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United States Department of Agriculture

Agricultural Research Service

Title: Capillary Electrophoresis with Laser Induced Fluorescence: Method for Ochratoxin A

Authors
item Corneli, Sylvia - ISTITUTO SUPERIORE, ROME
item Maragos, Chris

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 26, 1998
Publication Date: N/A

Interpretive Summary: Ochratoxin A (OA) is a mycotoxin that can be found as a natural contaminant in a large variety of commodities (cereals, meat products, coffee). It has been classified by the International Agency for Research on Cancer (IARC) as a possible human carcinogen. Once ochratoxin A has been formed in a food it would be difficult to remove by most forms of food processing. The method developed allowed a sensitive quantification of the OA at levels of 0.2 ppb. The technique allows rapid analysis and uses much smaller volumes of organic solvents relative to other methods thereby reducing the amount of solvent waste.

Technical Abstract: Ochratoxin A (OA) is a natural contaminant of a large variety of foods of plant and animal origin. Several sensitive methods, both biological and chemical, have been developed to analyze OA. In this study we report the development of a capillary electrophoresis (CE) method for the quantification of ochratoxin A in three very different commodities: roasted coffee, corn and sorghum. The extraction and isolation procedures combine a silica column and an immunoaffinity clean-up column analogous to other chromatographic methods. CE was performed using 20 mM phosphate buffer at pH 7.00 with 20 kV applied voltage. Laser induced fluorescence (LIF) (325 nm excitation, 465 nm emission) was used for detection. When OA was added to several foods over the range 0.2 to 10 ng/g (ppb) the average recoveries were: 86% for roasted coffee (SD=12.2; CV=14.1%; n=8); 99% for corn (SD=10.1; CV=10.2%; n=8); 91% for sorghum (SD=14.8; CV=16.3%; n=4). Each instrumental analysis, after extraction and purification, required 13 minutes, equivalent to HPLC analysis. CE-LIF can be applied to the quantification of OA in roasted coffee, corn and sorghum, reducing organic solvent usage relative to HPLC.

Last Modified: 10/1/2014
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