Hints For Choosing The Primary Flow - Agilent Technologies 1100 Series User Manual

Hints for Choosing the Primary Flow

• Primary Flow is a parameter which exists only when the nano pump is used
In all cases, primary flow is much higher than column flow. This must be considered when
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calculating the amount of solvent needed for unattended operation
The user cannot request a specific primary flow value. However, one of three
available primary flow ranges can be selected by the user:
Default range (500-800 µl/min)
The default range is the best compromise between performance and solvent
savings.
Low Solvent Consumption range (200-500 µl/min)
Since we use very shallow gradients and the time for analysis is usually
greater than 10 minutes, we will choose the low solvent consumption mode for
the Nanoflow, nanospray configuration.
Fast Gradients range (800-1300 µl/min)
In this range, the pump gradient delay time is as short as possible. This range
is specifically recommended for fast-gradient analyses (<3 min.). Solvent
consumption is highest in this range.
Table 2 on page 38 gives approximate primary flow values (in µl/min) as a
function of selected primary flow range vs. system pressure:
1100 Series Nano Pump User Manual
in the Micro mode. Primary flow is defined as the flow volume and
composition available at the inlet to the EMPV. Using this available primary
flow, the EMPV and flow sensor work together to deliver and control the
requested column flow. All primary flow in excess of the column flow is
delivered to waste via the 1/8 inch plastic waste tube connected to the
EMPV barbed waste fitting.
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