Traditional Chinese medicine -- Determination of pesticide residues in natural products by gas chromatography

This document specifies the method of determination of pesticide residues in natural products used in traditional Chinese medicine (TCM) by gas chromatography (GC), including Chinese materia medica (whole medicinal materials) and decoction pieces derived from plants.

Médecine traditionnelle chinoise -- Détermination des résidus de pesticides dans les produits naturels par chromatographie en phase gazeuse

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Publication Date
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INTERNATIONAL ISO
STANDARD 22258
First edition
2020-07
Traditional Chinese medicine —
Determination of pesticide
residues in natural products by gas
chromatography
Médecine traditionnelle chinoise — Détermination des résidus
de pesticides dans les produits naturels par chromatographie en
phase gazeuse
Reference number
ISO 22258:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO 22258:2020(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 22258:2020(E)
Contents Page

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

Introduction ..................................................................................................................................................................................................................................v

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

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

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

4 Sampling ........................................................................................................................................................................................................................ 1

5 Determination of pesticide residues ............................................................................................................................................... 2

5.1 Reagents........................................................................................................................................................................................................ 2

5.1.1 General...................................................................................................................................................................................... 2

5.1.2 Check for purity of reagents ................................................................................................................................... 2

5.2 Apparatus .................................................................................................................................................................................................... 2

5.3 Qualitative and quantitative analysis of pesticide residues ............................................................................. 2

5.4 Test .................................................................................................................................................................................................................... 3

6 Limits ................................................................................................................................................................................................................................ 3

Annex A (informative) Determination of pesticide residues in natural products used in TCM

by GC .................................................................................................................................................................................................................................. 4

Annex B (informative) Maximum limits of pesticide residue in natural products used in

TCM (based on the European Pharmacopoeia and US Pharmacopoeia) ....................................................7

Annex C (informative) Recommended limits of pesticide residues in dried fruit, vegetable

or herbal medicine from WHO and FDA/EPA ......................................................................................................................10

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

© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 22258:2020(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 ----------------------
ISO 22258:2020(E)
Introduction

A pesticide is any substance or mixture of substances intended to prevent, destroy or control any

pest, unwanted species of plants or animals causing harm during, or otherwise interfering with, the

production, processing, storage, transport or marketing of uncontaminated products. At present, there

is no uniformly accepted international standard which defines maximum limits for pesticides in natural

products used in traditional Chinese medicine (TCM), resulting in disputes about what levels should be

considered acceptable.

This document was developed in response to worldwide demand for harmonization of the determination

of pesticide residues. This document is applicable to natural products used in TCM.

For reference, the method of determination of pesticide residues by gas chromatography (GC) is

provided in Annex A, the maximum limits of pesticide residues in natural products used in TCM are

provided in Annex B and the recommended limits of pesticide residues in dried fruit and vegetables,

which is similar to TCM materials or herbal medicine from the World Health Organization (WHO) and

Food and Drug Administration/Environmental Protection Agency (FDA/EPA), are given in Annex C.

© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 22258:2020(E)
Traditional Chinese medicine — Determination
of pesticide residues in natural products by gas
chromatography
1 Scope

This document specifies the method of determination of pesticide residues in natural products used

in traditional Chinese medicine (TCM) by gas chromatography (GC), including Chinese materia medica

(whole medicinal materials) and decoction pieces derived from plants.
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
pesticide

substance or mixture of substances intended for preventing, destroying, repelling or reducing any pest

or weeds
[SOURCE: ISO 27065:2017, 3.9, modified — Note 1 to entry removed.]
3.2
pesticide residue

pesticide, pesticide derivative or pesticide adjuvant that remains in or on a natural product

Note 1 to entry: Pesticide residues are expressed in mg/kg.
3.3
acceptable daily intake
ADI

estimate of the amount of a pesticide 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 pesticide, as it appears in the natural products, per

kilograms of body mass per day (mg/kg/day).
4 Sampling

To reduce the effect of sampling in the determination of pesticide residues in natural products used in

TCM, ensure that the composition of the sample used is representative of the batch of natural products

used in TCM being examined. The sampling procedures may be used if they can be demonstrated to

produce representative batch samples.
© ISO 2020 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO 22258:2020(E)

Samples shall be accompanied with complete information (e.g. name, source, specification of the

samples) to ensure traceability.
5 Determination of pesticide residues
5.1 Reagents
5.1.1 General

Use reagents of purity suitable for pesticide residue analysis. All reagents shall be of recognized

chromatographic or analytical purity. Avoid possible contamination of water, solvents, sorbents

inorganic salts or other reagents.
5.1.2 Check for purity of reagents

When using GC the purity of the reagents used shall be checked by running a blank determination. The

chromatogram obtained from the solvents shall have a baseline without noticeable peak that would

interfere or overlap with the peaks from the chromatogram of the targeted pesticide residue (see

ISO 4389:2000, Clause 4).
5.2 Apparatus

All equipment, especially glassware, shall be thoroughly cleaned to ensure that it is free from

pesticides. All glassware shall be soaked for a minimum of 16 h in a solution of phosphate-free

detergent, rinsed repeatedly with distilled water to remove the detergent residue, then washed with

acetone, followed by hexane or heptane. Do not use ordinary plastics, for example PVC stoppers, in

vessels for storing standard materials and solutions as they can cause contamination. Polypropylene

(PP), polytetrafluoroethylene (PTFE) or nylon tubing and glass or PTFE stoppers usually present the

lowest risk of contamination.

Common laboratory glassware or equipment such as beakers, round-bottomed flasks, watch glasses,

pipettes, filter papers, glass wool, glass rods and glass beads are not listed in method in detail.

5.3 Qualitative and quantitative analysis of pesticide residues

Validated analytical procedures that satisfy the following criteria shall be used:

1) The chosen method, especially the purification steps, is suitable for the combination pesticide

residue/substance to be examined, and not susceptible to interference from co-extractives.

2) Natural occurrence of some constituents is considered in the interpretation of results (e.g. disulfide

from cruciferaceae).

3) The concentration of test and reference solutions and the setting of the apparatus are such that

the responses used for quantification of the pesticide residues are within the dynamic range of the

detector. Test solutions containing pesticide residues at a level outside the dynamic range may be

diluted within the calibration range, provided that the concentration of the matrix in the solution is

adjusted in cases where the calibration solutions must be matrix-matched.

4) Between 70 % and 120 % of each pesticide is recovered; lower recoveries may be acceptable in

certain justified cases.

5) Repeatability of the method: relative standard deviation (RSD) is not greater than the values

indicated in Table 1.

6) Reproducibility of the method: RSD is not greater than the values indicated in Table 1.

2 © ISO 2020 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 22258:2020(E)
Table 1 — The request of the repeatability and reproducibility of the method for
determination of pesticide residues
Concentration range of the pesticide Repeatability (RSD) Reproducibility (RSD)
mg/kg % %
0,001 – 0,01 30 60
> 0,01 – 0,1 20 40
> 0,1 – 1 15 30
> 1 10 20
5.4 Test

For reference, the method of determination of pesticide residues by GC is provided in Annex A. In certain

cases it is possible to improve the method performance by variations in equipment used, extraction,

clean-up and chromatographic conditions. Such variations shall always be clearly documented and

demonstrated to give valid results.
6 Limits
Limits for pesticides are calculated using the following formula:
Limit (mg/kg) = Am/100B
where
A is the ADI, in mg/kg of body mass;
m is body mass, in kg (60 kg);
B is the daily dose of the article, in kg.

The competent authority may grant total or partial exemption from the test when the complete history

(nature and quantity of the pesticides used, date of each treatment during cultivation and after the

harvest) of the treatment of the batch is known and can be checked precisely according to good

agricultural and collection practice (GACP).

Maximum limits of pesticide residues in natural products used in TCM are provided in Annex B.

© ISO 2020 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO 22258:2020(E)
Annex A
(informative)
Determination of pesticide residues in natural products used in
TCM by GC
A.1 Extraction

Use the following procedure for the analysis of samples of articles having a water content of less than

15 %. Samples having a higher water content may be dried, provided that the drying procedure does

not significantly affect the pesticide content.

Add 100 ml of acetone to 10 g of the coarsely powdered substance (pulverized through a 50-mesh

sieve) under test and allow to stand for 20 min. Add 1 ml of a solution in toluene containing 1,8 µg

of carbophenothion per ml. Mix in
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 22258
ISO/TC 249
Traditional Chinese medicine —
Secretariat: SAC
Determination of pesticide
Voting begins on:
2020­04­14 residues in natural products by gas
chromatography
Voting terminates on:
2020­06­09
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 22258:2020(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 22258:2020(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 22258:2020(E)
Contents Page

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

Introduction ..................................................................................................................................................................................................................................v

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

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

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

4 Sampling ........................................................................................................................................................................................................................ 1

5 Determination of pesticide residues ............................................................................................................................................... 2

5.1 Reagents........................................................................................................................................................................................................ 2

5.1.1 General...................................................................................................................................................................................... 2

5.1.2 Check for purity of reagents ................................................................................................................................... 2

5.2 Apparatus .................................................................................................................................................................................................... 2

5.3 Qualitative and quantitative analysis of pesticide residues ............................................................................. 2

5.4 Test .................................................................................................................................................................................................................... 3

6 Limits ................................................................................................................................................................................................................................ 3

Annex A (informative) Determination of pesticide residues in natural products used in TCM

by GC .................................................................................................................................................................................................................................. 4

Annex B (informative) Maximum limits of pesticide residue in natural products used in

TCM (based on the European Pharmacopoeia and US Pharmacopoeia) ....................................................7

Annex C (informative) Recommended limits of pesticide residues in dried fruit, vegetable

or herbal medicine from WHO and FDA/EPA ......................................................................................................................10

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

© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/FDIS 22258:2020(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 ----------------------
ISO/FDIS 22258:2020(E)
Introduction

A pesticide is any substance or mixture of substances intended to prevent, destroy or control any

pest, unwanted species of plants or animals causing harm during, or otherwise interfering with, the

production, processing, storage, transport or marketing of uncontaminated products. At present, there

is no uniformly accepted international standard which defines maximum limits for pesticides in natural

products used in traditional Chinese medicine (TCM), resulting in disputes about what levels should be

considered acceptable.

This document was developed in response to worldwide demand for harmonization of the determination

of pesticide residues. This document is applicable to natural products used in TCM.

For reference, the method of determination of pesticide residues by gas chromatography (GC) is

provided in Annex A, the maximum limits of pesticide residues in natural products used in TCM are

provided in Annex B and the recommended limits of pesticide residues in dried fruit and vegetables,

which is similar to TCM materials or herbal medicine from the World Health Organization (WHO) and

Food and Drug Administration/Environmental Protection Agency (FDA/EPA), are given in Annex C.

© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 22258:2020(E)
Traditional Chinese medicine — Determination
of pesticide residues in natural products by gas
chromatography
1 Scope

This document specifies the method of determination of pesticide residues in natural products used

in traditional Chinese medicine (TCM) by gas chromatography (GC), including Chinese materia medica

(whole medicinal materials) and decoction pieces derived from plants.
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
pesticide

substance or mixture of substances intended for preventing, destroying, repelling or reducing any pest

or weeds
[SOURCE: ISO 27065:2017, 3.9, modified — Note 1 to entry removed.]
3.2
pesticide residue

pesticide, pesticide derivative or pesticide adjuvant that remains in or on a natural product

Note 1 to entry: Pesticide residues are expressed in mg/kg.
3.3
acceptable daily intake
ADI

estimate of the amount of a pesticide 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 pesticide, as it appears in the natural products, per

kilograms of body mass per day (mg/kg/day).
4 Sampling

To reduce the effect of sampling in the determination of pesticide residues in natural products used in

TCM, ensure that the composition of the sample used is representative of the batch of natural products

used in TCM being examined. The sampling procedures may be used if they can be demonstrated to

produce representative batch samples.
© ISO 2020 – All rights reserved 1
---------------------- Page: 6 ----------------------
ISO/FDIS 22258:2020(E)

Samples shall be accompanied with complete information (e.g. name, source, specification of the

samples) to ensure traceability.
5 Determination of pesticide residues
5.1 Reagents
5.1.1 General

Use reagents of purity suitable for pesticide residue analysis. All reagents shall be of recognized

chromatographic or analytical purity. Avoid possible contamination of water, solvents, sorbents

inorganic salts or other reagents.
5.1.2 Check for purity of reagents

When using GC the purity of the reagents used shall be checked by running a blank determination. The

chromatogram obtained from the solvents shall have a baseline without noticeable peak that would

interfere or overlap with the peaks from the chromatogram of the targeted pesticide residue (see

ISO 4389:2000, Clause 4).
5.2 Apparatus

All equipment, especially glassware, shall be thoroughly cleaned to ensure that it is free from

pesticides. All glassware shall be soaked for a minimum of 16 h in a solution of phosphate­free

detergent, rinsed repeatedly with distilled water to remove the detergent residue, then washed with

acetone, followed by hexane or heptane. Do not use ordinary plastics, for example PVC stoppers, in

vessels for storing standard materials and solutions as they can cause contamination. Polypropylene

(PP), polytetrafluoroethylene (PTFE) or nylon tubing and glass or PTFE stoppers usually present the

lowest risk of contamination.

Common laboratory glassware or equipment such as beakers, round-bottomed flasks, watch glasses,

pipettes, filter papers, glass wool, glass rods and glass beads are not listed in method in detail.

5.3 Qualitative and quantitative analysis of pesticide residues

Validated analytical procedures that satisfy the following criteria shall be used:

1) The chosen method, especially the purification steps, is suitable for the combination pesticide

residue/substance to be examined, and not susceptible to interference from co-extractives.

2) Natural occurrence of some constituents is considered in the interpretation of results (e.g. disulfide

from cruciferaceae).

3) The concentration of test and reference solutions and the setting of the apparatus are such that

the responses used for quantification of the pesticide residues are within the dynamic range of the

detector. Test solutions containing pesticide residues at a level outside the dynamic range may be

diluted within the calibration range, provided that the concentration of the matrix in the solution is

adjusted in cases where the calibration solutions must be matrix-matched.

4) Between 70 % and 120 % of each pesticide is recovered; lower recoveries may be acceptable in

certain justified cases.

5) Repeatability of the method: relative standard deviation (RSD) is not greater than the values

indicated in Table 1.

6) Reproducibility of the method: RSD is not greater than the values indicated in Table 1.

2 © ISO 2020 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/FDIS 22258:2020(E)
Table 1 — The request of the repeatability and reproducibility of the method for
determination of pesticide residues
Concentration range of the pesticide Repeatability (RSD) Reproducibility (RSD)
mg/kg % %
0,001 – 0,01 30 60
> 0,01 – 0,1 20 40
> 0,1 – 1 15 30
> 1 10 20
5.4 Test

For reference, the method of determination of pesticide residues by GC is provided in Annex A. In certain

cases it is possible to improve the method performance by variations in equipment used, extraction,

clean-up and chromatographic conditions. Such variations shall always be clearly documented and

demonstrated to give valid results.
6 Limits
Limits for pesticides are calculated using the following formula:
Limit (mg/kg) = Am/100B
where
A is the ADI, in mg/kg of body mass;
m is body mass, in kg (60 kg);
B is the daily dose of the article, in kg.

The competent authority may grant total or partial exemption from the test when the complete history

(nature and quantity of the pesticides used, date of each treatment during cultivation and after the

harvest) of the treatment of the batch is known and can be checked precisely according to good

agricultural and collection practice (GACP).

Maximum limits of pesticide residues in natural products used in TCM are provided in Annex B.

© ISO 2020 – All rights reserved 3
---------------------- Page: 8 ----------------------
ISO/FDIS 22258:2020(E)
Annex A
(informative)
Determination of pesticide residues in natural products used in
TCM by GC
A.1 Extraction

Use the following procedure for the analysis of samples of articles having a water content of less than

15 %. Samples having a higher water content may be dried, provided that the
...

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