Determination of Aflatoxin B1 in Medical Herbs: Interlaboratory Study

A method was developed for the determination of aflatoxin B1 in medical herbs (senna pods, botanical name Cassia angustifolia; devil's claw, botanical name Harahophytum procumbens; and ginger roots, botanical name Zingiber oficinale). 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 extractanct (acetone-water) was tested and compared to the proposed methanol-water extractant. Several post-column derivatization options (electrochemically generated bromine, photochmical 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 92% 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 1µg/kg and above.

ARRANZ HERNANDEZ Isabel;  SIZOO E.;  EGMOND H;  KROEGER Katy;  LEGARDA T.M.;  BURDASPAL P;  REIF K;  STROKA Joerg; 

2007-01-29

AOAC INTERNATIONAL

JRC36283