Page 14 - Shimadzu Nexera Prep

High Separation via Preparative Recycling

Components Difficult to Separate can be Recovered at High Purity Levels and at Low Cost
Recycling Preparative System

What is the Recycling Separation Method?

Because long preparative columns are expensive, there is a need to use comparatively lower cost short columns.
In the recycling separation method (closed valve recycling), the eluate liquid containing the target components that has eluted
from the separation column is recycled into the column, enabling an equivalent separation capacity to that of a longer column.
Solvent delivery unit Detector
Column

Injector
Recycle
valve

Outlet
Recycle ow channels ow
channel
Mobile phase
Flow Lines for the Recycling Preparative System

The figure below shows the results of a seven-cycle recycling separation. In the first injection (typical separation), the separation
of the two components is insufficient (red area). However, when the column eluate is returned to the column from the detector,
it is separated a second time. If this recycling is repeated, the results obtained are equivalent to connecting a number of columns
in series corresponding to the number of repetitions. In this example, a 4.0 or better resolution was ultimately obtained with
seven recycling separation cycles (blue area).

First Elution

Second
Third
Fourth
Fifth
Sixth
Seventh

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 min

Example of the improvement in separation by recycling: The coeluting peaks (red) are completely separated (blue).
Flowrate : 10 mL/min
Detection wavelength : 254 nm
Column : Shim-pack ™ PREP-ODS(H) 20 mm I.D. × 250 mm L.
Mobile phase : Water/methanol = 1/9 (v/v)
Sample : Mixed 1% n-butylbenzene/iso-butylbenzene solution

14