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CycloGraph Centrifugal Chromatography System

1st April 2013


The CycloGraph system is a centrifugally accelerated device for performing preparative chromatographic separations. The device spins a layer of adsorbent material coated as a flat ring on a glass backing. A solvent pump is used to apply the sample and mobile phase to the centre of the spinning adsorbent ring. The centrifugal action accelerates the flow of the mobile phase through the adsorbent, separating the sample components as circular bands.

The mobile phase elutes continuously into a specially shaped collection channel inside the body of the instrument. Component bands are collected manually in test tubes or optionally by an automated fraction collector (not included). Separations occur quickly, usually within 20 minutes, versus the typical 90 to 120 minutes for preparative Thin Layer Chromatography (TLC) or Column Chromatography.

Features:

 

  • Variable speed motor (100-1400 RPM)
  • Integrated 4-watt UV lamp for hands-free viewing of the sample
  • On/Off switches for the motor and UV lamp
  • Adjustable plane angle setting of vessel(0-30 degrees)
  • Ultra quiet & accurate low flow solvent pump (0-15ml/min)
  • Compatible with all common chromatography solvents including acetic acid
  • Easily detachable chamber for submersible cleaning

 

Advantages

 

  • The CycloGraph centrifugal chromatography system combines the advantages of both preparative TLC and Column Chromatography. It delivers fast, efficient separations. Most separations occur in twenty minutes or less.
  • Fast separations are a result of the centrifugal action of the spinning Rotor driving the mobile phase through the adsorbent layer. The velocity of the mobile phase enables the use of smaller particle adsorbents. The Rotors for the CycloGraph use a 15 micron average particle adsorbent bed, similar to TLC. This smaller particle bed versus the 35-75 micron cut typical of low pressure column chromatography allows a higher degree of separation efficiency.
  • Centrifugal action combined with the use of a solvent pump to apply the mobile phase allow complete control of solvent velocity profile. Typical flow rates are in the range of approximately 2 - 3 ml/min per millimeter of adsorbent thickness. Tight bands mean eluted fractions can be collected in a minimum volume of solvent.
  • The solvent metering pump also makes the use of step gradients easy to perform with the CycloGraph. The inlet of the pump may be switched from a weak solvent to a more polar solvent during a run. This enables compounds with a wide range of polarities to be separated. Complex samples such as natural products are quickly separated into component classes.
  • Sweeping the polarity of the mobile phase from weak to strong makes it easy to reuse a Rotor for many sample separations. By concluding the run with a strong solvent, otherwise strongly adsorbed compounds will be flushed from the Rotor. This enables a Rotor to be reused for dozens of samples.
  • Separations on the CycloGraph scale easily and quickly. Rotors are available from 1 mm thick up to 8 mm thickness. For difficult cases, eluted components that are only partially resolved, can be cycled back onto the spinning Rotor. This effectively allows the chromatographer to increase "the length of the column" without the associated disadvantages. Separations on the CycloGraph can be monitored as they happen with the built in UV254 lamp.
  • Separated substances which absorb 254 nm light will be visible against the fluorescent green background of the Rotor. Optionally a UV366 source may be used to detect intrinsically fluorescent components. Chemical integrity of sensitive sample components can be preserved even with the use of active silica gel adsorbents.
  • Unlike TLC where the sample solvent is evaporated before chromatography, the sample introduced on CycloGraph need never be exposed to dry adsorbent. This minimises the possibility of reaction of sample components on the active adsorbent surface.
  • Further control of the atmosphere is possible by flushing the vessel with nitrogen gas during chromatography.




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