RestekCorporation
(800) 356-1688
Petrochemical
Rtx
®
-1:ANewBondedPackedColumn for
SimulatedDistillation
note
A
pplications
cat.#59570
• Rtx
®
-1bondedpackedcolumn requires
minimal conditioning.
• Meets or exceeds all specifications of
ASTMD2887 andD3710.
• Stablebaseline to350°Candrepeatable
RT’s “right from thebox”.
• Deactivated Silcosteel
®
tubing
and Silcoport
™
packing for high
inertness.
• Column lifetime superior to
existingSimDist columns.
SimulatedDistillation (SimDist),
according toASTM testmethodsD2887
orD3710canbeperformedusingeither
packedor capillarycolumns.Advantages
of capillary columns are the columns
are preconditionedso theycanbeusedafter
onlyminimal conditioning, and the
bonded stationaryphases exhibit stable
baselines and retention times.There are
many laboratories currentlyusing
packed columnswhichwould like to
take advantageof bondedphases but do
not haveGC equipment that canbe
easily converted for usewith capillary
columns.
Restek’sRtx
®
-1SimDist column is the
first in a newgenerationof bonded
packedcolumnshavingsuperior inertness
and stability compared to conventional
packedcolumns. These improvements
areobtainedbypreparing the columns
withSilcosteel
®
tubing andbonding the
Rtx
®
-1 stationaryphase to ahighly
deactivatedSilcoport
™
support. The
columndimensions andpacking (
1
/
8
"
Silcosteel
®
with 10%Rtx
®
-1on
Silcoport
™
) are designed to exceed all
requirements specified inASTMTest
MethodsD2887 andD3710.
Bonded stationaryphases require
minimal conditioning and give stable
baselines and retention times “right
from thebox.”
Simulated distillation is a gas chro-
matographicprocedurewhichdiffers
from typicalGC analysis requiring
peak resolution and integration. The
sample is analyzed using a linear
temperature program so that the
retention time of the hydrocarbons are
proportional to their boilingpoints. The
Table 1
shows the excellent retention
time repeatabilityobtainedwith the
column, indicating the column is
suitable for sample analysis after
minimal conditioning.
Column bleed is another important
consideration for selecting a Sim
Dist column. The baselinemust be
stable and free of any artifacts during
the temperature programup to350°C.
Althoughbaseline subtraction is
Questions?
Call Restek’s technical
service staff at
800-356-1688,
ext.4
Hydrocarbon MinRt
MaxRt
Avg. RT Stand. Dev.
C
5
0.241
0.243
0.242
0.001
C
6
0.493
0.497
0.495
0.002
C
10
5.746
5.765
5.752
0.005
C
20
18.482
18.491
18.486
0.004
C
28
25.093
25.103
25.098
0.004
C
40
32.160
32.171
32.166
0.004
C
44
34.316
34.328
34.326
0.007
Table I
RetentionTimeRepeatability forCalibrationafter only30minutes conditioning.
sample boiling range distribution is
calculated by comparing the sample
area and its retention time with that
of an alkanes calibration standard. In
order for the calibration tobe valid for
sample analysis, it is crucial that
retention times be repeatable until the
next calibration is performed.
Figure 1
is an example of the analysis of the
RestekD2887CalibrationMix (cat.#
31222) illustrating the typical pattern
obtained for the alkanes under tempera-
tureprogrammed conditions.To
demonstrate the stabilityof theRtx
®
-1
column, a series of calibration stan-
dardswere analyzed after only30
minutes of conditioning at 350°C.
permitted in themethod, this compensa-
tionwill produce errors if the baseline
is not consistent. Conventional packed
columns requireup to14hours of
conditioning and frequent updatingof
thebaseline compensation runbecause
the stationaryphase is not bonded.
Rtx
®
-1 columns, however, exhibit stable
