Photoelectrochemical determination of chemical oxygen demand
First Claim
1. A method of determining chemical oxygen demand of a water sample, comprising the steps ofa) applying a constant potential bias to a thin layer photoelectrochemical flow cell, having a photoactive nanoparticulate semiconductive working electrode and a counter electrode, and containing a supporting electrolyte solution;
- b) illuminating the working electrode with a light source and recording the background charge produced at the working electrode from the supporting electrolyte solution;
c) adding a 5 μ
l to 200 μ
l of water sample, to be analyzed, to the thin layer photoelectrochemical flow cell;
d) illuminating the working electrode with a light source and recording the total charge produced with the sample;
e) deducting the background charge from the total charge produced with the sample to obtain the net charge due to the oxidation of organic material in the sample; and
f) determining the chemical oxygen demand of the water sample under exhaustive degradation conditions from the equivalent oxygen concentration consumed in the reaction as defined by the equation;
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Accused Products
Abstract
A photoelectrochemical assay apparatus for determining chemical oxygen demand (COD) of a water sample which consists of
- a) a measuring cell for holding a sample to be analysed
- b) a titanium dioxide nanoparticle photoelectric working electrode and a counter electrode disposed in said cell,
- c) a UV light source adapted to illuminate the photoelectric working electrode
- d) control means to control the illumination of the working electrode
- e) potential measuring means to measure the electrical potential at the working and counter electrodes
- f) analysis means to derive a measure of oxygen demand from the measurements made by the potential measuring means.
The method of determining chemical oxygen demand of a water sample, comprises the steps of
- a) applying a constant potential bias to a photoelectrochemical cell, containing a supporting electrolyte solution;
- b) illuminating the working electrode with a UV light source and recording the background photocurrent produced at the working electrode from the supporting electrolyte solution;
- c) adding a water sample, to be analysed, to the photoelectrochemical cell;
- d) illuminating the working electrode with a UV light source and recording the total photocurrent produced;
- e) determining the chemical oxygen demand of the water sample according to the type of degradation conditions employed.
The determination may be under exhaustive degradation conditions, in which all organics present in the water sample are oxidised or under non-exhaustive degradation conditions, in which the organics present in the water sample are partially oxidised.
11 Citations
15 Claims
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1. A method of determining chemical oxygen demand of a water sample, comprising the steps of
a) applying a constant potential bias to a thin layer photoelectrochemical flow cell, having a photoactive nanoparticulate semiconductive working electrode and a counter electrode, and containing a supporting electrolyte solution; -
b) illuminating the working electrode with a light source and recording the background charge produced at the working electrode from the supporting electrolyte solution; c) adding a 5 μ
l to 200 μ
l of water sample, to be analyzed, to the thin layer photoelectrochemical flow cell;d) illuminating the working electrode with a light source and recording the total charge produced with the sample; e) deducting the background charge from the total charge produced with the sample to obtain the net charge due to the oxidation of organic material in the sample; and f) determining the chemical oxygen demand of the water sample under exhaustive degradation conditions from the equivalent oxygen concentration consumed in the reaction as defined by the equation; - View Dependent Claims (2, 3, 4, 5)
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6. A thin layer photoelectrochemical assay apparatus for determining oxygen demand of a water sample, of the apparatus comprising:
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a) a measuring thin layer flow cell for holding 5 μ
l to 200 μ
l of a sample to be analyzed,b) a photoactive nanoparticulate semiconductive working electrode and a counter electrode disposed in said cell, c) a light source adapted to illuminate the photoactive working electrode d) control means to control the illumination of the working electrode, the applied potential bias, and charge recording c) charge measuring means to measure the charge at the working electrode f) a processor to derive a measure of oxygen demand from the measurements made by the charge measuring means, wherein the chemical oxygen demand is determined under exhaustive degradation conditions, in which all organics present in the water sample are oxidized. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification