Melatonin determination in human urine by high-performance liquid chromatography with fluorescence detection

A sensitive internal standard method for the determination of melatonin in mammals using precolumn oxidation reversed-phase high-performance liquid chromatography

“…By this method, melatonin is converted to an oxidation compound [24] having strong fluorescence, N-[(6-methoxy-4-oxo-1,4-dihydroquinolin-3-yl)methyl]acetamide (6-MOQMA) (Fig. 1), and the sensitivity of this method is about 5-10 times higher than those already reported [16][17][18][19][20]. However, our HPLC method needs skillful techniques to obtain accurate results, and 5-methoxyindole-3-acetic acid (MIAA) has been proposed as the internal standard [23,24], because MIAA shows similar changes in the fluorescence spectra by the oxidation.…”

“…For the determination of melatonin, enzyme-linked immunosorbent assay [16] and radio-immunoassay [17] have been reported. The chromatographic methods using the native fluorescence of melatonin [18] or electrochemical detection [19,20] are also widely used. However, the amounts of melatonin in mammals, especially endogenous amounts, are too small, and the analytical methods with higher sensitivity are needed to determine melatonin in small tissues or small volumes of clinical samples.…”

Determination of Pineal Melatonin by Precolumn Derivatization Reversed-Phase High-Performance Liquid Chromatography and Its Application to the Study of Circadian Rhythm in Rats and Mice

“…Particularly in mice and rats, however, two species often used as experimental animals, the endogenous melatonin could not be detected in many tissues. For the determination of melatonin in biological samples, HPLC with fluorescence detection using its native fluorescence of indole (10,11), HPLC with electrochemical detection (12,13), or radioimmunoassay (14,15) are often used. The detection limits of these methods are a few femtomoles; however, a more sensitive method is needed for the determination of a lower amount of melatonin in the central nervous system and the periphery.…”

Microdialysis of Melatonin in the Rat Pineal Gland: Methodology and Pharmacological Applications

“…There are several reports of fluorimetric determination (FD) of levels of melatonin and related indolic compounds (Anderson et al, 1982;Mills and King, 1986;Chin, 1990;Mills et al, 1991). Fluorescence capacity at specific excitation and emission wavelengths is characteristic for the indole nucleus, making it possible to quantify melatonin with this technique without derivatization.…”