Four structural variants of microcystin, were detected by HPLC-PDA and the masses
confirmed by MALDI-TOF: microcystins -RR, -LR, -LA and -LF (Table 1). The
concentrations of microcystins in both samples were similar. The total concentration of
microcystins in the filtered material was 39.15 µg g
-1 dry weight in sample 1 and 41.4 µg g-1
dry weight in sample 2. The material did not contain detectable dhb-microcystin-LR,
microcystin-LW, microcystin-YR or anatoxin-a. In all samples tested the dissolved
cyanobacterial toxins were below detection limit of 1 µg L-1.