Waters MassPREP Micro Desalting Column - Manual (Page 2)

This configuration would leave the cartridge operating at room
temperature. The other configuration is to screw the cartridge
into one end of the included union connector. The connection of
proper tubing to the other end of the union connector would allow
the cartridge to be placed into a column heater to control the
desalting temperature.
III. LC /MS SYST EM CONFIGURATION TO
MINIMIZE MS SOURC E CONTAMINATION
Non-volatile salts (e.g., NaCl) can suppress protein ionization
and foul the ionization source of the mass spectrometer. It
is, therefore, important to avoid the introduction of these
compounds into the mass spectrometer. Figure 1 details an LC/MS
configuration that can effectively be used to load sample onto the
column and elute salt to waste prior to valve switching and protein
elution into the mass spectrometer.
Position 1: Sample Loading and Salt Elution to Waste
Gradient
UPLC/HPLC
System
MassPREP
Micro
Desalting
Column
Mass
Spectrometer
Waste
Position 2: Sample Elution to Mass Spectrometer
Gradient
UPLC/HPLC
System
MassPREP
Micro
Desalting
Column
Mass
Spectrometer
Waste
Figure 1. LC/MS Valve Switching Configuration for Use of MassPREP
Micro Desalting.
IV. USING MASSP REP MIC RO DESALTING
COLUMN TO MINIMIZE P ROT EIN CARRYOV ER
BET W EEN INJECTIONS
LC injector design, composition of injector wash solution, and
number of injector wash cycles between injections are some of the
factors that can effectively minimize protein carryover between
sample analyses. Waters MassPREP Micro Desalting Column, when
used with an appropriately performing UPLC/HPLC system and
injector wash protocol, can be used for the sequential analyses
of different samples due to the removal of protein carryover from
prior injections.
V. GUIDELINES FOR USE
1. Initial Column Conditioning. Prior to use, the MassPREP Micro
Desalting Column reversed-phase packing material must be
“wet” with organic solvent prior to equilibration with 95%
Eluent A / 5% Eluent B (e.g., Eluent A = 0.1% formic acid in
MS grade H20 and Eluent B = 100% Acetonitrile). This can
be accomplished by running a “blank injection” (i.e., Eluent A
injection followed by running the separation gradient) or by
washing the column with a minimum of five column volumes
(~20 µL) of 50% Eluent B followed by a ten column volume
equilibration at 95% Eluent A / 5% Eluent B prior to sample
injection.
2. The maximum recommended operating pressure for MassPREP
On-Line Desalting Cartridge, when configured WITHOUT
pre-column tubing, is approximately 150 psi. Use of pressure
generating tubing immediately before the MassPREP On-Line
Desalting Cartridge is required to generate sufficient UPLC
System back pressure for proper functioning. Thus, the total
reported UPLC System backpressure generated when BOTH the
pre-column tubing and MassPREP On-Line Desalting Cartridge
are configured for an application is approximately 5700 psi at
a flow of 0.5 mL/min with a 5% ACN/0.1% FA eluent.
3. Results obtained with Waters MassPREP Micro Desalting
Columns can vary depending upon the physical characteristics
of the analyzed proteins as well as on the performance
characteristics of the HPLC (or UPLC/MS System), injector, and
injector wash protocol used.
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[ CARE AND USE MANUAL ]
MassPREP Micro Desalting Column