ISO/TS 17306:2016
(Main)Petroleum products — Biodiesel — Determination of free and total glycerin and mono-, di- and tracylglycerols by gas chromatography
Petroleum products — Biodiesel — Determination of free and total glycerin and mono-, di- and tracylglycerols by gas chromatography
ISO/TS 17306:2016 establishes a methodology for quantitative determination of free glycerol, mono-, di-, triacylglycerols and total glycerol by gas chromatography in biodiesel produced from any raw material including coconut or palm oil and animal fat. It is not applicable for biodiesel from castor oil. In most actual cases, biodiesel is based on fatty acid methyl esters (FAME). These have also been used during the precision study for this test method. There is no indication that the methodology does not apply to other ester types, but the precision has not been determined nor compared. NOTE For the purposes of this Technical Specification, the term "% (m/m)" is used to represent the mass fraction, µ.
Produits pétroliers — Biogazole — Détermination de glycerine libre et totale et des mono-, di- et tracylglycerols avec chromatographie gazeuse
General Information
Standards Content (Sample)
TECHNICAL ISO/TS
SPECIFICATION 17306
First edition
2016-02-01
Petroleum products — Biodiesel
— Determination of free and
total glycerin and mono-, di- and
tracylglycerols by gas chromatography
Produits pétroliers — Biogazole — Détermination de glycerine
libre et totale et des mono-, di- et tracylglycerols avec
chromatographie gazeuse
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
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ii © ISO 2016 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Reagents and materials . 3
7 Preparation of the apparatus . 3
8 Sampling . 4
9 Preparation of the standard solutions . 4
9.1 Preparation of the stock solutions . 4
9.2 Preparation of the calibration curve . 5
9.3 Preparation of the sample . 6
9.4 Procedure . 7
10 Calculation and expression of results . 8
11 Precision .10
11.1 General .10
11.2 Repeatability, r .10
11.3 Reproducibility, R .10
12 Test report .11
Annex A (normative) Check chromatograms .12
Annex B (normative) Calculation of the coefficients for determination of the combined glycerol .16
Annex C (informative) Information on interlaboratory study .20
Bibliography .21
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
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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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 28, Petroleum products and related products of
synthetic or biological origin, Subcommittee SC 7, Liquid biofuels.
iv © ISO 2016 – All rights reserved
Introduction
This Technical Specification establishes a method for quantitative determination of free glycerol,
mono-, di-, triacylglycerols and total glycerol in fatty acid methyl esters (biodiesel) by gas
chromatography. High concentrations of these components can contribute to formation of deposits on
the pistons and valves of diesel cycle engines. Additionally, they can cause problems during storage and
in the engine’s fuel injection system.
[2] [3]
Alternative methods for similar determinations exist in ASTM D6584 and EN 14105, which
are tailor made to regional quality specification needs. This Technical Specification describes an
alternative technique using more easily available internal standards, instrumentation that can also
measure esters and a procedure applicable to short chain fatty acid esters, such as those from palm
kernel and coconut oil. This Technical Specification thus provides a wider usage with similar or worse
precision as other techniques.
TECHNICAL SPECIFICATION ISO/TS 17306:2016(E)
Petroleum products — Biodiesel — Determination of free
and total glycerin and mono-, di- and tracylglycerols by gas
chromatography
WARNING — The use of this Technical Specification may involve the usage of dangerous
materials and equipment. It is the responsibility of the user to establish the appropriate
security, health and environmental practices, and to determine the applicability of regulatory
limitations before their use.
1 Scope
This Technical Specification establishes a methodology for quantitative determination of free glycerol,
mono-, di-, triacylglycerols and total glycerol by gas chromatography in biodiesel produced from any raw
material including coconut or palm oil and animal fat. It is not applicable for biodiesel from castor oil.
In most actual cases, biodiesel is based on fatty acid methyl esters (FAME). These have also been used
during the precision study for this test method. There is no indication that the methodology does not
apply to other ester types, but the precision has not been determined nor compared.
NOTE For the purposes of this Technical Specification, the term “% (m/m)” is used to represent the mass
fraction, µ.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. 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.
3.1
biodiesel
fuel comprised of mono-alkyl esters of fatty acids, derived from vegetable oils or animal fats
3.2
bonded glycerol
glycerol portion of the mono-, di-, and triacylglycerols molecules
3.3
total glycerol
sum of free glycerol and bonded glycerol
3.4
monoacylglycerols
sum of monostearin, monopalmitin, monoolein, monolinolein, concentrations and/or other
monoacylglycerols present in the biodiesel
3.5
diacylglycerols
sum of diolein, dilinolein concentrations and/or other diacylglycerols present in the biodiesel
3.6
triacylglycerols
sum of triolein, trilinolein concentrations and/or other triacylglycerols present in the biodiesel
3.7
silylation
reaction to substitute the active hydrogen present in the mono- and diacylglycerol molecules to obtain
more volatile and stable compounds
4 Principle
A sample is injected into a gas chromatograph after silylation with N-methyl-N-trimethylsilyltrifluoro-
acetamide (MSTFA). The identification of the components in the sample is done by comparing the
retention times of four reference materials (glycerol, monoolein, diolein and triolein). The quantification
is done using calibration curves with internal standardization. For quantifying the glycerin and the
acylglycerols, ethylene glycol and tricaprin are used as internal standard, respectively. The total
glycerol is obtained from the sum of free and bonded glycerol concentrations.
5 Apparatus
5.1 Gas chromatograph equipped with flame ionization detector (FID), an on-column (or equivalent)
injector and oven with temperature programming.
5.2 Data acquisition system, an electronic instrument to obtain and record the peak area in the
chromatograms.
5.3 Column, fused silica capillary column, 30 m × 0,32 mm × 0,1 µm, with stationary phase 95 %
dimethylpolysiloxane and 5 % phenyl-methylpolysiloxane for high temperature (up to 400 °C).
NOTE 1 Any column with better or equivalent efficiency and selectivity can be used. Their usefulness can be
observed by comparing the chromatogram obtained with chromatograms presented in Annex A.
NOTE 2 A retention gap of 0,53 mm of internal diameter can be used.
5.4 Automatic sampler.
5.5 Balance, with resolution of 0,1 mg.
5.6 Volumetric flasks of 50 ml, 25 ml and 10 ml
5.7 Appropriate vials for automatic sampler, screw top vials can lead to sample evaporation.
5.8 Flask, with a capacity of 10 ml, with polytetrafluoroethylene (PTFE) faced septa.
5.9 Microlitre syringes, with a capacity of 5 µl for sample injection.
5.10 Microlitre syringes or micropipette, with a capacity of 100 µl and 250 µl for the preparation of
the solutions.
5.11 Pasteur pipettes.
2 © ISO 2016 – All rights reserved
5.12 Volumetric pipettes, graduated, with a capacity of 10 ml and 20 ml.
6 Reagents and materials
6.1 n-heptane, 99,0 % minimum purity.
6.2 Pyridine (dried), 99,0 % minimum purity, with a maximum water content of 0,1 %.
It is recommended that the pyridine be stored with a molecular sieve 5A, 4/8 mesh. Its conditioning
should be undertaken in a lab oven, at 350 °C throughout the night. Allow cooling down in a desiccant,
without silica.
1)
6.3 1-Glycerolmonooctadecenoate (glycerol monooleate or monoolein) (CAS No. 111-03-5),
99,0 % minimum purity.
6.4 1,3 Glycerol dioctadecenoate (glycerol dioleate or diolein) (CAS No. 2465-32-9), 99,0 %
minimum purity.
6.5 Glycerol trioctadecenoate (glycerol trioleate or triolein) (CAS No. 122-32
...
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