TITLE:
GC/MS Analysis of Long-Chain Aldehydes from Recent Coral
AUTHORS:
Shigenori Ogihara
KEYWORDS:
Aldehyde, Biomarker, Coral, GC/MS, Mass Spectra
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.9 No.1,
January
18,
2018
ABSTRACT: The
main objective of this study is to present the chromatograms and mass spectra
of aldehydes so that geochemists could easily identify these compounds in
sediment samples. Aldehydes are rare compounds found in the surface environment,
particularly in sediments. To date,
aldehydes have not been used as environmental proxies. In this study,
long-chain aldehydes detected from coral collected from the east coast of Kenya
are analyzed by gas chromatography mass spectrometry (GC/MS) using
the typical procedure for biomarker analysis. The retention time of the
long-chain aldehydes and fatty acid methyl esters slightly overlapped. Hence,
the peak corresponding to the aldehyde in the GC chromatogram is buried with
that corresponding to the ester, possibly overlooking the aldehyde. After assessing the difference in the retention time between the aldehydes and fatty
acids methyl ester, the aldehydes were easily detected using the standard
analytical procedure for biomarkers analysis. A molecular ion (M+) with
greater than 23 carbon atoms was detected from long-chain aldehydes. The base
peak was observed at m/z 82 in the
mass spectra of the aldehyde, where characteristic 68 + 14n ions corresponding to
even-numbered ions were observed. The M-18 ion, which was formed by the loss of
H2O, as well as M-46 or M-84 ions, was characteristic ions observed for
long-chain aldehydes of the number of all carbon. The results obtained from
this work, in which aldehydes were identified from coral samples, represent a
good example of what could be achieved by geochemists when working with sediment
samples and using aldehydes as environmental proxies.