• 4 •
800-356-1688
Intermediate Polarity Capillary GCColumn
for Basic Compounds
Rtx
®
-35 Amine Column Improves Analysis of Amines andNitrogenHeterocyclics
By Neil Mosesman, GCColumns Product MarketingManager
✔
Improved responses compared to conventional columns.
✔
Symmetrical peaks for basic compounds.
✔
Resolve lowmolecular weight primary amines.
Amines and nitrogen heterocyclics are used toman-
ufacture awide 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/µLwas analyzed on anRtx
®
-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, themaximum operating temperature
of this column, 220ºC, limits themolecular weight
range of the analytes. Alternatively, anRtx
®
-5 Amine
column has amuch highermaximum operating tem-
perature, 315ºC, but does not adequately resolve pri-
mary amines. AnRtx
®
-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. AnRtx
®
-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. AnRtx
®
-35 Amine column provides the
selectivity to analyze awide range of underivatized
drug compounds. Many over-the-counter and pre-
scribedmedications for cold and flu relief contain
amines and other basic compounds. The unique
deactivation and selectivity of anRtx
®
-35 Amine col-
umn, combinedwith its high thermal stability, sim-
plifies the analysis for these components (Figure 3).
Underivatized sympathomimetic amines also exhibit
excellent peak shape and separation on anRtx
®
-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 workingwith 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 4min.) to 200°C@ 8°C/min. (hold 5min.)
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
Figure1
AnRtx®-35Amine columnminimizes adsorptionand improves responses for amines.
GC_CH00577
Figure2
AnRtx®-35Amine columnoffers
good resolutionof primaryamines.
1
2/3
4
5
6
7
8
9
GC_CH00578
Rtx
®
-35 Amine 30m, 0.53mm ID, 1.0µm (cat.# 11355)
Sample:
primary amines, 50ppm on-column conc. inwater
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 5.0min.)
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 InletLiners
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-Deactivatedw/ Base-DeactivatedWool
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
Formore
info
For chromatograms of ethanolamines and
amphetamines on Rtx
®
-35 Amine columns,
request lit. cat.# 59380.
