SIST EN ISO 13885-1:2021

SLOVENSKI STANDARD
oSIST prEN ISO 13885-1:2021
01-maj-2021
Gelska permeacijska kromatografija (GPC) - 1. del: Tetrahidrofuran (THF) kot
izpiralna tekočina (eluent) (ISO 13885-1:2020)
Gel permeation chromatography (GPC) - Part 1: Tetrahydrofuran (THF) as eluent (ISO
13885-1:2020)
Gelpermeationschromatographie (GPC) - Teil 1: Tetrahydrofuran (THF) als Elutionsmittel
(ISO 13885-1:2020)
Chromatographie par perméation de gel (GPC) - Partie 1: Utilisation de tétrahydrofurane
(THF) comme éluant (ISO 13885-1:2020)
Ta slovenski standard je istoveten z: prEN ISO 13885-1
ICS:
87.060.20 Veziva Binders
oSIST prEN ISO 13885-1:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 13885-1:2021

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oSIST prEN ISO 13885-1:2021
INTERNATIONAL ISO
STANDARD 13885-1
Third edition
2020-07
Gel permeation chromatography
(GPC) —
Part 1:
Tetrahydrofuran (THF) as eluent
Chromatographie par perméation de gel (GPC) —
Partie 1: Utilisation de tétrahydrofurane (THF) comme éluant
Reference number
ISO 13885-1:2020(E)
©
ISO 2020

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oSIST prEN ISO 13885-1:2021
ISO 13885-1:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
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
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

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oSIST prEN ISO 13885-1:2021
ISO 13885-1:2020(E)

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
5.1 Eluent supply . 2
5.2 Pump . 3
5.3 Injection system . 3
5.4 Separation columns . 3
5.5 Column temperature control . 5
5.6 Detector . 5
6 Reagents . 5
7 Calibration of the apparatus . 6
7.1 General . 6
7.2 Requirements for the calibration standards . 6
7.3 Preparation of the calibration solutions for injection . 7
7.4 Conditions for calibration runs . 7
7.5 Measurement of elution volume . 7
7.6 Plotting the calibration curve . 7
8 Sampling . 8
9 Preparation for the test . 8
9.1 Preparation of the injection solution . 8
9.2 Preparation of the apparatus . 9
10 Analytical parameters . 9
11 Data acquisition and evaluation . 9
11.1 General . 9
11.2 Calculation of the net chromatogram from the raw data .10
11.2.1 Determination of the baseline .10
11.2.2 Correction of the measured values and of the net chromatogram .10
11.2.3 Evaluation limits .10
11.3 Calculation of the average values .10
11.4 Calculation of the distribution curves .11
12 Precision .12
12.1 General .12
12.2 Repeatability .12
12.3 Reproducibility .12
13 Test report .13
13.1 General .13
13.2 General data on the equipment and settings .13
13.2.1 Data on the equipment used .13
13.2.2 Calibration .13
13.2.3 Evaluation .14
13.3 Special data on the sample .14
Annex A (informative) Conversion of experimental parameters for variant column sizes .16
Annex B (informative) Example of a data sheet for a polymer standard .17
Annex C (informative) Explanations .18
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Bibliography .23
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oSIST prEN ISO 13885-1:2021
ISO 13885-1:2020(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 35, Paints and varnishes.
This third edition cancels and replaces the second edition (ISO 13885-1:2008), which has been
technically revised. The main changes compared to the previous edition are as follows:
— this document has been adapted to the actual state of the art, especially with regards to software
engineering;
— the scope has been revised;
— the definition for gel-permeation chromatography has been revised;
— the text has been revised editorially.
A list of all parts in the ISO 13885 series can be found on the ISO website.
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.
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oSIST prEN ISO 13885-1:2021

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oSIST prEN ISO 13885-1:2021
INTERNATIONAL STANDARD ISO 13885-1:2020(E)
Gel permeation chromatography (GPC) —
Part 1:
Tetrahydrofuran (THF) as eluent
WARNING — This document can involve hazardous materials, operations or equipment. It
does not purport to address all of the safety problems, if any, associated with its use. It is the
responsibility of the user to establish appropriate safety and health practices and to ensure
compliance with any national regulatory conditions.
1 Scope
This document specifies the determination of the molar-mass distribution and the average molar mass
values M (number average) and M (weight average) of polymers that are soluble in tetrahydrofuran
n w
(THF) by gel permeation chromatography (GPC).
NOTE Also known as size exclusion chromatography (SEC).
Even though the chromatograms obtained show good repeatability, it is possible that this method
cannot be used with certain polymer types because of specific interactions (e.g. adsorption) within the
sample/eluent/column system.
The conditions specified in this document are not applicable to the GPC analysis of polymer samples
6
with M values greater than 10 g/mol and/or of polymers with elution limits outside the calibration
w
range (see 7.6 and Annex C).
This document includes no correction method (e.g. for the elimination of peak broadening. If absolute
molar-mass values are required, an absolute method (e.g. membrane osmometry for M or light
n
scattering for M ) can be used.
w
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 1513, Paints and varnishes — Examination and preparation of test samples
ISO 4618, Paints and varnishes — Terms and definitions
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and the following 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/
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oSIST prEN ISO 13885-1:2021
ISO 13885-1:2020(E)

3.1
gel permeation chromatography
GPC
separation of molecules, mainly based on exclusion effects such as differences in the size and/or shape
of molecules (size exclusion chromatography) or in charge (ion exclusion chromatography)
3.2
system peak
signal peculiar to the gel permeation chromatography (3.1) using a refractive index detector
Note 1 to entry: These signals appear at the total penetration limit of the columns and are not part of the sample,
but of the overall system.
4 Principle
The dissolved (molecularly disperse) molecules of a polymer sample are fractionated on a porous
column material, with separation taking place according to the size of the molecule (or, more precisely,
the polymer coil size which forms in this eluent). Small molecules diffuse into the pores of the column
material more frequently and are therefore retarded more than large molecules. Thus, large molecules
are eluted earlier, small molecules later. Under the test conditions given, the elution volume is solely a
function of the coil size of the molecule.
The polymer content of a sample is determined, the sample is then diluted with eluent to give a
concentration of less than 5 g/l and an aliquot of the diluted sample is injected into the GPC system. The
concentration of the molecules eluted from the column is measured in order of decreasing coil size with
a concentration-sensitive detector (typically a differential refractometer). With the aid of a calibration
curve that has been determined for the particular GPC system, the relative molar-mass distribution, the
relative quantities M and M and the heterogeneity or polydispersity M /M are calculated from the
n w w n
chromatogram obtained.
5 Apparatus
The apparatus shall consist of the components shown in Figure 1, which are described below.
All the components which come into contact with the eluent or the sample solution shall be resistant
and shall not exhibit adsorption or memory effects in any form. The individual components of the GPC
apparatus, which in this case uses THF as eluent, shall be connected to capillary tubes made of high-
quality steel or titanium.
Figure 1 — Block diagram of a GPC apparatus
5.1 Eluent supply
The eluent reservoir shall adequately protect the eluent against external influences such as the
atmosphere and light, if necessary by means of a blanket of inert gas above the liquid level.
The eluent reservoir shall contain a sufficient quantity of the eluent to bring the apparatus to
equilibrium and to carry out several repeat analyses.
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oSIST prEN ISO 13885-1:2021
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The eluent shall be degassed, either before it is introduced into the reservoir or by use of a device fitted
between the reservoir and the pump, to prevent malfunctions of the pump or the formation of bubbles
in the detector. The method of degassing used (e.g. bubble trap, online purging with helium, or vacuum
degassing) is open to choice.
5.2 Pump
The pump shall ensure that the eluent flow through the separation column is as smooth and pulse free
as possible. The flow rate shall be 1 ml/min (see Annex A). To fulfil these requirements, the pump shall
operate at optimum efficiency at this flow rate.
The flow rate of the pump used shall have a variation of max. 0,1 %.
5.3 Injection system
The injection system serves to introduce a given amount of the sample solution into the eluent stream
in a rapid and smooth fashion. This introduction may be carried out either manually or automatically.
If the introduction is carried out manually, ensure that the sample loop is filled completely with solvent
before loading with the sample.
Memory effects from the previous sample solution in the injection system shall be avoided by adequate
flushing.
5.4 Separation columns
The apparatus shall have one or more columns connected in series and packed with spherical porous
material, the diameter of the pores corresponding to the size of the polymer molecules being analysed.
The packing material typically consists of a styrene/divinylbenzene copolymer (S/DVB), produced by
a special polymerization process, which swells only slightly in the solvent and therefore cannot deform
under the pressure developed at the set flow rate.
In addition to these macroporous spherical S/DVB particles, packing materials based on other organic
monomers or on silicon dioxide (silica) are also used. The criterion for their use is that no adsorptive
interaction shall occur between their surface and the polymer molecules in the sample. Furthermore,
the sample being analysed shall not be changed, either chemically or structurally, within the
chromatographic system.
Certain polymers interact with the surface of the packing material (e.g. by adsorption) and other effects
can sometimes interfere with the GPC separation mechanism. Details of such effects and notes on
possible remedies are discussed in Annex C. If it is intended to compare analyses of such polymers by
different laboratories, the laboratories shall agree on details of the test conditions that are not covered
by this document.
For good repeatability of test results, it is necessary to adhere to the minimum requirements specified
below with regard to peak broadening (expressed in terms of a number of theoretical plates) and
separation efficiency.
a) Number of theoretical plates
The number of theoretical plates, N, shall be determined, for the apparatus used per metre of
column used, from the peak width at half height (see Figure 2). Inject up to 20 µl of ethylbenzene
(mass concentration 1 g/l) on to the column (see Annex A) and evaluate the chromatogram obtained
under the same conditions as are used for analysing polymers, using Formula (1):
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oSIST prEN ISO 13885-1:2021
ISO 13885-1:2020(E)

2
 
V
100
e
N =×55, 4   × (1)
 
WL
1/2
 
where
V is the elution volume at the peak maximum;
e
W is the peak width at half height (see Figure 2); the same units shall be used for V and W ;
1/2 e 1/2
L is the length of the column (column combination), in centimetres.
Express as the result the number of theoretical plates per metre of column length. To conform to the
requirements of this document, the column combination shall have at least 20 000 theoretical plates
per metre.
NOTE See Annex C for tailing and fronting (asymmetry) of the peak used to calculate the plate count.
Key
X elution volume
Y peak intensity
1 injection
V elution volume at the peak maximum
e
W peak width at the half maximum height of the peak
1/2
h maximum peak height
σ standard deviation
Figure 2 — Determination of the number of theoretical plates by the half-height method
b) Separation efficiency
To ensure adequate resolution, the log M versus the elution volume, V , calibration curve for the
10 e
column combination used shall not exceed a specified gradient. For the purposes of this document,
the relation given in Formula (2) shall apply to the area of the peak maximum for the polymer
sample under investigation:
VV−
e,M e, 10×M
()
x x
>60, (2)
A
c
where
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oSIST prEN ISO 13885-1:2021
ISO 13885-1:2020(E)

V is the elution volume for polystyrene of molar mass M , in cubic centimetres;
x
e,M
x
V is the elution volume for 10 times that molar mass, in cubic centimetres;
e,10×M
()
x
A is the cross-sectional area of the column, in square centimetres.
c
M is the molar mass, that shall be selected such that the peak maximum for the poly-
x
mer sample under investigation lies in approximately halfway between these two
elution volumes.
5.5 Column temperature control
Carry out the test at room temperature (15 °C to 35 °C) or at a higher temperature of max. 40 °C. The
temperature of the column shall not change by more than 1 °C during the analysis (see Annex C).
5.6 Detector
Use a differential refractometer detector. The cell volume shall not exceed 0,010 ml.
NOTE For the restriction to a single detector type, see Annex C.
If copolymer samples or polymer blends are analysed, ensure that all the components give a similar
response factor (ratio of detector signal to concentration of analyte in the eluate or, in the case of
the differential refractometer, specific refractive index increment dn/dc), i.e. the relationship of the
response factors k and k for components i and j respectively is as follows:
i j
k
i
02, ≤≤5 (3)
k
j
If the ratio of the response factors does not fall within this range in the analysis of a set of samples,
a different detector or suitable combination of detectors may be used. If it is intended to compare
the results obtained by different laboratories for such a set of samples, the type of detector shall be
agreed upon. If a different detector is used, the reasons for using it shall be stated in the test report. See
Annex C.
The detector response obtained using the injection amounts specified in this document shall, at the
lowest setting for electronic damping, exhibit a noise level of less than 1 % of the maximum height of
the polymer peak. As the noise level is influenced by variations in pressure, temperature and flow rate,
particularly in the differential refractometer, suitable measures are to be taken to maintain a constant
temperature and to damp out pulses.
The signals from the detector are recorded by means of an electronic data system (see Clause 11 for
details).
6 Reagents
The eluent shall consist of THF with the following specification:
THF >99,5 % (mass fraction)
Water <0,05 % (mass fraction)
Peroxide <0,005 % (mass fraction)
THF may be stabilized with 2,6-di-tert-butyl-4-methylphenol (BHT) (up to a maximum of 0,250 g/l) to
prevent the formation of peroxides.
The peroxide content of THF shall be checked before use (e.g. using test strips).
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oSIST prEN ISO 13885-1:2021
ISO 13885-1:2020(E)

In exceptional cases, which shall be explained in the test report, it may be necessary to incorporate
further components in the THF eluent, up to a maximum of 10 g/l, to avoid interference with the
analysis of certain samples (see Annex C for details).
Discard the eluent used to condition the columns or to perform the analyses, and do not return it to the
eluent reservoir.
7 Calibration of the apparatus
7.1 General
The method is not an absolute one and requires calibration with commercially available unbranched
polystyrene standards that have been characterized by independent absolute methods. The results for
samples of polymers with different chemical structures are therefore only comparable within groups of
samples of the same type.
Calibrate the GPC apparatus with a series of unbranched polystyrene standards of narrow molar mass
distribution (see Annex C) and whose molar masses have been determined by independent, absolute
methods. The result is a calibration curve for the evaluation of GPC analyses of polystyrene samples.
If this calibration curve is used to analyse samples of other compositions, containing molecules with
[3]
other structures, the results shall be expressed as the “polystyrene molar mass equivalent” .
7.2 Requirements for the calibration standards
The molar-mass distribution of the standards shall be narrower than the limits given below as a
function of the molar mass at the peak maximum, M :
p
M < 2 000 g/mol M /M ≤ 1,2
p w n
6
2 000 g/mol ≤ M < 10 g/mol M /M ≤ 1,05
p w n
6
10 g/mol ≤ M M /M ≤ 1,2
p w n
The empirical peak-asymmetry factor for each chromatogram, calculated from the peak widths A and
B at half height before and after the perpendicular through the peak maximum, shall lie in the range
given by Formula (4).
A
=±10,,00 15 (4)
B
The widths A and B shall be determined from electronically acquired data on peaks defined by at least
60 measuring points.
The following minimum requirements shall be fulfilled in the characterization of each individual
polystyrene standard used for calibration:
a) at least one average molar mass value, M , M or M , shall be determined by an absolute method;
n w z
b) at least one method shall be used to determine the molar-mass distribution;
c) all the parameters involved in the method used shall be indicated;
d) the results and data for each batch analysed shall be presented in a comprehensible form for the user.
NOTE An example of a data sheet is given in Annex B.
If the calibration standards give a shoulder on either side of the peak, pre-peaks or a tailing peak, the
area represented by these anomalies shall be less than 2,0 % of the peak area, otherwise the calibr
...