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

15 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 27
Combination
RP x RP
IEC and RP
SEC and RP
NP and RP
Affinity and RP
SEC and NP
SEC and IEC
1
2
3
4
2D-LC - User Guide
Mode combinations in 2D-LC (LCxLC)
Orthogonality
1
3
+
+
+
+
+
+
Orthogonality,depends on the column choice or mobile phase choice
very good
good
not so good
Table 27 on page 333 summarizes the
Peak capacity Application
Peptidomics,
2
++
metabolomics,
pharmaceuticals,
foods, cosmetics
- Proteomics, pepti-
domics
Polymers, pro-
4
-
teomics
Polymers, phar-
maceuticals, oils
- Proteomics
- Polymers
- Proteomics
Comment
Miscible solvents, broad-
est application, fast
speed, gradient elution on
both dimensions
Solvent incompatibility,
limited application
333