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Original Paper
Attomole Analysis of Melatonin by Precolumn Derivatization Reversed-Phase Micro-HPLC |
| Tatsunosuke Tomita, Kenji Hamase, Hiromi Hayashi and Kiyoshi Zaitsu* |
| Graduate School of Pharmaceutical Sciences, Kyushu University, Maidashi, Higashi, Fukuoka 812 - 8582, Japan |
Abstract:
An improved method for the sensitive and selective determination of melatonin was demonstrated. To improve the selectivity, extraction of melatonin derivative using ethyl acetate was adopted. MIAA (5-methoxyindole-3-acetic acid) was used as the internal standard for the precise determination. The present method was successfully applied to the determination of rat pineal melatonin (within-day precision was 1.5% and day-to-day precision was 3.2%). The sensitivity of melatonin determination using a micro-ODS column of 1.0 mm i.d. was 20 times higher than that obtained by the conventional HPLC system. Using the micro-HPLC, daytime melatonin content in C3H mouse pineal gland was determined.
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| Keywords: | melatonin, fluorescence, micro-HPLC |
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