Waters Viridis SFC Columns - Manual (Page 5)

[ Care and Use ManUal ]
5 Viridis SFC Columns
b. Band-Spreading Minimization
Figure 5 shows the influence of tubing internal diameter on system
band-spreading and peak shape. As can be seen, the larger tubing
diameter causes excessive peak broadening and lower sensitivity.
Figure 5: Effect of Connecting Tubing on System
Diluted/Distorted Sample Band
0.005 inches
0.020 inches
0.040 inches
VI. tRoUBLesHootInG
1. One of the most common problems with regards to columns is
incorrect or non-priming of the co-solvent/modifier pump. If
no peaks are observed after an injection or unusually long
retention times occur, check the priming of the co-solvent/
modifier pump first.
2. If you see frosting on the column at the inlet or outlet, tighten
the compression screw on that side. If tightening doesn’t work,
depressurize the system and the column then replace the fitting
that is not sealing correctly.
3. If you see frosting on the column, turn off the CO
2
and vent the
system. Allow the column to depressurize fully before discon-
necting the inlet or outlet. Please contact your Waters repre-
sentative for additional support.
4. Excessive flow rates could damage the internal frits and accel-
erate column failure. Try to keep the pressure drop (∆P) below
100 bar across the column.
VII. CoLUMn CLeAnInG, ReGeneRAtInG AnD stoRAGe
a. Cleaning and Regeneration
Changes in peak shape, peak splitting, shoulders on the peak, shifts
in retention, change in resolution or increasing backpressure may
indicate contamination of the column. Flushing with a neat organic
solvent, taking care not to precipitate additives, is usually suffi-
cient to remove the contaminant. If the column performance is poor
after regenerating and cleaning, call your local Waters office for
additional support.
b. Storage
1. Ensure all additives are removed from the column by flushing
with an appropriate organic solvent. Allow the column to sta-
bilize at room temperature before pumping the desires single
solvent through the column for storage.
2. Do not store columns that might be under pressure or can
thermodynamically become pressurized.