Successful Mode Combinations - Agilent Technologies 1290 Infinity II 2D-LC User Manual

14 Theoretical Background

Successful Mode Combinations

Successful Mode Combinations

2D-LC separations are the more effective, the more the selectivity mechanisms
involved in the two stages differ. Completely different and independ mechanisms
are said to be orthogonal. Any correlation between the selectivity mechanisms
degrades orthogonality and reduces the efficiency of the 2D-LC system.
Thus, selecting the best combination of stationary and mobile phase is the major
issue to improve 2D-LC methods.
advantages and disadvantages of combinations of normal phase (NP), reverse
phase (RP), ionexchange (IEC) and size exclusion chromatography (SEC) for
2D-LC operation.
Table 45
Combination
RP x RP
IEC and RP
SEC and RP
NP and RP
Affinity and RP
SEC and NP
SEC and IEC
1
Orthogonality,depends on the column choice or mobile phase choice
2
very good
3
good
4
not so good
2D-LC User Guide
Mode combinations in 2D-LC (LCxLC)
Orthogonality Peak capacity
1
3
+
+
+
+
+
+
Table 45 on page 373 summarizes the
Application
Peptidomics,
2
++
metabolomics,
pharmaceuticals,
foods, cosmetics
- Proteomics,
peptidomics
4 Polymers,
-
proteomics
Polymers,
pharmaceuticals,
oils
- Proteomics
- Polymers
- Proteomics
Comment
Miscible solvents,
broadest application, fast
speed, gradient elution on
both dimensions
Solvent incompatibility,
limited application
373