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• 5 • 2008 vol. 3
Analytical Alternatives
Factory connected 0.32mmMXT®-Biodiesel TG
columns & 0.53mm retention gaps
For accurate analysis of heavy triglycerides, on-col-
umn injection is required. ASTMD-6584 describes
the use of a 0.32mm analytical column coupled
with a 0.53mm retention gap. The 0.53mm ID
retention gap allows the cool on-column technique
to be used, but care must be taken to minimize
dead volume and to establish a leak-tight connection.
Restek’s 0.32mmMXT®-Biodiesel TG columns are
factory-coupled to a 0.53mmMXT® retention gap
with an MXT® low-dead-volume connector, ensur-
ing a leak-tight connection. Target analytes resolve
well and the solvent and triglyceride peaks show
excellent symmetry (Figure 4).
0.53mmMXT®-Biodiesel TG columns
The 0.53mm MXT®-Biodiesel TG columns are a
simpler alternative to using a 0.32mm column
coupled to a 0.53mm retention gap. Restek applied
Integra-Gap™ technology to the 0.53mm MXT®-
Biodiesel TG columns, eliminating the column
coupling. These single unit leak-proof columns
feature a built-in retention gap, reducing the risk
of peak broadening and tailing. Chromatography
from the 0.53mm MXT®-Biodiesel TG with
Integra-Gap™ technology (Figure 5) is excellent
and comparable to that obtained on the 0.32mm
ID column in Figure 4.
Conclusion
As demonstrated, for high temperature GC analysis,
the metal MXT®-Biodiesel TG column is a rugged
column that withstands the harsh temperatures
required for total residual glycerin analysis. The
column has the resolution needed for accurate,
reliable results and is more stable at high tempera-
tures than competitive fused silica columns, leading
to longer column lifetimes. To improve the relia-
bility and robustness of your biodiesel analyses, try
a Restek MXT®-Biodiesel TG column.
Figure 4 Derivatized B100 samples resolve well on the 0.32mm
MXT®-Biodiesel TG column, which is factory-coupled to a 0.53mm
MXT® retention gap using an MXT® low-dead-volume.
Figure 5 Excellent chromatographic quality and resolution on the
0.53mm MXT®-Biodiesel TG analytical column with a built in
Integra-Gap™ retention gap.
Product Listing
0 10 20
Column: MXT®-Biodiesel TG, 15m, 0.32mm ID, 0.10µm (cat.# 70291) with a 2m x 0.53mm MXT® retention
gap connected with an MXT™ low dead-volume connector (17m total length)
Sample: biodiesel (B100), derivatized; Inj.: cool on-column injection 1µL in heptane; Inj. temp.: oven track;
Carrier gas: hydrogen, constant flow; Flow rate: 3mL/min.; Oven temp.: 50°C (hold 1 min.) to 180°C @
15°C/min. to 230°C @ 7°C/min. to 380°C @ 30°C/min. (hold 5 min.); Det.: FID @ 380°C
GC_PC00968
glycerin
butanetriol (IS)
tricaprin (IS)
monoglycerides monoglycerides diglycerides triglycerides
min.
monoglycerides monoglycerides diglycerides
0 10 20 GC_PC00969
triglycerides
glycerin
butanetriol (IS)
tricaprin (IS)
Column: MXT®-Biodiesel TG, 14m, 0.53mm ID, 0.16µm (cat.# 70289) with a 2m x 0.53mm with
Integra-Gap™ retention gap (16m total length)
Sample: biodiesel (B100), derivatized; Inj.: cool on-column injection 1µL in heptane; Inj. temp.: oven track;
Carrier gas: hydrogen, constant flow; Flow rate: 4mL/min.; Oven temp.: 50°C (hold 1 min.) to 180°C @
15°C/min. to 230°C @ 7°C/min. to 380°C @ 30°C/min. (hold 5 min.); Det.: FID @ 380°C
MXT®-Biodiesel TG Columns
(Siltek® treated stainless steel)
Restek Tubing Scorer for MXT® Columns
Designed to make perfectly round cut every time!
Description qty. cat.# price
Restek Tubing Scorer for MXT Columns
(0.25-0.53mm ID & 0.5-0.8mm OD) ea. 20523
Replacement Scoring Wheel ea. 20522
800-356-1688 •
temp limits: -60 to 380/430°C *Total column length=16 meters.
Description cat.# price
14m, 0.53mm ID, 0.16 w/2m Integra-Gap 70289
10m, 0.32mm ID, 0.10 70292
10m, 0.32mm ID, 0.10 w/2m x 0.53mm
retention gap 70290
15m, 0.32mm ID, 0.10 70293
15m, 0.32mm ID, 0.10 w/2m x 0.53mm
retention gap 70291