A GC/C/IRMS-based method for position-specific carbon isotopic analysis of saturated long chain fatty acids

Zhao, Yu1; Ma, Ran1,2; Qi, Yaoting1; He, Rong1; Zhu, Zhenyu1; Wang, Bo1; Wang, Ying1; Yan, Qiulin1; Julien, Maxime4; Zhou, Youping1,2,3

2023-09-01

10.1016/j.orggeochem.2023.104652

ORGANIC GEOCHEMISTRY   影响因子和分区

0146-6380

1873-5290

Intramolecular carbon isotope profiles (13C/12C) of mid- and long-chain saturated fatty acids represent a potentially rich source of pathway and flux information on fatty lipid biosynthesis. Accessing the PSIC-13C (position-specific carbon isotope composition) of saturated long chain fatty acids, however, proves a challenge as neither 13C NMR, nor online pyrolysis, can measure all carbons successfully. We have developed a wet chemistry procedure (& alpha;-bromination, & alpha;-hydrolysis and decarboxylation) to stepwise shorten the targeted saturated fatty acid, followed by GC/C/IRMS (gas chromatography/combustion/isotope ratio mass spectrometry) measurement of the 13C/12C ratios of fatty acids, with minimal purification. Isotope mass balance was then applied to calculate the 13C/12C ratios of individual carbons. The triplicated PSIA precision varies from position to position in the range 3.95-5.25 mUr (averaging 4.44 mUr, equivalent to & PTSTHOUSND;). Applying this method to a commercial C16:0 fatty acid of C3 botanical origin revealed an intramolecular oddover-even 13C enrichment pattern, consistent with that obtained with 13C NMR. Although PSIA-13C was attempted only on a single fatty acid, the method can potentially be applied to obtain PISC-13C for all fatty acids in a mixture simultaneously, and to long chain saturated alkanes after proper functionalization. The method should prove useful in studies of lipid metabolism and biogeochemistry as both saturated long chain fatty acids and alkanes are the dominant organic archives of climate in petroleum deposits, sediments and soils.

Fatty acid Intramolecular carbon isotope distribution GC/C/IRMS Position-specific isotope analysis

SCI ; EI

英语

通讯

Chinese NSF["42250203","42007408","32071507"] ; null[41973072]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:001053558700001

PERGAMON-ELSEVIER SCIENCE LTD

20233214510575

Carbon ; Gas chromatography ; Isotopes ; Mass spectrometry ; Petroleum deposits ; Saturated fatty acids ; Sediments

Soil Mechanics and Foundations:483 ; Petroleum Deposits:512.1 ; Chemistry:801 ; Chemical Operations:802.3 ; Chemical Products Generally:804 ; Organic Compounds:804.1

GEOSCIENCES

Web of Science

1.Shaanxi Univ Sci & Technol, Sch Chem & Chem Engn, Isotop Chem Biol ICB, Xian 710021, Peoples R China
2.Southern Univ Sci & Technol SUSTech, Dept Ocean Sci & Engn, Shenzhen 510085, Peoples R China
3.Nanjing Univ, Int Ctr Isotope Effects Res ICIER, Nanjing 210023, Peoples R China
4.GFZ German Res Ctr Geosci, Helmholtz Ctr Potsdam, Organ Geochem, Potsdam, Germany

Zhao, Yu,Ma, Ran,Qi, Yaoting,et al. A GC/C/IRMS-based method for position-specific carbon isotopic analysis of saturated long chain fatty acids[J]. ORGANIC GEOCHEMISTRY,2023,183.

Zhao, Yu.,Ma, Ran.,Qi, Yaoting.,He, Rong.,Zhu, Zhenyu.,...&Zhou, Youping.(2023).A GC/C/IRMS-based method for position-specific carbon isotopic analysis of saturated long chain fatty acids.ORGANIC GEOCHEMISTRY,183.

Zhao, Yu,et al."A GC/C/IRMS-based method for position-specific carbon isotopic analysis of saturated long chain fatty acids".ORGANIC GEOCHEMISTRY 183(2023).