Optimization of clean-up procedure for patulin determination in apple juice and apple purees by liquid chromatography

Patulin (PAT) is a mycotoxin produced in fruits, mainly in apples, by several fungal species that can be carried into industrial apple juice by-products during factory processing. An analytical method for determination of PAT in apple juice and another one for determination of this compound in apple purees and apple compotes by liquid chromatography are proposed in the present paper. These methods have better precision and sensitivity than previously reported methods and focus mainly on extraction and clean-up. To accomplish analytical methods with higher accuracy, lower limits of detection and simpler procedures for application in quality control of the goods, different extraction and clean-up procedures for PAT were comparatively studied. PAT recoveries in apple juice spiked with 1.0 mg PAT/kg varied between 52.3% and 81.0%. The highest PAT recovery in apple puree spiked with 0.1 mg PAT/kg was 82.9%. Addition of NaH2PO4 during the extraction phase here reported for the first time has the advantage of keeping the pH slightly acidic, thus avoiding PAT degradation.