Technical data

46 Agilent 1290 Infinity LC System Manual and Quick Reference
3 Optimization of the Agilent 1290 Infinity LC System
How to Configure the Optimum Delay Volume
volume is optimized for the use with 3mm and 4.6mm inner diameter
columns.
For pump operation it is recommended to set the correct solvent in the pump
setup screen. Even though the intelligent control will automatically tune the
pressure ripple to a minimum the solvent compressibility can have an effect
on maintaining absolutely correct flow rate at high pressure. This ensures that
the correct compressibility values are always applied for the mobile phases
used. Calibration functions are available for the Agilent 1290 Infinity Binary
and Quaternary Pump
In the 1290 Infinity Binary Pump the physical delay volume of the pump is
primarily dependent on the use of the Jet Weaver mixer. For UV detection the
Jet Weaver should always be used but for mass spectrometric detection the
user can decide to bypass the Jet Weaver removing 35 µl from the delay
volume. This only makes sense for ultra-fast gradient operation (less than
0.5 min) or for use with very small volume columns. Refer to Table 6 on
page 43 for the effect on the delay time in the system. If the Jet Weaver is
bypassed the connection tubing to the autosampler is routed directly from the
purge valve. Ensure that the Jet Weaver has been flushed with solvent
containing no buffers or other additives before disconnecting it.
Sometimes it may be advisable to increase the delay volume in the pump.
Specifically this can be the case when UV detection is employed and a strongly
UV-absorbing compound has been added to the mobile phase. This can have
the effect of emphasizing any pump noise and the most common example is
the use of trifluoro acetic acid (TFA) in the analysis of proteins and peptides.
The effect can be mitigated by increasing the mixer volume. The Jet Weaver
mixer has two alternative volumes in the same unit. The switch from the lower
volume, 35 µl, to the higher volume, 100 µl, is done by de-installing it, turning
it around from front to back and re-installing it. The mixing volume (and hence
delay volume) is increased by 65 µl and the baseline performance with
additives like TFA will be improved. The configuration of the Jet Weaver is
logged automatically by an attached RFID tag. For demanding applications
with the lowest possible UV baseline noise, a 380 µL Jet Weaver mixer is
available, which is installed analog to the standard Jet Weaver mixer.
The procedure for replacing a Jet Weaver in the 1290 Infinity Binary Pump is
illustrated in “Replacing the Jet Weaver in the 1290 Infinity Binary Pump” on
page 48.
Due to the different setup and mixing principle in the Agilent 1290 Infinity
Quaternary Pump, the physical delay volume is much bigger and in standard