title: Determination of aflatoxin B1 in medical herbs: interlaboratory study.
abstract: A method was developed for the determination of aflatoxin B1 in medical herbs (senna pods, botanical name Cassia angustifolia; devil's claw, botanical name Harpagophytum procumbens; and ginger roots, botanical name Zingiber officinale). The method, which was tested in a mini-collaborative study by 4 laboratories, is based on an immunoaffinity cleanup followed by reversed-phase high-performance liquid chromatography separation and fluorescence detection after post-column derivatization. It allows the quantitation of aflatoxin B1 at levels lower than 2 ng/g. A second extractant (acetone-water) was tested and compared to the proposed methanol-water extractant. Several post-column derivatization options (electrochemically generated bromine, photochemical reaction, and chemical bromination) as well as different integration modes (height versus area) were also investigated. No differences were found depending on the choice of derivatization system or the signal integration mode used. The method was tested for 3 different matrixes: senna pods, ginger root, and devil's claw. Performance characteristics were established from the results of the study and resulted in HorRat values ranging from 0.12 to 0.75 with mean recoveries from 78 to 91% for the extraction with methanol-water and HorRat values ranging from 0.10-1.03 with mean recoveries from 98 to 103% for the extraction with acetone-water. As a result, the method, with all tested variations, was found to be fit-for-purpose for the determination of aflatoxin B1 in medical herbs at levels of 1 microg/kg and above.
authors.affiliation: Institute for Reference Materials and Measurements, Retieseweg 111, B-2440 Geel, Belgium.
authors.forename: Isabel
authors.initials: I
authors.lastname: Arranz
authors.forename: Eric
authors.initials: E
authors.lastname: Sizoo
authors.forename: Hans
authors.initials: H
authors.lastname: van Egmond
authors.forename: Katy
authors.initials: K
authors.lastname: Kroeger
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Legarda
authors.forename: Pedro
authors.initials: P
authors.lastname: Burdaspal
authors.forename: Klaus
authors.initials: K
authors.lastname: Reif
authors.forename: Joerg
authors.initials: J
authors.lastname: Stroka
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis* / Q000302:isolation & purification*; D002138:Calibration; D002366:Cassia / Q000378:metabolism*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002846:Chromatography, Affinity / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D000432:Methanol / Q000737:chemistry; D010777:Photochemistry; D015203:Reproducibility of Results; D013050:Spectrometry, Fluorescence
chemical_list: D016604:Aflatoxin B1; D000432:Methanol