Preparation of analytical samples by liquid-liquid extraction using microporous hollow-fiber membranes
AssigneeSymBiotech Incorporated
InventorsRobert W. Coughlin, Edward M. Davis
Life of this patent
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Abstract
Method and apparatus are provided for accomplishing improved liquid-liquid extraction employing microporous hollow-fiber membranes. A number of possible modes of liquid-liquid extraction are possible according to the invention.
Claims23
A method of extracting a solute from a sample liquid through at least one microporous hollow fiber membrane and into a solvent liquid that is immiscible with said sample liquid, each of the liquids being in contact with an opposite side of the membrane, wherein the extraction is conducted as a batch operation for preparing a small laboratory sample, as for assay, comprising the steps:
- (a) placing said sample liquid in contact with one side of said membrane and said solvent liquid on the other side of said membrane, or within the pores of said membrane, so as to form an interface between the two liquids at or within said membrane,
- (b) mixing at least one of the liquids while it is in contact with said membrane,
- (c) extracting said solute from said sample liquid into said solvent liquid,
- (d) conducting an additional step chosen from the group consisting of:
- (i) back extracting said solute from said solvent liquid into a stripping liquid that is immiscible with said solvent liquid, and
- (ii) evaporating at least a portion of said solvent liquid.
In a process for liquid-liquid extraction of a solute using at least one microporous hollow-fiber membrane, a method for improving the selection of mode of operation from among more than one possible mode using a computer system, comprising the steps:
- (a) selecting and inputting values of parameters characteristic of a liquid-liquid extraction system and the desired volumes of feed liquid, product liquid, solvent liquid and pore volume of said hollow fiber membrane, said values being transferred from an input device means to a memory means,
- (b) selecting an appropriate mass balance relationship for each mode of operation contemplated, said relationship residing within said memory means,
- (c) computing CR or RR values using said mass-balance relationships selected in step b and said values inputted in step a,
- (d) outputting said values of CR and RR computed in step c for use in selecting a mode of operation.
An improved method of preparing a small volume of sample fluid for assay of a solute therein by extracting said solute from said sample fluid through at least one porous hollow fiber membrane and into a solvent fluid that is immiscible with said sample fluid, comprising the steps:
- (a) placing said sample fluid in contact with one side of the membrane and said solvent fluid on the other side of said membrane, or within pores in said membrane, so as to form an interface between the two fluids at or within said membrane,
- (b) mixing at least one fluid while it is in contact with said membrane,
- (c) extracting said solute from said sample fluid into said solvent fluid, and
- (d) conducting an additional step chosen from the group consisting of:
- (i) removing at least a portion of one of the fluids from said membrane and assaying the removed fluid for said solute,
- (ii) back extracting said solute from said solvent fluid into a stripping fluid that is immiscible with said solvent fluid, and
- (iii) evaporating at least a portion of said solvent fluid.
Dependencies are inferred from the claim text.