličnih aromatskih ogljikovodikov je izračunana na podlagi vsote diaromatskih in tri+-aromatskih ogljikovodikov, skupna vsebnost aromatskih spojin pa je izračunana na podlagi vsote posameznih vrst aromatskih ogljikovodikov. Spojine, ki vsebujejo žveplo, dušik in kisik, lahko povzročajo motnje pri določanju; monoalkeni ne povzročajo motenj pri določanju, konjugirani dialkeni in polialkeni pa jih lahko povzročajo, če so prisotni. Izjava o natančnosti postopka A za običajne destilate je bila določena za dizelska goriva s komponentami in brez komponent za mešanje z metilnimi estri maščobnih kislin, ki vsebujejo od šest odstotkov (m/m) do 30 odstotkov (m/m) monoaromatskih spojin, od en odstotek (m/m) do deset odstotkov (m/m) diaromatskih spojin, od 0 odstotkov (m/m) do dva odstotka (m/m) triaromatskih spojin, od en odstotek (m/m) do dvanajst odstotkov (m/m) policikličnih aromatskih spojin in od sedem odstotkov (m/m) do 42 odstotkov (m/m) skupnih aromatskih spojin. Izjava o natančnosti postopka A za nearomatske destilate je bila določena za dizelska goriva s komponentami in brez komponent za mešanje z metilnimi estri maščobnih kislin, ki vsebujejo od 0,2 odstotka (m/m) do 1,8 odstotka (m/m) monoaromatskih spojin, okoli 0,1 odstotka (m/m) diaromatskih in policikličnih aromatskih spojin in od 0,2 odstotka (m/m) do 2 odstotka (m/m) skupnih aromatskih spojin.

General Information

• Status: Withdrawn
• Public Enquiry End Date: 03-Aug-2017
• Publication Date: 05-Jun-2019
• Withdrawal Date: 23-Aug-2022
• ICS: 71.040.50 - Physicochemical methods of analysis
• ICS: 75.080 - Petroleum products in general
• Technical Committee: NAD - Petroleum products, lubricants and related products
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 19-Aug-2022
• Due Date: 11-Sep-2022
• Completion Date: 24-Aug-2022
• Ref Project: EN 12916:2019 - Petroleum products - Determination of aromatic hydrocarbon types in middle distillates - High performance liquid chromatography method with refractive index detection

Relations

• Consolidated By: SIST EN 12916:2019+A1:2022 - Petroleum products - Determination of aromatic hydrocarbon types in middle distillates - High performance liquid chromatography method with refractive index detection
• Effective Date: 18-Jan-2023
• Replaces: SIST EN 12916:2016 - Petroleum products - Determination of aromatic hydrocarbon types in middle distillates - High performance liquid chromatography method with refractive index detection
• Effective Date: 01-Jul-2019
• Amended By: SIST EN 12916:2019/oprA1:2021 - Petroleum products - Determination of aromatic hydrocarbon types in middle distillates - High performance liquid chromatography method with refractive index detection
• Effective Date: 01-Dec-2021
• Consolidated By: SIST EN 12916:2019+A1:2022 - Petroleum products - Determination of aromatic hydrocarbon types in middle distillates - High performance liquid chromatography method with refractive index detection
• Effective Date: 01-Oct-2022
• Replaces: SIST EN 12916:2016 - Petroleum products - Determination of aromatic hydrocarbon types in middle distillates - High performance liquid chromatography method with refractive index detection
• Effective Date: 08-Jun-2022

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 12916:2019
01-julij-2019
Nadomešča:
SIST EN 12916:2016
Naftni proizvodi - Določevanje aromatskih ogljikovodikov v srednjih destilatih -

Metoda tekočinske kromatografije visoke ločljivosti z detekcijo lomnega količnika

Petroleum products - Determination of aromatic hydrocarbon types in middle distillates -

High performance liquid chromatography method with refractive index detection
Mineralölerzeugnisse - Bestimmung von aromatischen Kohlenwasserstoffgruppen in

Mitteldestillaten - Hochleistungsflüssigkeitschromatographie-Verfahren mit Brechzahl-

Detektion

Produits pétroliers - Détermination des familles d'hydrocarbures dans les distillats

moyens - Méthode par chromatographie liquide à haute performance avec détection par

réfractométrie différentielle
Ta slovenski standard je istoveten z: EN 12916:2019
ICS:
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
75.080 Naftni proizvodi na splošno Petroleum products in
general
SIST EN 12916:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 12916:2019
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SIST EN 12916:2019
EN 12916
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2019
EUROPÄISCHE NORM
ICS 75.080 Supersedes EN 12916:2016
English Version
Petroleum products - Determination of aromatic
hydrocarbon types in middle distillates - High
performance liquid chromatography method with
refractive index detection

Produits pétroliers - Détermination des familles Mineralölerzeugnisse - Bestimmung von aromatischen

d'hydrocarbures aromatiques dans les distillats Kohlenwasserstoffgruppen in Mitteldestillaten -

moyens - Méthode par chromatographie liquide à Hochleistungsflüssigkeitschromatographie-Verfahren

haute performance avec détection par réfractométrie mit Brechzahl-Detektion
différentielle
This European Standard was approved by CEN on 15 April 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, 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 12916:2019 E

worldwide for CEN national Members.
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SIST EN 12916:2019
EN 12916:2019 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

1 Scope .................................................................................................................................................................... 4

2 Normative references .................................................................................................................................... 4

3 Terms and definitions ................................................................................................................................... 5

4 Principle ............................................................................................................................................................. 6

5 Reagents and materials ................................................................................................................................. 6

6 Apparatus ........................................................................................................................................................... 7

7 Sampling ............................................................................................................................................................. 8

8 Apparatus preparation ................................................................................................................................. 8

9 Calibration ...................................................................................................................................................... 11

10 Procedure........................................................................................................................................................ 12

10.1 Procedure A for diesel fuels and petroleum distillates .................................................................. 12

10.2 Procedure B for paraffinic diesel fuels ................................................................................................. 12

10.3 Procedure A and B continuation ............................................................................................................. 12

11 Calculation ...................................................................................................................................................... 15

11.1 Retention times ............................................................................................................................................. 15

11.2 Column resolution ....................................................................................................................................... 15

11.3 Cut times .......................................................................................................................................................... 15

11.4 Aromatic hydrocarbons type content ................................................................................................... 16

11.5 Polycyclic and total aromatic hydrocarbons content ..................................................................... 16

12 Expression of results ................................................................................................................................... 16

13 Precision .......................................................................................................................................................... 16

13.1 General ............................................................................................................................................................. 16

13.2 Repeatability, r .............................................................................................................................................. 17

13.3 Reproducibility, R ........................................................................................................................................ 17

14 Test report ...................................................................................................................................................... 17

Annex A (informative) Column selection and use ........................................................................................... 18

Annex B (informative) Practical instructions for paraffinic diesel fuel samples ................................. 19

Bibliography ................................................................................................................................................................. 20

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SIST EN 12916:2019
EN 12916:2019 (E)
European foreword

This document (EN 12916:2019) has been prepared by 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 November 2019, and conflicting national standards

shall be withdrawn at the latest by November 2019.

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 12916:2016.

Major change compared to the previous version is the addition of a procedure for the analysis of very

low contents of aromatics in paraffinic diesel fuels. The method now comprises two procedures, A and

B. Procedure A covers diesel fuels and other distillates. Procedure B is set up for paraffinic diesel fuels

which do not require a dilution step. Both procedures have a separate precision statement. Additionally,

the required accuracy of the weighing of the system calibration standards 1 and 2 was increased from

0,001 g to 0,000 1 g.

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, Former Yugoslav Republic of Macedonia,

France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,

Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
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SIST EN 12916:2019
EN 12916:2019 (E)
1 Scope

This document specifies a test method for the determination of the content of mono-aromatic,

di-aromatic and tri+-aromatic hydrocarbons in diesel fuels, paraffinic diesel fuels and petroleum

distillates.
This document defines two procedures, A and B.

Procedure A is applicable to diesel fuels that may contain fatty acid methyl esters (FAME) up to

30 % (V/V) (as in [1], [2] or [3]) and petroleum distillates in the boiling range from 150 °C to 400 °C (as

in [4].

Procedure B is applicable to paraffinic diesel fuels with up to 7 % (V/V) FAME. This procedure does not

contain a dilution of the sample in order to determine the low levels of aromatic components in these

fuels.

The polycyclic aromatic hydrocarbons content is calculated from the sum of di-aromatic and tri+-

aromatic hydrocarbons and the total content of aromatic compounds is calculated from the sum of the

individual aromatic hydrocarbon types.

Compounds containing sulfur, nitrogen and oxygen can interfere in the determination; mono-alkenes do

not interfere, but conjugated di-alkenes and poly-alkenes, if present, can do so.

NOTE 1 For the purpose of this European Standard, the terms “% (m/m)” and “% (V/V)” are used to represent

the mass fraction, µ, and the volume fraction, φ, of a material respectively.

NOTE 2 By convention, the aromatic hydrocarbon types are defined on the basis of their elution characteristics

from the specified liquid chromatography column relative to model aromatic compounds. Their quantification is

performed using an external calibration with a single aromatic compound for each of them, which may or may not

be representative of the aromatics present in the sample. Alternative techniques and test methods may classify

and quantify individual aromatic hydrocarbon types differently.
NOTE 3 Backflush is part of laboratory-internal maintenance.

WARNING — The use of this standard can involve hazardous materials, operations and

equipment. This standard does not purport to address all of the safety problems associated with

its use. It is the responsibility of users of this standard to take appropriate measures to ensure

the safety and health of personnel prior to application of the standard, and fulfil statutory and

regulatory requirements for this purpose.
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.

EN 14214, Liquid petroleum products — Fatty acid methyl esters (FAME) for use in diesel engines and

heating applications — Requirements and test methods
EN ISO 1042, Laboratory glassware — One-mark volumetric flasks (ISO 1042)
EN ISO 3170, Petroleum liquids — Manual sampling (ISO 3170)
EN ISO 3171, Petroleum liquids — Automatic pipeline sampling (ISO 3171)
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SIST EN 12916:2019
EN 12916:2019 (E)
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:

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
non-aromatic hydrocarbon

compound having a shorter retention time on the specified polar column than the majority of mono-

aromatic hydrocarbons
3.2
mono-aromatic hydrocarbon
MAH

compound having a longer retention time on the specified polar column than the majority of non-

aromatic hydrocarbons, but a shorter retention time than the majority of di-aromatic hydrocarbons

3.3
di-aromatic hydrocarbon
DAH

compound having a longer retention time on the specified polar column than the majority of mono-

aromatic hydrocarbons, but a shorter retention time than the majority of tri+-aromatic hydrocarbons

3.4
tri+-aromatic hydrocarbon
T+AH

compound having a longer retention time on the specified polar column than the majority of di-

aromatic hydrocarbons including chrysene
3.5
polycyclic aromatic hydrocarbon
POLY-AH
sum of the di-aromatic hydrocarbons and tri+-aromatic hydrocarbons
3.6
total aromatic hydrocarbon

sum of the mono-aromatic hydrocarbons, di-aromatic hydrocarbons and tri+-aromatic hydrocarbons

Note 1 to entry: Published and unpublished data indicate that the major constituents for each hydrocarbon type

include:

a) non-aromatic hydrocarbons: cyclic and acyclic alkanes (paraffins and naphthenes), mono-alkenes (if

present),

b) MAHs: benzenes, tetralins, indanes and higher naphthenobenzenes (e.g. octahydrophenanthrenes),

thiophenes, styrenes, conjugated polyalkenes,

c) DAHs: naphthalenes, biphenyls, indenes, fluorenes, acenaphthenes, benzothiophenes and dibenzothiophenes,

d) T+AHs: phenanthrenes, pyrenes, fluoranthenes, chrysenes, triphenylenes, benzanthracenes.

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SIST EN 12916:2019
EN 12916:2019 (E)
3.7
fatty acid methyl ester
FAME

mixture of fatty acid methyl esters derived from vegetable oil or animal fats and complying to the

specification defined in EN 14214
4 Principle

A known mass of sample is taken and a fixed volume of this sample is injected into a high performance

liquid chromatograph fitted with a polar column. Diesel fuels with a concentration of FAME up to

30 % (V/V) and petroleum distillates need to be diluted with heptane (Procedure A). Paraffinic diesel

fuels are injected neat (Procedure B).

This column has little affinity for non-aromatic hydrocarbons, while exhibiting a strong selectivity for

aromatic hydrocarbons. As a result of this selectivity, the aromatic hydrocarbons are separated from

the non-aromatic hydrocarbons and into distinct bands according to their ring structure, i.e. MAH, DAH

and T+AH compounds.

The column is connected to a refractive index detector which detects the components as they elute from

the column. The electronic signal from the detector is continually monitored by a data processor. The

amplitudes of the signals from the aromatics in the sample are compared with those obtained from

calibration standards in order to calculate the mass fraction of MAHs, DAHs and T+AHs in the sample.

The sum of the DAHs and T+AHs mass fractions is reported as the mass fraction of POLY-AH, and the

sum of the MAHs, DAHs and T+AHs mass fractions is reported as the mass fraction of total aromatic

hydrocarbons.

When following Procedure A, the column may be backflushed after the aromatics have eluted from the

column to allow any remaining components such as FAME to elute in a backflush peak. This will allow

for a better cleaning of the column but care should be taken as it can affect the lifetime of the column.

5 Reagents and materials

WARNING — Aromatic compounds can be volatile and flammable, their vapours can form

explosive mixtures with the air, and they can cause acute or chronicle harm when inhaled or in

case of contact with the skin. In addition, they can be water polluting.
5.1 General

The highest purity reagents and materials available should be used; those required to be of high

performance liquid chromatography (HPLC) grade are commercially available from major suppliers.

5.2 Cyclohexane, of 99 % (m/m) minimum purity (CAS registry number 110-82-7).
NOTE Cyclohexane can contain benzene as an impurity.

5.3 Heptane, HPLC analytical grade, as the mobile phase (CAS registry number 142-82-5).

Batch to batch variation of the solvent water content, viscosity, refractive index, and purity can cause

unpredictable column behaviour. Drying (for example, by standing over activated molecular sieve type

5A) and filtering the mobile phase can help reducing the effect of trace impurities present in the solvent.

It is recommended practice to de-gas the mobile phase before use; this can be done conveniently online

or off-line by helium sparging, vacuum degassing or ultrasonic agitation. A failure to de-gas the mobile

phase can lead to negative peaks.

5.4 1-Phenyldodecane, of 98 % (m/m) minimum purity (CAS registry number 123-01-3).

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SIST EN 12916:2019
EN 12916:2019 (E)

5.5 1,2-Dimethylbenzene (o-xylene), of 98 % (m/m) minimum purity (CAS registry number 95-47-

6).

5.6 Hexamethylbenzene, of 98 % (m/m) minimum purity (CAS registry number 87-85-4).

5.7 Naphthalene, of 98 % (m/m) minimum purity (CAS registry number 91-20-3).
5.8 Fluorene, of 98 % (m/m) minimum purity (CAS registry number 86-73-7).
5.9 Phenanthrene, of 98 % (m/m) minimum purity (CAS registry number 85-01-8).

5.10 Dibenzothiophene, of 95 % (m/m) minimum purity (CAS registry number 132-65-0).

5.11 9-Methylanthracene, of 95 % (m/m) minimum purity (CAS registry number 779-02-2).

5.12 Chrysene, of 95 % (m/m) minimum purity (CAS registry number 218-01-9).
5.13 FAME, compliant to EN 14214.
6 Apparatus

6.1 Liquid chromatograph, consisting of a high performance instrument capable of pumping the

mobile phase at flow rates from 0,5 ml/min to 1,5 ml/min, with a precision better than 0,5 % and a

pulsation of < 1 % full scale deflection under the test conditions described in Clause 8. Make sure that

the equipment for handling or testing the sample is not sensitive to FAME. Recommended materials are

Polytetrafluoroethylene, Viton® and Nylon.

6.2 Sample injection system, capable of nominally injecting 10 μl of sample solution with a

repeatability better than 1 %.

Equal and constant volumes of the calibration and sample solutions are injected into the

chromatograph. Both manual and automatic sample injection systems, using either complete or partial

filling of the sample loop, can meet these repeatability requirements when used correctly. When using

the partial filling mode, it is recommended that the injection volume is less than half the total loop

volume. For complete filling of the loop, best results are obtained by overfilling the loop at least six

times.

The repeatability of the injection system can be checked by comparing peak areas from at least four

injections of the system calibration standard (see 8.4).

Sample and calibration injection volumes different from 10 μl (typically in the range 3 μl to 20 μl) may

be used provided they meet the requirements for injection repeatability, refractive index sensitivity and

linearity (see 9.4), and column resolution (see 8.10).

6.3 Sample filter, if required (see 10.1 and 10.2), consisting of a microfilter of porosity 0,45 μm or

less, chemically inert towards hydrocarbon solvents, for the removal of particulate matter from the

sample solutions.
NOTE Polytetrafluorethylen (PTFE) filters have been found to be suitable.

Viton® is the trademark of a fluoroelastomer supplied by the Chemours Company, Wilmington, Delaware 19899

(USA). This information is given for the convenience of users of this document and does not constitute an

endorsement by CEN of the product named. Equivalent products may be used if they can be shown to lead to the

same results.
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6.4 Column system, consisting of a stainless steel HPLC column(s) packed with a commercial 3 μm,

5 μm or 10 μm amino-bonded (or amino/cyano-bonded) silica stationary phase meeting the resolution

requirements given in 8.7, 8.8, 8.10 and 8.12 . See Annex A for guidance on the selection and use of

suitable column systems.

6.5 Temperature controls, for different parts of the apparatus (column, sample injection system,

solvent, refractive index detector). Maintain the sample injection system at the same temperature as the

sample solution, for the column a heating block or an air-circulating HPLC column oven may be used.

Also, a temperature-controlled laboratory, capable of maintaining a constant temperature in the range

(20 ± 1) °C to (40 ± 1) °C may be used.

The refractive index detector is sensitive to both sudden and gradual changes in the temperature of the

eluent. All necessary precautions should be taken to establish constant temperature conditions

throughout the liquid chromatograph system. The temperature should be optimized depending on the

stationary phase.

6.6 Refractive index detector, capable of being operated over the refractive index range 1,3 to 1,6

and giving a linear response over the calibration ranges with a suitable output signal for the data

system.

If the detector is equipped with a device for independent temperature control, it is recommended that it

is set at the same temperature as the column oven.

6.7 Computer or computing integrator, compatible with the refractive index detector, having a

minimum sampling rate of 1 Hz and capable of peak area and retention time measurements. It shall also

have minimum capabilities for post-analysis data processing such as baseline correction and re-

integration.

The ability to perform automatic peak detection and identification and to calculate sample

concentrations from peak area measurements is recommended, but is not essential.

6.8 Volumetric flasks, 10 ml and 100 ml capacity, conforming to grade A of EN ISO 1042.

6.9 Analytical balance, capable of weighing to the nearest 0,1 mg.
7 Sampling

Unless otherwise specified in the commodity specification, samples shall be taken as described in

EN ISO 3170 or EN ISO 3171 and/or in accordance with the requirements of national standards or

regulations for the sampling of the product under test.

A storage temperature of 19 °C ± 5 °C shall be maintained. If for some reason, the samples have been

exposed to temperatures above 25 °C for a long period during storage or in custody (that you are aware

of), this shall be reported.
At least 24 h before a test the blend shall be placed at ambient temperature.

After finishing the tests completely, replace the air by nitrogen or any noble gas before closing the

container tightly.
8 Apparatus preparation

8.1 Ensure that the equipment and any sample distribution system is clean and dry before use.

8.2 Set up the liquid chromatograph (6.1), sample injection system (6.2), column (6.4), refractive

index detector (6.6) and computing integrator (6.7) as in Figure 1 and in accordance with the

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manufacturer’s manuals. If a column oven is used (6.5), install the HPLC column in the column oven.

Maintain the sample injection system at the same temperature as the sample solution; in most cases this

should be at room temperature.

Regular maintenance of the liquid chromatograph and its components is important and thus

recommended to ensure consistent performance. Leakages and partial blockage of filters, frits, injector

needles and valve rotors can produce flow rate inconsistencies and poor injector repeatability.

Key
1 pump 4 column
2 injection device 5 refractive index detector
3 oven 6 data acquisition system
Figure 1 — Diagrammatic representation of a liquid chromatograph

8.3 Adjust the flow rate of the mobile phase to a constant between 0,8 ml/min and 1,2 ml/min. Allow

the temperature of the column and of the refractive index detector, if it is equipped with temperature

control, to stabilize.

In order to minimize instrument drift, the reference cell of the detector should be filled with mobile

phase, either by flushing mobile phase through the reference cell immediately prior to the analysis, and

then isolating the reference cell to prevent evaporation, or by compensating for evaporation by

supplying a steady flow of mobile phase through the reference cell. The flow should be optimized so

that cell mismatch due to drying-out (reference cell) or temperature or pressure gradients (reference or

analysis cells, depending the type of detector) are minimized; with some detectors this can be

accomplished using a mobile phase flow through the reference cell of one tenth of that through the

analysis cell.

8.4 Prepare into a 100 ml volumetric flask (6.8) a system calibration standard 1 (SCS1) by weighing

to the nearest 0,000 1 g:
— (1,0 ± 0,1) g cyclohexane (5.2),
— (0,1 ± 0,01) g 1-phenyldodecane (5.4),
— (0,5 ± 0,05) g 1,2-dimethylbenzene (5.5),
— (0,1 ± 0,01) g hexamethylbenzene (5.6),
— (0,1 ± 0,01) g naphthalene (5.7),
— (0,05 ± 0,005) g dibenzothiophene (5.10), and
— (0,05 ± 0,005) g 9-methylanthracene (5.11).

Place the flask and its contents into an ultrasonic bath until a visual examination shows that all the

components have dissolved into the 1,2-dimethylbenzene/cyclohexane mixture. Remove from the

ultrasonic bath and make up to the mark with heptane.
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The SCS1 may be kept for at least one year if stored in a tightly stoppered bottle in a cool dark place (for

example in a refrigerator).

8.5 Prepare into a 100 ml volumetric flask a system calibration standard 2 (SCS2) by weighing to the

nearest 0,000 1 g, (0,4 ± 0,1) g FAME (5.13) and (0,04 ± 0,01) g chrysene (5.12) and making up to the

mark with heptane (5.3). Keep the solution into an ultrasonic bath at 35 °C.
Ensure the appearance is homogeneous without deposits of chrysene on the bottom.

NOTE 25 min has been found to be a suitable time for all the components to become dissolved.

The SCS2 may be kept for at least one year if stored in a tightly stoppered bottle in a cool dark place (for

example in a refrigerator).

8.6 When operating conditions are steady, as indicated by a stable horizontal baseline, inject 10 μl of

the SCS1 (8.4). Ensure the baseline drift over the period of the HPLC analysis run is less than 1 % of the

peak height for cyclohexane.

NOTE A baseline drift greater than this indicates problems with the temperature control of the

column/refractive index detector and/or material eluting from the column.

8.7 Ensure the components of the SCS1 are eluted in the order: cyclohexane, phenyldodecane,

1,2-dimethylbenzene, hexamethylbenzene, naphthalene, dibenzothiophene and 9-methylanthracene.

8.8 Ensure that baseline separation is obtained between all components of the SCS1 (see Figure 2).

Key
1 cyclohexane 5 naphthalene
2 phenyldodecane 6 dibenzothiophene
3 1,2 dimethylbenzene 7 9-methylanthracene
4 hexamethylbenzene
x-axis time (min) y-axis signal (mV)
Figure 2 — Chromatogram of the system calibration standard SCS1
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8.9 Measure the retention times of the cyclohexane, phenyldodecane, 1,2-dimethylbenzene,

hexamethylbenzene, dibenzothiophene and 9-methylanthracene peaks using the data system.

8.10 Ensure that the resolution between cyclohexane and 1,2-dimethylbenzene is between 5,7 and 10

(see 11.2).
8.11 Calculate the cut times using the equations given in 11.3.

8.12 Ensure the appearance of SCS2 is homogeneous (8.5) and then, inject 10 μl of the SCS2 and check

the chrysene peak elutes just before or together with the first peak of FAME.

Ensure the retention time of chrysene peak be higher than the retention time of 9-methylanthracene

peak.

Test the column with the SCS2 to verify its performances when starting the method with a new column,

after a period of time of inactivity or when samples with FAME should be run.
9 Calibration
9.1 Prepare
...