1. Biomedical Mass Spectrometry Laboratory, Clinical Research Center; University of Florida, Gainesville, FL 32610-0322; USA
2. Institute of Chemistry, Academy of Sciences of the Republic of Moldova; Academiei Str. 3, Chişinău, MD-2028; Republic of Moldova
3. Department of Chemistry and Chemical Technology, Moldova State University; Alexei Mateevici Str. 60, Chişinău, MD-2009; Republic of Moldova