Traditional Chinese medicine -- Determination of sulfur dioxide in natural products by titration

This document specifies the determination method of sulfur dioxide in natural products used in traditional Chinese medicine, which includes the requirements of the device, chemicals, operational procedures and formula. It is applicable to natural products of traditional Chinese medicine, including Chinese materia medica (whole medicinal materials) and decoction pieces derived from plants or animals. It is not applicable to minerals used in traditional Chinese medicine.

Médecine traditionnelle chinoise -- Dosage du dioxyde de soufre dans les produits naturels par titrage

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Status
Published
Publication Date
02-Nov-2020
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
28-Jul-2020
Completion Date
27-Jul-2020
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INTERNATIONAL ISO
STANDARD 22590
First edition
2020-11
Traditional Chinese medicine —
Determination of sulfur dioxide in
natural products by titration
Médecine traditionnelle chinoise — Dosage du dioxyde de soufre dans
les produits naturels par titrage
Reference number
ISO 22590:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO 22590:2020(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

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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 22590:2020(E)
Contents Page

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

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

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

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

4 Apparatus ..................................................................................................................................................................................................................... 2

5 Reagents ........................................................................................................................................................................................................................ 2

6 Sampling and preservation of samples ......................................................................................................................................... 2

6.1 Sampling ....................................................................................................................................................................................................... 2

6.1.1 Laboratory samples ....................................................................................................................................................... 2

6.1.2 Sample identification ................................................................................................................................................... 2

6.2 Sample preparation and preservation ................................................................................................................................ 3

6.2.1 Sample preparation ....................................................................................................................................................... 3

6.2.2 Sample preservation ..................................................................................................................................................... 3

7 Test method ............................................................................................................................................................................................................... 3

7.1 T est procedure ......................................................................................................................................................................................... 3

7.2 Calculation .................................................................................................................................................................................................. 4

Annex A (informative) Reference of national, regional and organizational limits of

sulfur dioxide in food and natural products of traditional Chinese medicine and

calculated limits using target hazard quotients based on USEPA and WHO ..........................................6

Annex B (informative) Gas chromatography — Determination of sulfur dioxide in natural

traditional Chinese medicine materials ....................................................................................................................................... 9

Annex C (informative) Analysis of the similarities and differences of acid-base titration

in different countries ....................................................................................................................................................................................10

Bibliography .............................................................................................................................................................................................................................13

© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 22590:2020(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 249, Traditional Chinese medicine.

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.
iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 22590:2020(E)
Traditional Chinese medicine — Determination of sulfur
dioxide in natural products by titration
1 Scope

This document specifies the determination method of sulfur dioxide in natural products used in

traditional Chinese medicine, which includes the requirements of the device, chemicals, operational

procedures and formula.

It is applicable to natural products of traditional Chinese medicine, including Chinese materia medica

(whole medicinal materials) and decoction pieces derived from plants or animals.
It is not applicable to minerals used in traditional Chinese medicine.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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/
3.1
sulfur dioxide

toxic gas with a pungent, irritating odour, the chemical compound with the formula SO

3.2
sulfur dioxide residue
sulfur dioxide that remains in or on a natural product
Note 1 to entry: Sulfur dioxide residue is expressed as mg/kg.
3.3
maximum residue limit
MRL
highest level of sulfur dioxide that is permitted in or on a natural product
Note 1 to entry: Maximum residue limit is expressed as mg/kg.
3.4
acceptable daily intake
ADI

estimate of the amount of sulfur dioxide in natural products that can be safely consumed daily over a

lifetime without adverse health effects

Note 1 to entry: ADI is expressed in milligrams of the sulfur dioxide, as it appears in the natural products, per

kilograms of body mass per day (mg/kg/day).
© ISO 2020 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO 22590:2020(E)
3.5
acid-base titration

determination of the concentration of an acid or base by exactly neutralizing the acid or base with a

base or acid of known concentration
4 Apparatus
4.1 Glass sample, cleaned thoroughly before use.
4.2 Electronic balance, with a minimum reading of 0,1 mg.
4.3 Separatory funnel, with a capacity of 50 ml or 100 ml.
4.4 Round-bottom flask, with a capacity of 500 ml or 1 000 ml.
5 Reagents

All reagents shall be of recognized chromatographic grade or analytical purity. Distilled water or water

of equivalent purity or above, recently boiled, shall be used.
5.1 Distilled water.

5.2 Bromophenol blue, 1 g/l solution of bromophenol blue in ethanol (20 % volume fraction).

5.3 Hydrochloric acid, 6 mol/l solution of diluted hydrochloric acid. Dilute one volume of concentrated

hydrochloric acid.

5.4 Hydrogen peroxide, 3 % volume fraction solution of diluted hydrogen peroxide, free from

sulfate ions.

5.5 Sodium hydroxide, 0,1 mol/l solution of sodium hydroxide (standard volumetric solution).

6 Sampling and preservation of samples
6.1 Sampling
6.1.1 Laboratory samples

Raw material samples received by the laboratory shall be accompanied with complete information such

as the source and time of collection of the samples. The samples for testing can include Chinese materia

medica (whole medicinal materials) and decoction pieces derived from plants or animals.

6.1.2 Sample identification

When a sample is received, it shall be immediately assigned a unique label which will accompany it

through all stages of the analysis to the reporting of the results. Samples shall be subject to the

appropriate disposal review system and all records shall be accurately kept.
2 © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 22590:2020(E)
6.2 Sample preparation and preservation
6.2.1 Sample preparation

Before testing, the sample shall be dried and powdered. Samples shall be pre-treated as soon as possible

and stored in a cool and dry place – if possible, in a refrigerator.
6.2.2 Sample preservation

If samples cannot be analysed immediately, they shall be stored in a cool and dry place, away from the

direct sunlight, and analysed within a few days.
7 Test method
7.1 Test procedure

a) Introduce 150 ml of water into the flask (see Figure 1, key 1), open the condenser pipe (key 3) and

pass carbon dioxide through the whole system for 15 min at a rate of 100 ± 5 ml/min. To 10 ml of

diluted hydrogen peroxide solution add 0,15 ml of a 1 g/l solution of bromophenol blue in ethanol

(20 % volume fraction).

b) Add 0,1 M sodium hydroxide until a violet-blue colour is obtained, without exceeding the end point.

c) Place the solution in the test tube (key 4). Without interrupting the stream of carbon dioxide,

remove the funnel (key 2) and introduce through the opening into the flask 25,0 g of the prepared

sample, with the aid of 100 ml of water.
d) Replace the funnel.
e) Close the tap of the funnel
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 22590
ISO/TC 249
Traditional Chinese medicine —
Secretariat: SAC
Determination of sulfur dioxide in
Voting begins on:
2020­06­01 natural products by titration
Voting terminates on:
Médecine traditionnelle chinoise — Dosage du dioxyde de soufre dans
2020­07­27
les produits naturels par titrage
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/FDIS 22590:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2020
---------------------- Page: 1 ----------------------
ISO/FDIS 22590:2020(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

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
CH­1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 22590:2020(E)
Contents Page

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

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

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

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

4 Apparatus ..................................................................................................................................................................................................................... 2

5 Reagents ........................................................................................................................................................................................................................ 2

6 Sampling and preservation of samples ......................................................................................................................................... 2

6.1 Sampling ....................................................................................................................................................................................................... 2

6.1.1 Laboratory samples ....................................................................................................................................................... 2

6.1.2 Sample identification ................................................................................................................................................... 2

6.2 Sample pre­treatment and preservation .......................................................................................................................... 3

6.2.1 Sample pre­treatment ................................................................................................................................................. 3

6.2.2 Sample storage .................................................................................................................................................................. 3

7 Test method ............................................................................................................................................................................................................... 3

7.1 Test procedure ......................................................................................................................................................................................... 3

7.2 Calculation .................................................................................................................................................................................................. 4

Annex A (informative) Reference of national, regional and organizational limits of

sulfur dioxide in food and natural products of traditional Chinese medicine and

calculated limits using target hazard quotients based on USEPA and WHO ..........................................6

Annex B (informative) Gas chromatography — Determination of sulfur dioxide in natural

traditional Chinese medicine materials ....................................................................................................................................... 9

Annex C (informative) Analysis of the similarities and differences of acid-base titration

in different countries ....................................................................................................................................................................................10

Bibliography .............................................................................................................................................................................................................................13

© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 22590:2020(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 non­governmental, 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 249, Traditional Chinese medicine.

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.
iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 22590:2020(E)
Traditional Chinese medicine — Determination of sulfur
dioxide in natural products by titration
1 Scope

This document specifies the determination method of sulfur dioxide in natural products used in

traditional Chinese medicine, which includes the requirements of the device, chemicals, operational

procedures and formula.

It is applicable to natural products of traditional Chinese medicine, including Chinese materia medica

(whole medicinal materials) and decoction pieces derived from plants or animals.
It is not applicable to minerals used in traditional Chinese medicine.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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/
3.1
sulfur dioxide

toxic gas with a pungent, irritating smell, the chemical compound with the formula SO

3.2
sulfur dioxide residue
sulfur dioxide that remains in or on a natural product
Note 1 to entry: Sulfur dioxide residue is expressed as mg/kg.
3.3
maximum residue limit
MRL
highest level of sulfur dioxide that is permitted in or on a natural product
Note 1 to entry: Maximum residue limit is expressed as mg/kg.
3.4
acceptable daily intake
ADI

estimate of the amount of sulfur dioxide in natural products that can be safely consumed daily over a

lifetime without adverse health effects

Note 1 to entry: ADI is expressed in milligrams of the sulfur dioxide, as it appears in the natural products, per

kilograms of body mass per day (mg/kg/day).
© ISO 2020 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO/FDIS 22590:2020(E)
3.5
acid-base titration

determination of the concentration of an acid or base by exactly neutralizing the acid or base with a

base or acid of known concentration
4 Apparatus
4.1 Glass sample, cleaned thoroughly before use.
4.2 Electronic balance, with a minimum reading of 0,1 mg.
4.3 Separatory funnel, with a capacity of 50 ml or 100 ml.
4.4 Round-bottom flask, with a capacity of 500 ml or 1 000 ml.
5 Reagents

All reagents shall be of recognized chromatographic or analytical purity. Distilled water or water of

equivalent purity or above, recently boiled, shall be used.
5.1 Distilled water.

5.2 Bromophenol blue, 1 g/l solution of bromophenol blue in ethanol (20 % volume fraction).

5.3 Hydrochloric acid, 6 mol/l solution of diluted hydrochloric acid. Dilute one volume of concentrated

hydrochloric acid.

5.4 Hydrogen peroxide, 3 % volume fraction solution of diluted hydrogen peroxide, free from

sulfate ions.

5.5 Sodium hydroxide, 0,1 mol/l solution of sodium hydroxide (standard volumetric solution).

6 Sampling and preservation of samples
6.1 Sampling
6.1.1 Laboratory samples

Raw material samples received by the laboratory shall be accompanied with complete information such

as the source and time of collection of the samples. The samples for testing can include Chinese materia

medica (whole medicinal materials) and decoction pieces derived from plants or animals.

6.1.2 Sample identification

When a sample is received, it shall be immediately assigned a unique label which will accompany it

through all stages of the analysis to the reporting of the results. Samples shall be subject to the

appropriate disposal review system and all records shall be accurately kept.
2 © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/FDIS 22590:2020(E)
6.2 Sample pre-treatment and preservation
6.2.1 Sample pre-treatment

Before testing, the sample shall be dried and powdered. Samples shall be pre­treated as soon as possible

and stored in a cool and dry place – if possible, in a refrigerator.
6.2.2 Sample storage

If samples cannot be analysed immediately, they shall be stored in a cool and dry place, away from the

direct sunlight, and analysed within a few days.
7 Test method
7.1 Test procedure

a) Introduce 150 ml of water into the flask (see Figure 1, key 1), open the condenser pipe (key 3) and

pass carbon dioxide through the whole system for 15 min at a rate of 100 ± 5 ml/min. To 10 ml of

diluted hydrogen peroxide solution add 0,15 ml of a 1 g/l solution of bromophenol blue in ethanol

(20 % volume fraction).
b) Add 0,1 M sodium hydroxide until a violet-blue colour is
...

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