Use of electrospray tandem mass spectrometry for identification of microcystins during a cyanobacterial bloom event - Frias, Humberto Vieira; Mendes, Maria Anita; Cardozo, Karina Helena Morais; Carvalho, Valdemir Melechco; Tomazela, Daniela; Colepicolo, Pio; Pinto, Ernani (Biochemical and Biophysical Research Communications, 2006)