Creating a Gradient Table 175
Reducing Flow
Include a final line in the gradient table to reduce the flow rate after the last injection to
conserve eluent when the sample set completes.
This final line in the gradient table should:
• Appear as the last line in the table.
• Be set to a time at least 5 to 10 minutes longer than the time required for another
injection to occur.
• Specify a flow rate of either 0.0 mL/min, or a reduced flow rate, usually 0.1
mL/min.
• Use the eluent composition from the previous line.
• Specify curve #11 (see Analysis Plan and File Sheet) so that the flow rate does not
decrease until the last line in the table executes. If an injection occurs before this
line executes, the flow rate does not decrease.
Sample Gradient Table
Figure 10-1 is an example of an Auto•Blend gradient table for an analysis with a run time
of 30 minutes. It includes a 5-minute segment that returns the eluent composition to initial
conditions at the end of the run and a segment that reduces the flow rate to 0.0 mL/min if
an injection is not made within 50 minutes of the previous injection.
Figure 10-1 Example of an Auto•Blend Gradient Table
Time Flow %A %B %C %D Curve
Initial 1.00 10 10 0 80 *
30.00 1.00 10 10 80 0 6
35.00 1.00 10 10 0 80 6
50.00 0.00 10 10 0 80 11
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