Waters XSelect CSH130 C18 3.5 μm and 5 μm Columns - Manual (Page 3)

[ CARE AND USE MANUAL ]
XSelect CSH130 C
18
Columns 3
II. COLUMN USE
To ensure the continued high performance of XSelect CSH130 C
18
Columns,
follow these guidelines:
a. Guard Columns
Use a Waters guard column of matching chemistry and particle size between
the injector and main column. It is important to use a high performance
matching guard column to protect the main column while not compromising
or changing the analytical resolution.
Guard columns need to be replaced at regular intervals as determined by
sample contamination. When system backpressure steadily increases above
a set pressure limit, it is usually an indication that the guard column
should be replaced. A sudden appearance of split peaks is also indicative
of a need to replace the guard column.
b. Sample Preparation
1. Sample impurities often contribute to column contamination.
One option to avoid this is to use Waters Oasis ® solid-phase
extraction cartridges/columns or Sep-Pak ® cartridges of the
appropriate chemistry to clean up the sample before analysis.
2. It is preferable to prepare the sample in the operating mobile
phase or a mobile phase that is weaker (less organic modifier)
than the mobile phase for the best peak shape and sensitivity.
3. If the sample is not dissolved in the mobile phase, ensure that
the sample, solvent and mobile phases are miscible in order to
avoid sample and/or buffer precipitation.
4. Filter sample with 0.2 µm filters to remove particulates. If the
sample is dissolved in a solvent that contains an organic modifier
(e.g., acetonitrile, methanol, etc.) ensure that the filter material
does not dissolve in the solvent. Contact the filter manufacturer
with solvent compatibility questions. Alternatively, centrifugation
for 20 minutes at 8,000 rpm, followed by the transfer of the
supernatant liquid to an appropriate vial, could be considered.
c. Operating pH Limits
The recommended operating pH range for XSelect CSH130 C
18
, 3.5 µm
and 5 µm columns are 1 to 11. A listing of commonly used buffers and
additives is given in Table 2. Additionally, the column lifetime will vary
depending upon the operating temperature, the type and concentration of
buffer used.
Column internal diameter (mm)
Column Length (mm) 1.0 2.1 4.6 10 19 30 50
50 0.04 0.17 0.83 3.9 14 35 98
100 0.08 0.35 1.7 7.8 28 70 196
150 0.12 0.52 2.5 12 42 106 294
Table 1: Empty Column Volumes in mL (multiply by 10 for flush solvent volumes)