2
Concepts of 2D-LC
Active Solvent Modulation (ASM)
2D-LC User Guide
36
Example: ASM with HILIC in
1
D and reversed phase in
2
D
In this example, a HILIC separation was run in the first dimension and a reversed
phase separation in the second dimension. If sample cuts are transferred to the
second dimension, 40 µL of high organic solvent are brought to a reversed phase
column.
1
1 1
D analysis of pesticides using:
1
D: Zorbax RX-SIL (150 x 2.1 mm ID, 5 µm), A = 10 mM NH
4
Ac in
H
2
O; B = ACN, Gradient: 100 to 95% acetonitrile in 5 min, 500 µL/min. MHC with 40 µL loops.
2
D :
Bonus RP (50 x 2.1 mm, 1.8 µm), H
2
O/acetonitrile gradient (0.2% formic acid), weak solvent 3%
acetonitrile, 400 µL/min, EICs from conventional 2D-LC (undiluted)
Figure 15 Analysis of pesticides using a HILIC separation with high organic solvent composition in
1
D
2D resolution with conventional valve
2D resolution with ASM valve
The high elution strength of
1
D solvent causes bad separation
with broad and distorted peaks in the left
2
D chromatogram.
In the right 2D chromatogram a 2D-LC Valve ASM was used
instead of a conventional 2D-LC valve. Peaks are resolved and
the sensitivity is increased.
Figure 16
Conventional analysis of Cut#3 using a reversed
phase separation in
2
D
Figure 17
ASM analysis of Cut#3 using a reversed phase
separation in
2
D
