Figure 1. The detection of melatonin by HPLC.

Overlaid chromatograms of a melatonin standard (green, 1×10⁻⁸ gr mL⁻¹) and a sea anemone tissue extract (N. vectensis) with (black) and without (red) melatonin enrichment (1×10⁻⁸ gr mL⁻¹). Chromatographic separation of tissue extracts was conducted based on fluorimetric detection (λex = 280 nm and λem = 345 nm). The mobile phase consisted of a mixture of 0.1% (v/v) formic acid in acetonitrile:water 17∶81 (v/v), which was delivered isocratically at a flow-rate of 1 mL min⁻¹. The detailed conditions are described in the Materials and Methods.