Abstract
An easy and sensitive method for the determination of serotonin (5-HT), tryptamine (Try) and gramine (Gra) was developed by using solid-substrate room-temperature phosphorimetry on a poly (vinyl alcohol) substrate. The method did not require a dry gas flush during the measurement of phosphorescence. The phosphorescence intensities of the compounds were enhanced by using a NaOH solution {water-ethanol, 50:50 (v/v)} as the solvent, and potassium iodide and sodium dodecyl sulfate as enhancers. The order of spotting phosphor and enhancers onto the substrate also affected the phosphorescence intensity. The analytical figures of merit for these three compounds were as follows. The linear dynamic ranges of 5-HT, Try and Gra were 5500, 2.5250 and 2.5250 pmol/spot (5 μl), respectively. The correlation coefficients of the calibration curves were over 0.991 and the relative standard deviations at 50 pmol/spot (5 μl) varied from 5.0 to 6.5%, showing a good precision of the proposed method.
