EGU2020-1601
https://doi.org/10.5194/egusphere-egu2020-1601
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

High-precision compound-specific carbon isotopic analysis of underivatized amino acids using a multi-dimensional-HPLC and nano-EA/IRMS

Yuchen Sun1,2,3, Naoto F. Ishikawa1, Nanako O. Ogawa1, Hodaka Kawahata2,3, Yoshinori Takano1,3, and Naohiko Ohkouchi1
Yuchen Sun et al.
  • 1Biogeochemistry Program, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan (sonyuushin@jamstec.go.jp)
  • 2Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan
  • 3Department of Earth and Planetary Science, The University of Tokyo, Tokyo, Japan

We have developed an analytical method for the precise δ13C measurement of individual amino acid using a multi-dimensional high-performance liquid chromatography (HPLC) and a nano-scale elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). Although this method is time-consuming, it can offer higher precision and accuracy than does the conventional analytical method such as GC/C/IRMS, because the derivatization of amino acids is not required. A reversed-phase column (CAPCELL PAK C18, Shiseido, Japan) and a mixed-mode column (Primesep A, SIELC Technologies, U.S.A.) were applied for the HPLC (Agilent Technologies, U.S.A.) with a charged aerosol detector (Thermo Fisher Scientific, U.S.A.) (Ishikawa et al., 2018). We conducted the isolation of underivatized amino acids in a standard mixture containing 15 proteinogenic amino acids (Gly, Ala, Glu, Arg, Val, Pro, Met, Tyr, Ile, Leu, Phe, Thr, His, Asp, Ser), and confirmed that all these amino acids were successfully isolated. Each collected amino acid was filtered through a 0.45 μm membrane filter (Pall, U.S.A.) and washed with diethyl ether to remove hydrophobic impurities. The δ13C values of these amino acids before and after the separation and purification were consistent, which proved that the whole experimental procedure did not change the δ13C values of amino acids. We applied this method to several aquatic organisms. The results show that the δ13C values of amino acids vary as large as 30‰ with Gly being most enriched in 13C.

Reference

Ishikawa et al., (2018) Anal. Chem., 90, 20, 12035-12041.

 

How to cite: Sun, Y., Ishikawa, N. F., Ogawa, N. O., Kawahata, H., Takano, Y., and Ohkouchi, N.: High-precision compound-specific carbon isotopic analysis of underivatized amino acids using a multi-dimensional-HPLC and nano-EA/IRMS, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1601, https://doi.org/10.5194/egusphere-egu2020-1601, 2019

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