IEC TR 62697-3:2018

IEC TR 62697-3 ®
Edition 1.0 2018-02
TECHNICAL
REPORT
colour
inside
Test methods for quantitative determination of corrosive sulfur compounds in
unused and used insulating liquids –
Part 3: Test method for quantitative determination of elemental sulfur
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IEC TR 62697-3 ®
Edition 1.0 2018-02
TECHNICAL
REPORT
colour
inside
Test methods for quantitative determination of corrosive sulfur compounds in

unused and used insulating liquids –

Part 3: Test method for quantitative determination of elemental sulfur

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.040.10 ISBN 978-2-8322-5361-8

– 2 – IEC TR 62697-3:2018 © IEC 2018
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Sampling . 9
5 Procedure . 9
5.1 Principle . 9
5.1.1 Determination with gas chromatography . 9
5.1.2 Determination with differential pulse voltammetry . 9
5.2 Significance and use . 9
5.3 Interferences. 10
5.3.1 Co-eluting compounds . 10
5.3.2 Electron capture detector (ECD) . 10
5.3.3 Flame photometric detector (FPD) . 10
5.3.4 Mass spectrometer (MS) . 10
5.3.5 Interference from the matrix . 10
5.4 Apparatus . 10
5.4.1 Balance . 10
5.4.2 Gas chromatography system . 11
5.4.3 Differential pulsed voltammetry . 11
5.5 Reagents and materials . 11
5.5.1 Purity of reagents . 11
5.5.2 Gases . 11
5.5.3 Solvents . 12
5.6 Standard materials . 12
5.6.1 Elemental sulfur . 12
5.6.2 Diphenyl disulfide (DPDS) . 12
5.6.3 Blank oil . 12
5.7 Standard solutions . 12
5.7.1 Stock solutions . 12
5.7.2 Internal standard (IS) solution . 13
6 Instrument set-up . 13
6.1 Gas chromatograph . 13
6.1.1 General . 13
6.1.2 Carrier gas . 13
6.1.3 Injector . 13
6.1.4 Separation parameters . 13
6.1.5 ECD detection . 14
6.1.6 FPD detection . 14
6.1.7 MS detection . 14
6.2 Calibration . 14
6.2.1 General . 14
6.2.2 Calibration procedure . 14
6.2.3 Response factor determination (ECD and FPD) . 15
6.2.4 Response factor determination (MS) . 15

6.3 Analysis . 15
6.3.1 Sample pre-treatment . 15
6.3.2 Sample injection . 16
6.3.3 Chromatographic run . 16
6.3.4 Peak integration . 16
6.4 Calculations . 16
6.4.1 ECD and FPD . 16
6.4.2 Mass spectrometer (MS) . 16
6.4.3 Differential pulse voltammetry measurements . 17
6.5 Results . 17
7 Precision data . 18
7.1 Detection limit . 18
7.2 Repeatability . 18
7.3 Reproducibility . 18
8 Report . 18
Annex A (informative) Figures with typical chromatograms and results . 19
Annex B (informative) RRT results Statistical evaluation of elemental sulfur data GC-
ECD/FPD . 21
Bibliography . 23

Figure 1 – Typical peak form and concentration calculation . 17
–1
Figure A.1 – GC-ECD chromatogram of 5 mg kg elemental sulfur and (IS) in white
mineral oil . 19
–1
Figure A.2 – GC-ECD chromatogram of 100 mg kg elemental sulfur and (IS) in white
mineral oil . 20

Table 1 – Column oven temperature programming parameters . 14
Table 2 – Mass spectrometer parameters . 14
Table 3 – Repeatability limit . 18
Table 4 – Reproducibility limit . 18
Table B.1 – Reproducibility with same chemical analysis approach . 21
Table B.2 – Reproducibility with different chemical analysis approach . 21
Table B.3 – Repeatability . 22

– 4 – IEC TR 62697-3:2018 © IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TEST METHODS FOR QUANTITATIVE DETERMINATION
OF CORROSIVE SULFUR COMPOUNDS IN UNUSED
AND USED INSULATING LIQUIDS –
Part 3: Test method for quantitative determination
of elemental sulfur
FOREWORD
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