Determination of Ochratoxin A in Wine by means of Immunoaffinity and Aminopropyl Solid-Phase Column Clean-Up and Fluorometric Detection

A new analytical method for the determination of ochratoxin A (OTA) in red wine has been developed by using a
double-extract cleanup and a fluorometric measurement after spectral deconvolution. Wine samples were diluted with a solution
containing 1% polyethylene glycol and 5% sodium hydrogencarbonate, filtered, and purified by immunoaffinity and aminopropyl
solid-phase column. OTA contents in the purified extract were determined by a spectrofluorometer (excitation wavelength, 330
nm; emission wavelength, 470 nm) after deconvolution of fluorescence spectra. Average recoveries from wine samples spiked
with OTA at levels ranging from 0.5 to 3.0 ng/mL were 94.5-105.4% with relative standard deviations (RSD) of <15% (n = 4).
The limit of detection (LOD) was 0.2 ng/mL, and the total time of analysis was 30 min. The developed method was tested on 18
red wine samples (naturally contaminated and spiked with OTA at levels ranging from 0.4 to 3.0 ng/mL) and compared with
AOAC Official Method 2001.01, based on immunoaffinity column cleanup and HPLC with fluorescence detector. A good
correlation (r2 = 0.9765) was observed between OTA levels obtained with the two methods, highlighting the reliability of the
proposed method, the main advantage of which is the simple OTA determination by a benchtop fluorometer with evident
reductions of cost and time of analysis.