IonPac CS14 Manual
Doc. No. 034848-10
Page 24 of 54
5.8
Elution of Morpholine with Mono-, Di- and Trimethylamines With Resolution Enhancement
Through Gradient Elution
The determination of morpholine in the presence of mono-, di- and trimethylamines, ammonia, alkali and alkaline earth metals
can be accomplished by isocratic elution with 10 mM MSA and 0.3% acetonitrile. Further enhancement of resolution between
ammonium and methylamine and also between dimethylamine and potassium while still eluting trimethylamine rapidly and with
good peak shape can be accomplished by increasing the solvent to 2.5 % acetonitrile and running a methanesulfonic acid
gradient from 5 to 13 mM.
Sample Loop Volume:
6.25 µL (2-mm), 25 µL (4-mm)
Analytical Column:
IonPac CS14 Analytical Column
Eluent:
See Chromatogram
Eluent Flow Rate:
0.25 mL/min (2-mm), 1.0 mL/min (4-mm)
SRS Suppressor:
Cation Self-Regenerating Suppressor, CSRS ULTRA (2-mm or 4-mm)
External Water Mode
or MMS Suppressor:
Cation MicroMembrane Suppressor, CMMS III (2-mm or 4-mm)
MMS Regenerant:
100 mN TBAOH
(tetrabutylammonium hydroxide)
Expected Background Conductivity:
< 1 µS
Storage Solution:
Eluent
Eluent 1:
Type I DI Water
Eluent Flow Rate:
1.0 mL/min
Eluent 2:
100 mM MSA
(4-mm System)
Eluent 3:
10% Acetonitrile
TIME (min)
%E1
%E2
%E3
C o m m e n t s
Equilibration
0.0
70
5
25
Equilibrate to 5.0 mM MSA / 2.5% ACN
7.0
70
5
25
Analysis
0.0
70
5
25
Inject, 5.0 mM MSA / 2.5% ACN
0.1
70
5
25
Inject Valve to Load Position
7.0
69
6
25
6.0 mM MSA / 2.5% ACN
12.0
62
13
25
13.0 mM MSA / 2.5% ACN
18.0
62
13
25
13.0 mM MSA / 2.5% ACN
Figure 7
Elution of Morpholine with Mono-, Di- and Trimethylamines, Ammonia, the Alkali and Alkaline Earth Metals
Gradient Eluent: As listed above
Analyte
mg/L
1.
Li
+
0.5
2.
Na
+
2.0
3.
NH
4
+
2.5
4.
Methylamine
10.0
5.
K
+
5.0
6.
Dimethylamine
10.0
7.
Trimethylamine
30.0
8.
Morpholine
25.0
9.
Mg
2+
2.5
10. Ca
2+
5.0
1 mg/L = 1 ppm
Isocratic Eluent: 10 mM MSA / 0.3% ACN
0
5
10
15
μ
S
0
Minutes
1
2
3
4
5
5
10
7
8
9
6
10
0
5
10
15
μ
S
0
Minutes
1
2
3
4
5
5
10
7
8
9
6
10
20