ComparingFusedSilica toMetal
High temperature applications shorten the life-
time of fused silica columns due to deterioration
of the polyimide resinused tomake the columns.
When fused silica columns are exposed to oven
temperatures over 400°C the polyimide coating
becomes brittle and the deactivation of the col-
umn is compromised. Figure 3 shows the effect of
cycling a commercially available fused silica col-
umn to 430°C for 5minutes 100 times. Although
the columnwas labeled as stable up to 430°C, the
polyimide coating showsdamage.The inertnessof
the column also deteriorates as shown by the loss
of peak symmetry for the internal standard
butanetriol overmultiple injections (Figure 4).
Metal MXT®-Biodiesel TG columns are a better
alternative to fused silica columns. As shown in
Figure 4, they clearly outperform high tempera-
ture fused silica columns under the cycling condi-
tions required forbiodiesel analysis.MetalMXT®-
Biodiesel TG columns offer greater stability and
longer column lifetimes compared
to fused silica columns.
Figure3
Fused silicacolumns, labeledas stableup to430°C, show
significantpittingandbreakdown.
100 temperature cycles to430°C totaling500minutes at
maximum temperature.
Before
After
Figure4
Stablepeak shape for internal standardbutanetriol on
MXT®-Biodiesel TG columnsgivesmoreaccuratequantification.
0.8
1
1.2
1.4
1.6
1.8
2
1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 100
Numberof Injections
Asymmetryvalue
HTFusedSilica
MXT-BiodieselTG
MXT® tubing is
more stable than
fused silica!
3
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