IonPac NS1 Manual
Document No. 034024-06
Page 19 of 35
4.1.5 Separation of Aliphatic Quaternary Ammonium Ions Using Ion-Pairing with Suppressed Conductivity
(MPIC)
The separation of a series of aliphatic quaternary ammonium ions can be obtained by using an anionic ion-pair reagent such as
nonafluoropentanoic acid. The eluent is suppressed with a CSRS ULTRA II operated in the external water mode. The separation
uses an acetonitrile gradient from 20% to 80%* in 10 minutes. As the concentration of acetonitrile increases, a decrease in the
background conductivity is observed.
Column:
IonPac NS1 (10 µm)
Eluent:
2 mM Nonafluoropentanoic acid, 20% to 80%* Acetonitrile in 10 min
Flow Rate:
1.0 mL/min
Injection Loop:
25 µL
Detection:
Suppressed conductivity, CSRS ULTRA II
* Chemical Suppression is recommended for eluents containing solvents above 40% by volume
Peaks
mg/L
(as the chloride salts)
1.
Tetrapropylammonium
25
2.
Tributylmethylammonium
50
3.
Decyltrimethylammonium
25
4.
Tetrabutylammonium
50
5.
Dodecyltrimethylammonium
50
6.
Tetrapentylammonium
100
7.
Hexadecyltrimethylammonium
100
where 1 mg/L= 1 ppm
Figure 5
Separation of Aliphatic Quaternary Ammonium Ions
Using Ion-Pairing with Suppressed Conductivity (MPIC)
