Sensitive detection of urea and related compounds in water
AssigneeGE Analytical Instruments
InventorRichard D. Godec
Life of this patent
Estimating the term…
Abstract
Methods and apparatus (FIG. 4a) are disclosed for selective and very sensitive detection of certain hydrolyzable compounds, especially urea, in water by hydrolyzing said hydrolyzable compounds in a sample of the water to one or more carbon dioxide group compounds and determining the difference in the carbon dioxide content of the water and the hydrolyzed sample using conductivity measurements or other carbon dioxide detector outputs.
Claims32
Apparatus for estimating a measure as carbon dioxide of the total of carbon dioxide, carbonic acid, bicarbonate and carbonate released by hydrolysis of hydrolyzable entities dissolved and/or dispersed in water containing such entities based on comparison of a carbon dioxide measurement on a sample of said water before hydrolysis with a carbon dioxide measurement on a sample of said water after hydrolysis, such apparatus comprising:
- (a) a measuring system for obtaining a first measure of total concentration of carbon dioxide, carbonic acid, bicarbonate and carbonate using a sample of said water before hydrolysis, wherein said measuring system comprises in combination:
- (i) a CO2-selective measuring system membrane having juxtaposed to one surface thereof a flow path for deionized water;
- (ii) the membrane also having juxtaposed to an opposite surface thereof a flow path for said sample of water before hydrolysis;
- and, (iii) a conductivity measuring element for measuring electrical conductivity of water in said flow path for deionized water downstream of said measuring system membrane;
- (b) a hydrolysis system effective substantially to hydrolyze said hydrolyzable entities dissolved and/or dispersed in a sample of said water whereby a hydrolyzed sample is obtained comprising carbon dioxide, carbonic acid, bicarbonate and/or carbonate and other hydrolysis products;
- (c) a measuring system for obtaining a second measure of total concentration of carbon dioxide, carbonic acid, bicarbonate and carbonate using said hydrolyzed sample wherein said measuring system comprises in combination:
- (i) a CO2-selective measuring system membrane having juxtaposed to one surface thereof a flow path for deionized water;
- (ii) the membrane also having juxtaposed to an opposite surface thereof a flow path for said hydrolyzed sample;
- and, (iii) a conductivity measuring element for measuring electrical conductivity of water in said flow path for deionized water downstream of said measuring system membrane;
- and,
- (d) an estimating system for estimating from said first and second measures of total concentration of carbon dioxide, carbonic acid, bicarbonate and carbonate a measure as carbon dioxide of total carbon dioxide, carbonic acid, bicarbonate and carbonate released by hydrolysis of said hydrolyzable entities dissolved and/or dispersed in said water.
A method for estimating a measure as carbon dioxide of the total of carbon dioxide, carbonic acid, bicarbonate and carbonate released by hydrolysis of hydrolyzable entities dissolved and/or dispersed in water containing such entities based on comparison of a carbon dioxide measurement on a sample of said water before hydrolysis with a carbon dioxide measurement on a sample of said water after hydrolysis, said method comprising the steps of:
- (a) obtaining a first measure of total concentration of carbon dioxide, carbonic acid, bicarbonate and carbonate using a sample of water before hydrolysis by contacting said sample of water before hydrolysis with a surface of a CO2-selective measurement system membrane, the opposite surface of which is juxtaposed to a flow path carrying deionized water, and by measuring the electrical conductivity of water in said flow path carrying deionized water downstream of the measurement system membrane;
- (b) hydrolyzing said hydrolyzable entities dissolved and/or dispersed in a sample of said water whereby a hydrolyzed sample is obtained comprising carbon dioxide, carbonic acid, bicarbonate and/or carbonate and other hydrolysis products;
- (c) passing said hydrolyzed sample to a measurement system and then obtaining a second measure of total concentration of carbon dioxide, carbonic acid, bicarbonate and carbonate using said hydrolyzed sample by contacting said hydrolyzed sample with a surface of a CO2-selective measurement system membrane, the opposite surface of which is juxtaposed to a flow path carrying deionized water, and by measuring the electrical conductivity of water in said flow path carrying deionized water downstream of the measurement system membrane;
- and,
- (d) estimating from said first and second measures of total concentration of carbon dioxide, carbonic acid, bicarbonate and carbonate a measure as carbon dioxide of total carbon dioxide, carbonic acid, bicarbonate and carbonate released by hydrolysis of said hydrolyzable entities dissolved and/or dispersed in said water.
Dependencies are inferred from the claim text.