Agilent 1290 Infinity Binary Pump User Manual 67
How to Optimize the Performance of Your Module
5
How to Achieve Higher Resolution
• %B = change in fraction of solvent B during the gradient,
• S = constant (ca. 4-5 for small molecules).
This shows that k and hence resolution can be increased by having a shallower
gradient (2 to 5 %/min change is a guideline), higher flow rate and a smaller
volume column. This equation also shows how to speed up an existing gradient
– if the flow is doubled but the gradient time is halved, k
*
remains constant
and the separation looks the same but happens in half the time. Recently
published research has shown how a shorter STM column (at temperatures
above 40 °C) can generate higher peak capacity than a longer STM column by
virtue of running it faster. (Refer to Petersson et al., J.Sep.Sci, 31, 2346-2357,
2008, Maximizing peak capacity and separation speed in liquid
chromatography).
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