1. Department of Chemistry , Trnava University , Priemyselná 4, P.O.BOX 9, 918 43 Trnava , Slovakia
2. Department of Biology and Ecology, Faculty of Natural Sciences , Matej Bel University , Tajovského 40, 974 01 Slovakia
3. Spojená škola Sv. rodiny, Grade School , Gercenova 10, 851 01 Bratislava , Slovakia