Chemistry: analytical and immunological testing – Including sample preparation – Liberation or purification of sample or separation of...
Reexamination Certificate
2001-02-02
2003-09-02
Ludlow, Jan (Department: 1743)
Chemistry: analytical and immunological testing
Including sample preparation
Liberation or purification of sample or separation of...
C422S081000, C422S082000, C422S105000, C436S052000, C436S053000
Reexamination Certificate
active
06613579
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to instrumental chemical analysis. More particularly, the present invention relates to an automated instrumental apparatus and method for carrying out sequential injection liquid-liquid extraction. The principal advantages of this automated technology over the prior art are elimination of the need for dynamic phase separation; on-line pre-extraction chemical conditioning; a substantial reduction in solvent, reagent, and sample usage; and a similar substantial reduction in waste generation.
SUMMARY OF THE INVENTION
In general, the present invention in a first aspect provides an apparatus for sequential injection liquid-liquid extraction. The apparatus comprises (a) a bidirectional precision pump for controlling fluid flow; (b) a holding/mixing coil, for holding and mixing liquids, and carrying out liquid-liquid extraction; (c) a selection valve, for withdrawing, transferring, and injecting a plurality of fluids; (d) a separation cell, for separating an extract phase from a raffinate phase; (e) a detector, for detecting the quantity of a component which was extracted from a sample by an extraction solvent; and (f) a microprocessor, for controlling the selection valve and the bidirectional precision pump.
In a second aspect the invention provides a method for sequential injection liquid-liquid extraction. The method comprises (a) using a bidirectional precision pump under suction to transfer a sample through an inlet line to a holding/mixing coil, to purge the inlet line; (b) discharging the sample from the holding/mixing coil; (c) flushing the holding/mixing coil with a carrier solvent, to remove residual sample; (d) disposing a plurality of liquid zones in the holding/mixing coil, using a microprocessor to control the selection valve; (e) mixing the zones and providing efficient contact between an extraction solvent and the sample by passing the plurality of liquid zones through the holding/mixing coil; (f) reversing the flow through the holding/mixing coil, to provide further mixing of the zones and further liquid-liquid contact between the extraction solvent and the sample; (g) transferring the liquid zones from the holding/mixing coil to a separation cell; (h) holding the liquid zones in the separation cell, to separate an extract phase from a raffinate phase; (i) withdrawing the extract phase from the separation cell; (j) transferring the extract phase to a detector, for determining the quantity of a component extracted from the sample; and (k) determining the amount of the component extracted by measuring the response of the detector.
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Global FIA, Inc.
Ludlow Jan
Roberts, Jr. Reginald F.
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