1. a Department of Chemistry , University of Oradea, Faculty of Science , Romania
2. b Faculty of Pharmacy , University of Medicine and Pharmacy “Iuliu Haţieganu,” , Romania
3. c Analytical Chemistry Department , University Babes-Bolyai , Cluj-Napoca , Romania
4. d Boerhringer-Ingelheim Pharmaceutical, Inc. , Ridgefield , Connecticut , USA