prEN ISO 11337

Plastics - Polyamides - Determination of e-caprolactam and w-laurolactam by gas chromatography (ISO/DIS 11337:2022)

ISO 11337:2010 specifies a method for determining epsilon‑caprolactam and omega‑laurolactam in polyamides by gas chromatography. It is suitable particularly for the determination of epsilon‑caprolactam in polyamide 6 and omega‑laurolactam in polyamide 12. Bearing in mind that gas chromatography offers a wide range of possible conditions, the method specified is that shown to have been suitable in practice.
Two variants of the basic method are specified:
Method A is an extraction method with boiling methanol, and the extract is injected into a gas chromatograph.
Method B is a method using a solvent, and the solution is injected into a gas chromatograph.

Kunststoffe - Polyamide - Gaschromatographische Bestimmung von ε-Caprolactam und ω-Laurolactam (ISO/DIS 11337:2022)

Plastiques - Polyamides - Détermination du e-caprolactame et du w-laurolactame par chromatographie en phase gazeuse (ISO/DIS 11337:2022)

L'ISO 11337:2010 spécifie une méthode de dosage du epsilon-caprolactame et du omega-laurolactame dans les polyamides par chromatographie en phase gazeuse. Elle convient particulièrement au dosage du epsilon-caprolactame dans le polyamide 6 et du omega-laurolactame dans le polyamide 12. Compte tenu du fait que la chromatographie en phase gazeuse présente un large éventail de conditions possibles, la méthode spécifiée est celle qui a fait ses preuves dans la pratique.
Deux variantes de la méthode de base sont spécifiées:
Méthode A, par extraction au méthanol en ébullition, où les extraits sont injectés dans un chromatographe en phase gazeuse.
Méthode B, utilisant un solvant, où la solution est injectée directement dans un chromatographe en phase gazeuse.

Polimerni materiali - Poliamidi - Določanje e-kaprolaktama in w-laurolaktama s plinsko kromatografijo (ISO/DIS 11337:2022)

General Information

• Status: Not Published
• ICS: 83.080.20 - Thermoplastic materials
• Technical Committee: CEN/TC 249 - Plastics
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Due Date: 21-Sep-2022
• Completion Date: 21-Sep-2022
• Ref Project: oSIST prEN ISO 11337:2022 - Plastics - Polyamides - Determination of e-caprolactam and w-laurolactam by gas chromatography (ISO/DIS 11337:2022)

RELATIONS

• Revised: EN ISO 11337:2010 - Plastics - Polyamides - Determination of e-caprolactam and w-laurolactam by gas chromatography (ISO 11337:2010)
• Effective Date: 06-Oct-2021

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN ISO 11337:2022
01-september-2022
Polimerni materiali - Poliamidi - Določanje e-kaprolaktama in w-laurolaktama s
plinsko kromatografijo (ISO/DIS 11337:2022)
Plastics - Polyamides - Determination of e-caprolactam and w-laurolactam by gas
chromatography (ISO/DIS 11337:2022)
Kunststoffe - Polyamide - Gaschromatographische Bestimmung von ε-Caprolactam und
ω-Laurolactam (ISO/DIS 11337:2022)

Plastiques - Polyamides - Détermination du e-caprolactame et du w-laurolactame par

chromatographie en phase gazeuse (ISO/DIS 11337:2022)
Ta slovenski standard je istoveten z: prEN ISO 11337
ICS:
83.080.20 Plastomeri Thermoplastic materials
oSIST prEN ISO 11337:2022 en,fr,de

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

---------------------- Page: 1 ----------------------
oSIST prEN ISO 11337:2022
---------------------- Page: 2 ----------------------
oSIST prEN ISO 11337:2022
DRAFT INTERNATIONAL STANDARD
ISO/DIS 11337
ISO/TC 61/SC 9 Secretariat: KATS
Voting begins on: Voting terminates on:
2022-06-09 2022-09-01
Plastics — Polyamides — Determination of e-caprolactam
and w-laurolactam by gas chromatography

Plastiques — Polyamides — Détermination du e-caprolactame et du w-laurolactame par chromatographie

en phase gazeuse
ICS: 83.080.20
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 11337:2022(E)
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. © ISO 2022
---------------------- Page: 3 ----------------------
oSIST prEN ISO 11337:2022
ISO/DIS 11337:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 11337:2022
ISO/DIS 11337:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Method A: Extraction method ................................................................................................................................................................1

4.1 Principle ....................................................................................................................................................................................................... 1

4.2 Reagents ....................................................................................................................................................................................................... 2

4.3 Apparatus and materials ............................................................................................................................................................... 2

4.4 Preparation of test sample ........................................................................................................................................................... 3

4.5 Procedure .................................................................................................................................................................................................... 4

4.5.1 Test portion ............................................................................................................................................................................. 4

4.5.2 Extraction ................................................................................................................................................................................. 4

4.5.3 Preparation of internal-standard solution .................................................................................................. 4

4.5.4 Preparation of sample solution ............................................................................................................................. 4

4.5.5 Preparation of calibration solution .................................................................................................................... 4

4.5.6 Gas-chromatographic analysis of sample and calibration solutions ................................... 4

4.5.7 Evaluation of gas chromatographic peaks .................................................................................................. 5

4.6 Expression of results ........................................................................................................................................... .............................. 5

4.7 Precision ......... .................................................................................................................................. ............................................................ 5

4.8 Test report .................................................................................................................................................................................................. 6

5 Method B: Dissolution method .............................................................................................................................................................. 6

5.1 Principle ....................................................................................................................................................................................................... 6

5.2 Reagents ....................................................................................................................................................................................................... 6

5.3 Apparatus .................................................................................................................................................................................................... 7

5.4 Preparation of internal-standard solutions ................................................................................................................. 8

5.4.1 General ........................................................................................................................................................................................ 8

5.4.2 Internal standard for unextracted polyamide 6 .................................................................................... 8

5.4.3 Internal standard for extracted polyamide 6 ........................................................................................... 8

5.4.4 Internal standard for polyamide 12 .................................................................................................................. 8

5.4.5 Preparation of calibration solutions ................................................................................................................. 8

5.4.6 Calibration ................................... ........................................................................................................ ..................................... 9

5.5 Procedure ................................................................................................................................................................................................. 10

5.5.1 Preparation and injection of sample solution ....................................................................................... 10

5.5.2 Evaluation of gas-chromatographic peaks............................................................................................... 10

5.5.3 Solvent recovery .............................................................................................................................................................. 10

5.6 Expression of results ........................................................................................................................................... ........................... 10

5.7 Precision ......... .................................................................................................................................. ......................................................... 11

5.8 Test report ............................................................................................................................................................................................... 11

iii
© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
oSIST prEN ISO 11337:2022
ISO/DIS 11337:2022(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.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International

Standards adopted by the technical committees are circulated to the member bodies for voting.

Publication as an International Standard requires approval by at least 75 % of the member bodies

casting a vote.

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.

ISO 11337 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 5, Physical-

chemical properties.

This second edition cancels and replaces the first edition (ISO 11337:2004), which has been technically

revised. It also incorporates the Technical Corrigendum ISO 11337:2004/Cor.1:2007.

© ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
oSIST prEN ISO 11337:2022
DRAFT INTERNATIONAL STANDARD ISO/DIS 11337:2022(E)
Plastics — Polyamides — Determination of e-caprolactam
and w-laurolactam by gas chromatography

SAFETY STATEMENT — Persons using this document should be familiar with normal laboratory

practice, if applicable. This document does not purport to address all of the safety concerns, 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 regulatory requirements.
1 Scope

This document specifies a method for determining ε-caprolactam and ω-laurolactam in polyamides by

gas chromatography. It is applicable particularly to the determination of ε-caprolactam in polyamide 6

and ω-laurolactam in polyamide 12.
Two variants of the basic method are specified:

— Method A is an extraction method with boiling methanol, and the extract is injected into a gas

chromatograph.

— Method B is a method using a solvent, and the solution is injected into a gas chromatograph.

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 amendment)

applies.
ISO 472, Plastics — Vocabulary

ISO 565, Test sieves — Metal wire cloth, perforated metal plate and electroformed sheet — Nominal sizes

of openings
3 Terms and definitions

For the purposes for this document, the terms and definitions given in ISO 472 apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org
4 Method A: Extraction method
4.1 Principle

A test portion is extracted with boiling methanol and a small volume of the extract injected into a gas

chromatograph equipped with a suitable detector to separate and detect the volatile components.

The extract contains 1-dodecanol as an internal standard.
© ISO 2022 – All rights reserved
---------------------- Page: 7 ----------------------
oSIST prEN ISO 11337:2022
ISO/DIS 11337:2022(E)
4.2 Reagents
During the analysis, use only reagents of recognized analytical grade.
4.2.1 Solvent such as methanol.
4.2.2 Internal standard such as 1-dodecanol or isopropanol.
4.2.3 ε-Caprolactam.
4.3 Apparatus and materials
Ordinary laboratory apparatus, plus the following:
4.3.1 Mill, for reducing the sample to the required grain size.

A mill in which the sample is ground at a low temperature is preferred. Large pieces can be reduced in

size with a pair of scissors before they are fed to the mill.

4.3.2 Two sieves, with aperture sizes of 710 µm and 500 µm respectively, complying with the

requirements of ISO 565.

4.3.3 Extraction apparatus, that will accommodate an extraction crucible or porous ceramic

thimble containing the test portion.

The apparatus shall be of such a design that the crucible or thimble is heated by the rising methanol

vapour or the apparatus shall be constructed of an extraction flask with a Soxhlet-type reflux condenser.

Examples of suitable extraction apparatus designed along these lines are
EXAMPLE 1
— 250 ml extraction flask;

— extraction chamber to accommodate the extraction crucible so that it is enveloped on all sides by

the rising methanol vapour and the condensed methanol drips through it continuously;

— glass triangle to support the crucible;
— reflux condenser;
— sintered-glass filter crucible, pore size 40 µm to 50 µm, capacity 30 ml;

— porcelain filter-plate of slightly smaller diameter than the crucible, with holes of diameter 0,4 mm.

EXAMPLE 2
— 250 ml extraction flask;
— jacketed Soxhlet extractor;
— reflux condenser;

— sintered-glass filter crucible, pore size 40 µm to 50 µm, capacity 30 ml, or a porous ceramic thimble

of similar capacity (the dimensions shall be such that the crucible or thimble can be satisfactorily

accommodated in the Soxhlet apparatus);

— porcelain filter-plate of slightly smaller diameter than the crucible or thimble, as appropriate, with

holes of diameter 0,4 mm.
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
oSIST prEN ISO 11337:2022
ISO/DIS 11337:2022(E)
4.3.4 Suitable heating device for extraction apparatus.
4.3.5 Analytical balance, accurate to 0, 2 mg.
4.3.6 Liquid nitrogen or solid carbon dioxide, if necessary.
4.3.7 Gas chromatograph, with suitable detector.
a) Column
The following columns are suitable:

— a glass column (3 mm Æ × 1,6 m), packed with acid-washed Chromosorb® W of particle diameter

0,149 mm to 0,177 mm (80 mesh to 100 mesh) coated with 10 % (by mass) poly(ethylene glycol)

20M;
TM1)

— a megabore Carbowax column (0,53 mm Æ × 15 m) of corresponding separation efficiency.

The method of packing is not specified but shall be such as to obtain satisfactory separation efficiency.

Other column dimensions may be used as long as a sufficient separation efficiency is achieved.

A capillary column may also be used.

Suggested operating conditions for using a glass column and a FID detector are shown in Table 1.

Table 1 — Operating conditions for gas chromatograph
Item Value
Column temperature 200 °C
Injector temperature 250 °C
Detector temperature 250 °C
Carrier gas Helium or nitrogen
Carrier gas flow rate 20 ml/min

Other types of columns and/or detectors may require different operating temperatures and types and

flow rates of carrier and makeup gas.
b) Detector

Use a suitable detector with adequate selection of operating temperature and type and flow rate of

carrier and makeup gas so that:
— the sensitivity is high;

— the relationship between response and concentration is linear over the whole measurement range;

— small changes in flow rate produce only insignificant effects on response and sensitivity.

4.3.8 Microsyringes, with capacities from 1 µl to 10 µl.
4.4 Preparation of test sample

Take a representative sample of the polymer and grind it in the mill (4.3.1). Grind the material in small

portions to prevent undue heat development (i.e. to avoid the temperature rising above about 40 °C),

letting the mill cool down in between portions. Solid carbon dioxide or liquid nitrogen (4.3.6) may be

1) Examples of suitable products available commercially. This information is given for the convenience of users of

this International Standard and does not constitute an endorsement by ISO of these products.

© ISO 2022 – All rights reserved
---------------------- Page: 9 ----------------------
oSIST prEN ISO 11337:2022
ISO/DIS 11337:2022(E)

ground together with the polymer to prevent heat build-up. With a large mill having a greater heat

capacity, these precautions may not be required. Collect the fraction that passes through a sieve with

mesh aperture 710 µm (4.3.2), but not through the one with mesh aperture 500 µm.
4.5 Procedure
4.5.1 Test portion

Weigh, to the nearest 0,001 g, (5 ± 0,5) g (mass m ) of the test sample into the filter crucible or porous

thimble (4.3.3). With low-concentration samples, it is preferable to increase the mass of the test portion

so that it contains approximately 0,01 g to 0,05 g of ε-caprolactam.

NOTE Polyamides can contain a small amount of water, forming part of the mass of the test portion (m ).

This water is not allowed for in the calculation of the methanol-extractable matter content since its effect is small

compared the variance of the determination.
4.5.2 Extraction

Cover the test portion (see 4.5.1) with the filter-plate, pour about 50 ml of methanol (4.2.1) into the

extraction flask, place the crucible or thimble containing the test portion in the extraction chamber and

fit the condenser to the chamber. Heat the solvent in the flask to boiling. When the apparatus described

in 4.3.3, Example 1, is used, a
...