Coacervative extraction of Ochratoxin A in wines prior to liquid chromatography/fluorescence determination
Author
García-Fonseca, S.
Ballesteros-Gómez, A.
Rubio Bravo, Soledad
Pérez-Bendito, Dolores
Publisher
ElsevierDate
2008Subject
Ochratoxin AWine
SUPRAS
Mycotoxins
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Show full item recordAbstract
Coacervates made up of reverse micelles of decanoic acid were assessed as a new strategy
for the simplification of wine sample treatment in the determination of Ochratoxin A (OTA).
Simultaneous extraction/concentration of this contaminantwas based on both hydrophobic
and hydrogen bond OTA:coacervate interactions. Parameters affecting extraction efficiency
and concentration factors were studied. Concentrations of decanoic acid and tetrahydrofuran
(THF) were the most influential parameters, being 0.5% of acid and 5% of THF the
selected ones. The procedure was very robust, so that the extractions were not influenced
by the pH and the nature or concentration of matrix components. OTA recoveries from different
types of wines (white, ros´e and red) ranged between 85 and 100% and the actual
concentration factors varied from 105 to 125 for sample volumes of 15 mL. The detection
limits for OTA, after liquid chromatography/fluorimetry (LC/FL) analysis of the coacervate
(20 uL),were 4.5 ng/L in white and ros´e wines and 15 ng/L in red wines, values whichwere
far below the threshold limit established for OTA by EU directives (2.0 ug/L). No clean-up of
the extractswas required for any of the samples analysed. The overall sample treatment took
about 15–20 min and several samples could be simultaneously treated using conventional
lab equipment. The precision of the method, expressed as relative standard deviation, was
about 5%. The approach developed was successfully applied to the determination of OTA in
different wine samples from the South of Spain. The concentrations found ranged between
0.015 and 0.091ug/L.