ARS | Publication request: OCHRATOXIN A IN CORN: CAPILLARY ELECTROPHORESIS METHOD

Submitted to: Association Official Analytical Chemists Midwest Section Program Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: June 11, 1997
Publication Date: N/A

Technical Abstract: The AOAC approved (1992) analytical method for the determination of ochratoxin A (OA) in corn was modified for use with capillary electrophoresis. Samples were extracted with dicloromethane acidified with a solution of phosphoric acid, and the OA was isolated by a liquid-liquid partitioning into a bicarbonate solution. The clean-up step was performed with a C18 column and the OA was eluted with an ethyl acetate-methanol-acetic acid solution (95/5/0.5 V/V/V). The procedure employed separation of matrix components from OA by capillary zone electrophoresis using a phosphate buffer at pH 7.00 with 20.00 KV applied voltage. Laser induced fluorescence (325 nm excitation) was used for detection. Recoveries of OA from corn samples spiked at five levels from 0.5 to 10.0 ng/g ranged from 80-108% with a medium value of 89% (standard deviation = 8.4). The sensitivity of the method was 0.5 ng/g. The capillary electrophoresis can be applied to the quantification of OA in corn, reducing organic solvent usage relative to HPLC.