Instrument for measurement of the organic carbon content of water
First Claim
1. Apparatus for measurement of total organic carbon contained by a sample of deionized water, comprising:
- a sample cell having a window;
a source of ultraviolet radiation of a frequency which causes oxidation of organic carbon compounds in a water sample disposed in juxtaposition to said window, the window being substantially transparent to said radiation;
a pair of electrodes disposed in said sample cell;
means rendered photocatalytic active in response to said ultraviolet radiation for providing oxidative species in said sample cell;
means for monitoring the electrical conductivity of the water between said electrodes and means for correlating the conductivity of the water sample to its total organic carbon content.
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Accused Products
Abstract
Apparatus and methods for measurement of total organic carbon content of water, particularly of low relative organic content, are described, featuring a single sample cell for exposure of a static sample to ultraviolet radiation and comprising electrodes for measuring the conductivity of the water. The conductivity is monitored as a function of time and the second time derivative of the conductivity signal is monitored to indicate when the oxidation reaction has been completed. Compensation for the contribution to conductivity of the water sample made by the instrument is achieved by subtracting a quantity proportional to the first time derivative of the conductivity at a time when the second time derivative reaches zero, indicating that the oxidation reaction is complete, from the change in the total conductivity measurement, the remainder being equal to the contribution to conductivity made by oxidation of the organic content of the water. The electrodes may have surfaces of a material which when irradiated by the ultraviolet radiation catalyzes the oxidation reaction. Electrophoresis may also be employed to speed the reaction.
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Citations
63 Claims
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1. Apparatus for measurement of total organic carbon contained by a sample of deionized water, comprising:
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a sample cell having a window; a source of ultraviolet radiation of a frequency which causes oxidation of organic carbon compounds in a water sample disposed in juxtaposition to said window, the window being substantially transparent to said radiation; a pair of electrodes disposed in said sample cell; means rendered photocatalytic active in response to said ultraviolet radiation for providing oxidative species in said sample cell; means for monitoring the electrical conductivity of the water between said electrodes and means for correlating the conductivity of the water sample to its total organic carbon content. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. Apparatus for monitoring organic carbon contained by samples of a water stream in a real time, on-line manner, comprising:
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a first conductivity cell, comprising first and second electrodes in a chamber for measuring the conductivity of a water sample in said chamber; a source of ultraviolet radiation; an ultraviolet exposure chamber, in which a sample of water may be exposed to ultraviolet radiation from said source; catalyst means activated upon exposure to said ultraviolet radiation for supply of oxidative radicals to said ultraviolet exposure chamber; a second conductivity cell, comprising first and second electrodes in a chamber for monitoring the conductivity of water in said cell; and means for comparing the conductivity in said second cell to the conductivity measured in the first cell, and for determining the amount of organic material present in said water sample as a function of the change in conductivity of said water sample resulting from irradiation of said water sample and said catalyst means in said exposure chamber with ultraviolet radiation from said source. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. An apparatus for measuring total organic carbon contained in a steam of deionized water, comprising:
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a sample cell, said cell comprising a window formed of a material transparent to ultraviolet radiation; a pair of electrodes disposed in said sample cell, said electrodes having surfaces of a material which when irradiated by ultraviolet radiation of known wavelength catalyzes the oxidation of organic materials; a source ultraviolet radiation including at least a portion of said known wavelength disposed in juxtaposition to said window; means connected to said electrodes for monitoring the conductivity of water in said sample cell; wherein said electrode surfaces are arranged so as to be directly exposed to incident ultraviolet radiation from said source; and means for correlating the monitored conductivity to the total organic carbon content. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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28. A method for measuring total organic carbon contained by a sample of deionized water, comprising the steps of:
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introducing said sample to a sample cell, said cell comprising a window formed of a material transparent to ultraviolet radiation, and a pair of electrodes, said electrodes having surfaces of a material which when irradiated with ultraviolet radiation of specified wavelength catalyzes oxidation of organic compounds, said electrode surfaces being arranged to be directly exposed to incident ultraviolet radiation; irradiating said sample and said electrodes with ultraviolet radiation including at least a portion of said specified wavelength; monitoring the conductivity of said sample of water in said sample cell; and determining the total organic carbon content of said sample of water responsive to the monitored conductivity. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36)
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37. An apparatus for measuring total organic carbon contained by a sample of deionized water, comprising:
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a sample cell having a window formed of a material transparent to ultraviolet radiation formed therein; a source of ultraviolet radiation disposed in juxtaposition to said window; first and second electrodes in said cell, the surfaces of said electrodes being formed of a catalytic material, said electrode surfaces being arranged so as to be directly exposed to incident ultraviolet radiation from said source thereof; means connected to said electrodes for monitoring the conductivity of a water sample in said cell; means for applying an electric potential across said electrodes in order to cause electrophoresis to take place; and means for correlating the conductivity to the total organic carbon content. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45)
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46. An apparatus for measuring total organic carbon contained by a steam of deionized water, comprising:
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a sample cell, said cell comprising a window formed of a material transparent to ultraviolet radiation; a source of ultraviolet radiation including at least a portion in the 170-190 nm wavelength range disposed in juxtaposition to said window; a pair of electrodes disposed in said sample cell, said electrodes having surfaces arranged so as to be directly exposed to incident ultraviolet radiation from said source; means connected to said electrodes for monitoring the conductivity of water in said sample cell; and means for determining the total organic carbon content of said water responsive to its conductivity. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54)
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55. A method for measuring total organic carbon contained in a sample of deionized water, comprising the steps of:
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introducing said sample to a sample cell, said cell comprising a window formed of a material transparent to ultraviolet radiation, and a pair of electrodes, said electrodes having surfaces arranged to be directly exposed to incident ultraviolet radiation through said window; irradiating said sample and said electrodes with ultraviolet radiation including at least a portion in the 170-190 nm wavelength range; monitoring the conductivity of said sample of water between said electrodes in said sample cell; and determining the total organic carbon content of said sample of water responsive to its conductivity. - View Dependent Claims (56, 57, 58, 59, 60, 61, 62, 63)
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Specification