Simultaneous Determination of o-Phthalaldehyde Derived Serotonin and Melatonin Using Second Derivative and Synchronized Scanning Fluorimetry

Abstract Analysis of serotonin and melatonin mixtures by both simple synchronous fluorimetry and synchronous fluorimetry in combination with spectral differentiation after mixture derivatization with o-phthalaldehyde (OPA) is described. A computerised instrumental system permits the rapid selection of the optimum wavelength interval for synchronous fluorimetry from automatically generated, three-dimensional plots. Detection limits in the range of subnanograms per milliliter and relative standard deviations better than 5% have been obtained.