Practical Issues - Agilent Technologies 1290 Infinity II 2D-LC Solution User Manual

15 Theoretical Background

Practical Issues

Practical Issues

The table below gives an overview, which practical issues have to be considered
in 2D-LC.
Table 29 Practical issues in 2D-LC
Issue Theoretical base
Choice of first dimen- Has impact on trade off between optimum first dimension flow
sion column diameter rate and amount of sample injected into the second dimension
column for each second column run
Ratio of column diam- Causes significant analyte dilution effects
eter in the two dimen-
sions
Goals of the analytical Chosen parameter depend on what is important in analysis:
method •
•
Selection of the sta- For RPLC in both dimensions the retentivity of the second
tionary phases and dimension column must be much higher than that of the first
column formats dimension column required because:
•
•
2D-LC - User Guide
separate as many constituents as possible or
focused on resolution and quantitation of a specific constit-
uent
a relatively large volume of the sample will be collected and
injected into the second column
to minimize peak broadening the sample should be focused
at the inlet of the second column
Comment
True gradient elution in the second
dimension separation provides
better peak capacity than in isocra-
tic elution.
Gradient elution is the best avail-
able mechanism for achieving
peak focusing.
340