Geology Reference
In-Depth Information
Cockroach cuticle
m/z
83+85
C
2
P
C
1
P
C
3
Py
C
3
P
C
2
Py
C
1
In
C
2
Id
C
3
Id
C
1
Py
C
2
Pyr
B
2
B
1
P
Retention time
Fig. 8.4
Partial pyrolysis-GC-MS chromatograms of cockroach cuticle matured after lipid extrac-
tion followed by saponifi cation
.
Annotations as in Fig.
8.2
. The analysis time was 55 min
Table 8.1
The products of maturation of different arthropod cuticle biochemical components
Starting material
Composition
Chemical treatment
Products of maturation
Commercial chitin
Pure chitin
Extraction
Matured chitin products
and no aliphatics
Fresh scorpion,
shrimp and
cockroach cuticle
Chitin + pro-
tein + lipids
None
Matured chitin products + acids +
amides + aliphatics
a
Fresh scorpion and
cockroach cuticle
Matured chitin products
and no aliphatics
a
Shrimp cuticle matured with CaCO
3
or clay and without any chemical pre-treatment also yielded
these moieties
Chitin + protein
Extraction +
saponifi cation
alteration of the cuticle. Alkenes and alkanes with aliphatic carbon chain numbers
up to
n
-C
30
, signifi cantly higher than those observed here, were the dominant pyrol-
ysis products, and phenols were barely detected. Indenes and amides, which occur
in our experiments, were not reported. These differences probably refl ect alteration
of the chitin-protein complex through decay prior to the maturation process; the
cuticles used in the present experiments were not decayed.
In the present experiments artifi cial maturation of untreated arthropod cuticle at
350 °C resulted in signifi cant changes in the macromolecular composition
(Table
8.1
). Thermally induced changes to the chitin-protein complex (deacety-
lation of chitin and formation of aromatic products of both chitin and protein)
resulted in the presence of phenol and alkyl substituted phenols in the pyrolysate.
The presence of
n
-alk-1-enes and
n
-alkanes indicate that an aliphatic component
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