Normal phase solvents order of polarity:
hexane > dichloromethane > chloroform > isopropanol>ethanol, etc.
Reversed phase solvents order of hydrophobicity:
buffers > water > methanol > acetonitril > ethanol > isopropanol
REVERSED PHASE to NORMAL PHASE
waters -> methanol -> isopropanol -> hexane
|
NORMAL PHASE to REVERSED PHASE
hexane -> isopropanol -> methanol -> waters
- Do not keep any of those polar solvents in the reservoirs when working with normal phase solvents!
2. Isopropanol (IPA) mixes with hexane AND with H2O, ACN, MeOH
- Always keep isopropanol as a reservoir when working with normal phase solvents, it will be used as the final wash solvents to the entire HPLC system.
- When finishing with normal phase solvents always wash the entire system: pump-autosampler-detector-sealwash and needlewash with Isopropanol. Use a zero-dead-volume-union instead of the column if needed.
- Wash with IPA: minimum of 10 ml should pass through each line A, B, C, D, and through the injector (Purge injector) and through the detector (just use the flow).
- Wash with MeOH: minimum of 10 ml should pass through each line A, B, C, D, and through the injector (Purge injector) and through the detector (just use the flow).
- Wash with H2O: minimum of 10 ml should pass through each line A, B, C, D, and through the injector (Purge injector) and through the detector (just use the flow).
- Only after the system was washed with H2O it is ready for reversed phase.