SE130:/MS1

Sample Set Information

ID	TSE14
Title	Chemical Assignment of Structural Isomers of Sulfur-Containing Metabolites in Garlic by Liquid Chromatography−Fourier Transform Ion Cyclotron Resonance−Mass Spectrometry
Description	BACKGROUND: The chemical assignment of metabolites is crucial to understanding the relation between food composition and biological activity. OBJECTIVE: This study was designed to detect and chemically assign sulfur-containing metabolites by using LC-Fourier transform ion cyclotron resonance-mass spectrometry (FTICR-MS) in Allium plants. METHODS: Ultrahigh resolution (>250,000 full width at half-maximum) and mass accuracy (<1 mDa) by FTICR-MS allowed us to distinguish ions containing sulfur isotopes ((32)S and (34)S). RESULTS: Putative 69 S-containing monoisotopic ions (S-ions) were extracted from the metabolome data of onion (Allium cepa), green onion (Allium fistulosum), and garlic (Allium sativum) on the basis of theoretical mass differences between (32)S-ions and their (34)S-substituted counterparts and on the natural abundance of (34)S. Eight S-ions were chemically assigned by using the reference data according to the guidelines of the Metabolomics Standards Initiative. Three ions detected in garlic were assigned as derived from the isomers γ-glutamyl-S-1-propenylcysteine and γ-glutamyl-S-2-propenylcysteine and as S-2-propenylmercaptoglutathione on the basis of differences in key product ions identified in reference tandem MS spectra. CONCLUSION: The ability to discriminate between such geometric isomers will be extremely useful for the chemical assignment of unknown metabolites in MS-based metabolomics.
Authors	Ryo Nakabayashi, Yuji Sawada, Morihiro Aoyagi, Yutaka Yamada, Masami Yokota Hirai, Tetsuya Sakurai, Takahiro Kamoi, Daryl D Rowan, Kazuki Saito
Reference	Nakabayashi et al. (2016) The Journal of Nutrition.13:397S–402S doi: 10.3945/jn.114.202317.
Comment	The raw files were converted to netCDF files and stored in DROP Met as "Metabolome data in Allium plants and MS/MS spectra of S-containing compounds"

PubMed

The raw data files are available at DROP Met web site in PRIMe database of RIKEN.

Analytical Method Details Information

ID	MS1
Title	LC-FTICR-MS analysis
Instrument	LC, Agilent 1200 series; MS, Bruker Daltonics solariX 7.0 T
Instrument Type	LC-FTICR-MS
Ionization	ESI
Ion Mode	Positive
Description	Extraction of metabolites The freeze-dried samples were extracted with 50 μL of 80% MeOH containing 2.5 μM lidocaine per mg dry weight using a mixer mill (MM300, Retsch) with zirconia beads for 10 min at 20 Hz and 4 °C. After centrifugation for 10 min, the supernatant was filtered using an HLB μElution plate (Waters). LC–FTICR-MS Analysis A liquid sample (1 μL) was analyzed using LC–FTICR-MS (LC, Agilent 1200 series; MS, Bruker Daltonics solariX 7.0 T). Analytical conditions were as follows. LC: column, Xselect CSH C18 (3.5 μm, 2.1 mm ×150 mm, Waters); solvent system, solvent A (water with 0.1% formic acid) and solvent B (acetonitrile with 0.1% formic acid); gradient program, 99.5% A/0.5% B at 0 min, 0.5% A/99.5% B at 30.0 min, 0.5% A/99.5% B at 45.0 min, 99.5% A/0.5% B at 45.1 min, and 99.5% A/0.5% B at 60.0 min; flow rate, 0.3 mL/min; column temperature, 35 °C; wavelength, 200–600 nm; MS detection (resolution 260 000 at m/z 400, see Figure S1 in the Supporting Information); polarity, positive; calibrant, low concentration TuningMix (Agilent); lock mass target, diethylhexylphthalate (C24H38O4, [M + H]+m/z 391.28429); MS/MS detection (resolution 35 000 at m/z 400, see Figure S2 in the Supporting Information).
Comment_of_details	Nakabayashi et al. Anal Chem. 2013 Feb 5;85(3):1310-5.

PubMed