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

Page: 35 / 395

2D-LC User Guide 35
2 Concepts of 2D-LC
Active Solvent Modulation (ASM)
Active Solvent Modulation (ASM)
Introduction to Active Solvent Modulation (ASM)
In conventional 2D-LC,
1
D solvent in the sample loop is injected to the second
dimension column. If the
1
D solvent has high elution strength in respect to the
2
D
column, it impairs separation in the second dimension. This results in unretained
elution, broad and distorted peaks, and loss of separation (see
Figure 16 on
page 36).
Active Solvent Modulation (ASM) dilutes the content of the sampling loop
(sample and
1
D solvent) with weak
2
D solvent before it reaches the
2
D column
and therefore improves the separation in the second dimension (see Figure 17 on
page 36).
Different ASM capillaries allow optimizing the dilution for different applications
(see
“Understanding the ASM Factor” on page 42).
The ASM solution is primarily designed for 2D-LC modes multiple heart-cutting
and high-resolution sampling. The 2D-LC Valve ASM is backward compatible to
the standard 2D-LC valve G4236A. If ASM is not needed or for use in
comprehensive 2D-LC, the ASM functionality can be disabled.
Figure 14 Schematic representation of the ASM 2D-LC Valve (G4243A) with MHC in countercurrent flow