Original

Rapid and simultaneous determination of tetra cyclic peptide phytotoxins, tentoxin, isotentoxin and dihydrotentoxin, from Alternaria porri by LC/MS.

Masayuki Horiuchi^1*, Naoshige Akimoto², Keiichiro Ohnishi³, Masakazu Yamashita³ and Takashi Maoka¹

¹ Research Institute for Production Development, 15 Shimogamo.Morimoto.cho, Sakyo.ku, Kyoto 606-0805, Japan
² Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida.Shimoadachi.cho, Sakyo.ku, Kyoto, 606-8501, Japan
³ Department of Molecular Science and Technology, Faculty of Engineering, Doshisha University, 1-3, Tatara Miyakotani, Kyotanabe-si, Kyoto 610-0312, Japan

Abstract:

Tentoxin (1) and its related compounds, isotentoxin (2) and dihydrotentoxin (3), from Alternaria porri were determined simultaneously by APCI, ESI and FAB.MS. LC/APCI.MS was a most suitable method with sufficient sensitivity and selectivity for determination of tentoxins. Because, APCI.MS provided not only [M + H]+ but also [M + H . Gly . (N.Me.Ala)]+ and the intensity ratio of these ions of three tentoxins were similar ratio, 100 / 7, 100 / 10 and 100 / 7, respectively. Selective ion mass chromatogram provided by LC/APCI.MS gave quantitative information of tentoxins with high linearity from 100 ng/injection to 10 μg/injection. Furthermore, one assay can be performed within 15 min. Therefore, this method was applied for the determination of tentoxins in the culture liquid of A. porri.

Keywords: tentoxin; isotentoxin; dihydrotentoxin; Alternaria porri; LC/APCI.MS

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