Overview
ISO 18664:2015 - Traditional Chinese Medicine - Determination of heavy metals in herbal medicines used in Traditional Chinese Medicine - specifies standardized analytical methods for measuring the four key heavy metals lead (Pb), arsenic (As), cadmium (Cd) and mercury (Hg) in natural TCM materials. It applies to Chinese materia medica (whole medicinal materials) and decoction pieces derived from plants or animals that are sold or used as food supplements, functional foods or natural medicines in international trade. The standard is a methods and risk‑assessment reference - it does not set national maximum limits (MLs) for heavy metals and is not applicable to mineral drugs.
Key topics
- Target analytes: Lead (Pb), arsenic (As), cadmium (Cd), mercury (Hg).
- Sample scope: Natural TCM materials and decoction pieces for ingestion or therapeutic use (plants and animals); excludes mineral drugs.
- Instrumental methods referenced:
- Atomic Absorption Spectrometry (AAS) - flame and electrothermal approaches, hydride generation for As and others.
- Inductively Coupled Plasma - Atomic Emission Spectrometry (ICP‑AES / ICP‑OES) - multi‑element simultaneous analysis.
- Inductively Coupled Plasma - Mass Spectrometry (ICP‑MS) - highest sensitivity for trace detection.
- Method comparisons: The standard includes a comparison (detection limits, precision, interferences, throughput, costs) to help laboratories choose an appropriate technique.
- Normative references: ISO provides specific referenced methods (e.g., ISO 11212 series, ISO 11885, ISO 17294) for detailed procedures and validation.
- Risk assessment guidance: Annex A summarizes national/regional limits and demonstrates use of Target Hazard Quotients (THQ) and WHO/USEPA guidance to derive safe concentration references for TCM materials.
Applications and users
ISO 18664:2015 is practical for:
- Analytical and contract testing laboratories validating and reporting heavy metal results for TCM products.
- Quality assurance and R&D teams in herbal medicine, dietary supplement and functional food manufacturers.
- Regulators and customs authorities seeking harmonized test methods for international trade compliance and safety assessments.
- Importers/exporters and certification bodies needing standardized methods to support product declarations and risk evaluations.
- Risk assessors and public‑health scientists calculating exposure and THQs for TCM product intake.
Using ISO 18664 helps ensure consistent, comparable heavy‑metal data across markets and supports evidence‑based risk assessment and trade compliance.
Related standards
- ISO 11212 (As, Hg, Pb, Cd methods), ISO 11885 (ICP‑OES), ISO 17294 (ICP‑MS), ISO 6561 series and other ISO documents cited in the standard for specific procedures and validation details.