Waters Dextro-Pak Cartridge - Manual (Page 6)

[ Care and Use ManUal ]
Dextro-Pak Cartridge 6
IX. operatIng tIps
• The usual flow rate is 1 mL/min. Slower flow rates will produce
slightly improved separations. Faster flow rates are limited
only by the permissable upper limit of the 8x10 Holder.
• Dedicate your cartridge to sugar analysis. Using the cartridge
for other reversed-phase analyses may adversely affect its abil-
ity to properly separate sugars.
• Avoid strong solvents to prolong useful cartridge life. The water
mobile phase will hydrolyze the bonded phase very slowly.
Solvents such as 100% methanol or acetonitrile may wash off
some of the hydrolyzed bonded phase, with a consequent partial
loss of retention. Rely on guard columns to protect the cartridge
from adsorbed compounds and stray particulate matter.
• If it is necessary to wash the cartridge, use a mobile phase of
20% acetonitrile/80% water. Because this is a weak solvent,
the hydrolyzed bonded phase remains in place and continues to
provide the required sample retention.
X. Care & t roubleshootIng proCedures
a. Column Storage
If the Dextro-Pak cartridge is to be stored for a significant period (up
to 12 hours), lace the effluent line in the mobile phase supply vessel
and recirculate the mobile phase at a reduced flow rate o 0.2 ml/
min.
b. Long Term Storage
• If it is necessary to store the cartridge for an extended length
of time (more than 12 hours), a 20:80 acetonitrile: water
mixture will inhibit microbial growth during cartridge storage.
If stored in this manner; the Dextro-Pak cartridge is ready for
immediate use once the solvent is flushed from the system.
• If the cartridge is removed from the 8x10 Holder, it must be
sealed with the caps originally supplied with the cartridge.
• If the cartridge dries out during storage, re-wet the cartridge
using the startup procedure. To avoid drying of the cartridge,
store in a stoppered test tube filled with 20:80 acetonitrile:
water. This will also ensure that no microorganism growth will
occur inside the packing.
IN
JE
CT
W
V R
N
V R
W = Column efficency (plates)
= Volume to peak apex (mL)
= Volume at 4.40% of peak height (mL)