1. 1Chemistry Department of Natural Sciences, Technical Educational Institution (T.E.I) of Kavala, St. Lucas Str., Kavala, 654 04, Greece
2. 2Faculty of Chemistry, University of Sofia “St. Kl. Okhridski”, J. Bourchier Blvd. 1, 1164, Sofia, Bulgaria
3. 3Laboratory of Land Analysis and Leaf diagnosics, Agricultural Cooperative Union of Pageon, Fr. Papachristidi 98, 64100, Elefteroupoli, Greece