Geology Reference
In-Depth Information
a
Undecayed scorpion cuticle
7
1
m/z
85+83
6
e
d
b
a
c
13
13
2
12
2
3
4
d
11
12
b
After 44 weeks of decay
7
a
d
1
b
6
m/z
85+83
c
e
13
2
13
d
3
4
11
12
Retention time
Fig. 6.3
Analysis of an undecayed scorpion cuticle (
a
) and scorpion cuticle decayed for 44 weeks
(
b
), revealing the presence of diagnostic chitin-protein moieties using py-GC-MS. Both samples
reveal a similar relative abundance of chitin-protein derived pyrolysis products indicating very
little chemical change in the cuticle over the 44 week decay period. No macromolecular aliphatic
component is detected (cf. Fig.
6.4
). Key to annotated symbols on peaks as in Fig.
6.4
with the
addition of 13: C
2
phenol and
e
: isobutylpyrimidine
results obtained using mass spectrometry. As all samples were solvent extracted, the
aliphatic carbon peak derived from lipids (in Fig.
6.4c
) is a component of the mac-
romolecule. The spectrum is normalized to the total intensity, and it is evident that
gains in aliphatic carbon are paralleled by a concomitant loss of chitin as a conse-
quence of decay.
The importance of lipids in generating an aliphatic composition during diagen-
esis was demonstrated previously by subjecting arthropods (Stankiewicz et al.
2000
;
Gupta et al.
2006c
), leaves (Gupta et al.
2007c
) and their lipids and other constituent
biopolymers to artifi cial maturation in a gold tube hydrothermal apparatus. The
cuticle of the emperor scorpion, following degradation for 8.5 months in a bacterial
inoculum, generated abundant phenol at 260 °C (Stankiewicz et al.
2000
). Markers
directly related to chitin and protein were absent, showing that thermal maturation
alone can transform chitin, but C
5
to C
20
n
-alk-1-enes and
n
-alkanes were present,
indicating the presence of an
n
-alkyl component. Thermal maturation at 350 °C
resulted in extensive alteration of the arthropod cuticle. Alkenes and alkanes with
Search WWH ::
Custom Search