IonPacAS9-SC
034656-06
Page 7 of 28
3.3.1 The 4-mm System Injection Loop, 10 - 50
μ
L
For most applications on a 4-mm analytical system, a 10 - 50 µL injection loop will be sufficient. Generally, do not inject more
than 10 nanomoles (100 - 200 ppm) of any one analyte onto the 4-mm analytical column. Injecting larger volumes of samples
can result in overloading the column which can affect peak efficiency and resolution.
3.4
The IonPac AG9-SC Guard Column
An IonPac AG9-SC Guard Column is normally used with the IonPac AS9-SC Analytical Column. Retention times will increase
by approximately 20% when a guard column is placed in-line prior to the analytical column. A guard is placed prior to the
analytical column to prevent sample contaminants from eluting onto the analytical column. It is easier to clean or replace a guard
column than it is an analytical column. Replacing the AG9-SC Guard Column at the first sign of peak efficiency loss or decreased
retention time will prolong the life of the AS9-SC Analytical Column.
3.5
Installing the Anion Trap Column, ATC-3
When performing a gradient anion exchange application, a borate eluent system should be used instead of a carbonate system
because of its low background conductivity. An IonPac Anion Trap Column (ATC-3 (4-mm),
P/N 059660) should be installed
between the Gradient Pump and the injection valve. Remove the high pressure Gradient Mixer if present. The ATC is filled with
high capacity anion exchange resin which
helps to minimize the baseline shift caused by increasing anionic contaminant levels
in the eluent as the ionic concentration of the eluent is increased over the course of the gradient analysis.
To install the ATC-3 (4-mm), complete the following steps:
A. Remove the Gradient Mixer, if installed between the gradient pump pressure transducer and the injection valve.
B. Connect the gradient pump directly to the ATC-3. Connect a waste line to the ATC-3 outlet and direct the line to a waste
container.
C. Flush the ATC-3 (4-mm) with 200 mL of 70 mM Na
2
B
4
O
7
at a flow rate of 2.0 mL/min.
D. Rinse the ATC-3 with the strongest eluent that will be used during the gradient analysis.
E.
After flushing the ATC-3 with eluent, connect the ATC-3 to the eluent line that is connected to the injection valve.
The background conductivity of your system should be less than 7 µS when Na
2
B
4
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7
is being pumped through the chromatographic
system with the ASRS in-line and properly functioning. The baseline shift should be no greater than 10 µS during a borate gradient
eluent concentration ramp from 0 to 70 mM Na
2
B
4
O
7
. If the baseline shifts are greater than 10 µS, the ATC should be cleaned
using steps A - E above.
The ATC-3 can be flushed, at the end of each operating day, to remove any impurities that may have accumulated on it. This will
minimize periodic maintenance and lost data.
A. Flush the ATC-3 with 30 mL of 70 mM Na
2
B
4
O
7.
B. Prior to next day use of the chromatographic system, flush the ATC-3 with 30 mL of the strongest eluent used in the
gradient program.
See the Product Manual for the IonPac ATC-3 (P/N 032697) for instructions on cleaning a contaminated Anion Trap Column.
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