High-performance liquid chromatographic separation of microcystins and nodularin, cyanobacterial peptide toxins, on C₁₈ and amide C₁₆ sorbents

Four C₁₈ columns and a novel amide C₁₆ column were assessed in the HPLC separation of eight microcystins and nodularin-R. Gradient mobile phases of acetonitrile combined with trifluoroacetic acid, formic acid or ammonium acetate were compared. Special attention was paid to the resolution of four possible coeluting microcystin pairs. Generally speaking, the acidic mobile phases were superior to the ammonium acetate-based mobile phase in terms of resolution and selectivity. The amide C₁₆ column had the best overall performance and unique selectivity properties.