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Intermediate Polarity Capillary GC Column
for Basic Compounds
Rtx®-35 Amine Column Improves Analysis of Amines and Nitrogen Heterocyclics
By Neil Mosesman, GC Columns Product Marketing Manager
✔ Improved responses compared to conventional columns.
✔ Symmetrical peaks for basic compounds.
✔ Resolve low molecular weight primary amines.
Amines and nitrogen heterocyclics are used to man-
ufacture a wide variety of products, including dyes,
chelating agents, stabilizers, pesticides, and pharma-
ceuticals. Gas chromatographic analysis of these and
other basic compounds can be difficult, because the
active compounds typically exhibit adsorption and
peak tailing. An
Rtx®-35 Amine col-
umn is ideal for
analyses of these
polar and low
molecular weight
amines.
The proprietary
deactivation of the
35% phenyl Rtx ®-35
Amine phase improves response and peak symmetry
compared to conventional 35% phenyl columns. A
test mixture of amines at concentrations of 10 to
15ng/µL was analyzed on an Rtx®-35 Amine column
and a conventional 35% phenyl column.
Ethanolamines are particularly difficult to analyze
because in addition to their basic nature they have a
hydroxyl group that can interact with silanol groups
on the inner surface of the column. The convention-
al column completely adsorbed diethylenetriamine
and diethanolamine, but the Rtx®-35 Amine column
gave excellent responses and peak shapes for all
compounds (Figure 1).
Primary amines often are analyzed on a Stabilwax®-
DB column because it resolves these compounds
well. However, the maximum operating temperature
of this column, 220ºC, limits the molecular weight
range of the analytes. Alternatively, an Rtx®-5 Amine
column has a much higher maximum operating tem-
perature, 315ºC, but does not adequately resolve pri-
mary amines. An Rtx ®-35 Amine column combines
the advantages of a Stabilwax®-DB column and an
Rtx®-5 Amine column: it resolves primary amines
and has high thermal stability. An Rtx®-35 Amine col-
umn offers excellent peak shape and high responses
for these active compounds (Figure 2).
When analyzing basic drugs by GC, derivatization
often is required to reduce peak tailing or improve
response. These complex procedures can improve
quantitative results, but they add time and cost to the
analysis. An Rtx® -35 Amine column provides the
selectivity to analyze a wide range of underivatized
drug compounds. Many over-the-counter and pre-
scribed medications for cold and flu relief contain
amines and other basic compounds. The unique
deactivation and selectivity of an Rtx® -35 Amine col-
umn, combined with its high thermal stability, sim-
plifies the analysis for these components (Figure 3).
Underivatized sympathomimetic amines also exhibit
excellent peak shape and separation on an Rtx ®-35
Amine column (request lit. cat.# 59380).
Because the Rtx ®-35 Amine column offers excellent
response and peak symmetry for amines and polar
basic compounds, and has high thermal stability,
analysts working with these analytes can improve the
reliability and consistency of their data.
Rtx®-35Amine 30m, 0.53mm ID, 1.0µm (cat.# 11355)
Sample: amine test mix (cat.# 35002), 450–900ppm in
methanol/methylene chloride
Inj.: 1.0µL, split (10:1), 4mm base-deactivated
single gooseneck inlet liner (cat.# 20798-210.1)
Inj. temp.: 250°C
Carrier gas: helium, constant pressure
Linear velocity: 30cm/sec
Oven temp.: 110°C (hold 4 min.) to 200°C @ 8°C/min. (hold 5 min.)
Det. FID @ 300°C
1. pyridine
2. 1,2-butanediol
3. C10
4. 2-nonanol
5. diethylenetriamine
6. C12
7. diethanolamine
8. 2,6-dimethylaniline
Figure 1 An Rtx®-35 Amine column minimizes adsorption and improves responses for amines.
GC_CH00577
Figure 2 An Rtx®-35 Amine column offers
good resolution of primary amines.
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GC_CH00578
Rtx®-35 Amine 30m, 0.53mm ID, 1.0µm (cat.# 11355)
Sample: primary amines, 50ppm on-column conc. in water
Inj.: 1.0µL, split (10:1), 4mm base-deactivated single
gooseneck inlet liner (cat.# 20798-210.1)
Injector: 250°C
Carrier gas: helium, constant pressure
Linear velocity: 35.7cm/sec
Oven temp.: 35°C (hold 5.0 min.)
Det.: FID @ 300°C
1. methylamine
2. dimethylamine
3. trimethylamine
4. ethylamine
5. isopropylamine
6. tert-butylamine
7. n-propylamine
8. diethylamine
9. sec-butylamine
Base-Deactivated Inlet Liners
Add the corresponding suffix number to the liner catalog number. For inlet liners, see our 2004 Chromatography
Products Guide(lit. cat.# 59854).
qty. Base-Deactivated Base-Deactivated w/ Base-Deactivated Wool
each -210.1 addl. cost -211.1 addl. cost
5-pk. -210.5 addl. cost -211.5 addl. cost
25-pk. -210.25 addl. cost -211.25 addl. cost
For more info
For chromatograms of ethanolamines and
amphetamines on Rtx®-35 Amine columns,
request lit. cat.# 59380.