Immunoaffinity chromatography

This technique uses the binding properties between Ab-Ag for the selective extraction of an analyte from complex food and environmental matrices. The technique is especially useful for polar organic analytes. Immunoaffinity sorbents are used for pre-concentration of closely related compounds, that are later eluted, separated and analyzed; an example of application is the detection of isoproturon in water samples, allowing determination of 0.1 mg/L [87], or of bisphenol A [88]. The main limitations of these procedures are the effects of the matrix on immunoreagents, the small volume admitted by the immunosorbents and the desorbtion step that is sometimes difficult.

Recent applications in food analysis have been focused on aflatoxins and ocratoxine. Prado et al. [89] performed the analysis of OTA in beers by immunoaffinity column and HPLC using a fluorescence detector. Recoveries of OTA from beer samples spiked at levels from 8.0 to 800 pg/mL ranged from 81.2 to 95.0%, with coefficient of variation between 0.1 and 11.0%. Detection limit and quantification limit were 2.0 and 8.0 pg/mL, respectively.

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