# US 2017/0254752 A1 · Optical nitrate sensor for multiparameter water quality measurement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0254752 A1 - Document ID: US20170254752A1 - Status: Published application - Kind: A1 - Application number: 15/451,853 - Filed: 2017-03-07 - Published: 2017-09-07 - Earliest claimed: 2016-03-07 - Assignees: YSI Incorporated - Applicants: Ysi, Inc. - Inventors: Christopher John PALASSIS; Miguel A. ROJO - Web page: https://patentgrep.com/patent/US20170254752A1 ## CPC - G01N 21/59: Transmissivity (G01N21/25 takes precedence) - G01N 21/0303: {Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment (G01N21/031 - G01N21/15 take precedence)} - G01N 21/33: using ultraviolet light (G01N21/39 takes precedence) - G01N 33/188: {Determining the state of nitrification} - G01N 2021/0307: {Insert part in cell} - G01N 2201/062: LED's - G01N 2201/0668: Multiple paths; optimisable path length - G01N 2201/12: Circuits of general importance; Signal processing - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract An optical nitrate sensor features a signal processor or signal processing module configured to: receive signaling containing information about a measurement (M) of UV optical absorbance of nitrate dissolved in water of a UV light that is generated by a UV LED centered at 229 nm and that traverses a confined volume of the water within a prescribed region of a sensor body, and also about a reference sample (R) of a portion of the UV light not traversing the confined volume of the water; and determine corresponding signaling containing information about the concentration of nitrate dissolved in the water, based upon the signaling received. ## Claims ### Claim 1 Apparatus comprising: a signal processor or signal processing module configured to: receive signaling containing information about a measurement (M) of UV optical absorbance of nitrate dissolved in water of a UV light that is generated by a UV LED centered at 229 nm and that traverses a confined volume of the water within a prescribed region of a sensor body, and also about a reference sample (R) of a portion of the UV light not traversing the confined volume of the water; and determine corresponding signaling containing information about the concentration of nitrate dissolved in the water, based upon the signaling received. ### Claim 2 (depends on 1) Apparatus according to claim 1, wherein the signal processor or signal processing module is configured to determine the measurement of the UV optical absorbance based upon the following equation: Absorbance=−log(optical transmittance)=−log(M/aR), where a is a proportionality constant that can be adjusted for electrical gain normalization. ### Claim 3 (depends on 1) Apparatus according to claim 1, wherein the signaling containing information about the measurement (M) is measured and received from a measurement photodiode, where a photocurrent is generated and is subsequently converted into a voltage via a transimpedance amplifier. ### Claim 4 (depends on 1) Apparatus according to claim 1, wherein the signaling containing information about the reference sample (R) is measured and received from a reference photodiode, where a photocurrent is generated and is subsequently converted into a voltage via a transimpedance amplifier. ### Claim 5 (depends on 1) Apparatus according to claim 1, wherein the UV light traverses the confined volume of the water over a varying path length that depends on a concentration range of interest for the nitrate concentration determined. ### Claim 6 (depends on 1) Apparatus according to claim 1, wherein the apparatus comprises the sensor body configured with a path length of the confined volume of the water within the prescribed region. ### Claim 7 (depends on 6) Apparatus according to claim 6, wherein the sensor body comprises a cell spacer configured within part of the path length. ### Claim 8 (depends on 5) Apparatus according to claim 5, wherein the sensor body comprises a variable cell configured to be adapted with a first path length for determining high concentrations of nitrate dissolved in the water, or with a second path length for determining low concentrations of nitrate dissolved in the water, including where the first path is shorter than the second path. ### Claim 9 (depends on 1) Apparatus according to claim 1, wherein the signal processor or signal processing module is configured to provide the corresponding signaling containing information about the concentration of nitrate dissolved in the water. ### Claim 10 (depends on 1) Apparatus according to claim 1, wherein the prescribed region of the sensor body comprises a sampling chamber for containing the water. ### Claim 11 (depends on 1) Apparatus according to claim 1, wherein the apparatus comprises a quartz tube, and the prescribed region of the sensor body forms part of the quartz tube. ### Claim 12 (depends on 1) Apparatus according to claim 1, wherein the sensor body comprises a sonde having a sampling chamber for containing the water. ### Claim 13 (depends on 12) Apparatus according to claim 12, wherein the sampling chamber is a two-part construction having a first sub-chamber and a second sub-chamber. ### Claim 14 (depends on 13) Apparatus according to claim 13, wherein the first sub-chamber includes a first sub-chamber extension; the second sub-chamber includes a second sub-chamber extension; and the first sub-chamber extension and the second sub-chamber extension are configured to form either a first path for a high concentration measurement or a second path for a low concentration measurement. ### Claim 15 (depends on 14) Apparatus according to claim 14, wherein the first path for the high concentration measurement is shorter than the second path for the low concentration measurement. ### Claim 16 (depends on 14) Apparatus according to claim 14, wherein the first sub-chamber extension and the second sub-chamber extension are coupled together and configured with an O-ring seal inbetween. ### Claim 17 (depends on 16) Apparatus according to claim 16, wherein the first sub-chamber extension and the second sub-chamber extension are slidably coupled together. ### Claim 18 (depends on 1) Apparatus according to claim 1, wherein the prescribed region includes a sampling chamber; and the apparatus comprises a UV LED configured on one side of the sampling chamber, and a combination of a filter and measurement photodiode configured on the other side of the sampling chamber. ### Claim 19 (depends on 18) Apparatus according to claim 18, wherein the apparatus comprises one or more light pipes, each configured to channel light to or from the sampling chamber. ### Claim 20 (depends on 1) Apparatus according to claim 1, wherein the apparatus comprises a photodiode replacement module having a plug, a diode housing and a measurement diode arranged therein. ### Claim 21 (depends on 1) Apparatus according to claim 1, wherein the apparatus comprises an LED replacement module having a UV LED and a reference photodiode. ### Claim 22 (depends on 1) Apparatus according to claim 1, wherein the apparatus comprises an optical nitrate sensor for multiparameter water quality monitoring. ### Claim 23 A method comprising steps for receiving in a signal processor or processing module signaling containing information about a measurement (M) of UV optical absorbance of nitrate dissolved in water of a UV light that is generated by a UV LED centered at 229 nm and that traverses a confined volume of the water within a prescribed region of a sensor body, and also about a reference sample (R) of a portion of the UV light not traversing the confined volume of the water; and determining in the signal processor or processing module corresponding signaling containing information about the concentration of nitrate dissolved in the water, based upon the signaling received. ### Claim 24 (depends on 23) A method according to claim 23, wherein the method comprises providing from the signal processor or signal processing module the corresponding signaling containing information about the concentration of nitrate dissolved in the water. ### Claim 25 (depends on 23) A method according to claim 23, wherein the method comprises determining with the signal processor or signal processing module the measurement of the UV optical absorbance based upon the following equation: Absorbance=−log(optical transmittance)=−log(M/aR), where a is a proportionality constant that can be adjusted for electrical gain normalization.