DETERMINATION OF SEROTONIN, TRYPTAMINE, A ND GRAMINE BY SOLID-SUBSTRATE ROOM-TEMPERATURE PHOSPHORIMETRY ON A POLY(VINYL ALCOHOL) SUBSTRATE

An easy and sensitive method for the determination of serotonin (5-HT) , tryptamine (Try) and gramine (Gra) was developed by using solid-subs trate room-temperature phosphorimetry on a poly (vinyl alcohol) substr ate. 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 enh ancers. The order of spotting phosphor and enhancers onto the substrat e 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 5 similar to 500, 2.5 similar to 250 and 2.5 similar to 250 pmol/spot (5 mu l), respectively. The correlat ion coefficients of the calibration curves were over 0.991 and the rel ative standard deviations at 50 pmol/spot (5 yl) varied from 5.0 to 6. 5%, showing a good precision of the proposed method.