演題概要

3D-O1-1027

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LC-ESI-MS代謝解析中に出たドーパミンゴーストの正体

(¹沖縄科技大・ ²横市大・ ³山梨大)
^o本郷やよい¹・ 福山大輔²・ Chen, Lee Chuin³・ 関本奏子²・ 渡邉寛¹

Unpredictable in-source alteration of compounds must disturb the molecular characterizations with LC–ESI-MS/MS, especially in exploring the endogenous metabolites of a new type of animal model which has been less known about the metabolic characters. The artifacts are sometime inevitable due to the large complexity of the biological extract, and hardly distinguished from true in-vivo metabolites based on a single data. Dopamine “ghost” was detected in the analyses of the emerging model cnidarian Nematostella vectensis extract with a risk causing false positive or overestimate in the in-vivo dopamine analysis. True identity of the dopamine “ghost” (m/z 154) was characterized as oxidized(+16u) tyramine (m/z 138), however the oxidative electrolysis was not sufficient to explain the simultaneous detection of the “ghost” in the negative-ion mode. We showed the predominant contribution of the gas-phase Corona discharge on the “ghost”. The in-source oxidation was also evaluated for other relevant endogenous molecules containing aromatic group. With a successful liquid chromatography separation, endogenous metabolic repertoire specific to the primitive animal was revealed, including 2-oxo tryptamine which has never listed as an animal metabolite.