Combined phenyl silane and immunoaffinity column cleanup with liquid chromatography for determination of ochratoxin A in roasted coffee: Collaborative study.
ENTWISLE, A.C., WILLIAMS, A.C., MANN, P.J., RUSSELL, J., SLACK, P.T. and GILBERT, J.
Journal of AOAC International 84: 444 – 450.
2001
บทคัดย่อ
A collaborative study was conducted to evaluate an LC method for OA using sequential phenyl silane and immunoaffinity column cleanup. The test portion was extracted with methanol and sodium bicarbonate by shaking. The extract was filtered, centrifuged and then cleaned up on a phenyl silane column before being eluted from the washed column with methanol – water. The eluate was diluted with phosphate buffered saline and applied to an OA immunoaffinity column, which was washed with water. OA was eluted with methanol, the solvent was evaporated and the residue was redissolved in injection solvent and applied to a reversed phase LC apparatus followed by fluorescence detection. In samples spiked with OA at 4 mg/kg recoveries ranged from 65 to 97%. The relative standard deviation for repeatability (RSDr) ranged from 2 to 22% and the relative standard deviation for reproducibility (RSDg) ranged from 14 to 26%. The method showed acceptable within and between laboratory precision, as evidenced by HORRAT values, at the low level of determination for OA in roasted coffee.