Column switching combined with hydrophilic interaction chromatography-tandem mass spectrometry for the analysis of saxitoxin analogues, and their biosynthetic intermediates in dinoflagellates.
Hydrophilic-interaction chromatography (HILIC) is reportedly useful for the analysis of saxitoxin (STX) analogues, collectively known as paralytic shellfish toxins. Column switching and two-step gradient elution using HILIC combined with mass spectrometry enabled the simultaneous analysis of the 15 primary STX analogues and their biosynthetic intermediates, arginine, Int-A', and Int-C'2, and the shunt product, Cyclic-C'. Crude extracts of toxin-producing dinoflagellates can be injected without any treatment except filtration. Enrichment of the compounds using this method was highly reproducible with respect to retention times (% RSD was under 1%) and highly sensitive (limits of detection (LODs) were in the range 0.9 (Int-C'2) - 116 (C3) μM) in terms of avoiding matrix effects associated with co-eluting substances. Validation studies demonstrated acceptable performance of this method for specificity, repeatability, linearity and recovery. A comparison of the quantitative results for STX analogues in Alexandrium tamarense using HPLC with post-column fluorescent derivatization and the column-switching HILIC-MS method revealed good agreement. The presence of Int-A', Int-C'2, and Cyclic-C' in toxic dinoflagellate species with different toxin profiles was confirmed using this method. Our data support the hypothesis that the early stages of the STX biosynthesis and shunt pathways are the same in dinoflagellates and cyanobacteria.
Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555, Japan. Electronic address: choyuko@m.tohoku.ac.jp.
Yuko
Y
Cho
Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555, Japan.
Shigeki
S
Tsuchiya
Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555, Japan.
Renpei
R
Yoshioka
Laboratory of Aquatic Science Consultant Co., LTD. 2-30-17, Higashikamata, Ota-ku, Tokyo, 144-0031, Japan.
Takuo
T
Omura
Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555, Japan.
Keiichi
K
Konoki
Graduate School of Life Sciences, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai, 980-8577, Japan.
Yasukatsu
Y
Oshima
Graduate School of Agricultural Science, Tohoku University, 1-1, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555, Japan.
Mari
M
Yotsu-Yamashita
D004141:Dinoflagellida / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D057230:Limit of Detection; D008968:Molecular Conformation; D012015:Reference Standards; D015203:Reproducibility of Results; D012530:Saxitoxin / Q000031:analogs & derivatives* / Q000032:analysis*; D057096:Shellfish Poisoning; D053719:Tandem Mass Spectrometry
D012530:Saxitoxin
Alexandrium catenella; Alexandrium tamarense; Biosynthetic intermediates; Dinoflagellate; HILIC–LC–MS; Paralytic shellfish toxins