Page 447 - Handbook of Materials Failure Analysis

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the composition of sludge on the surface of the compressor wall from car air condi-
tioner are demonstrated. In addition, the identification of scaling of a valve block unit
from a failed medical oxygen resuscitation apparatus is presented.

2 EXPERIMENTAL
2.1 SAMPLES

Passenger car tires, car brake fluids, varnishes, rubber membrane from the pressure
vessel of an automotive integral accumulator, a part from car air conditioner, and a
valve block unit from the medical oxygen resuscitation device were used in the
investigation.
Poly(vinyl alcohol) (PVA) obtained from Celanese Chemicals Europe GmbH
(Frankfurt/Main, Germany) and polyvinylpyrrolidone (PVP) (Luvitec K 30) obtained
from BASF AG (Ludwigshafen, Germany) were used as standards for qualitative
identification of samples.

2.2 INSTRUMENTATION AND ANALYTICAL CONDITIONS
Approximately 100-200 μg of a solid sample were cut out with scalpel and inserted
without further preparation into the bore of the pyrolysis solids-injector and then
placed with a plunger on the quartz wool of the quartz tube of the furnace pyrolyzer
Pyrojector II™ (SGE Analytical Science, Melbourne, Australia) (Figure 17.2). The
pyrolyzer was operated at constant temperature of 550 or 700 °C. The pressure of
helium carrier gas at the inlet to the furnace was 95 kPa.
Py-GC/MS measurements were made by using two apparatuses. In the first
apparatus (1), the pyrolyzer was connected to a Trace 2000 GC (ThermoQuest/
CE Instruments, Milan, Italy) with a quadrupole MS Voyager (ThermoQuest/
Finnigan, MassLab Group, Manchester, UK) operated in electron impact ionization
(EI) mode. The fused silica GC capillary column (Elite-5ms 60 m long, 0.25 mm
I.D., 0.25 μm film thicknesses; PerkinElmer Instruments, Shelton, CT, USA) was
used. The gas chromatographic conditions were as follows: programmed tempera-
ture of the capillary column from 60 °C (7 min hold) at 5 °C min 1 to 100 °C and
then 10 °C min 1 to 280 °C (25 min hold at 280 °C). The temperature of the split/
1
3
splitless injector was 250 °C and the split flow was 10 cm min . Helium, grade
5.0 (Westfalen AG, Mu ¨nster, Germany) was used as a carrier gas at constant pres-
sure of 70 kPa during the whole analysis. The transfer line temperature was 280 °C.
The MS EI ion source temperature was kept at 250 °C. The ionization occurred
with a kinetic energy of the impacting electrons of 70 eV. The current emission
of the rhenium filament was 150 μA. The MS detector voltage was 350 V. Mass
spectra and reconstructed chromatograms (total ion current (TIC)) were obtained
by automatic scanning in the mass range m/z 35-450 u. Py-GC/MS data was