Kromasil Chiral technical evidence

• Bonded phases - Introduction
• Bonded phases - Mechanical and chemical stability
• Bonded phases - Loadability
• Coated phases - Introduction
• Coated phases - Mechanical stability
• Coated phases - Performance stability
• Coated phases - Loadability

Performance stability of Kromasil Chiral coated phases

Performance after mobile phase changes

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You can run Kromasil CelluCoat with maintained stability and performance when switching between compatible normal or polar organic phases. Figure 1 illustrates the impact of a mobile phase switch from heptane/2-propanol (90/10) to 100% acetonitrile and back, then to 100% 2-propanol and back. Performance is measured with trans-stilbene oxide as the efficiency on the first eluted peak (Knox plot) and the selectivity. Neither seems hardly affected by the mobile phase switches.

Fig. 1 - Stability of Kromasil CelluCoat. Efficiency (Knox plot) and selectivity.
Conditions:
Solute: trans-Stilbene oxide
Stationary phase: Kromasil CelluCoat, 5 μm
Mobile phase: heptane/2-propanol (90/10)
Column size: 4.6 x 250 mm
Flow rates: 0.1-1.2 ml/min
Temperature: 25 °C

Negligible memory effects

Additives, like TFA or DEA, are commonly used in chiral chromatography for enhancing the separation of acidic and basic racemates. These additives can strongly interact with the stationary phase in such a way that so-called memory effects occurs. Tedious washing and equilibration may be needed to restore the performance of the phase. In figure 2 is shown a sequence of separations on Kromasil CelluCoat using TFA and DEA as respective additive. The equilibration time in between is relatively short and the performance is retrieved without hassle.

Fig. 2 - Negligible memory effect of additives on Kromasil CelluCoat.
Conditions:
Stationary phase: Kromasil CelluCoat, 3 μm
Mobile phase 1:
Heptane/2-Propanol/TFA (90/10/0.1)
Mobile phase 2:
Heptane/2-Propanol/DEA (90/10/0.1)
Column size: 4.6 x 150 mm
Flow rate: 1 ml/min
Temperature: 25 °C