Page 121 - Applied Pharmacognosy
P. 121
Mobile Phase Handling
Degassing
❑ Before use, solvents should be degassed either off-line or
online to remove gases, dissolved air bubbles and oxygen.
❑ Air bubbles create difficulties for pumps (unstable delivery),
columns, and detectors.
❑ Dissolved O2 absorbs ultraviolet radiation in the 200-250 nm
wavelength range interfering with ultraviolet detection.
Gases interfere with pump & detector
120
inaccurate flow and inconsistent retention times noisy or drifting base lines
