Overview
ISO 22283:2020 - Traditional Chinese medicine - Determination of aflatoxins in natural products by LC‑FLD specifies a validated laboratory method to detect and quantify the four major aflatoxins AFB1, AFB2, AFG1 and AFG2 in raw materials and manufactured traditional Chinese medicine (TCM) products. The method uses liquid chromatography with fluorescence detection (LC‑FLD) following immunoaffinity column cleanup and either iodine or photochemical post‑column derivatization to improve fluorescence responses.
Key topics and technical requirements
- Scope: Applicable to plant‑ and animal‑derived decoction pieces, raw materials and finished TCM products.
- Sample preparation:
- Grind to powder, sieve (24‑mesh), mix 15.0 g sample with 3.0 g NaCl.
- Extract with methanol:water (70:30 v/v), homogenize (>11 000 rpm, 2 min), centrifuge (2 500 rpm, 5 min).
- Dilute supernatant, filter (0.45 µm) and perform immunoaffinity column cleanup; elute with methanol and concentrate to 0.5 ml.
- LC‑FLD system and column:
- Stainless‑steel column packed with octadecylsilyl (C18) silica; isocratic mobile phase methanol–acetonitrile–water.
- Fluorescence detection with excitation λex = 360 nm (or 365 nm) and emission λem = 450 nm.
- System suitability: resolution between adjacent peaks > 1.5.
- Derivatization:
- Iodine derivatization: 0.05% iodine solution (prepared as specified), derivatization pump flow 0.3 ml/min, reactor at 70 °C.
- Photochemical derivatization: UV reactor at 254 nm (mercury lamp).
- Calibration and quantification:
- Stock standards prepared for AFB1, AFB2, AFG1, AFG2; working ranges: AFB1/AFG1 0.10–100.00 ng/ml and AFB2/AFG2 0.03–30.00 ng/ml.
- Inject 25 µl standards and samples; quantify via calibration curves.
Applications and who uses this standard
- Quality control laboratories testing TCM raw materials and finished products for mycotoxin safety.
- Pharmaceutical manufacturers and herbal product producers implementing routine aflatoxin screening.
- Regulatory bodies and food/drug safety agencies referencing an analytical method for compliance and surveillance.
- Third‑party testing laboratories and exporters/importers needing reproducible, internationally recognized LC‑FLD methodology for TCM trade.
Related standards and references
- ISO 22283:2020 was prepared by ISO/TC 249 (Traditional Chinese medicine).
- LC‑MS/MS is noted in the standard as an alternative high‑sensitivity analytical approach for aflatoxins (see Annex A for method comparison).
- Annex C of ISO 22283 lists national/regional limits and references for aflatoxin regulatory limits - consult local regulations for permissible levels.
Keywords: ISO 22283:2020, Traditional Chinese medicine, aflatoxins, AFB1, AFB2, AFG1, AFG2, LC‑FLD, immunoaffinity column, photochemical derivatization, iodine derivatization, HPLC, mycotoxin testing.