25th International Meeting on Organic Geochemistry IMOG 2011

P-017
Brazilian Miocene amber from Acre Basin (Solimões Formation):
comprehensive two-dimensional gas chromatography coupled
with time-of-flight mass spectrometry applied on its
paleobotanical source
Ricardo Pereira 1 , Ismar de Souza Carvalho 1 , Antonio Carlos Sequeira Fernandes 1 ,
Karen Adami Rodrigues 2 , Raphael Salles Ferreira Silva 1 , Renata Filgueiras Soares 1 ,
Rosane Aguiar da Silva San Gil 1 , Débora de Almeida Azevedo 1
1 Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 2 Universidade Federal de Pelotas, Pelotas,
Brazil (corresponding author:ricardo.geologia@uol.com.br)
Amber is a fossil resin mainly constituted of organic
polymers originated through complex maturation
processes [1]. Despites the occurrence of important
amber deposits around the world, registers of this
material in Brazil are rare being known in Lower
Cretaceous sediments from Amazonas, Araripe and
Recôncavo basins. All Brazilian samples analyzed
until this moment were linked to conifer families
mainly Araucariaceae, Podocarpaceae or
Cheirolepidiaceae [2,3]. Comprehensive twodimensional
gas chromatography coupled with timeof-flight
mass spectrometry (GC×GC-TOFMS) could
be particularly useful for investigating the composition
of complex mixtures, such as amber extracts. The aim
of this study was to carry out an individual
identification of terpenes in extracts from amber
samples collected in fluvial sediments of Miocene age
localized in Solimões Formation (Acre Basin, Brazil)
by GCxGC-TOFMS. The data obtained were used to
assess the paleobotanical source of the amber.
Three amber samples, named SOL-01, SOL-02
and SOL-03, were extracted (CH2Cl2:CH3OH, 1:1,
V:V) and analysed in a GCxGC-TOFMS System
Pegasus 4D (Leco). The column set used was a DB-
5MS (30 m) as first dimension and a BPX-50 (1.3 m)
as second dimension.
The total ion chromatogram (TIC) for the SOL-03
sample is showed in the Figure 1. TIC acquired are
analogous for the three samples, indicating that the
amber samples are probably derived from the same
or similar botanical source. The chromatograms
revealed three distinct regions, associated to
monoterpenoids, hydrocarbonic sesquiterpenoids and
decalines, and polar sesquiterpenoids and
diterpenoids. Several compounds of aromadendrane,
humulane, germacrane caryophyllane, bisabolane,
labdane, abietane and kaurane skeletons were
present. These compounds were tentatively identified
by the use of ChromaTOF 2.32 Software, Nist Mass
Spectral Database and elution order.
The molecular composition pointed to Fabaceae
(Leguminosae) family. This angiosperm group have
resins based on sesquiterpenes that most often occur
as hydrocarbons as well as diterpenes of labdane
class [1], both identified in the analyzed samples.
Moreover, Fabaceae fossilized leaves were found in
the same stratigraphic level of the amber samples. In
this way, the family indicated by the molecular
composition of ambers finds support in the fossil
record of the Solimões Formation. So, this work
allowed expanding the knowledge about Brazilian
fossil resins and its botanical source, including
angiosperms as amber producers and using GCxGC-
TOFMS to elucidate amber chemical composition.
Fig. 1. Total ion chromatogram for SOL-03 sample extract,
showing some compounds identified: (1) Camphene, (2)
Cymene, (3) Fenchol, (4) Borneol, (5) Aromadendrene, (6)
Methyloctahydronaphthalenone, (7) Germacrene, (8)
Humulene, (9) Bisabolene, (10) Kaur-16-ene, (11) Abieta-
8,11,13-trien-18-ol, (12) Kauren-13-ol.
References
[1] Langenheim, J.H. (2003). Plant Resins:
Chemistry,Evolution, Ecology, and Ethnobotany, 1 st
Edition, Timber Press: Portland, 586 pp.
[2] Pereira, R., Carvalho, I.S., Simoneit, B.R.T., Azevedo,
D.A. (2009). Org. Geochem. 40, 863-875.
[3] Pereira, R., San gil, R.A.S., Carvalho, I.S., Fernandes,
A.C., Azevedo, D.A. (2011). J. Braz. Chem. Soc. 22,
92-97.
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