Investigation on Ochratoxin A stability using different extraction techniques.

The stability of Ochratoxin A during its extraction using different extraction techniques has been evaluated. Microwave-assisted extraction and pressurised liquid extraction, in addition to two other reference methods of extraction, i.e. ultrasound-assisted and magnetic stirring-assisted extraction, were evaluated. The effect of extraction temperature using the cited techniques was checked. The results show that Ochratoxin A can be extracted using microwave-assisted extraction at temperatures up to 150 degrees C without degradation. Pressurised liquid extraction can be used at temperatures up to 100 degrees C, for extraction times of less than 30min. Further, both ultrasound-assisted extraction and magnetic stirring extraction can be applied at temperatures up to 65 degrees C. High-performance liquid chromatography combined with fluorescence detection using a Chromolith RP-18e column at a flow rate of 5mL min(-1) was used to quantify the Ochratoxin A. The retention time for the Ochratoxin A was 1.3min. The limits of detection (LOD) and of quantification (LOQ) were 0.03 and 0.10microg L(-1), respectively.