ISO 23956:2022
(Main)Traditional Chinese medicine - Determination of benzopyrene in processed natural products
Traditional Chinese medicine - Determination of benzopyrene in processed natural products
This document specifies the method for the determination of benzopyrene content in processed natural products. It is applicable to processed natural products such as processed Rehmannia root, processed Cyperus rhizome, processed ginseng and processed mume fruit. It is not applicable to the analysis of minerals used in traditional Chinese medicine.
Médecine traditionnelle chinoise — Dosage du benzopyrène dans les produits naturels transformés
General Information
Overview
ISO 23956:2022 - Traditional Chinese medicine: Determination of benzopyrene in processed natural products - specifies validated laboratory methods to detect and quantify benzopyrene (benzo[a]pyrene, BaP) in heat‑processed herbal materials used in Traditional Chinese Medicine (TCM). The standard covers processed plant products such as processed Rehmannia root, processed Cyperus rhizome, processed ginseng and processed mume fruit (not applicable to mineral TCMs). It responds to carcinogenicity concerns (IARC Group 1) about BaP formation during high‑temperature processing (200–600 °C).
Key topics and technical requirements
- Scope and definitions: Benzopyrene (C20H12) and related polycyclic aromatic hydrocarbons (PAHs).
- Sample preparation: Typical procedure - 5 g sample powder extracted in water, hexane extraction with an internal standard (3‑methylcholanthrene), drying over anhydrous sodium sulfate, rotary evaporation, Florisil SPE cleanup, nitrogen concentration and filtration prior to analysis.
- Internal standard & calibration:
- Internal standard: 3‑methylcholanthrene (analysis grade).
- Stock solutions: BaP and internal standard at 1 μg/ml (store at 4 °C; replace every six months).
- Calibration points: 3, 5, 10, 20 and 40 ng/ml with 50 ng/ml internal standard.
- HPLC‑FLD method:
- Column: Supelcosil LC‑PAH 4.6 × 250 mm, 5 μm (or equivalent).
- Mobile phase: acetonitrile:water (8:2), flow 1.0 ml/min, column temp 35 °C.
- FLD detection: excitation 294 nm, emission 404 nm.
- Identification by retention time within ±0.2% of standard.
- GC‑MS method:
- Column: 5% phenylmethylsiloxane, 30 m × 0.25 mm × 0.25 μm.
- Carrier gas He 1 ml/min; injection 300 °C; transfer line 280 °C; stepped oven program to 310 °C.
- Detection by electron impact ionization (70 eV) in selected ion monitoring (SIM) mode (BaP quantifier ion m/z 252; qualifiers m/z 253, 125).
- Quality control: SPE cleanup, use of internal standard, linear calibration curve and defined chromatographic/ion criteria.
Applications
- Routine quality control testing of processed herbal TCM products for BaP contamination.
- Regulatory compliance testing to meet national limits (e.g., Germany smoked BaP 1 ng/g; China total PAHs 5 ng/g; Republic of Korea processed Rehmannia BaP 5 ng/g).
- Risk assessment and product safety verification after thermal processing or traditional roasting/smoking steps.
- Method transfer, validation and proficiency testing in testing laboratories.
Who should use this standard
- TCM manufacturers and processors applying heat treatments.
- Analytical laboratories (pharmacopoeial, contract testing, QC labs) performing HPLC‑FLD or GC‑MS analyses.
- Regulatory bodies and inspectors developing or enforcing limits on PAHs in herbal medicines.
- Research groups studying formation and mitigation of PAHs in processed natural products.
Related standards and references
- Prepared by ISO/TC 249 (Traditional Chinese medicine).
- The document references national pharmacopeia methods, national regulations and other standardized PAH test methods (see Annex B for country limits and Annexes A–D for chemical data, example chromatograms and alternate cases).
Keywords: ISO 23956, benzopyrene, benzo[a]pyrene, BaP, PAH, HPLC‑FLD, GC‑MS, Traditional Chinese Medicine, processed natural products, quality control, analytical method.
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 23956
First edition
2022-02
Traditional Chinese medicine —
Determination of benzopyrene in
processed natural products
Médecine traditionnelle chinoise — Dosage du benzopyrène dans les
produits naturels transformés
Reference number
© 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
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or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: +41 22 749 01 11
Email: copyright@iso.org
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test methods . 2
4.1 Reagents and apparatus . 2
4.1.1 Reagents . 2
4.1.2 Apparatus . 2
4.2 Sample preparation . 2
4.3 HPLC-FLD method . 3
4.3.1 Chromatographic condition . 3
4.3.2 Identification . 3
4.3.3 Construction of calibration curve . 3
4.3.4 Quantification . 3
4.4 GC-MS method . 4
4.4.1 Chromatographic conditions . 4
4.4.2 Assay . 4
Annex A (informative) Chemical information of benzopyrene . 6
Annex B (informative) National regulations and limitations of benzopyrene .7
Annex C (informative) The example of HPLC pattern about benzopyrene(s) .8
Annex D (informative) Determination of benzopyrene(s) in wood creosote .9
Bibliography .10
iii
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
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electrotechnical standardization.
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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
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Attention is drawn to the possibility that some of the elements of this document may be the subject of
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expressions related to conformity assessment, as well as information about ISO's adherence to
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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
Introduction
The International Agency for Research on Cancer (IARC) classified benzopyrene (C H ) as a carcinogen
20 12
[1]
(Group 1) in 2006. Benzopyrene is produced by the incomplete combustion of carbohydrates, proteins
and fats during high-temperature cooking and processing of raw materials. To prevent hazards induced
by benzopyrene, it is important to determine the benzopyrene content in processed natural products
used in traditional Chinese medicine (e.g. processed Rehmannia root, Cyperus rhizome and mume fruit),
which are processed by the application of high temperatures (200 °C to 600 °C).
Some national pharmacopeias have technical guidelines for the determination of benzopyrene
[2,3]
content . This document describes an analytical method, including the device specifications,
chemical reagents, operation procedures and formulae to determine benzopyrene content, considering
each national pharmacopeia, as well as giving references to other standardized testing methods,
maximum limits and risk assessment.
v
INTERNATIONAL STANDARD ISO 23956:2022(E)
Traditional Chinese medicine — Determination of
benzopyrene in processed natural products
1 Scope
This document specifies the method for the determination of benzopyrene content in processed natural
products.
It is applicable to processed natural products such as processed Rehmannia root, processed Cyperus
rhizome, processed ginseng and processed mume fruit. It is not applicable to the analysis of 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 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/
3.1
benzopyrene
C H
20 12
organic compound of pentacyclic hydrocarbons made of pyrene and phenylene group
Note 1 to entry: The chemical information of benzopyrene is described in Annex A. National regulations and
limitations of benzopyrene are given in Annex B.
3.2
polycyclic aromatic hydrocarbon
PAH
compound that contains two or more fused aromatic rings made of only carbon and hydrogen atoms
[SOURCE: ISO 11338-1:2003, 3.3]
3.3
high-performance liquid chromatography
HPLC
technique in analytical chemistry used to separate, identify and quantify each component in a mixture
Note 1 to entry: High-performance liquid chromatography relies on pumps to pass a pressurized liquid solvent
containing the sample mixture through a column filled with a solid adsorbent material. Each component
in the sample interacts differently with the adsorbent material, resulting in different flow rates for different
components, thereby leading to the separation of components as these flow out of the column.
3.4
gas chromatography
GC
analytical technique used to separate and determine the components of complex mixtures based on
partitioning between gas and stationary phases
[SOURCE: ISO 11504:2017, 3.8, modified — definition revised.]
3.5
fluorescence detector
FLD
device used to measure the parameters of fluorescence, its intensity and wavelength distribution of the
emission spectrum after excitation b
...
Frequently Asked Questions
ISO 23956:2022 is a standard published by the International Organization for Standardization (ISO). Its full title is "Traditional Chinese medicine - Determination of benzopyrene in processed natural products". This standard covers: This document specifies the method for the determination of benzopyrene content in processed natural products. It is applicable to processed natural products such as processed Rehmannia root, processed Cyperus rhizome, processed ginseng and processed mume fruit. It is not applicable to the analysis of minerals used in traditional Chinese medicine.
This document specifies the method for the determination of benzopyrene content in processed natural products. It is applicable to processed natural products such as processed Rehmannia root, processed Cyperus rhizome, processed ginseng and processed mume fruit. It is not applicable to the analysis of minerals used in traditional Chinese medicine.
ISO 23956:2022 is classified under the following ICS (International Classification for Standards) categories: 11.120.10 - Medicaments. The ICS classification helps identify the subject area and facilitates finding related standards.
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