Optical chemical sensor and method for measuring a luminescent analyte in a measurement medium

Abstract

The invention relates to an optochemical sensor (1) for measuring a luminescent analyte in a measurement medium, comprising a sensor housing (2), a light source (4), a functional element (30), a photodetector (6) and a control unit (7), wherein the sensor housing (2) has a window (3) which is suitable for coming into contact with the measurement medium, wherein the light source (4) is configured to emit an excitation signal (S1) such that the excitation signal (S1) is partially emitted onto the functional element (30) and such that the excitation signal (S1) is partially emitted through the window (3) into the measurement medium in order to excite a first analyte (A1) present in the measurement medium, wherein the functional element (30) has a reference dye (RF) which comprises an inorganic material and which is suitable for emitting a first luminescence signal (L1) upon excitation with the first excitation signal (S1).

Description

Technical Field

[0001] This invention relates to a photochemical sensor for measuring luminescent analytes in a measurement medium, and a method for measuring luminescent analytes in a measurement medium. Background Technology

[0002] In analytical measurement techniques, particularly in water management, environmental analysis, industry—such as food technology, biotechnology, and pharmaceuticals—and in the most diverse laboratory applications, analyte variables such as pH, conductivity, or even the concentration of analytes—e.g., ions or dissolved gases in gaseous or liquid measurement media—are crucial. These analyte variables can be detected, for example, using photochemical or optical sensors.

[0003] To analyze the presence of oil or algae in a measurement medium, an optical sensor is typically used. This sensor emits a light signal of a predetermined wavelength into the medium. Since oil and algae emit fluorescence when excited by a specific light signal, this fluorescence signal can be detected by a photodetector. Based on the detected fluorescence signal, the concentration of oil or algae in the measurement medium can be inferred.

[0004] However, the light signal emitted into the measurement medium must be strong enough to excite the oil or algae so that it emits fluorescence detectable by a photodetector. Of course, a strong excitation signal is also associated with correspondingly high power consumption of the light source.

[0005] However, in some industrial applications, the power consumption of the sensor is limited to a predetermined level, thus preventing the transmission of strong excitation signals. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a sensor that can be used in a universal manner and allows for the reliable and accurate measurement of luminescent analytes in a measurement medium.

[0007] According to the present invention, this objective is achieved by the photochemical sensor according to claim 1.

[0008] The photochemical sensor according to the invention includes a sensor housing, a light source, a functional element, a photodetector, and a control unit. The sensor housing has a window adapted to contact a measurement medium. The light source is configured to emit an excitation signal such that the excitation signal is at least partially emitted onto the functional element and at least partially emitted through the window into the measurement medium to excite a first analyte present in the measurement medium. The functional element has a reference dye comprising an inorganic material and is adapted to emit a first luminescence signal when excited by the first excitation signal. The photodetector is configured to detect the first luminescence signal and a second luminescence signal emitted by the first analyte present in the measurement medium and overlapping with the first luminescence signal. The control unit is connected to the light source and the photodetector and is adapted to control the light source and evaluate the luminescence signal detected by the photodetector.

[0009] The photochemical sensor according to the invention enables signal overlap between the luminescence signal emitted by the measurement medium—more precisely, the fluorescence signal—and the luminescence signal emitted by the reference dye—more precisely, the phosphorescence signal—which ultimately results in a measurement signal strong enough for a photodetector. Therefore, the sensor can excite the reference dye and the fluorescent analyte present in the measurement medium and detect their luminescence signals.

[0010] Therefore, this measurement can not only detect the presence of oil, water emulsions, or algae, but also distinguish different algal species and determine their concentration in the measurement medium. Furthermore, individual or parallel optical measurements can be performed on various parameters such as pH, CO2, oxygen, cations, anions, and organic substances such as glucose or lactose.

[0011] According to one embodiment of the invention, the control unit includes a memory with tables or mathematical functions. The control unit is adapted to determine the analyte content of a first analyte located in the measurement medium and / or identify the first analyte based on a first emission signal, a second emission signal, and the tables or mathematical functions and stored coefficients.

[0012] According to one embodiment of the invention, the functional element is transparent, and a reference dye is arranged in the functional element such that at least 10%, more preferably at least 30%, and most preferably at least 50% of the first excitation signal passes through the reference dye.

[0013] According to one embodiment of the invention, the functional element is arranged in a window such that it is adapted to contact the measurement medium. The functional element has an indicator dye (see, for example, document references: DE102019133805.0, DE102020134517.8, or DE102020134515.1), which comprises an organic material and is adapted to emit a third luminescent signal upon excitation with a first excitation signal. During the emission of the third luminescent signal, the indicator dye is affected by a second analyte present in the measurement medium.

[0014] According to one embodiment of the invention, the functional element is partially coated with a reflective layer such that the excitation signal, when leaving the functional element, can be reflected back into the functional element along the direction of the reflective layer.

[0015] According to one embodiment of the invention, the sensor housing is partially coated with a reflective layer and is designed such that the measuring medium can be arranged between the window and the reflective layer.

[0016] The above objective can also be achieved by the method for measuring luminescent analytes in a measuring medium according to claim 7.

[0017] The method according to the present invention includes at least the following steps:

[0018] - A photochemical sensor according to the invention is provided, which is in contact with a measurement medium, wherein at least one first analyte is present in the measurement medium.

[0019] - The light source is controlled by the control unit so that the excitation signal is emitted onto the functional element and into the measurement medium to excite the first analyte and reference dye present in the measurement medium.

[0020] - A photodetector is used to detect a first luminescence signal emitted by a reference dye and a second luminescence signal emitted by at least a first analyte and overlapping with the first luminescence signal.

[0021] According to one embodiment of the present invention, the control unit includes a memory having tables or mathematical functions. The method further includes the step of evaluating a first luminescence signal and a second luminescence signal using tables or mathematical functions stored in the memory of the control unit to determine the analyte content of a first analyte located in the measurement medium and / or identify the first analyte.

[0022] According to one embodiment of the invention, the functional element is arranged in a window such that it is adapted to contact the measurement medium. The functional element has an indicator dye comprising an organic material and is adapted to emit a first luminescent signal when excited by a third excitation signal. During the emission of the third luminescent signal, the indicator dye is affected by a second analyte present in the measurement medium. During the step of controlling the light source by a control unit, the excitation signal also excites the indicator dye present in the functional element. The detection step further includes detecting the third luminescent signal emitted by the indicator dye using a photodetector.

[0023] According to one embodiment of the present invention, the method further includes the following steps: evaluating a third luminescent signal by means of a table or mathematical function stored in the memory of the control unit to determine the analyte content of a second analyte located in the measurement medium and / or identify the second analyte. Attached Figure Description

[0024] The invention will be explained in more detail below based on the accompanying drawings. In the drawings:

[0025] - Figure 1 An embodiment of the photochemical sensor according to the present invention is shown.

[0026] - Figure 2 It shows Figure 1 A further embodiment of the photochemical sensor shown,

[0027] - Figure 3 It shows a product with an additional indicator dye. Figure 1 Alternative embodiments of the photochemical sensor shown are provided.

[0028] - Figure 4 It shows Figure 1 An alternative embodiment of the photochemical sensor shown has a reflective layer for amplifying the first emission signal.

[0029] - Figure 5 It shows Figure 1 An alternative embodiment of the photochemical sensor shown is provided, which has a reflective layer for amplifying the second luminescence signal. Detailed Implementation

[0030] The photochemical sensor 1 according to the present invention includes a sensor housing 2, a light source 4, a functional element 30, a photodetector 6, and a control unit 7, for example, through... Figure 1 As shown in the example.

[0031] The sensor housing 2 has a window 3 suitable for contact with the measurement medium. The window 3 is made of, for example, glass, plastic, sapphire, or other transparent materials. This material allows both excitation and emission light to pass through simultaneously. As further explained below, according to one embodiment of the photochemical sensor 1, functional elements 30 can be arranged in the window 3.

[0032] Light source 4 is suitable for emitting excitation signal S1. Excitation signal S1 preferably has a wavelength in the near-infrared range or between 200 nm and 650 nm. Light source 4 is, for example, an LED, alternating LEDs, or an array of multiple LEDs. Light source 4 may also include one or more lasers. In the case of multiple LEDs, the light emitted by the different LEDs preferably has different wavelengths. Excitation signal S1 can preferably be generated by light source 4 such that the wavelength, duration, signal form, and frequency of the first excitation signal S1 are adjustable. For example, excitation signal S1 is a pulse with a predetermined duration and intensity.

[0033] The light source 4 is arranged such that the excitation signal S1 is partially emitted onto the functional element 30 and partially emitted into the measurement medium through the window 3. By emitting the first excitation signal S1 into the measurement medium, the first analyte A1 present in the measurement medium can be excited. To achieve this simultaneous excitation of the functional element 30 and the measurement medium, the light source 4 emits the excitation signal S1 at a sufficiently wide angle, or multiple light sources 4 may emit it. Alternatively or supplementarily, the excitation signal S1 can also be guided from the light source 4 to the functional element 30 and into the measurement medium via an optical waveguide. The optical waveguide 5 will be discussed in more detail later. The light source 4 may also have a filter unit to ensure, for example, that the excitation signal S1 has a predetermined wavelength.

[0034] Functional element 30 includes a reference dye RF. The reference dye RF comprises an inorganic material that emits a first luminescence signal L1 when excited by a first excitation signal S1. The first luminescence signal L1 is preferably a phosphorescent signal. The reference dye RF is insensitive to the analyte, i.e., it is unaffected by the presence of the analyte in the measurement medium during the emission of the first luminescence signal L1. The reference dye RF preferably has a particle size between 5 μm and 20 μm, or a particle size greater than 20 μm, particularly preferably greater than 50 μm. The first luminescence signal L1 emitted by the reference dye RF preferably has a decay time between 0.1 μs and 500 μs.

[0035] The functional element 30 may be attached to the window 3 and / or the surface of the window 3 and / or to the optical waveguide 5 and / or the interface of the optical waveguide 5 and / or to the surface of the sensor housing 2, which is in contact with the measurement medium and can be excited by the excitation signal S1.

[0036] In a particular embodiment, the optical waveguide 5 includes a reference dye RF. In this case, the reference dye RF may cover the surface of the optical waveguide 5 or be located within the optical waveguide 5 itself. In this case, the functional element 30 is part of the optical waveguide 5. This functional element is preferably applied to an optical fiber of the optical waveguide 5, which extends from the light source 4 to the measurement medium or reflective layer R. The branch of the optical waveguide 5 leading from the measurement medium to the photodetector 6 preferably does not have the reference dye RF.

[0037] In embodiments where the reference dye RF partially or completely covers at least one surface of window 3 as a coating, the reference dye RF preferably has a particle size greater than 5 μm, more preferably greater than 20 μm, and most preferably greater than 50 μm. The coating can completely cover the surface of window 3 while remaining transparent to both light emitted by the light source 4 and light emitted by the reference dye RF. This is the case for highly emissive dyes and thin coating thicknesses (i.e., between 1 nm and 500 nm), preferably between 1 nm and 50 nm. In this context, "coating" is understood to refer to a functional layer 30 applied to the surface (in this case, window 3).

[0038] Preferably, the coating allows the excitation signal S1 to excite the reference dye RF, the analyte present in the measurement medium, and the indicator dye IF attached to or in the window 3 (matrix), thereby generating a (total) signal that can be detected by the photodetector 6. Ideally, the reference dye RF is located between the light source 4 and the measurement medium. The optical waveguide 5 preferably has an optical fiber in a Y-shaped bundle, which is suitable for capturing the emitted signal.

[0039] The reference dye RF preferably contains at least one of the following substances: such as (Y,Gd,Tb)3Al5O 12 :Ce 3+ Garnets; such as (Ca,Sr,Ba)2SiO4:Eu 2+ Orthosilicates such as Ba2SiO4:Eu2+; and Ga2O3Cr 3+ Indium gallium nitride (IGNB) containing chromium-doped inorganic compounds such as GAB:Cr, YAB:Cr, YAB:Ho,Nd, YAB:Nd,Cr, YAB:Ho,Nd,Cr, etc.; and KMgF3:Eu 2+ Fluorides; such as SrB4O7:Eu 2+ borates; such as SrP2O7:Eu 2+ Phosphates; such as BaSO4:Eu 2+ sulfates; such as BaMgAl 10 O 17 Eu 2+ Sr4Al 14 O25 Eu 2+ SrAl2O4:Eu 2+ SrSiAl2O3N:Eu 2+ Aluminates; such as SrGa2S4Eu 2+ SrSi2N2O2:Eu 2+ The sulfides. Cr-GAB represents chromium-doped gadolinium aluminum borate, and Cr-YAB represents chromium-doped yttrium aluminum borate. The element responsible for luminescence is listed after the colon.

[0040] The photodetector 6 is configured to detect a first emission signal L1 emitted by a reference dye RF in the functional element 30. Furthermore, the photodetector 6 is adapted to detect a second emission signal L2, which is generated by superimposing the first emission signal L1 and the emission signal emitted by the first analyte A1. The photodetector 6 is, for example, a photodiode, a photodiode array, a CCD camera, a spectrometer, or other photosensitive element. The photodetector 6 is arranged such that the first emission signal L1 and the second emission signal L2 are detectable by the photodetector 6. For example, the optical waveguide 5 is designed to allow the first emission signal L1 to travel from the functional element 30 to the photodetector 6, and to allow the second emission signal L2 to travel from the measurement medium to the photodetector 6. The photodetector 6 may also have filter elements, such as filtering out interfering ambient light or other parasitic light.

[0041] Control unit 7 is connected to light source 4 and photodetector 6. Control unit 7 controls light source 4 to emit a predetermined excitation signal S1 having a predetermined wavelength, signal form, frequency, and duration. In addition, control unit 7 evaluates the first and second emission signals L1 and L2 detected by photodetector 6.

[0042] According to one embodiment, the control unit 7 has a memory 10. A table or one or more mathematical functions and coefficients are stored in the memory 10. The table preferably contains information about the signal characteristics of various luminescent signals emitted by algae or oil. The mathematical functions preferably describe the signal form of the luminescent signals emitted by the various algae or oil.

[0043] Control unit 7 is suitable for evaluating mixed signals (i.e., mixed luminescence signals) as well as individual signals. These signals are uniquely assigned by control unit 7 to a specific type of analyte and / or a specific analyte concentration. For example, this assignment is performed in the following manner:

[0044] a) Spatial separation of the luminous signal (through different excitation LEDs or LED arrays),

[0045] b) Time separation of the emitted signal (using a measurement clock, measurement pulse, or modulation frequency),

[0046] c) Spectral separation of the emitted signal (using a grating and / or prism in front of a photodiode or CCD camera).

[0047] Furthermore, excitation or measurement can be performed using different modulation frequencies and / or measurement clock frequencies and / or measurement pulse frequencies and / or time interval measurements. These parameters can be constant or variable. Alternating measurements using different parameter values ​​are also possible. Measurements of decay time, phase shift, or intensity with stray light correction are suitable for evaluation.

[0048] The control unit 7 is adapted to determine the analyte content of the first analyte A1 in the measurement medium based on the first luminescent signal L1, the second luminescent signal L2, and a table or mathematical function. It can also quantify and / or identify the type of algae or oil in the medium by comparing the detected second luminescent signal with the luminescent signals stored in a table. Using functions or multiple functions stored in the memory 10, the control unit 7 can also quantify and / or identify different algae or oils in the measurement medium.

[0049] Figure 2 An embodiment of a photochemical sensor 1 with a transparent functional element 30 is shown. In this case, the functional element 30 is arranged between the light source 4 and the window 3, and between the photodetector 6 and the window 3. In this case, a reference dye RF is arranged in the functional element 30 such that 90%, 70%, or 50% of the first excitation signal S1 strikes the reference dye RF, i.e., excites the reference dye RF. The portion of the first excitation signal S1 that does not excite the reference dye RF preferably crosses the functional element 30 to excite a first analyte A1 present in the measurement medium. For example, the pH value or CO2 content of the measurement medium can be obtained from the first analyte A1.

[0050] Figure 3 Another embodiment of the photochemical sensor 1 is shown, wherein a functional element 30 is arranged in a window 3. The functional element 30 is arranged in the window such that it is adapted to contact the measurement medium. In this embodiment, in addition to the reference dye RF, the functional element 30 also has an indicator dye IF. The indicator dye IF comprises an organic material and is adapted to emit a third luminescence signal L3 when excited with a first excitation signal S1. The indicator dye IF is sensitive to a second analyte A2; therefore, the indicator dye IF should be in contact with the measurement medium. Thus, during the emission of the third luminescence signal L3, the indicator dye IF may be affected by the second analyte A2 present in the measurement medium (in... Figure 3(Indicated by the arrow between the second analyte A2 and the indicator dye IF). The second analyte A2 includes, for example, oxygen molecules or another substance present in the measurement medium. For example, the third luminescent signal L3 is a fluorescence signal. Of course, in this embodiment, the reference dye RF can also be arranged outside the window 3, since contact with the measurement medium is meaningless for the reference dye RF. Therefore, assuming that the reference dye RF can be excited by the excitation signal S1, the functional element 30 with the reference dye RF can also be arranged on the optical waveguide 5 or elsewhere in the sensor housing 2.

[0051] Figure 4 Another embodiment of the photochemical sensor 1 is shown, wherein the functional element 30 is partially coated with a reflective layer R. The reflective layer R is applied to or defines the functional element 30 such that the excitation signal S1, upon leaving the functional element 30, is reflected back into the functional element 30 along the direction of the reflective layer R. Therefore, stronger excitation of the reference dye RF in the functional element 30 is achieved. In all embodiments, an optical waveguide 5 (e.g., a Y-shaped optical waveguide 5) can be used to guide the excitation signal S1, the first emission signal L1, the second emission signal L2, and the third emission signal L3.

[0052] Figure 5 It shows Figure 4 This is an improved form of the photochemical sensor 1 shown. In this case, the reflective layer R is attached to the sensor housing 2 so that a portion of the first excitation signal S1 emitted into the measurement medium is reflected back into the photochemical sensor 1. In this case, for example, the sensor housing 2 is partially coated with the reflective layer R and is, for example, partially U-shaped so that the measurement medium can be arranged between the window 3 and the reflective layer R. In this embodiment, the first analyte A1 present in the measurement medium is more strongly excited by the excitation signal S1, which generates a stronger second luminescent signal L2. Instead of the reflective layer R, the functional layer 30 can also be arranged on the sensor housing 2, or on it in addition to the reflective layer R. Therefore, the optical path traversed by the excitation signal S1 terminates in the functional layer 30. Thus, at least from the perspective of the photodetector 6, the functional layer 30 is actually arranged in or behind the measurement medium.

[0053] All embodiments of the photochemical sensor 1 described above can be combined with each other, provided that this is technically feasible.

[0054] The method for measuring luminescent analytes in a measurement medium using the aforementioned photochemical sensor 1 will be described below.

[0055] In the first step, the photochemical sensor 1 is set up in a state ready for measurement. This means that the photochemical sensor 1 is in contact with the measurement medium. Of course, at least the first analyte A1 is also present in the measurement medium.

[0056] Next, the light source 4 is controlled by the control unit 7 so that the excitation signal S1 is emitted onto the functional element 30 and into the measurement medium. Thus, the reference dye RF present in the functional element 30 and the first analyte A1 located in the measurement medium are excited. Due to the excitation by the excitation signal S1, the reference dye RF emits a first emission signal L1. Similarly, the first analyte A1 emits an emission signal that overlaps with the first emission signal L1 to form a second emission signal L2.

[0057] Then, the first light emission signal L1 and the second light emission signal L2 are detected by the photodetector 6.

[0058] The control unit 7 evaluates the detected signal using a dual lifetime reference method, thereby determining the initial signal component of the second luminescent signal L2 emitted by the first analyte A1.

[0059] The control unit 7 preferably has a memory 10 containing tables or mathematical functions, or multiple mathematical functions. The coefficients used by the mathematical functions are also stored in the memory 10.

[0060] The method advantageously further includes the step of evaluating the first luminescent signal L1 and the second luminescent signal L2 using a table or mathematical function stored in the memory 10 of the control unit 7. This can determine the analyte content of the first analyte A1 present in the measurement medium and / or identify the first analyte A1. For this purpose, the signal component of the second luminescent signal L2 emitted by the first analyte A1 is extracted and compared with luminescence information stored in a table or described by a mathematical function or multiple mathematical functions based on stored coefficients. Therefore, the first analyte A1 can be quantified and / or identified.

[0061] When functional element 30 such Figure 3 When the functional element 30 is arranged in window 3 such that it is suitable for contact with the measurement medium and the functional element 30 has an indicator dye IF, in the step of emitting the first excitation signal S1, the excitation signal S1 is emitted from the light source 4 so that the indicator dye IF is also excited in addition to the reference dye RF.

[0062] Then, the indicator dye IF emits a third luminescent signal L3. The third luminescent signal L3 is captured in the photochemical sensor 1 through window 3 for detection by the photodetector 6. If the photochemical sensor 1 has an optical waveguide 5, the optical waveguide guides the third luminescent signal L3 to the photodetector 6.

[0063] In this case, the third emission signal L3 is also detected by the photodetector 6 in the detection step.

[0064] When the control unit 7 evaluates the detected light emission signal, it will also evaluate the third light emission signal L3. For example, the evaluation of the third light emission signal L3 occurs by comparing it with the light emission signals stored in a table, in particular their decay behavior after the excitation pulse.

[0065] Instead of tables, mathematical functions or different functions can be used to determine the analyte content of the second analyte A2 present in the measurement medium and / or to identify the second analyte A2.

[0066] In all embodiments of the method, the excitation signal S1 may also be generated by two or more LEDs of the light source 4. In this case, each LED preferably has a different wavelength, such that the excitation signal S1 consists of two overlapping partial signals.

[0067] For example, when using multiple LEDs, each emitting radiation at different wavelengths, phytocyanin present in the measurement medium can be excited by orange radiation, while phytoerythrin present in the measurement medium can be excited by green radiation. Any chlorophyll present in the measurement medium can also be excited by the emitted light of phytocyanin / phytoerythrin. Chlorophyll can preferably also be excited by blue light emitted by light source 6. Therefore, time-shifted emission signals emitted by chlorophyll can be detected. The measured values ​​of chlorophyll concentration and other components can be calculated by control unit 7 using stored functions.

[0068] In all embodiments of the method, the evaluation can also be performed by a combination of the decay time of the emission signal and the decay time of the phase angle difference between the excitation signal S1 and the emission signals L1, L2.

[0069] In all embodiments of the method, the light source 4 is preferably controlled such that it absorbs less than 0.3W of electrical energy.

[0070] According to one embodiment, the functional element 30 has a thickness of 1 nm to 500 nm.

[0071] According to one embodiment of the present invention, the functional element 30 is arranged between the light source 4 and the measuring medium M and / or the reflective layer R.

[0072] According to one embodiment of the invention, the functional element 30 is transparent, and a reference dye RF is disposed within the functional element 30 such that at least 10%, more preferably 30%, and most preferably 50% of the first excitation signal S1 passes through the reference dye RF. The window 3 is preferably made of a discontinuous coating, i.e., the functional element 30, which is covered with reference dye particles larger than 5 μm, more preferably larger than 20 μm, and most preferably larger than 50 μm. The functional element 30 is preferably disposed between the light source 4 and the measurement medium M and / or the reflective layer R.

[0073] According to one embodiment of the present invention, the functional element 30 is composed of at least one optical waveguide fiber or an externally coated fiber doped with a reference dye.

[0074] According to one embodiment of the present invention, the functional element 30 has at least one reference dye RF, the at least one reference dye having an emission wavelength range greater than or equal to 100 nm, more preferably greater than 200 nm, and most preferably greater than 300 nm.

[0075] The functional element 30 is arranged in the optical path of the excitation signal S1 emitted by the light source 4.

[0076] All objects traversed by the excitation signal S1 along the optical path preferably have the same or similar refractive index. If the refractive indices are not similar, the distance must be kept low. In this case, low means a few millimeters.

[0077] The optical path has an excitation path from the light source 4 to the analyte, and an emission path from the analyte to the photodetector 6.

[0078] Functional element 30 includes a reference dye RF, which is phosphorescent and has a decay time preferably between 1 μs and 500 μs. Functional element 30 is arranged in the excitation path.

[0079] Reference dyes (RF) can also include mixtures of different substances.

[0080] The chemical and physical variables being measured are possible:

[0081] a) The chemical analyte is entirely determined using fluorescent substances.

[0082] b) Physically measured variables can be achieved using both fluorescent and phosphorescent substances.

[0083] The reference dye is usually phosphorescent.

[0084] The term "interference light" should be understood to mean light that is not emitted by the analyte as fluorescence or phosphorescence, and is therefore independent of the parameter being measured.

[0085] According to one embodiment of this measurement method, parallel individual fluorescence measurements can be performed on at least one further analyte. This is a combined sensor consisting of simple fluorescence measurements and the present invention.

[0086] List of reference numerals

[0087] 1 Photochemical sensor

[0088] 2 Sensor Housing

[0089] 3 windows

[0090] 4 light sources

[0091] 5 Optical waveguides

[0092] 6 photodetectors

[0093] 7 control units

[0094] 10 memory

[0095] 30 functional components

[0096] S1 excitation signal

[0097] L1 first light signal

[0098] L2 second light signal

[0099] L3 third light signal

[0100] IF indicator dye

[0101] RF reference dye

[0102] R Reference Layer

[0103] A1 First Analyte

[0104] A2 second analyte

Claims

1. A photochemical sensor (1) for measuring luminescent analytes in a measurement medium, comprising: The sensor housing (2), light source (4), functional element (30), photodetector (6), and control unit (7) are included. The sensor housing (2) has a window (3) suitable for contacting the measuring medium. The light source (4) is configured to emit an excitation signal (S1) such that the excitation signal (S1) is at least partially emitted onto the functional element (30) and at least partially emitted into the measurement medium through the window (3) to excite the first analyte (A1) present in the measurement medium. The functional element (30) includes a reference dye (RF), which comprises an inorganic material and is adapted to emit a first luminescent signal (L1) when excited by the excitation signal (S1). The photodetector (6) is configured to detect the first luminous signal (L1) and a second luminous signal (L2) emitted by a first analyte (A1) present in the measurement medium and overlapping with the first luminous signal (L1). The control unit (7) is connected to the light source (4) and the photodetector (6), and is adapted to control the light source (4) and evaluate the light emission signals (L1, L2) detected by the photodetector (6).

2. The photochemical sensor (1) according to claim 1, wherein, The control unit (7) includes a memory (10) with tables or mathematical functions, wherein the control unit (7) is adapted to determine the analyte content of a first analyte (A1) present in the measurement medium and / or identify the first analyte (A1) based on the first luminescent signal (L1), the second luminescent signal (L2), and the tables or mathematical functions and the stored coefficients.

3. The photochemical sensor (1) according to claim 1 or 2, wherein, The functional element (30) is transparent, and the reference dye (RF) is arranged in the functional element such that at least 10% of the excitation signal (S1) passes through the reference dye (RF).

4. The photochemical sensor (1) according to claim 3, wherein, The reference dye (RF) is arranged in the functional element such that at least 30% of the excitation signal (S1) passes through the reference dye (RF).

5. The photochemical sensor (1) according to claim 3, wherein, The reference dye (RF) is arranged in the functional element such that at least 50% of the excitation signal (S1) passes through the reference dye (RF).

6. The photochemical sensor (1) according to claim 1 or 2, wherein, The functional element (30) is arranged in the window (3) such that the functional element (30) is adapted to contact the measuring medium, wherein the functional element (30) has an indicator dye (IF) comprising an organic material and is adapted to emit a third luminescent signal (L3) when excited by the excitation signal (S1). During the emission of the third luminescent signal (L3), the indicator dye (IF) is affected by the second analyte (A2) present in the measurement medium.

7. The photochemical sensor (1) according to claim 1 or 2, wherein, The functional element (30) is partially coated with a reflective layer (R) such that the excitation signal (S1) is reflected back into the functional element (30) along the direction of the reflective layer (R) when it leaves the functional element (30).

8. The photochemical sensor (1) according to claim 1 or 2, wherein, The sensor housing (2) is partially coated with a reflective layer (R) and is designed such that the measuring medium can be arranged between the window (3) and the reflective layer (R).

9. A method for measuring a luminescent analyte in a measurement medium by means of a photochemical sensor (1), the method comprising at least the following steps: - Provides a photochemical sensor (1) according to any one of claims 1 to 8, the photochemical sensor being in contact with a measurement medium, wherein at least one first analyte (Al) is present in the measurement medium. - The control unit (7) controls the light source (4) so ​​that the excitation signal (S1) is emitted onto the functional element (30) and into the measurement medium to excite the first analyte (Al) and the reference dye (RF) present in the measurement medium. - The photodetector (6) detects a first luminescent signal (L1) emitted by the reference dye (RF) and a second luminescent signal (L2) emitted by the at least one first analyte (A1) and superimposed on the first luminescent signal (L1).

10. The method according to claim 9, wherein, The control unit (7) includes a memory (10) with tables or mathematical functions. The method further includes the following steps: evaluating the first luminescent signal (L1) and the second luminescent signal (L2) by means of a table or mathematical function stored in the memory (10) of the control unit (7) to determine the analyte content of the first analyte (A1) present in the measurement medium and / or identify the first analyte (A1).

11. The method according to claim 9 or 10, wherein, The functional element (30) is arranged in the window (3) such that the functional element (30) is adapted to contact the measurement medium, wherein the functional element (30) has an indicator dye (IF) comprising an organic material and is adapted to emit a third luminescent signal (L3) when excited by the excitation signal (S1), wherein during the emission of the third luminescent signal (L3), the indicator dye (IF) is affected by a second analyte (A2) present in the measurement medium. During the step of controlling the light source (4) via the control unit (7), the excitation signal (S1) also excites the indicator dye (IF) present in the functional element (30). The detection step further includes detecting a third luminescent signal (L3) emitted by the indicator dye (IF) using the photodetector (6).

12. The method according to claim 11, wherein, The method further includes the following steps: evaluating the third luminescent signal (L3) by means of a table or mathematical function stored in the memory (10) of the control unit (7) to determine the analyte content of the second analyte (A2) present in the measurement medium and / or to identify the second analyte (A2).

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