1. Department of Agriculture, Food and Environment; University of Pisa; via del Borghetto 80 56124 Pisa Italy
2. Crop Research Institute; Drnovska 507 161 06 Prague 6 Czech Republic
3. HPLC-MS Laboratory; University of Camerino; via S. Agostino 1 62032 Camerino Italy
4. School of Pharmacy; University of Camerino; via S. Agostino 1 62032 Camerino Italy