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1260 Infinity Binary LC - System User Guide
3
Optimization of the Agilent 1260 Infinity Binary LC
How to Achieve Shorter Cycle Times
How to Achieve Shorter Cycle Times
Shorter cycle times can be achieved by selecting a short column with good
selectivity. The column dimensions are also determined by the detection
system that is used. For UV detection, 3.0 mm inner diameter columns are
ideal, because here the highest linear velocities can be obtained. With
4.6 mm inner diameter columns, high linear velocities can also be reached,
but the maximum flow rate is limited to 5 mL/min.
The pump should be used in its standard delay volume configuration (see
on page 43) for 4.6 mm inner diameter and 3.0 mm inner
diameter columns. For 2.1 mm inner diameter columns, the low delay
volume configuration should be used. In addition, when using 2.1 mm
inner diameter columns, the low dispersion kit should be installed to
provide lowest extra- column volume. For highest UV sensitivity, it is
recommended in addition to use the short mixer ( Low volume mixer (
200 µL) (5067- 1565)).
Chromatographic conditions strongly depend on the compounds that are
to be analyzed, but some rules of thumb can be used to achieve short run
times:
•
The flow rates should be as high as possible, depending on the required
resolution, back- pressure and the detection system used.
•
Steep gradients should be used.
•
High column temperatures are recommended to enable high flow rates
to be used, and to shorten run time even further. Zorbax SB columns
can be used up to 90 °C, at low pH.
Alternating column regeneration
Even shorter cycle times can be achieved by using a column regeneration
valve in combination with a regeneration pump. Using this setup, the
regeneration of the column that is used previously takes place during the
analysis on the second column. This shortens cycle time significantly.
Using two columns, two pumps and one 2- position 10- port valve allows
switching between these columns for shortest cycle times from injection to
injection. Typically, columns of the same chemistry and the same batch
provide a retention time precision that allows data processing using the
same calibration table.
Please refer to the Valve Solution User Guide for a more detailed
description of the alternating column regeneration.
