Determination of ochratoxin A in wine and beer by immunoaffinity column cleanup and liquid chromatographic analysis with fluorometric detection: Collaborative study

The accuracy, repeatability, and reproducibility characteristics of a liqui d chromatographic method for the determination of ochratoxin A (OTA) in whi te wine, red wine, and beer were established in a collaborative study invol ving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, an d naturally contaminated materials at levels ranging from less than or equa l to0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted wi th a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liqui d chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ran ging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging f rom 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for withi n-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative st andard deviations for between-laboratories reproducibility (RSDR) ranged fr om 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were less than or equal to0.4 for the 3 matrixes.