US 4,172,770 AGranted

Flow-through electrochemical system analytical method

AssigneeTechnicon Instruments Corporation

InventorsFrank E. Semersky, Barry Watson

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Abstract

An electrochemical system using a flow-through electrode design employing a dual separation method to lower electrode poisoning due to large chemical species and interference current due to small electroactive species is disclosed. The system includes a fluid inlet to a reaction chamber and a fluid outlet from the chamber, with the chamber in contact with an electrode system. The electrode is protected from poisoning and interference by a membrane system comprising a semipermeable membrane having well defined pore ranges therethrough which allow diffusion of only selected size small molecules. A unique sample stream flow control coupled with the size selective membrane combine to remove large, or macromolecule poisoning species and substantially reduce small species interference at the active surfaces of the electrode means.

Claims11

Dependent claims

A method of determining the solution concentration in a sample liquid stream of an electroactive species in the presence of at least one interfering electroactive species comprising placing an electrode means adjacent a flow-through type reaction chamber;

subsequently
separating said electrode means from said reaction chamber by a membrane system comprising at least one layer of a membrane material which has pores therethrough which allow selective diffusion across said membrane system, said membrane material permitting diffusion therethrough of said at least one interfering electroactive species at a lower rate than said electroactive species;
subsequently
flowing a sample stream adjacent to said membrane system at a predetermined flow rate to allow diffusion of said electroactive species from said reaction chamber to said electrode means to the substantial exclusion of said at least one interfering electroactive species;
monitoring the response of said electrode means;
and
flowing a buffer stream adjacent to said membrane to allow diffusion of said electroactive species and said at least one interfering electroactive species into said buffer stream preparatory to the flowing of a different sample liquid stream adjacent said membrane for determining the solution concentration of said electroactive species therein.

4 more elements

Dependencies are inferred from the claim text.