SAMPLE LOADING ONTO A LOW PRESSURE COLUMN USING AN AUX PUMP

The Econo Gradient Pump (EGP) and the EP-1 Econo pump are ideal for loading samples onto a low pressure column. When using a low pressure column, such as an Econo-Pac cartridge, remove the 40 psi backpressure regulator from the post-column position. Place it between the Workstation pump and the mixer. This will allow the check valves to properly seat and ensure pump flow performance. In addition, low pressure columns may burst if the backpressure regulator is placed after the column.

8.3.1 System Setup

The DuoFlow can be used with the following auxiliary pumps:

• Econo Gradient Pump (EGP). This pump connects directly to the system Instrument bus.

• Model EP-1 Econo Pump.

The EP-1 Econo pump must contain firmware version 2.12 or higher to function with the DuoFlow system. To confirm the firmware version, simultaneously press and hold down the Direction key and the down arrow key on the front panel of the EP-1 Econo pump. If the EP-1 Econo pump does not have the correct firmware version, contact Bio-Rad for information on how to upgrade the pump.

The Econo pump receives start/stop signals only. The flow rate of the EP-1 Econo pump is set from the pump, and the flow rate is recorded in the yellow data entry boxes of the Load/Inject Sample dialog box.

Note: The DuoFlow system does not control the flow of the EP-1 Econo pump, but sends only starts/stops to the Aux pump. The correct flow rate must be set at the Aux pump.

• Other external pumps.

The DuoFlow system sends a TTL signal to control an external pump. This signal is normally TTL high (5 volts). The DuoFlow system commands the external pump to run by holding Pin 4 "low". Any pump accepting this signal may be used with the DuoFlow system as a sample loading pump. Refer to your pump’s separate documentation when connecting the pump to the DuoFlow.

Figure 8-6. Connecting an EP-1 Econo Pump to the DuoFlow Workstation

ECONO PUMP REAR PANEL

SYSTEM CABLE 7

RED TO PIN #6

AUTOMATED VALVES INSTR. BUS

4

To connect the EP-1 Econo pump with the DuoFlow, make the following cable connections:

1. Obtain System Cable 7.

2. Connect the red and blue wires on the cable to the DuoFlow Workstation. (See Figure 8-6.) Note: Cut short all other wires and isolate with tape.

a. Connect the red wire to pin 6 of the Aux connector.

b. Connect the blue wire to pin 9 of the Aux connector.

3. Plug the 8-pin mini-DIN connector into the Aux connector on the rear panel of the EP-1 Econo pump.

PharMed tubing is recommended for use in the pumpheads of the Econo Gradient Pump or the EP-1 Econo pump. For additional information on these pumps, consult their instruction manuals. The AVR7-3 inject valve is plumbed without a sample loop. Plumb the AVR7-3 valve as shown below, with the Aux pump connected to port 3 of the inject valve.

Figure 8-7. Plumbing an AVR7-3 Inject Valve with an Auxiliary Load Pump

In the Setup screen, select the AVR7-3 valve as the Sample Inject Valve and add the Aux pump to the Setup list. When using an auxiliary pump to load sample directly to an AVR7-3 sample inject valve, it is possible to have a valve, such as an SVT3-2 valve, assigned as the “Aux Pump Inlet” to allow switching between samples and rinse solutions.

8.3.2 Writing the Protocol

The following steps should be programmed in the protocol, as shown in Figure 8-8.

1. Ensure that the column is properly equilibrated by using an Isocratic Flow step.

2. When you select Load/Inject Sample, specify Direct Inject and choose Aux pump as the inlet through which the sample will be delivered. Note the message displayed in yellow, “Aux Pump Flow Rate not under Biologic control,” and that the flow rate also is displayed in yellow. This is to serve as a reminder that the DuoFlow only starts/stops the Aux pump and that the actual flow rate must be set at the Aux pump.

2. Enter the volume of sample and the flow rate for the injection step. The step starting time or volume appears to the left of the options buttons.

Note: The DuoFlow system does not control the flow of the EP-1 Econo pump. The correct flow rate

LOW PRESSURE COLUMN

AUXILIARY LOAD PUMP

PURGE

AUXILIARY LOAD PUMP WORKSTATION PUMP

WASTE

WASTE

6 7 1

2 3

4

5

AVR7-3

3. Continue writing your desired separation protocol.

Figure 8-8. Writing the Protocol: Direct Sample Loading

In the configuration shown below, the valve operates as follows:

• Load. While in this position the valve connects ports 5 and 4 for equilibration of the column and for sample elution.

• Inject. While in this position the valve connects ports 3 and 4 to load sample onto the column.

• Purge. While in this position the valve connects ports 5 and 7 and allows purging or buffer changes without the need to remove the column from the system.

Figure 8-9. AVR7-3 Valve Positions During a Run with Direct Sample Loading and Injection

LOAD INJECT PURGE

15.0 End of Protocol Edit Load/Inject Sample

Step 2, Volume = 10.00 ml Load/Inject Sample Fill Before Inject

Buffer A

Alarm will sound and Protocol will HOLD for Start of Injection, then CONTINUE at end of this step.

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