The Dow Chemical Company

Mark W Spence

Timothy S Stevens

Andrew J Strandjord

Robert A Bredeweg

Brenton S Coyne

Reid S Willis

The invention relates to a membrane assisted analytical chemical method for the determination of the concentration of an organic compound in an aqueous matrix. The membrane partitions the matrix from a receiving fluid. The organic compound permeates the membrane and passes into the receiving fluid which is then analyzed for the permeated compound by, for example, liquid or gas chromatography. The membrane is selected to prevent contamination of the receiving fluid from otherwise interferring components of the matrix. The concentration of the organic compound is above its solubility limit in water which would ordinarily prevent effective use of such a membrane assisted method. However, when the organic compound is emulsified with, for example, a surfactant, then a membrane assisted method is successful. The sensitivity of the method can be improved by using a thermal focusing/gas chromatography technique to concentrate the permeated organic compound from the receiving fluid and the membrane can be protected from physical damage by enclosing it in a perforate structure.

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Midland, MI, United States of America

Mark W Spence