Flow-through electrochemical system analytical method
First Claim
1. 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;
- subsequentlyseparating 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;
subsequentlyflowing 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.
1 Assignment
0 Petitions
Accused Products
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.
635 Citations
11 Claims
-
1. 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;
subsequentlyflowing 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- subsequently
-
10. A method of electrochemically measuring the concentration of relatively low mass electroactive species of interest in a sample stream in the presence of high and low mass interfering species, comprises the steps of:
-
providing a flow path over a membrane protected electrode means wherein said membrane has a molecular mass diffusion cutoff such that said high mass molecules with masses higher than the molecular mass cutoff are excluded from the electrode;
then precisely controlling the flow rate of said sample stream so that the diffusion ratio of the low mass interfering species and the low mass electroactive species of interest is such that substantially all of said low mass interfering species is excluded from said electrode means;
thenmeasuring the response of said electrode means to the electrochemical reaction of said low mass species of interest at said electrode means. - View Dependent Claims (11)
-
Specification