Gas chromatographic-mass spectrometric assay for 6-hydroxymelatonin sulfate and 6-hydroxymelatonin glucuronide in urine
Francis, P.L.; Leone, A.M.; Young, I.M.; Stovell, P.; Silman, R.E.
Clinical Chemistry 33(4): 453-457
1987
ISSN/ISBN: 0009-9147 PMID: 3829375 Document Number: 293931
Circulating melatonin is hydroxylated to 6-hydroxymelatonin and excreted in urine as the sulfate and glucuronide conjugates. We extracted these two compounds from urine by using octadecylsilane-bonded silica cartridges to eliminate most of the urea and electrolytes, and silica cartridges to separate the sulfate and glucuronide conjugates. After hydrolyzing the separated conjugates enzymically, we determined the free hydroxymelatonin by gas chromatography-mass spectrometry. Though recoveries were low and variable, we were able to quantify the analyte in the original sample by adding deuterated sulfate and glucuronide conjugates to the urines before extraction.