kSIST FprEN 15199-4:2026
(Main)Petroleum products - Determination of boiling range distribution by gas chromatography method - Part 4: Light fractions of crude oil
- Abstract
This document specifies a method for the determination of the boiling range distribution of petroleum products by capillary gas chromatography using flame ionization detection. This document is applicable to stabilized crude oils and for the boiling range distribution and the recovery up to and including n-nonane. A stabilized crude oil is defined as having a Reid Vapour Pressure equivalent to or less than 82,7 kPa as determined by IP 481 [3].
Annex C specifies an algorithm for merging the boiling point distribution results obtained using this method with the results obtained with EN 15199-3. This will result in a boiling range distribution and recovery up to C120.
This precision presented in this document is applicable to the boiling range distribution up to n-nonane. For the precision of the boiling range distribution from n-nonane through C120, see EN 15199-3.
NOTE 1 There is no specific precision statement for the combined results obtained after merging the results of EN 15199-3 and EN 15199-4.
NOTE 2 For the purposes of this document, the terms "% (m/m)" and "% (V/V)" are used to represent respectively the mass fraction, ω, and the volume fraction, φ.
WARNING - The use of this document can involve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this document to take appropriate measures to ensure safety and health of personnel prior to application of the document and fulfil statutory and regulatory requirements for this purpose.
- Status
- Not Published
- Public Enquiry End Date
- 30-Sep-2025
- Technical Committee
- NAD - Petroleum products, lubricants and related products
- Current Stage
- 5020 - Formal vote (FV) (Adopted Project)
- Start Date
- 30-Sep-2026
- Due Date
- 18-Nov-2026
kSIST FprEN 15199-4:2026 is a draft CEN European Standard for determining the boiling range distribution of petroleum products by capillary gas chromatography with flame ionization detection (FID). It applies to stabilized crude oils and measures recovery up to and including n-nonane. Annex C gives a way to merge its results with EN 15199-3 so the boiling range distribution can be extended to C120.
What does kSIST FprEN 15199-4:2026 specify?
kSIST FprEN 15199-4:2026 specifies a laboratory method for boiling range distribution in stabilized crude oil samples using gas chromatography. The practical value of the method is that it separates the light end of the crude, quantifies identified hydrocarbons up to n-nonane, and gives a cumulative boiling point distribution that can be reported and, if needed, merged with EN 15199-3 results.
The scope defines stabilized crude oil as having a Reid Vapour Pressure equivalent to or less than 82.7 kPa as determined by IP 481. The document also warns that the method uses hazardous materials, operations and equipment, so safety controls and regulatory checks are part of normal use.
The document is organized into 12 clauses and 3 informative annexes.
| Annex | What it covers |
|---|---|
| Annex A | Analysis assistance, including an example crude oil analysis and example chromatograms |
| Annex B | Apparatus configuration schematics |
| Annex C | Algorithm for merging EN 15199-3 and EN 15199-4 boiling point distribution results |
What are the key requirements of kSIST FprEN 15199-4:2026?
kSIST FprEN 15199-4:2026 is built around a specific GC setup, defined sample handling, response factor calculation, and reporting rules. For a buyer or laboratory, the most important point is that the method is not just a detector run - it depends on a controlled pre-column backflush arrangement, a suitable internal standard, and defined calculation steps.
Sample handling and preparation
Clause 7 requires sampling in accordance with EN ISO 3170 or EN ISO 3171. Clause 9 then directs the analyst to weigh about 5 g of sample, add about 0.15 g of internal standard, and avoid degassing during mixing; carbon disulfide may be added to improve viscosity. In practice, this means the sample must be handled to preserve the light ends before injection, otherwise the front-end distribution will be biased.
GC configuration and separation checks
Clause 5 and Clause 6 require a bonded polydimethylsiloxane (PDMS) stationary phase and an analytical system with a pre-column plus analytical capillary column. Two pre-column arrangements are allowed: a heated valve switching box with a 1 m pre-column, or a short pre-column in a temperature-programmable injection port with backflush capability. This matters because the method relies on backflushing higher boilers after n-nonane has passed the analytical column.
Clause 6 also sets performance checks for the system. The FID must be sensitive enough to detect 1 % mass n-heptane, baseline drift must be limited, and the analytical column must give at least 2.0 resolution between the internal standard and the nearest n-paraffin peak when Hexene-1 is used as I.S. The n-hexane peak skewness must stay within the stated ratio range, which helps keep quantitation stable and peak integration reliable.
Backflush timing and detector/data settings
Clause 9 requires the analyst to determine the backflush time with a valve switching mixture of normal alkanes from pentane to decane. The switching point is adjusted so that the highest required alkane is fully recovered and the next alkane is partly recovered. This is the control point that makes the method suitable for light fractions and prevents heavier material from overstaying on the column.
Clause 6 also gives minimum data-sampling rates: 5 Hz for the analytical column system and 20 Hz for the accelerated analytical column. That matters because too slow a sampling rate can miss narrow peaks and weaken the calculated distribution.
Quantitation and response factors
Clause 8 calculates FID response factors relative to methane, which is taken as unity. The method then uses those factors in Clause 9 to calculate each hydrocarbon component up to n-nonane from peak area and internal standard area. In practical terms, the analyst must match detector area to chemistry, not just read peaks, or the reported mass percentages will be wrong.
Reporting, precision, and merging with EN 15199-3
Clause 10 requires reporting cumulative mass percent versus boiling point to the nearest 0.01 % (m/m) and 0.5 °C. Clause 11 gives repeatability and reproducibility expressions derived from an interlaboratory study on 14 laboratories and 8 crude oil samples.
The stated precision applies up to n-nonane. For the boiling range from n-nonane through C120, the document points to EN 15199-3, and Annex C provides the merge algorithm for combining the two sets of results. The document also notes that there is no specific precision statement for the merged result.
Clause 12 defines the minimum test report items: the document used, material identification, result, any unusual features, and the test date. That makes the output usable for customer reports, audits, and internal quality records.
What terms does kSIST FprEN 15199-4:2026 define?
- Recovery - the combined mass percentages of all identified light hydrocarbons in the chromatogram, excluding the internal standard peak, up to and including n-nonane.
- Stabilized crude oil - a crude oil with a Reid Vapour Pressure equivalent to or less than 82.7 kPa as determined by IP 481.
- Internal standard (I.S.) - a compound added in known amount before analysis so the hydrocarbon peaks can be quantified against it.
- Flame ionization detector (FID) - the GC detector used in this method to measure the hydrocarbon signal.
- Pre-column - the first column in series that receives the injected sample before separation on the analytical column.
- Analytical column - the capillary column that separates hydrocarbons in boiling point order.
- % (m/m) and % (V/V) - the document uses these terms to represent mass fraction (ω) and volume fraction (φ).
Who uses kSIST FprEN 15199-4:2026?
kSIST FprEN 15199-4:2026 is used by petroleum testing laboratories, refinery laboratories, and crude oil analysts who need the front-end boiling range of stabilized crude oil. It is also relevant to quality managers and buyers who need a common test method for product specification, batch comparison, or acceptance work.
The sampling references show that it fits both manual and automatic pipeline sampling workflows. The precision section also shows that it is written for interlaboratory use, method validation, and routine quality control.
What changed in kSIST FprEN 15199-4:2026 from the previous edition?
kSIST FprEN 15199-4:2026 will supersede EN 15199-4:2021. The technical change stated in the foreword is that the figures under Annex A have been corrected, complemented, and improved to assist the user.
Which standards are used with kSIST FprEN 15199-4:2026?
- EN ISO 3170 - manual sampling of hydrocarbon liquids.
- EN ISO 3171 - automatic pipeline sampling of petroleum liquids.
- EN 15199-3 - the companion part for crude oil; it is used with Annex C to merge results and extend the distribution to C120.
- IP 481 - supports the definition of stabilized crude oil through air-saturated vapour pressure.
- EN ISO 4259 (all parts) - provides the precision framework used for repeatability and reproducibility treatment.
- IP 601 - the document says kSIST FprEN 15199-4:2026 is compatible with this method for light hydrocarbons in stabilized crude oils.
- ASTM D7900 - the document says kSIST FprEN 15199-4:2026 is compatible with this test method for light hydrocarbons in stabilized crude oils.
What does the kSIST FprEN 15199-4:2026 document contain?
The document contains the method principle, reagent and material requirements, apparatus requirements, sampling guidance, response-factor calculation, procedure, reporting rules, precision statements, and test report content. It also includes formulas for resolution, response factors, component calculation, repeatability, and reproducibility.
Annex A provides an example crude oil analysis with identified components and example chromatograms. Annex B shows three apparatus configurations, including the heated valve switching box and two injection-port arrangements. Annex C gives a step-by-step array-based merge procedure for combining EN 15199-3 and EN 15199-4 results, including normalization logic when recovery exceeds 100 % by mass.
Relations
- Effective Date
- 01-Sep-2025
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Frequently Asked Questions
kSIST FprEN 15199-4:2026 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Petroleum products - Determination of boiling range distribution by gas chromatography method - Part 4: Light fractions of crude oil". This standard covers: This document specifies a method for the determination of the boiling range distribution of petroleum products by capillary gas chromatography using flame ionization detection. This document is applicable to stabilized crude oils and for the boiling range distribution and the recovery up to and including n-nonane. A stabilized crude oil is defined as having a Reid Vapour Pressure equivalent to or less than 82,7 kPa as determined by IP 481 [3]. Annex C specifies an algorithm for merging the boiling point distribution results obtained using this method with the results obtained with EN 15199-3. This will result in a boiling range distribution and recovery up to C120. This precision presented in this document is applicable to the boiling range distribution up to n-nonane. For the precision of the boiling range distribution from n-nonane through C120, see EN 15199-3. NOTE 1 There is no specific precision statement for the combined results obtained after merging the results of EN 15199-3 and EN 15199-4. NOTE 2 For the purposes of this document, the terms "% (m/m)" and "% (V/V)" are used to represent respectively the mass fraction, ω, and the volume fraction, φ. WARNING - The use of this document can involve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this document to take appropriate measures to ensure safety and health of personnel prior to application of the document and fulfil statutory and regulatory requirements for this purpose.
This document specifies a method for the determination of the boiling range distribution of petroleum products by capillary gas chromatography using flame ionization detection. This document is applicable to stabilized crude oils and for the boiling range distribution and the recovery up to and including n-nonane. A stabilized crude oil is defined as having a Reid Vapour Pressure equivalent to or less than 82,7 kPa as determined by IP 481 [3]. Annex C specifies an algorithm for merging the boiling point distribution results obtained using this method with the results obtained with EN 15199-3. This will result in a boiling range distribution and recovery up to C120. This precision presented in this document is applicable to the boiling range distribution up to n-nonane. For the precision of the boiling range distribution from n-nonane through C120, see EN 15199-3. NOTE 1 There is no specific precision statement for the combined results obtained after merging the results of EN 15199-3 and EN 15199-4. NOTE 2 For the purposes of this document, the terms "% (m/m)" and "% (V/V)" are used to represent respectively the mass fraction, ω, and the volume fraction, φ. WARNING - The use of this document can involve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this document to take appropriate measures to ensure safety and health of personnel prior to application of the document and fulfil statutory and regulatory requirements for this purpose.
kSIST FprEN 15199-4:2026 is classified under the following ICS (International Classification for Standards) categories: 71.040.50 - Physicochemical methods of analysis; 75.080 - Petroleum products in general. The ICS classification helps identify the subject area and facilitates finding related standards.
kSIST FprEN 15199-4:2026 has the following relationships with other standards: It is inter standard links to SIST EN 15199-4:2021. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
kSIST FprEN 15199-4:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
oSIST prEN 15199-4:2025
01-september-2025
Naftni proizvodi - Določanje porazdelitve območja vrelišč z metodo plinske
kromatografije - 4. del: Lahke frakcije surovega olja
Petroleum products - Determination of boiling range distribution by gas chromatography
method - Part 4: Light fractions of crude oil
Mineralölerzeugnisse - Gaschromatographische Bestimmung des Siedeverlaufes - Teil
4: Leichte Fraktionen des Rohöls
Produits pétroliers - Détermination de la répartition dans l'intervalle de distillation par
méthode de chromatographie en phase gazeuse - Partie 4 : Fractions légères du pétrole
brut
Ta slovenski standard je istoveten z: prEN 15199-4
ICS:
71.040.50 Fizikalnokemijske analitske Physicochemical methods of
metode analysis
75.080 Naftni proizvodi na splošno Petroleum products in
general
oSIST prEN 15199-4:2025 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
oSIST prEN 15199-4:2025
oSIST prEN 15199-4:2025
DRAFT
EUROPEAN STANDARD
prEN 15199-4
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2025
ICS 75.080 Will supersede EN 15199-4:2021
English Version
Petroleum products - Determination of boiling range
distribution by gas chromatography method - Part 4: Light
fractions of crude oil
Produits pétroliers - Détermination de la répartition Mineralölerzeugnisse - Gaschromatographische
dans l'intervalle de distillation par méthode de Bestimmung des Siedeverlaufes - Teil 4: Leichte
chromatographie en phase gazeuse - Partie 4 : Fraktionen des Rohöls
Fractions légères du pétrole brut
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 19.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15199-4:2025 E
worldwide for CEN national Members.
oSIST prEN 15199-4:2025
prEN 15199-4:2025 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Principle . 4
5 Reagents and materials . 5
6 Apparatus . 5
7 Sampling and sample handling . 8
8 Calculation of response factors . 8
9 Procedure . 9
9.1 Sample preparation . 9
9.2 Determination of backflush time . 9
9.2.1 Initial work . 9
9.2.2 Analytical column . 9
9.2.3 Accelerated analytical column . 10
9.3 Sample analysis . 10
9.3.1 Initial work . 10
9.3.2 Calculation of individual components results . 10
9.3.3 Boiling point distribution of fraction up to and including nonane . 11
10 Reporting . 11
11 Precision . 11
11.1 General. 11
11.2 Repeatability, r . 12
11.3 Reproducibility, R . 12
12 Test report . 12
Annex A (informative) Analysis assistance . 13
Annex B (informative) Apparatus configuration . 18
Annex C (informative) Algorithm for merging boiling point distribution results of EN 15199-3
and EN 15199-4 . 20
Bibliography . 28
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prEN 15199-4:2025 (E)
European foreword
This document (prEN 15199-4:2025) 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 document will supersede EN 15199-4:2021.
prEN 15199-4:2025 includes the following significant technical changes with respect to
EN 15199-4:2021:
— The figures under Annex A have been corrected, complemented and improved for better assisting
the user.
EN 15199 consists of the following parts, under the general title Petroleum products — Determination of
boiling range distribution by gas chromatography method:
— Part 1: Middle distillates and lubricating base oils
— Part 2: Heavy distillates and residual fuels
— Part 3: Crude oil
— Part 4: Light fractions of crude oil
EN 15199-4 is compatible with IP 601 [1] and ASTM D7900 [2].
oSIST prEN 15199-4:2025
prEN 15199-4:2025 (E)
1 Scope
This document specifies a method for the determination of the boiling range distribution of petroleum
products by capillary gas chromatography using flame ionization detection. This document is applicable
to stabilized crude oils and for the boiling range distribution and the recovery up to and including n-
nonane. A stabilized crude oil is defined as having a Reid Vapour Pressure equivalent to or less than
82,7 kPa as determined by IP 481 [3].
Annex C specifies an algorithm for merging the boiling point distribution results obtained using this
method with the results obtained with EN 15199-3. This will result in a boiling range distribution and
recovery up to C120.
This precision presented in this document is applicable to the boiling range distribution up to n-nonane.
For the precision of the boiling range distribution from n-nonane through C120, see EN 15199-3.
NOTE 1 There is no specific precision statement for the combined results obtained after merging the results of
EN 15199-3 and EN 15199-4.
NOTE 2 For the purposes of this document, the terms “% (m/m)” and “% (V/V)” are used to represent
respectively the mass fraction, ω, and the volume fraction, φ.
WARNING — The use of this document can involve hazardous materials, operations and equipment. This
document does not purport to address all of the safety problems associated with its use. It is the
responsibility of the user of this document to take appropriate measures to ensure safety and health of
personnel prior to application of the document 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 ISO 3170, Hydrocarbon Liquids - Manual Sampling (ISO 3170)
EN ISO 3171, Petroleum liquids - Automatic pipeline sampling (ISO 3171)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
recovery
combined mass percentages of all light hydrocarbon identified in the chromatogram (except the internal
standard peak) of the sample up to and including n-nonane
4 Principle
An amount of internal standard is quantitatively added to an aliquot of the stabilized crude oil. A portion
of this mixture is injected into a pre-column in series via a splitter with a capillary analytical column.
When the n-nonane has quantitatively passed to the analytical column, the pre-column is back-flushed to
oSIST prEN 15199-4:2025
prEN 15199-4:2025 (E)
vent the higher boiling components. The individual components are identified by comparison with
reference chromatograms and a database of hydrocarbon compounds (see Annex A). The boiling point
distribution and recovery up to and including n-nonane (n-C9) is calculated.
5 Reagents and materials
5.1 Stationary phase for columns, with a bonded polydimethylsiloxane (PDMS) stationary phase for
both the pre-column and the analytical capillary column.
5.2 Compressed gases
5.2.1 Carrier gas, helium or hydrogen of at least 99,995 % (V/V) purity or higher is required. Any
oxygen present shall be removed by a suitable chemical filter.
CAUTION — If hydrogen is used as carrier gas, follow the safety instructions from the GC instrument
manufacturer.
5.2.2 Combustion gases, hydrogen and clean air for the flame ionization detector, and suitable filters
shall be used to ensure adequate gas cleanliness.
5.3 Internal standard (I.S.), having a baseline resolution from any adjacent eluting peaks (Hexene-1
or 3,3-dimethyl-1-butene (99 % pure) have been found to be suitable).
5.4 Valve switching mixture, a qualitative mixture of approximately 1 % (m/m) of each normal alkane
from pentane to decane.
5.5 Carbon disulfide (CS ), purity 99,7 % (V/V) minimum.
WARNING — Extremely flammable and toxic by inhalation.
6 Apparatus
6.1 Analytical balance capable of weighing to the nearest 0,1 mg.
6.2 Gas chromatograph.
The typical operational characteristics of the gas chromatograph are described in Table 1.
Two different pre-column configurations are possible.
The first configuration (A) employs a 1 metre column contained in a temperature-controlled valve box,
separately controlled. The valve box in this configuration is isothermal (see Annex B).
The second configuration (B) is a short pre-column (a packed injection port liner), that fits into the
injection port. The injection port will be temperature programmed (see Annex B).
6.3 Flame ionization detector (FID) with sufficient sensitivity to detect 1 % mass n-heptane with a
peak height of at least 10 % full-scale deflection under the conditions given in the method.
When operating at this sensitivity level, detector stability shall be such that a baseline drift of not more
than 1 % per hour is obtained. The detector shall be connected to the column carefully to avoid any cold
spots. The detector shall be capable of operating at a temperature equivalent to the maximum column
temperature used.
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prEN 15199-4:2025 (E)
Table 1 —Typical chromatographic conditions
Unit Pre-column Pre-column Analytical Accelerated
A B Analytical
m
Column length 1,0 0,075 50 or 100 40
mm
Column internal diameter 2 2,5 0,25 0,10
Column material polydimethylsiloxane
%
Phase loading 5 10
µm
Film thickness 0,5
µL
Injection volume 0,1 0,1
Injector split ratio 100 : 1 600 : 1
°C
Injector temperature 300 100
°C
Pre-column temperature 200 100
°C/min
Injector program rate 50
°C
Final injector temperature 300
°C
Initial oven temperature 35 35
min
Hold time 30 2,6
°C/min 50 → 45 °C
Oven program rate 2
(hold time 3 min)
5 → 60 °C
(hold time 3 min)
9,5 → 200 °C
°C
Final oven temperature 200 200
min
Hold time 20 1
°C
Flame ionization detector 300 300
6.4 Pre-column configurations
6.4.1 Heated valve switching box (see Figure B.1)
For the isothermal 1 metre pre-column, a heated valve box is needed with its own temperature control.
The box will contain an automated six-port valve which is used to back-flush the pre-column.
The six-port valve should be made out of material which will not be corroded by the sample (some crude
oils contain high amounts of sulfur components). The valve shall be situated in a heated isothermal oven
and be attached to the injector, pre-column, splitter, analytical column and the detector without any cold
spots.
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prEN 15199-4:2025 (E)
6.4.2 Injection port (see Figure B.2 and B.3)
A temperature programmable injection port capable of containing a 7,5 cm pre-column, and this injection
port shall be equipped with a back-flush option. This injector can be connected directly to the capillary
column (Figure B.2) or via a splitter (Figure B.3).
6.5 Analytical column
6.5.1 General
The column elutes hydrocarbons in a boiling point order. The eluate from the injector passes through the
pre-column before eluting onto the analytical column.
6.5.2 Resolution
Determine the resolution between the internal standard and the nearest n-paraffin peak as per
Formula (1).
2 tt−
( )
2 1
Ρ = (1)
1,699 w + w
( )
where
P is the column resolution;
t is the retention time of the first peak (peak 1, see Figure 1);
t is the retention time of the second peak (peak 2, see Figure 1);
w is the peak width at half height of peak 1;
l
w is the peak width at half height of peak 2.
With Hexene-1 as I.S., the resolution is determined between the I.S and n-hexane. The resolution shall be
at least 2,0.
Figure 1 — Determination of resolution
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6.6 Skewness
Determine the skew of the n-hexane peak by measuring the width of the leading part of the peak at 5 %
peak height (A) and the width of the following part of the peak at 5 % peak height (B). The ratio (B)/(A)
shall be not less than 1 or more than 4. See Figure 2 for further clarification.
Figure 2 —Calculation of peak skewness
6.7 Data collection
A PC based chromatography data system or integrator with suitable software can be used. For systems
using the analytical column, a data -sampling rate of 5 Hz is the recommended minimum.
For systems using the accelerated analytical column, a data-sampling rate of 20 Hz is required.
7 Sampling and sample handling
Take samples in accordance with either EN ISO 3170 or EN ISO 3171.
8 Calculation of response factors
Calculate the flame ionization detector (6.3) response factor relative to methane, which is considered to
have a response factor of unity (= 1), for each hydrocarbon group type of a particular carbon number
using Formula (2).
C ×+C H × H × 0,748 7
( ) ( )
aw n aw n
RRf = (2)
C × C
( )
aw n
where
RRf is relative response factor for a hydrocarbon type group of a particular carbon number;
C is atomic mass of carbon, 12,011;
aw
C is number of carbon atoms in the hydrocarbon type group, of a particular carbon
n
number;
H is atomic mass of hydrogen, 1,008,
aw
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H is number of hydrogen atoms in the hydrocarbon type group of a particular carbon
n
number, and 0,748 7 is factor to normalize the result to a methane response of unity
(= 1).
Table 2 gives some response factors already calculated.
Table 2 — Calculated response factors for hydrocarbons
No. of Carbon Naphthenes Paraffins Cyclic olefins Mono-olefins Aromatics
atoms
3 0,916 0,874
4 0,906 0,874
5 0,874 0,899 0,849 0,874
6 0,874 0,895 0,853 0,874 0,811
7 0,874 0,892 0,856 0,874 0,820
8 0,874 0,890 0,859 0,874 0,827
9 0,874 0,888 0,860 0,874 0,832
9 Procedure
9.1 Sample preparation
Weigh to the nearest 0,1 mg, approximately 5 g ± 0,2 g of sample into a tared, screw-capped vial.
Add approximately 0,15 g ± 0,02 g of internal standard and reweigh to the nearest 0,1 mg. Where the
mass of available sample is less than 5 g, the internal standard shall be added to create the equivalent of
a 3 % concentration.
Gently mix the two liquids without causing the sample to degas. Carbon disulfide (5.5) can be added to
improve the viscosity of the sample.
Fill the sample into GC vials with a minimum amount of headspace. Store the vials in a sub ambient
cupboard until use.
NOTE The amount of sample and internal standard taken can vary according to the level of Iight-end
components in the sample and the amount of the sample available.
9.2 Determination of backflush time
9.2.1 Initial work
With the pre-column and analytical column in series, inject an aliquot of the pre-column switch test
mixture (5.4) and determine the ratio of the alkanes.
9.2.2 Analytical column
Set the switching time to 1 min and repeat the analysis. Increase or decrease the valve time to ensure the
complete recovery of the highest alkane required (e.g. nonane) and partly recovery of the next alkane
(e.g. decane). See 9.3.1 and the example chromatogram in Figure 3.
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prEN 15199-4:2025 (E)
9.2.3 Accelerated analytical column
Set the switching time to 30 s and repeat the analysis. Increase or decrease the valve time to ensure the
recovery of the highest alkane required (e.g. nonane) and partly recovery of the next alkane (e.g. decane).
(For assistance in the identification of individual components see [1] and [2] and example chromatogram
(Figure 3)).
Key
1 n-pentane 3 n-heptane 5 n-nonane
2 n-hexane 4 n-octane 6 n-decane
Figure 3 — Example chromatogram showing elution for determining backflush time
9.3 Sample analysis
9.3.1 Initial work
Inject a suitable aliquot of the sample and internal standard (5.3) onto the inlet of the pre-column which
is in series with the analytical column. At the time determined above (9.2) switch the valve and back-
flush the high boilers to vent.
The valve time reflects the highest carbon number required. As a general rule, if alkane with carbon
number z (zC) is required, then the most part of the next alkane [(z+1)C] shall be eluted.
9.3.2 Calculation of individual components results
Calculate each of the individual hydrocarbons up to and including n-nonane the mass fraction ω using
Q
Formula (3):
A ⋅ RRf
QQ
ω ×ω (3)
Q IS
A ⋅ RRf
IS IS
where
RRf and RRf are the relative response factors relative to methane respectively for
Q IS
component Q and the internal standard IS as calculated in Clause 8;
=
oSIST prEN 15199-4:2025
prEN 15199-4:2025 (E)
A and A are the areas resulting from the integration of the chromatographic detector
Q IS
signal within the specified retention time interval for component Q and for the
internal standard IS, respectively; and
ω is the mass fraction (in %) of the internal standard.
IS
These generic response factors can be transformed when using an internal standard (in this case a
C olefin for which the response relative to methane is 0,874) to specific factors belonging to this internal
standard, by dividing all the generic factors by 0,874.
By summation of all the mass percentages per peak up to and including nonane, the mass percent of this
fraction shall be calculated.
See EN 15199-3 [4] and Annex C for merging of the results to give a full crude analysis.
9.3.3 Boiling point distribution of fraction up to and including nonane
Plot for all the hydrocarbons (beginning with the lowest boiling point) the cumulative mass percent
versus the boiling point up to the last peak of interest, e.g. n-nonane.
10 Reportin
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