IonPac CS14 Manual
Doc. No. 034848-10
Page 33 of 54
5.14 Elution of Di- and Triethanolamines
The determination of diethanolamine in the presence of ammonia, alkali and alkaline earth metals can be accomplished by
isocratic elution using 9 mM methanesulfonic acid (MSA).
Triethanolamine is widely used in personal care products such as shampoos and industrially in scrubber solutions. The elution
of triethanolamine requires the use of 10 mM methanesulfonic acid (MSA) with 1.5% acetonitrile. Either methanesulfonic acid
or trifluoroacetic acid can be used with similar chromatographic results. Slightly lower concentrations of methanesulfonic acid
are required to achieve identical retention times. Eluent conditions can be optimized for the specific amines of interest. Since
the eluent contains solvent the Cation Self-Regenerating Suppressor is operated in the AutoSuppression External Water
Mode to suppress the eluent.
Sample Loop Volume:
See Chromatogram
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)
Recycle Mode or 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
Gradient Eluent: 9 mM MSA
CSRS ULTRA: AutoSuppression Recycle Mode
Gradient Eluent: 10 mM MSA / 1.5% ACN
CSRS ULTRA: AutoSuppression External Water Mode
Figure 13
Analysis of Substituted Di- and Triethanolamine
Injection Volume 25 µL (4-mm)
Analyte
mg/L
1.
Li
+
0.5
2.
Na
+
2.0
3.
NH
4
+
2.5
4.
Diethanolamine
50.0
5.
K
+
5.0
6.
Mg
2+
2.5
7.
Ca
2+
5.0
1 mg/L = 1 ppm
Injection Volume 18 µL (4-mm)
Analyte
mg/L
1.
Li
+
0.5
2.
Na
+
2.0
3.
NH
4
+
2.5
4.
Triethanolamine
400.0
5.
K
+
5.0
6.
Mg
2+
2.5
7.
Ca
2+
5.0
1 mg/L = 1 ppm
0
5
10
15
μ
S
0
Minutes
1
2
3
4 5
5
10
7
6
20
0
5
10
15
μ
S
0
Minutes
1
2
3
4
5
5
10
7
6
20
