# US 11,906,452 B2 · PH-sensor for determining and/or measuring a pH-value of a medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,452 B2 - Document ID: US11906452B2 - Status: Granted - Kind: B2 - Application number: 17/664,468 - Filed: 2022-05-23 - Published: 2022-11-24 - Granted: 2024-02-20 - Earliest claimed: 2022-05-23 - Assignees: Endress+Hauser Conducta GmbH+Co. KG - Applicants: Endress+Hauser Conducta GmbH+Co. KG - Inventors: Thomas Wilhelm; Mohammad Sadegh Ebrahimi; Raphael Kuhnen; Matthäus Speck - Web page: https://patentgrep.com/patent/US11906452B2 ## CPC - G01N 24/006: {using optical pumping (magnetometers using optical pumping G01R33/26, optical pumping of lasers H01S3/091)} - G01R 33/323: {Detection of MR without the use of RF or microwaves, e.g. force-detected MR, thermally detected MR, MR detection via electrical conductivity, optically detected MR} - G01K 7/16: using resistive elements - G01K 13/00: Thermometers specially adapted for specific purposes - G01N 24/08: by using nuclear magnetic resonance (G01N24/12 takes precedence) - G01N 24/10: by using electron paramagnetic resonance (G01N24/12 takes precedence) - 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) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) ## Abstract The present disclosure relates to a pH-sensor for determining and/or monitoring a pH value of a medium, having a sensor unit with a wall in contact with the medium, and at least one pH-sensitive material, which has at least one spin state that changes as a function of a pH value. The at least one pH-sensitive material is arranged in or on a region of the wall in such a way that the at least one spin state is subjected to a change in the pH value of the medium. The pH-sensor also includes a spin-sensitive unit, which is configured to detect a variable associated with the at least one spin state, wherein the spin-sensitive unit is arranged in an environment of the at least one pH-sensitive material such that the spin-sensitive unit is subjected to a change in the spin state of the at least one pH-sensitive material. ## Claims ### Claim 1 A pH-sensor for determining and/or monitoring a pH value of a medium, having: a sensor unit with a wall, wherein the wall is in contact with the medium, at least one pH-sensitive material, which has at least one spin state that changes as a function of a pH value, wherein the at least one pH-sensitive material is arranged in or on a region of the wall in such a way that the at least one spin state is subjected to a change in the pH value of the medium, a spin-sensitive unit, which is configured to detect a variable associated with the at least one spin state, wherein the spin-sensitive unit is arranged in an environment of the at least one pH-sensitive material in such a way that the spin-sensitive unit is subjected to a change in the spin state of the at least one pH-sensitive material, and an evaluation unit which, based upon the variable detected by the spin-sensitive unit and associated with the at least one spin state, determines the pH value of the medium. ### Claim 2 (depends on 1) The pH-sensor according to claim 1, wherein the spin-sensitive unit is a crystal body having at least one vacancy or is a gas cell. ### Claim 3 (depends on 2) The pH-sensor according to claim 2, wherein the crystal body is a diamond having at least one silicon-vacancy center or at least one nitrogen-vacancy center, is silicon carbide having at least one silicon-vacancy, or is hexagonal boron nitride having at least one vacancy color center. ### Claim 4 (depends on 2) The pH-sensor according to claim 2, wherein the gas cell is a cell enclosing at least one gaseous alkali metal. ### Claim 5 (depends on 2) The pH-sensor according to claim 2, wherein the spin-sensitive unit has an excitation unit for optical excitation of the crystal body or of the gas cell and a detection unit for detecting a spin-dependent fluorescence signal of the crystal body or of the gas cell. ### Claim 6 (depends on 1) The pH-sensor according to claim 1, wherein the at least one pH-sensitive material and the spin-sensitive unit are embedded in the wall of the sensor unit. ### Claim 7 (depends on 1) The pH-sensor according to claim 1, wherein the spin-sensitive unit is configured as a first layer, which is applied on a surface, facing the medium, of the wall, wherein the at least one pH-sensitive material is embedded in the wall of the sensor unit. ### Claim 8 (depends on 1) The pH-sensor according to claim 1, wherein the at least one pH-sensitive material is configured as a second layer, which is arranged on a surface, facing the medium, of the wall, wherein the spin-sensitive unit is configured as a third layer, which is arranged between the second layer and the wall or on a surface, facing away from the medium, of the wall. ### Claim 9 (depends on 1) The pH-sensor according to claim 1, wherein the at least one pH-sensitive material comprises an oxidic or nitridic species. ### Claim 10 (depends on 1) The pH-sensor according to claim 1, wherein the at least one pH-sensitive material comprises Ti(III) ions. ### Claim 11 (depends on 10) The pH-sensor according to claim 10, wherein the Ti(III) ions can be produced by an excess of Ti(IV) ions in a glass containing TiO2. ### Claim 12 (depends on 1) The pH-sensor according to claim 1, wherein the wall the sensor unit is made of glass. ### Claim 13 (depends on 1) The pH-sensor according to claim 1, wherein a temperature sensor is arranged in the region of the sensor unit in such a way that the temperature sensor determines and/or monitors a temperature of the medium. ### Claim 14 (depends on 1) The pH-sensor according to claim 1, wherein the evaluation unit is configured to determine and/or monitor a temperature of the medium on the basis of the variable associated with the at least one spin state. ### Claim 15 (depends on 1) The pH-sensor according to claim 1, wherein a magnetic field device is provided which generates a magnetic field at least in the region of the pH-sensitive material.