[Comparison between the post-column derivatization with bromine by HPLC and the fluorometric analysis for determination of aflatoxins in medicinal herbs and plant extracts].
OBJECTIVE
To compare the post-column derivatization technique (IAC-PCD-HPLC) for the determination of aflatoxins B1, B2, G1 and G2 and the rapid procedure with fluorometric analysis (SFB) for the determination of total aflatoxins.


METHODS
The method of post-column derivatization with bromine by HPLC consisted of extraction of the sample with MeOH-H2O (70:30) followed by clean-up of the extracts with immunoaffinity columns and finally, HPLC determination with fluorescence detection. Aflatoxins B1 and G1 were determined as their bromine derivatives, produced in an on-line post-column derivatization system. In SFB method, samples were ground and extracted with methanol-water (70:30). A portion of the extract was cleaned up by passage through a immunoaffinity column, One mL of purified extract was derivatized with a bromine reagent, and fluorescence of the solution was immediately quantified with a calibrated fluorometer containing a broad wavelength pulsed xenon light source.


RESULTS
In IAC-HPLC method, the overall average recoveries for three different medicinal herbs spiked at levels of 1.3 and 2.6 ng x g(-1) of total aflatoxins ranged from 93% to 97%. The detection limit was 0. 06 microg x kg(-1) for both G2 and B2 and 0.20 microg x kg(-1) for both G1 and B1, based on a signal/noise 3:1 and the precision (within-laboratory relative standard deviation) ranged from 0.8% to 1.4%. Each of aflatoxins B1, B2, G1 and G2 in 39 kind medicinal materials were determined by IAC-PCD-HPLC, and the total aflatoxins were determined by SFB.


CONCLUSIONS
The SFB method is not the suitable method for the determination of total aflatoxins in medicinal herbs and plant extracts.
Zhang
Xue-hui
XH
Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100094, China.
Chen
Jian-min
JM
D016604:Aflatoxin B1 / Q000032:analysis; D000348:Aflatoxins / Q000032:analysis*; D001966:Bromine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D029745:Codonopsis / Q000737:chemistry; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry*; D027861:Prunus / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods
D000348:Aflatoxins; D004365:Drugs, Chinese Herbal; C027955:aflatoxin G1; D016604:Aflatoxin B1; D001966:Bromine