3
– Operation
Thermo Scientific
Product Manual for CarboPac PA200 Columns
Page 18 of 37
065734-01
For Research Use Only. Not for use in diagnostic procedures.
3.4
Method Development
For users who are familiar with the manually-prepared sodium acetate/sodium hydroxide eluent
system, the general guideline to convert an existing method using the sodium acetate/sodium
hydroxide eluents to a method using the EGC-generated potassium methanesulfonate/potassium
hydroxide eluents is to follow an estimated conversion of concentration:
C
KMSA
≈ (1/3 to 1/2) *
C
NaOAc
In practice, the selectivity is governed by a combination of potassium methanesulfonate and
potassium hydroxide concentrations. Therefore, it’s recommended to start from the above basic
estimation, and make necessary adjustments to the concentrations of both potassium
methanesulfonate and potassium hydroxide.
To achieve good peak resolution and sensitivity, it’s
also recommended to use higher concentration of hydroxide when using potassium
methanesulfonate/potassium hydroxide eluent, as compared to using sodium acetate/sodium
hydroxide eluent. As the eluting strength of methanesulfonate ion is stronger than that of acetate
ion, an increase in pH as a result of the increase in hydroxide concentration favors the ionization
and the retention of the analytes.
3.5
System Re-start
The systems under Dual EG mode are designed to be operated non-stop for months at a
time. If the system has been shut down for more than 1-2 days, the system should be re-
started using the following procedure (applied to both analytical and capillary systems):
3.5.1
System Re-Start Procedure for Dionex CarboPac PA200, 1 mm Column
A.
.
B.
C.
Set the flow rate to 0.1 mL/min. Turn the pump and EGC power on. With Eluent Polarity set to
Basic Eluents, set KMSA
prog
to 50 mM and KOH_
prog
to 20 mM. Allow the system to run for
30 min.
D.
Turn the EGC power off.
E.
Keep the pump on at 0.1 mL/min for 10 min.
F.
Turn the pump off.
G.
Connect the OUTLET of the Dionex EGC 400 KOH cartridge to the ELUENT IN of the
Dionex RFIC EGC 400 KOH Degasser (Item # 22181-60201). Direct the ELUENT OUT of
the DIonex RFIC EGC 400 KOH Degasser to waste.
H.
Set the flow rate to 0.1 mL/min and turn the pump on for 10 min. Keep EGC power off.
I.
Turn the pump off.
J.
ELUENT OUT of the DIonex RFIC EGC 400 KOH Degasser to P port of the
injection valve.
K.
Install the CarboPac PA200 (1 x 50 mm) guard column and the CarboPac PA200 (1 x 250 mm)
separator column to C port of the injection valve. Direct the OUTLET of the column to waste.
L.
Set the flow rate to 0.063 mL/min. With EGC power off, pump DI water through the system
for 10 min.
M.
Turn the pump off.
N.
Connect the outlet of the separator column to the ED cell.
O.
Direct the outlet of the ED cell to waste.
P.
Turn the pump and EGC power on. Set to the required application condition.
Q.
When the pH reading of the ED detector shows pH > 11, turn the ED cell on.
R.
Allow the system to equilibrate for 30-45 minutes prior to collecting data.
NOTE
!
