TCM pesticide residue blank matrix
Application of Pesticide-Free Matrix in Traditional Chinese Medicine (TCM) — Revisions to TCM Pesticide Residue Testing Standards in the 2025 Edition of Chinese Pharmacopoeia
Pesticide residues refer to trace amounts of pesticides remaining in organisms, agricultural products (or food), and the environment after pesticide application. This term encompasses not only the pesticides themselves but also their toxic metabolites and impurities. A matrix is defined as the sum of all components in a sample except the target analytes during analytical testing. Traditional Chinese Medicines (TCMs) are classified as agricultural by-products, and most are cultivated artificially. Excessive pesticide spraying during cultivation may lead to residue accumulation.
A pesticide-free matrix sample for TCM pesticide residue analysis refers to the entirety of components in herbal materials excluding the target pesticide residues. These matrices are rigorously selected from high-quality, authentic medicinal materials and undergo multi-step processing combined with high-precision instrumental analysis. They are free from 33 prohibited pesticides and are utilized for detecting these residues in TCMs, including processed slices. Notably, the testing for these 33 residues is not merely quantitative; the standard is set at the quantitation limit. If the detected pesticide residue levels in herbal materials exceed the detection limit but remain below the quantitation limit, enterprises must conduct risk assessments encompassing sampling, pretreatment, and instrumental analysis processes.
The 2025 edition of Chinese Pharmacopoeia significantly revises TCM pesticide residue testing standards. The original "Method V" (previously used for multi-residue determination of prohibited pesticides in plant-based herbs and processed slices) has been reclassified as "Method I", expanding the scope from 33 to 47 prohibited pesticides. This revision reflects a substantial broadening of detectable pesticide categories. Additionally, the draft introduces a list of 36 restricted pesticides across 11 herbal materials to enhance coverage of pesticide types and improve testing accuracy and efficiency. A newly added "Method III" specifically targets the determination of dithiocarbamate pesticide residues in herbs and processed slices, underscoring a more meticulous focus on TCM safety through specialized residue detection protocols.
Q: Is a matrix blank required for every TCM material?
A: According to the Chinese Pharmacopoeia, a matrix blank is mandatory for all herbal materials unless qualitative analysis is performed. A blank matrix sample refers to a same-species material confirmed to be free of the target pesticide residues. Priority should be given to matrices where "no prohibited pesticides are detected by instruments", followed by those with residue concentrations below the general quantitation limit (LOQ).
Q: Can reference materials from the National Institutes for Food and Drug Control (NIFDC) be used as blank matrices?
A: No. NIFDC reference materials are intended solely for qualitative applications (e.g., thin-layer chromatography identification) and are not guaranteed to meet blank matrix criteria. Therefore, they cannot be directly utilized as blank matrices.
Regulatory Compliance Statement:
In response to the newly published TCM pesticide residue regulations, Hengyuan Fine Chemical and PCL will continue to monitor regulatory developments closely, adapt to evolving standards, and provide clients with efficient, high-quality solutions to ensure compliance and safety in TCM production.
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