Py-GC/MS Analysis Method for Aliphatic Biomarker in Desert Lake Sediment and Its Application in Paleoclimatic Study

SHANG Wenyu; SUN Jingyi; XIE Manman; CEN Kuang; CAI Ze; ZHAN Nan; LING Yuan; SUN Qing

doi:10.15898/j.cnki.11-2131/td.202201120009

2022 Vol. 41, No. 5

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SHANG Wenyu, SUN Jingyi, XIE Manman, CEN Kuang, CAI Ze, ZHAN Nan, LING Yuan, SUN Qing. Py-GC/MS Analysis Method for Aliphatic Biomarker in Desert Lake Sediment and Its Application in Paleoclimatic Study[J]. Rock and Mineral Analysis, 2022, 41(5): 836-848. doi: 10.15898/j.cnki.11-2131/td.202201120009

Citation:

SHANG Wenyu, SUN Jingyi, XIE Manman, CEN Kuang, CAI Ze, ZHAN Nan, LING Yuan, SUN Qing. Py-GC/MS Analysis Method for Aliphatic Biomarker in Desert Lake Sediment and Its Application in Paleoclimatic Study[J]. Rock and Mineral Analysis, 2022, 41(5): 836-848. doi: 10.15898/j.cnki.11-2131/td.202201120009

Py-GC/MS Analysis Method for Aliphatic Biomarker in Desert Lake Sediment and Its Application in Paleoclimatic Study

1.
Key Laboratory of Eco-Geochemistry, Ministry of Natural Resources; National Research Center for Geoanalysis, Beijing 100037, China
2.
School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China
3.
Huainan Normal University, Huainan 232038, China
4.
Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China

More Information

Corresponding authors: CEN Kuang, cenkuang@cugb.edu.cn ; SUN Qing, sunqing1616@yahoo.com

Received Date: 12 January 2022

Revised Date: 29 April 2022

Accepted Date: 30 May 2022

Publish Date: 28 September 2022

Abstract

Abstract

BACKGROUND
Methylene chain backbone compounds (MCCs) in lake sediments are sensitive to climate change, and changes in environmental conditions could promote the transformation of MCCs lipids between free and bound states, hence providing a series of biomarkers for paleoclimate reconstruction. In previous studies, free MCCs lipids were typically extracted by mixed solvents, bound MCCs lipids with chemical bonding or physical adsorption could not be obtained by organic solvent extraction, and the indicator information of the characteristics of bound components on paleoclimate change was missing.
OBJECTIVES
To study the suitable analytical conditions for bound MCCs lipids, and establish proxy based on bound MCCs lipids to provide an effective tool for paleoclimate reconstruction of terrestrial ecosystems.
METHODS
Optimized analytical method of pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) was established and used to evaluate the bound MCCs in typical Desert Lake sediment.
RESULTS
Total of 71 bound MCCs compounds were identified and analyzed based on fine characterization of organic matter composition in the sediments of the Yiheshariwusu Lake in Inner Mongolia. Pyrolysis temperature was the main factor affecting the distribution characteristics of bound MCCs in sediment. Low pyrolysis energy under 450℃ led to insufficient resolution of bound MCCs. At 550℃ and 650℃, total bound n-alkanes, n-alkenes, and n-alkan-2-ones were on-line separated, identified and analyzed. The average chain length characteristics of bound n-alkanes at 550℃ and the carbon isotope of free n-alkanes as a traditional climate substitute index δ¹³C_27-33 had the best correlation (R=0.83, n=11, p < 0.01).
CONCLUSIONS
Proxy ACL₂₅_-₃₁ of bound n-alkanes respond to the change characteristics of regional effective precipitation, identify the drought periods around 5.6ka and 3.9ka in the region, reflect the intensity change of East Asian summer monsoon, and correspond to the change of effective precipitation in the mid-latitude of the northern hemisphere.
- pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) /
- Yiheshariwusu Lake /
- bound methylene chain backbone compounds lipid /
- paleoclimate

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References

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