Waters Styragel Columns - Manual (Page 9)

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Styragel Columns 9
2) Column Efficiency Test
The column-efficiency test described below may be used to calculate a theoreti-
cal plate count, which is a measurement of column efficiency within your system.
Solvents
It is not necessary to use the solvent that your column is shipped in to deter-
mine the efficiency of your column. Initial plate counts that are determined
using different solvents will have different values. Test columns individually
using your normal operating solvent.
Test procedure
To perform a column efficiency test:
1. Slowly increase the flow rate to 1.0 mL/min for the HR 0.5,
HR 1, HR 2, and HR 4E columns, or to 2.0 mL/min for all
other columns.
2. Adjust the detector to an attenuation that achieves a peak of 70
percent full scale (noise level <0.5 percent full scale).
3. Set the recorder chart speed to 50 mm/min, or the data system
sampling rate to at least 5 data points per second.
4. Inject up to 20 µL of marker solution. Use a solution of up to 10
percent marker in solvent. Use up to 5 µL for solvent efficient
columns.
Refer to Table 4, Table 5, or Table 6 for the marker to use when performing
the efficiency test.
5. Record the retention time, instrument settings, and column con-
figuration so you can reproduce them exactly for comparison in
the future.
6. Compute the plate count using the tangent method (see
Figure 6). Use these results for comparison throughout the life
of your column.
7. Replace any column that exhibits a plate count more than 30
percent below the original value.
Table 4. Conditions and sample for 7.8 mm for Column Efficiency Test:
HR Columns
1
Dicyclohexylphthalate
Table 5. Conditions and Sample for 4.6 mm Column Efficiency Test:
HR Columns
Column
Type
Toluene THF DMF
Flow Rate
mL/min
HR 0.5 Acetone Propylbenzene Ethyleneglycol 1.0
HR 1 Acetone Propylbenzene Ethyleneglycol 1.0
HR 2 Acetone Propylbenzene Ethyleneglycol 1.0
HR 3 ODCB Acetone Acetone 2.0
HR 4 ODCB Acetone Acetone 2.0
HR 4E Acetone Propylbenzene Ethyleneglycol 1.0
HR 5E DCHP2 Acetone Acetone 2.0
Column
Type
Toluene THF DMF
Marker
Flow Rate
(mL/min)
Marker
Flow Rate
(mL/min)
Marker
Flow Rate
(mL/min)
HR 0.5 ODCB 0.3 Acetone 0.3 Acetone 0.3
HR 1 ODCB 0.3 Acetone 0.3 Acetone 0.3
HR 2 ODCB 0.3 Acetone 0.3 Acetone 0.3
HR 3 ODCB 0.3 Acetone 0.3 Acetone 0.3
HR 4 ODCB 0.3 Acetone 0.3 Acetone 0.3
HR 4E ODCB 0.3 Acetone 0.3 Acetone 0.3
HR 5E DCHP 2 0.3 Acetone 0.3 Acetone 0.3