Modular SFC - Enabling SFC with Convenient HPLC-like Fraction Collection

Technology

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Novel Centrifugal Technology Overcomes the Complexities and Inconvenience of Conventional SFC Fraction Collection

Modular SFC’s patent pending fraction collector technology provides HPLC-like fraction collector convenience for SFC applications. The novel centrifugal fraction collection system operates at atmospheric pressure and uses standard laboratory glass containers to capture the non-volatile components from the gaseous CO₂ eluant stream with greater than 90% recovery.

The patent pending methodology is based on a rotor that spins at 1,500 rpm (concentrator speed) and contains up to 24 disposable glass fraction collection tubes. Flexible tubing directs the eluant flow into each sample collection container in turn. The eluant tube dispenses eluant having volatile and non-volatile compounds (even solid precipitates) from the connected SFC system. The centrifugal force causes the highest density components (liquids and solids) to accumulate in the bottom of the collection container while allowing the expanded gaseous components to escape from the opening of the container.

WASTE/COLLECT and NEXT FRACTION controls are enabled by contact closure outputs on the SFC instrument and executed while the carrier is spinning at 1,500 rpm. Future versions will be internally programmable to operate these functions by time or by detecting peak height thresholds generated by an analog output from the SFC system’s detector.

Centrifan Provides Simultaneous Fraction Drying with Fraction Collection
The CFC-3's Centrifan (patent pending) blows rotor chamber gas into the collection tubes while fractions are being collected. Centrifugal force generated by the rotor captures non volatile sample particles from the eluant flow stream. The centrifugal force also maintains fraction integrity as the Centrifan delivers more than 50L per minute of airflow or inert gas to the fraction solutions. Drying rates with water at room temperature are 2.5 mL/hr./container, fully 5x higher than the room temperature rate delivered by popular vacuum- centrifuges. The rotor chamber is at atmospheric pressure during the collect/dry operation so no vacuum pump is required.

Video Demonstration (please click play button to view)

A flexible tube contains eluant flow from a connected SFC system and dispenses eluant having volatile and non-volatile compounds. Fractions are collected while the centrifugal sample carrier is spinning at 1500 rpm (click the play button to view video of NEXT FRACTION tube change mechanism).	To demonstrate the efficacy of the novel eluant dispensing system, a camera was installed on the rotor with the ability to capture the process while the centrifugal sample carrier was spinning at 1500 rpm (click the play button to view video of camera setup).	The centrifugal force causes the highest density components (liquids and solids) to migrate to the bottom of the collection container while allowing the expanded gaseous components to escape from the opening of the container. Vapors are directed through a vent hose to the nearest exhaust facility. (click the play button to view video of collection with and without centrifugal force).

* Centripetal vs. Centrifugal footnote:

The question is often asked, “Doesn’t centripetal, not centrifugal, force capture the non-volatile compounds in the collection containers?” The answer is that it all depends on the observer’s frame of reference.

When taking a hard right while driving, physics describes the car applying a “real” centripetal force to the driver to make the person change direction. Alternatively, the apparent feeling that the driver’s shoulder is pushing outwards on the car door is the “fictional” centrifugal force.

The bottom line is that 500 years of instrument naming convention has resulted in calling the laboratory equipment which performs density separations by spinning containers a centrifuge. Therefore, Centrifugal Fraction Collector is what everyone would expect the CFC-3 instrument to be called. Any other name would be a distraction.