Dispersive liquid-liquid microextraction combined with high-performance liquid chromatography-tandem mass spectrometry for the identification and the accurate quantification by isotope dilution assay of Ochratoxin A in wine samples

A novel approach for the rapid analysis of ochratoxin A (OTA) in wine samples is presented. Mycotoxin was extracted and concentrated from matrix using dispersive liquid-liquid microextraction (DLLME). The final extract is analyzed by liquid chromatography coupled to positive electrospray ionization tandem mass spectrometry employing [2H5]-ochratoxin A as internal standard. Some important parameters, such as the nature and volume of extraction solvent and dispersive solvent, and salt effect were investigated and optimized to achieve the best extraction efficiency and higher enrichment factor. Under the optimum extraction condition, the method provided enrichment factor around 80 times and showed a high sensitivity with method detection and quantification limits of 0.005 and 0.015 ng mL-1, respectively. To test the accuracy of the analytical procedure, the optimized method was applied to the analysis of reference material T1755 (naturally contaminated white wine), with excellent results (accuracy of 103%) and showing a good precision with a CV (n = 6) of 5.8%. The proposed method, which is demonstrated to be quick, cheap, accurate and highly selective, was successfully applied to the analysis of Italian wines. [Figure not available: see fulltext.] © 2010 Springer-Verlag.