Chemistry Reference
In-Depth Information
modern method development systems typically require a column heater module. It is
also an advantage for the column module to accommodate several columns of vari-
ous geometries that can be randomly accessed from a software-controlled solvent
switching valve. For UHPLC, the column module should also have the capability
of adequately preheating the mobile phase without adding too much dispersion to
prevent band broadening within the column.
3.4.8 c
olumnS
for
m
ethod
d
eveloPment
The myriad of column stationary phases available may at first make choosing a col-
umn for method development seem like a daunting task. There are, however, a few
basic guidelines to keep in mind, and some tools available, which make the task
much simpler.
During method development, the primary goal is to manipulate selectivity for
the analytes of interest. In order to do that, it is important to choose columns that
are orthogonal. For column screening, common columns might include a selection
of C
18
, phenyl, an embedded polar group stationary phase, and perhaps a column
selected for highly polar compounds or a C
8
. Many column vendors provide column
selectivity charts, which can provide valuable information about columns that are
similar, or different, in selectivity. The USP also provides information of this type;
as shown in Figure 3.13, the USP maintains a searchable database of column evalu-
ations on their website that can also be used to find both equivalent or orthogonal
(different) columns (for validation and development, respectively) [26].
PQRI Database
Symmetry C18 (Waters)
You have the option to see the columns that are the most similar to the column of your interest, or the columns that are the most
different (for applications in orthogonal methods), by selecting View Different or View Similar.
You are viewing different columns.
View Similar
�e database will automatically display the first 10 columns that, theoretically, could be equivalent or very different to/from your
column, depending on the option you selected. �e column with rank 0 is your column. �e smaller the F value more similar
are the columns, at least theoretically. �e higher the F value more different are the columns.
USP
Designation
Rank
F
Column
H
S
A
B
C(2.8) C(7.0) Type
Manufacturer
0
0
Symmetry C18
1.052
0.063
0.018
-0.021
-0.302
0.123
B
EP
EP
L1
Waters
Macherey
Nagel
1
246.6
EC Nucleosil 100-5 Protect 1
Zorbax Bonus RP
Hypersil Prism C18 RP
ZirChrom-PBD
ZirChrom-EZ
Apex II C18 (ODS??)
Inertsil CN-3
Resolve C18
ZirChrom-PS
Supelcosil LC-18
0.544
0.048
-0.411
0.309
-3.213
-0.573
2
230.89
0.654
0.107
-1.046
0.373
-2.971
-1.103
Agilent
�ermo
Scientific
3
214.32
0.645
0.089
-0.459
0.301
-2.817
-0.716
EP
Other
Other
L1
4
207.39
1.284
0.158
-0.384
-0.072
2.188
2.188
ZirChrom
5
200.88
1.04
0.117
-0.999
-0.001
2.089
2.089
ZirChrom
6
7
195.98
193.68
1.008
0.369
-0.074
0.049
0.235
-0.808
0.123
0.083
2.039
-2.607
2.69
-1.297
A
CN
L1
L10
Grace-Jones
GL Science
8
185.77
0.968
-0.127
0.335
-0.046
1.921
2.144
A
L1
Waters
9
173.99
0.589
-0.232
-0.477
0.062
1.75
1.75
Other
ZirChrom
10
160.06
1.018
-0.047
0.181
0.162
1.595
1.752
A
L1
Supelco
FIgure 3.13
USP Column Equivalency Database. Searchable database of column infor-
mation that can be used to find orthogonal/different (for method development) or similar (for
method validation) columns. (See http://usp.org/USPNF/columnsDB.)
