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Biotage

Selekt User Manual | © Biotage 2018

Set Up a Purification

Gradient Parameters

CV/mL/mm:ss:

The gradient length unit. CV (column

volumes), milliliters, or minutes and seconds; see Figure 12.

Start:

The percentage of Solvent B at the

beginning of the gradient segment.

End:

The percentage of Solvent B at the

end of the gradient segment.

Length:

The length of the gradient segment.

Solvent A and B:

The solvents to be used.

Equil.:

The column is equilibrated before the run, unless

this options is turned off. The equilibration volume and
flow rate are set automatically and have been optimized
for the selected column type. To see the settings,
expand the

Column

panel (see Figure 14). We strongly

recommend that the equilibration is not turned off.

Figure 12.

The gradient length unit can be selected in the gradient table.

Calculate a Gradient from TLC Data

Note the following when using the TLC to Gradient editor:

Accuracy of prediction can be reduced if using
alcohols, such as methanol and ethanol, very volatile
modifiers such as diethyl ether, or modifiers that
permanently alter the properties of the silica.

Reversed-phase TLC is not supported.

Slight variations in migration rates may occur if samples are
applied too close to the edge of the TLC plate. Apply samples
at least 10 mm from the edge to avoid the edge effect.

To calculate a purification gradient from the R

values obtained

from a TLC analysis:

1. Open the

TLC to Gradient

editor (see Figure 13) by

pressing

TLC

2. Select the

Strong Solvent

text box and enter the percentage

of the strongest (most polar) solvent in the TLC analysis.

3. Mark the solvent front of the TLC plate by sliding the

Front

line to the correct position.

4. Enter the R

value of the product of interest in the

Product

text box or by sliding the

Product

line to the correct position

on the TLC plate.

5. Enter the R

value of the impurity closest below and above

the product in the

Impurity 1

and

Impurity 2

text boxes

or by sliding the corresponding lines to the correct positions
on the TLC plate. A value for R

Impurity 1 is required.

6. If you have two plates, press

Add Plate

and repeat steps

2 through 5 for the second plate. One plate gives a linear
gradient and two plates give a step gradient.

7. To calculate a purification gradient and the column load

capacity, press

Create

Figure 13.

The TLC to Gradient editor.

Specify the Information Parameters

User:

The name of the user. If you have not been assigned

a user name, please contact your system supervisor.

Run Name:

The name of the run. If left blank, the

name will be auto-generated based on date and
time when the purification is performed.

Comments:

Comments on the purification run. (Optional)

Specify the Column Parameters

Sample Mass:

The crude sample mass.

Column Type:

The column type. Either scan the

column using the QR reader underneath the touch
screen or select a column type from the drop-down
list. If the column name is orange or red, its load
capacity is smaller than the entered sample mass.

Flow Rate:

The default (recommended) flow rate

for the selected column type is preselected. If you
want to change it, consider that the maximum flow
rate that can be used depends on the following:

The column and any other accessories used in the setup.

The maximum aspiration rate(s)
defined for the used solvent(s).

Note:

If you expand the

Column

panel, all of the settings for the

selected column type are displayed (see Figure 14). For more
information, see “Manage Column Types” on page 13.