IonPac NS1 Manual
Document No. 034024-06
Page 16 of 35
Figure 2
Separation of Anions by Ion-Pairing (MPIC) with
Suppressed Conductivity and the Effect of Solvent
0.25
µ
S
0
0
5
10
15
20
1
2 3
4
5
6
7
Peaks
mg/L
1.
Fluoride
5
2.
Chloride
1
3.
Nitrite
2
4.
Bromide
2
5.
Nitrate
2
6.
Sulfate
2
7.
Phosphate
3
8.
Thiosulfate
5
9.
Thiocyanate
5
10. Perchlorate
10
where 1 mg/L= 1 ppm
Minutes
Minutes
0.25
µ
S
0
0
5
10
15
20
25
30
1
2
4
5
6
8
9
10
4.1.2 Separation of Anions by MPIC with Suppressed Conductivity Detection and Solvent
Ion-pairing can separate monovalent anions, such as chlorate and nitrate, which differ in hydration energy. Because ion pairing
has low selectivity for higher valency ions, selected monovalent and higher valency ions can be eluted isocratically on the IonPac
NS1 analytical column. Example B illustrates the use of a higher solvent concentration to elute hydrophobic anions such as
thiosulfate and perchlorate.
Column:
IonPac NS1 (10 µm
Eluent:
See Chromatogram
Flow Rate:
1.0 mL/min.
Injection Loop:
50 µL
Detection:
Suppressed conductivity, ASRS ULTRA II
AutoSuppression MPIC Mode
Regenerant:
10 mN H
2
SO
4
Eluent A
1mM TBAOH, 1mM
Na
2
CO
3
, 10% ACN
Eluent B
1mM TBAOH, 1mM
Na
2
CO
3
, 20% ACN
