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United States Department of Agriculture

Agricultural Research Service

Title: Analysis of Aflatoxin B1 in Corn Using Capillary Electrophoresis with Laser-Induced Fluorescence Detection

Authors
item Maragos, Chris
item Greer, Judith

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 5, 1997
Publication Date: N/A

Interpretive Summary: Aflatoxins are a group of mycotoxins capable of causing disease in animals and are suspected human carcinogens that can be found in a variety of human foods, including corn, nuts, and milk. The Food and Drug Administration has established a regulatory limit of 20 ppb of aflatoxin B1 (AFB1) in human food. Sensitive analytical methods that reduce the volume of organic solvent used in the analysis were needed. We report the development of a method that allows for the sensitive detection of AFB1 in corn (limit of detection 0.5 ppb) and uses substantially less organic solvent in the process. The method is also 2,000 fold more sensitive than the only other previously reported capillary electrophoresis method for the aflatoxins. Agencies or companies that routinely analyze for aflatoxin B1 may benefit directly from the reduced reliance upon organic solvents relative to HPLC (and reduced disposal costs as well) and indirectly from the additional confirmatory power of the method as an adjunct to other technologies for aflatoxin analysis.

Technical Abstract: The carcinogenic mycotoxin aflatoxin B1 has long been the object of intense study due to the impact of this toxin upon agricultural productivity. The result has been the development of a number of rapid and sensitive methods for the aflatoxins in foods. We report the development of a capillary electrophoresis (CE) method for the quantitation of aflatoxin B1 (AFB1) in corn. The instrumentation can be assembled easily from readily available components and takes advantage of the native fluorescence of AFB1 by using a helium/cadmium laser to provide the excitation light. After extraction of the aflatoxins from corn, the method incorporates either a silica column or an affinity column clean-up step analogous to commonly used chromatographic methods. After extraction and clean-up, analysis of each sample required only 15 min., 10 min. of which was used for the electrophoresis and 5 min. of which was used for rinsing the capillary before and after the analysis. The results with the CE method were compared to an established HPLC-fluorescence method for the determination of AFB1 in artificially and naturally contaminated corn samples. The CE technique had a limit of detection (signal to noise ratio of 4) of 0.5 ppb AFB1 in corn, with a useful range for quantitation of between 1.0 to 100 ppb. Recovery of AFB1 from artificially contaminated corn samples averaged 85% over the range of 1 to 50 ppb (89% by HPLC). Forty naturally contaminated corn samples examined by both methods showed good agreement (r2=0.969). The reported CE-LIF method is suitable for the routine analysis of corn samples as an alternative to HPLC.

Last Modified: 4/18/2014
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