Optical nitrate sensor compensation algorithm for multiparameter water quality measurement
First Claim
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1. An optical nitrate sensor for sampling a confined volume of water within a prescribed region of a sampling chamber, comprising:
- a UV LED combination configured to generate a first UV LED signal centered at 229 nm and a second UV LED signal centered in a range of 250-275 nm that traverse the confined volume of water within the prescribed region of the sampling chamber in order to sense nitrates in the water with first UV LED signal and dissolved organic matter (DOM) in the water with second UV LED signal;
a reference photodiode configured to respond to part of the first UV LED signal and the second UV LED signal, and provide photodiode reference signaling containing information about the part of the first UV LED signal and the second UV LED signal received;
a measuring photodiode configured to sense the first UV LED signal and the second UV LED signal that pass through the confined volume of water within the prescribed region of the sampling chamber, and provide photodiode measured signaling containing information about a nitrate absorption of the water related to the first UV LED signal and a DOM absorption background related to the second UV LED signal;
a transimpedance amplifier configured to respond to the photodiode reference signaling and the photodiode measured signaling, and provide transimpedance amplifier signaling containing information about a photocurrent to voltage reference signaling conversion of the photodiode reference signaling without interaction with the water, and also a photocurrent to voltage measured signaling conversion of the photodiode measured signaling after interaction with the water; and
a signal processor or signal processing module configured to;
receive the transimpedance amplifier signaling, anddetermine corresponding signaling containing information about a DOM background corrected concentration of nitrates dissolved in the water by compensating the concentration of the nitrate absorption sensed in the water at 229 nm for the DOM background absorption sensed in the water in the range of 250-275 nm, based upon the transimpedance amplifier signaling received.
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Abstract
An optical nitrate sensor features a signal processor or signal processing module configured to:
- receive signaling containing information about a concentration of nitrate dissolved in the water based upon a first UV optical absorbance of light centered at 229 nm, and also containing information about a dissolved organic matter (DOM) sensed in the water based upon a second UV optical absorbance of associated light centered in a range of 250 nm to 275 nm; and
- determine corresponding signaling containing information about a corrected concentration of nitrate dissolved in the water by compensating the concentration of nitrate for the DOM sensed in the water, based upon the signaling received.
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Citations
13 Claims
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1. An optical nitrate sensor for sampling a confined volume of water within a prescribed region of a sampling chamber, comprising:
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a UV LED combination configured to generate a first UV LED signal centered at 229 nm and a second UV LED signal centered in a range of 250-275 nm that traverse the confined volume of water within the prescribed region of the sampling chamber in order to sense nitrates in the water with first UV LED signal and dissolved organic matter (DOM) in the water with second UV LED signal; a reference photodiode configured to respond to part of the first UV LED signal and the second UV LED signal, and provide photodiode reference signaling containing information about the part of the first UV LED signal and the second UV LED signal received; a measuring photodiode configured to sense the first UV LED signal and the second UV LED signal that pass through the confined volume of water within the prescribed region of the sampling chamber, and provide photodiode measured signaling containing information about a nitrate absorption of the water related to the first UV LED signal and a DOM absorption background related to the second UV LED signal; a transimpedance amplifier configured to respond to the photodiode reference signaling and the photodiode measured signaling, and provide transimpedance amplifier signaling containing information about a photocurrent to voltage reference signaling conversion of the photodiode reference signaling without interaction with the water, and also a photocurrent to voltage measured signaling conversion of the photodiode measured signaling after interaction with the water; and a signal processor or signal processing module configured to; receive the transimpedance amplifier signaling, and determine corresponding signaling containing information about a DOM background corrected concentration of nitrates dissolved in the water by compensating the concentration of the nitrate absorption sensed in the water at 229 nm for the DOM background absorption sensed in the water in the range of 250-275 nm, based upon the transimpedance amplifier signaling received. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for sampling a confined volume of water within a prescribed region of a sampling chamber with an optical nitrate sensor, comprising:
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generating with a UV LED combination a first UV LED signal centered at 229 nm and a second UV LED signal centered in a range of 250-275 nm that traverse the confined volume of water within the prescribed region of the sampling chamber in order to sense nitrates in the water with first UV LED signal and dissolved organic matter (DOM) in the water with second UV LED signal; responding with a reference photodiode to part of the first UV LED signal and the second UV LED signal, and providing photodiode reference signaling containing information about the part of the first UV LED signal and the second UV LED signal received; sensing with a measuring photodiode the first UV LED signal and the second UV LED signal that pass through the confined volume of water within the prescribed region of the sampling chamber, and providing photodiode measured signaling containing information about a nitrate absorption of the water related to the first UV LED signal and a DOM absorption background related to the second UV LED signal; responding with a transimpedance amplifier to the photodiode reference signaling and the photodiode measured signaling, and providing transimpedance amplifier signaling containing information about a photocurrent to voltage reference signaling conversion of the photodiode reference signaling without interaction with the water, and also a photocurrent to voltage measured signaling conversion of the photodiode measured signaling after interaction with the water; and receiving with a signal processor or signal processing module the transimpedance amplifier signaling, and determining corresponding signaling containing information about a DOM background corrected concentration of nitrates dissolved in the water by compensating the concentration of the nitrate absorption sensed in the water at 229 nm for the DOM background absorption sensed in the water in the range of 250-275 nm, based upon the transimpedance amplifier signaling received. - View Dependent Claims (12, 13)
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Specification