Dual optical path detection method and device for total alkalinity analysis of seawater

Abstract

The application provides a double-light-path detection method and device for seawater total alkalinity analysis, wherein the method comprises the following steps: S1, collecting dark current signals of a measurement branch and a reference branch; S2, collecting original signals of the measurement branch and the reference branch under a blank state of a seawater sample to be measured at each wavelength light source; S3, deducting and preprocessing the original signals in the step S2 corresponding to the dark current, and calculating blank normalized transmission signals; S4, repeating the steps S2 and S3 under a color developing state of the seawater sample to be measured, and calculating color developing normalized transmission signals; S5, calculating net absorbances of each wavelength respectively, and then calculating an absorbance ratio Q according to the net absorbances; and S6, calculating pH in a color developing solution of the seawater sample to be measured according to the absorbance ratio Q, in combination with a dissociation equilibrium relationship of a color developing agent, temperature, salinity and related molar absorption coefficient parameters. The application effectively eliminates influences of light source intensity fluctuation, circuit drift and environmental disturbance on absorbance measurement results.

Description

Technical Field

[0001] This invention relates to the technical field of water quality testing, specifically to a dual-optical-path detection method and apparatus for analyzing total alkalinity in seawater. Background Technology

[0002] Seawater carbon cycle and seawater acidification are key areas of global marine research. Total alkalinity (TA), as a core parameter of the carbonate system, is a crucial indicator for assessing seawater acidification. Spectrophotometry, with its fast measurement speed and high accuracy, is widely used for in-situ TA measurement. However, existing TA analyzers still have certain shortcomings in photoelectric detection:

[0003] (1) Single-path detection: Traditional single-path structures have significant shortcomings. Single-path systems collect signals after passing through the flow cell. These signals include not only the light intensity attenuation caused by the sample but also signal changes caused by interference factors such as fluctuations in the light source intensity, power supply disturbances, and ambient light interference. Therefore, when the brightness of the light source fluctuates, the system has difficulty determining whether the detection signal is caused by a change in the absorbance of the sample solution or a change in the light source output, which can easily lead to absorbance detection errors.

[0004] (2) Poor environmental interference resistance: In complex sea conditions, the instrument is affected by temperature changes, unstable power supply, light source aging, or platform vibration, which will lead to baseline drift, reduced repeatability, and unstable absorbance calculation, ultimately affecting the accuracy and reliability of the total alkalinity measurement results.

[0005] In summary, there is a need to design a dual-optical-path detection method and device for the analysis of total alkalinity in seawater to solve the above-mentioned problems in the existing technology. Summary of the Invention

[0006] This invention proposes a dual-optical-path detection method and apparatus for the analysis of total alkalinity in seawater, which can eliminate the influence of light source intensity fluctuations, circuit drift and environmental disturbances on absorbance measurement results.

[0007] To achieve the goal of solving the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A dual-optical-path detection method for total alkalinity analysis in seawater includes the following steps:

[0009] S1. Turn off the LED light source and collect the dark current signal of the measurement branch and the dark current signal of the reference branch;

[0010] S2. With the seawater sample in a blank state, turn on the light sources of the first, second, and third wavelengths in sequence, and collect the raw signals I of the measurement branch under each wavelength light source. sig,blank,λ The original signal I of the reference branch ref,blank,λ ;

[0011] S3. Subtract and preprocess the corresponding dark current from the original signal in step S2 to obtain the effective signal I' of each wavelength light source in the measurement branch under the blank state of the seawater sample to be tested. sig,blank,λ The effective signal I' of the reference branch ref,blank,λ Then, the blank normalized transmission signal R is calculated based on the effective signal. blank,λ ;

[0012] S4. With the seawater sample under color development state, repeat steps S2 and S3 to obtain the effective signal I of each wavelength light source in the measurement branch under the color development state of the seawater sample. sig,sample,λ The effective signal I of the reference branch ref,sample,λ Then, the colorimetric normalized transmission signal R is calculated based on the effective signal. sample,λ ;

[0013] S5. Calculate the net absorbance for each wavelength, and then calculate the absorbance ratio Q based on the net absorbance.

[0014] S6. Based on the absorbance ratio Q, combined with the dissociation equilibrium of the colorimetric reagent, temperature, salinity, and relevant molar absorptivity parameters, calculate the pH of the colorimetric solution of the seawater sample to be tested.

[0015] In some embodiments of the present invention, the formula for calculating the net absorbance is as follows:

[0016] A λ =lg(R blank,λ / R sample,λ );

[0017] Among them, R blank,λ For blank normalized transmission signal, the calculation formula is: R blank,λ =I' sig,blank,λ / I' ref,blank,λ ;

[0018] R sample,λ The normalized transmission signal for color development is calculated using the following formula: R sample,λ =I' sig, sample,λ / I' ref, sample,λ .

[0019] In some embodiments of the present invention, the formula for calculating the absorbance ratio Q is:

[0020] Q = (A λ2 - A λ3 ) / (A λ1 - A λ3 );

[0021] Among them, A λ1 The first net absorbance, Aλ2 For the second net absorbance, A λ3 The third net absorbance; the first wavelength is less than the second wavelength, and the third wavelength is a non-absorption reference wavelength.

[0022] In some embodiments of the present invention, the blank state refers to blank seawater and seawater samples before the addition of the titration colorimetric reagent, and the colorimetric state refers to seawater samples mixed with a titration colorimetric reagent containing acid and bromocresol green in a set ratio.

[0023] In some embodiments of the present invention, the measuring branch is provided with a flow detection pool, which is used to place the seawater sample to be tested.

[0024] In some embodiments of the present invention, a dual-optical-path detection device for seawater total alkalinity analysis is provided, comprising:

[0025] Light source module, used to provide light sources of different wavelengths;

[0026] A measurement module is connected to the light source module via a beam splitter; the measurement module includes a measurement branch and a reference branch; the measurement branch is equipped with a flow detection cell for the sample to be tested, and the reference branch does not pass through the flow detection cell;

[0027] The signal acquisition module includes a measurement photoelectric detection unit and a reference photoelectric detection unit, which correspond to the measurement branch and the reference branch, respectively, and are used to acquire the measurement branch signal and the reference branch signal;

[0028] The data processing module is used to calculate the pH of the sample to be tested based on the measurement branch signal and the reference branch signal.

[0029] In some embodiments of the present invention, the light source module includes an LED light source and a narrowband filter; the LED light source is selected from LEDs with a center wavelength of 444nm, 616nm, and 740nm; the narrowband filter is disposed in the light emission direction of the LED light source, and the center wavelength of the narrowband filter matches the wavelength of the LED light source.

[0030] In some embodiments of the present invention, the measurement module includes a beam splitter, a measurement branch, and a reference branch; the beam splitter is a Y-type beam splitting fiber, one output branch of the Y-type beam splitting fiber is the measurement branch, and the other output branch is the reference branch.

[0031] In some embodiments of the present invention, an electronic device is provided, comprising:

[0032] A processor, and a memory and a transceiver communicatively connected to the processor;

[0033] The memory stores computer-executed instructions; the transceiver is used for sending and receiving data.

[0034] The processor executes the computer execution instructions stored in the memory to implement the above detection method.

[0035] In some embodiments of the present invention, a computer-readable storage medium is provided, characterized in that,

[0036] The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the detection method described above.

[0037] The technical solution of the present invention has the following technical effects compared with the prior art:

[0038] This invention splits light emitted from the same light source into a measurement light and a reference light. Both are from the same source and are influenced by it. The measurement light is detected by the photoelectric detection module via a flow cell, while the reference light is directly detected by the same module. The system simultaneously acquires photoelectric signals from both optical paths and normalizes the results using the ratio of the measurement photoelectric signal to the reference photoelectric signal, thereby eliminating the influence of light source intensity fluctuations, circuit drift, and environmental disturbances on the absorbance measurement results. Simultaneously, a non-absorption reference wavelength is added to monitor the flow cell status and serves as a background correction wavelength to compensate for detector fluctuations, sample particle scattering, or non-specific light attenuation. Attached Figure Description

[0039] Figure 1 This is one of the flowcharts illustrating the detection method in Embodiment 1 of the present invention;

[0040] Figure 2 This is a second schematic flowchart of the detection method shown in Embodiment 1 of the present invention;

[0041] Figure 3 This is a schematic diagram of the dual-optical-path detection device shown in Embodiment 2 of the present invention;

[0042] Figure 4 This is a schematic diagram of the structure of the electronic device.

[0043] Reference numerals: 100, Dual-optical-path detection device; 110, Light source module; 111, LED light source; 112, Narrow-band filter; 113, Light source housing; 120, Measurement module; 121, Beam splitter; 122, Measurement branch; 123, Reference branch; 124, Flow detection cell; 130, Signal acquisition module; 140, Data processing module; 200, Electronic equipment; 210, Processor; 220, Memory; 230, Transceiver. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Example 1, Reference Figure 1 As shown, a dual-optical-path detection method for total alkalinity analysis in seawater includes the following steps:

[0046] S1. Turn off the LED light source and collect the dark current signal of the measurement branch and the dark current signal of the reference branch.

[0047] Specifically, under conditions of no light incidence, photodetectors generate inherent dark currents due to factors such as thermal excitation, device leakage, and operating bias, resulting in a fixed DC offset. This causes a zero-point shift in the acquisition, disrupting the linear correspondence between the optical and electrical signal outputs. To improve the stability and accuracy of the photoelectric signal, the dark current signal I of the measurement branch is first acquired with the LED light source off. sig,dark,λ The dark current signal I of the reference branch ref,dark,λ This provides a data foundation for subsequent photoelectric signal processing.

[0048] The measurement branch is equipped with a flow detection pool, which is used to hold the seawater sample to be tested.

[0049] S2. With the seawater sample in a blank state, turn on the light sources of the first, second, and third wavelengths in sequence, and collect the raw signals I of the measurement branch under each wavelength light source. sig,blank,λ The original signal I of the reference branch ref,blank,λ .

[0050] In some embodiments, the blank state of the seawater sample to be tested refers to the blank seawater and the seawater sample before the addition of the titration colorimetric reagent. This blank state of the seawater sample to be tested serves as a reference state for establishing the current detection baseline.

[0051] In some embodiments, LED light sources with a first wavelength of 444nm, a second wavelength of 616nm, and a third wavelength of 740nm are lit sequentially. The first wavelength of 444nm and the second wavelength of 616nm are used for the absorption detection of bromocresol green in acidic and basic states, respectively. 740nm is a non-absorption reference wavelength used to monitor the state of the flow cell and as a background correction wavelength to compensate for detector fluctuations, sample particle scattering, or non-specific light attenuation.

[0052] S3. Subtract and preprocess the corresponding dark current from the original signal in step S2 to obtain the effective signal I' of each wavelength light source in the measurement branch under the blank state of the seawater sample to be tested. sig,blank,λ The effective signal I' of the reference branch ref,blank,λ Then, the blank normalized transmission signal R is calculated based on the effective signal. blank,λ .

[0053] Specifically, preprocessing includes averaging, moving average, and outlier removal of the original signal.

[0054] In some embodiments, the preprocessing process is existing technology, and will not be described again in this embodiment.

[0055] Under blank conditions of the seawater sample to be tested, the effective signal I' of the measurement branch is... sig,blank,λ =I sig,blank,λ -I sig,dark,λ ;

[0056] Specifically, for the first wavelength of 444nm, the effective signal of the measurement branch is I' sig,blank,444 =I sig,blank,444 -I sig,dark,444 ;

[0057] For the second wavelength of 616nm, the effective signal of the measurement branch is I' sig,blank,616 =I sig,blank,616 -I sig,dark,616 ;

[0058] For the third wavelength of 740nm, the effective signal of the measurement branch is I' sig,blank,740 =I sig,blank,740 -I sig,dark,740 .

[0059] Under blank conditions of the seawater sample to be tested, the effective signal I' of the reference branch ref,blank,λ =I ref,blank,λ -I ref,dark,λ ;

[0060] Specifically, for the first wavelength of 444nm, the effective signal I' of the reference branch ref,blank,444 =I ref,blank,444 -I ref,dark,444 ;

[0061] For the second wavelength of 616nm, the effective signal I' of the reference branch ref,blank,616 =I ref,blank,616 -I ref,dark,616 ;

[0062] For the third wavelength of 740nm, the effective signal I' of the reference branch ref,blank,740 =I ref,blank,740 -I ref,dark,740.

[0063] In some embodiments, at any detection wavelength λ, the signal received by the measurement optical path can be expressed as:

[0064]

[0065] Among them, I sig,λ To measure the photoelectric signal of the optical path under λ, k sig,λ To measure the optical path transmission coefficient and photoelectric conversion coefficient of the branch, I source,λ T represents the output light intensity of the LED light source at a given wavelength. λ This represents the transmittance of the liquid in the flow detection cell at this wavelength.

[0066] The received signal of the reference branch can be expressed as:

[0067]

[0068] Among them, I ref,λ As the reference optical path signal, k ref,λ The optical transmission and photoelectric conversion coefficients of the reference optical path.

[0069] The control processing module calculates the ratio of the measurement optical path signal to the reference optical path signal:

[0070]

[0071] Among them, R λ This is the normalized transmission signal after reference correction. From the above equation, we can see that the light source output intensity term I... source,λ Since the LED light source fluctuations are reduced, this method can mitigate the impact of LED light source fluctuations on the detection results.

[0072] The normalization process in this embodiment refers to using the reference branch signal as a benchmark to perform ratio correction on the measurement branch signal, converting the absolute light intensity signal into a relative transmission signal. This normalization does not simply compress the data to 0-1, but rather compensates for changes in the light source output in real time through the reference branch.

[0073] In some embodiments, the blank normalized transmission signal R blank,λ The calculation formula is:

[0074] R blank,λ =I' sig,blank,λ / I' ref,blank,λ .

[0075] Specifically, for the first wavelength of 444nm, the blank normalized transmission signal is:

[0076] R blank,444 =I' sig,blank,444 / I' ref,blank,444 ;

[0077] For the second wavelength of 616nm, the blank normalized transmission signal is R. blank,616 =I' sig,blank,616 / I' ref,blank,616 ;

[0078] For the third wavelength of 740nm, the blank normalized transmission signal is R. blank,740 =I' sig,blank,740 / I' ref,blank,740 .

[0079] S4. With the seawater sample under color development state, repeat steps S2 and S3 to obtain the effective signal I of each wavelength light source in the measurement branch under the color development state of the seawater sample. sig,sample,λ The effective signal I of the reference branch ref,sample,λ Then, the colorimetric normalized transmission signal R is calculated based on the effective signal. sample,λ .

[0080] In some embodiments, the color development state is achieved by mixing a seawater sample with a titration colorimetric reagent containing acid and bromocresol green in a predetermined ratio.

[0081] Specifically, the following steps are included:

[0082] S41. With the seawater sample under color development mode, sequentially turn on the LED light sources at wavelengths of 444nm, 616nm, and 740nm, and collect the raw signal I of the measurement branch under each wavelength light source. sig,sample,λ The original signal I of the reference branch ref,sample,λ .

[0083] S42. Subtract and preprocess the corresponding dark current from the original signal in step S41 to obtain the effective signal I' of each wavelength light source in the measurement branch under the color development state of the seawater sample to be tested. sig,sample,λ The effective signal I' of the reference branch ref,sample,λ Then, the blank normalized transmission signal R is calculated based on the effective signal. sample,λ .

[0084] Specifically, under the color development state of the seawater sample to be tested, the effective signal I' of the measurement branch... sig,sample,λ =I sig,sample,λ -I sig,dark,λ ;

[0085] Specifically, for the first wavelength of 444nm, the effective signal of the measurement branch is:

[0086] I' sig,sample,444 =I sig,sample,444 -I sig,dark,444 ;

[0087] For the second wavelength of 616nm, the effective signal of the measurement branch is:

[0088] I' sig,sample,616 =I sig,sample,616 -I sig,dark,616 ;

[0089] For the third wavelength of 740nm, the effective signal of the measurement branch is:

[0090] I' sig,sample,740 =I sig,sample,740 -I sig,dark,740 .

[0091] Under the color development state of the seawater sample to be tested, the effective signal I' of the reference branch ref,sample,λ =I ref,sample,λ -I ref,dark,λ ;

[0092] Specifically, for the first wavelength of 444nm, the effective signal I' of the reference branch ref,sample,444 =I ref,sample,444 -I ref,dark,444 ;

[0093] For the second wavelength of 616nm, the effective signal I' of the reference branch ref,sample,616 =I ref,sample,616 -I ref,dark,616 ;

[0094] For the third wavelength of 740nm, the effective signal I' of the reference branch ref,sample,740 =I ref,sample,740 -I ref,dark,740 .

[0095] In some embodiments, the colorimetric normalized transmission signal R sample,λ The calculation formula is: R sample,λ =I' sig,sample,λ / I' ref,sample,λ .

[0096] Specifically, for the first wavelength of 444nm, the colorimetric normalized transmission signal R sample,444 =I' sig,sample,444 / I' ref,sample,444 ;

[0097] For the second wavelength of 616 nm, the colorimetric normalized transmission signal R sample,616 =I' sig,sample,616 / I' ref,sample,616 ;

[0098] For the third wavelength of 740nm, the colorimetric normalized transmission signal R sample,740 =I' sig,sample,740 / I' ref,sample,740 .

[0099] S5. Calculate the net absorbance for each wavelength, and then calculate the absorbance ratio Q based on the net absorbance.

[0100] Specifically, in this embodiment, the absorbance is not calculated directly using the original light intensity of a single path. Instead, the normalized transmission signal is first obtained by measuring the ratio of the branch and the reference branch, and then the net absorbance is calculated using the normalized transmission signals in the blank state and the mixed color development state.

[0101] Specifically, refer to Figure 2 As shown in Figure S51, calculate the net absorbance at each wavelength according to the Lambert-Beer law.

[0102] The net absorbance at the first wavelength of 444nm is: A 444 =lg(R blank,444 / R sample,444 );

[0103] The net absorbance at the second wavelength of 616 nm is: A 616 =lg(R blank,616 / R sample,616 );

[0104] The net absorbance at the third wavelength of 740nm is: A 740 =lg(R blank,740 / R sample,740 ).

[0105] S52. Use the third wavelength of 740nm to perform background correction and calculate the absorbance ratio Q.

[0106] 740nm is a non-absorption reference wavelength used to monitor the state of the flow cell and as a background correction wavelength to compensate for detector fluctuations, sample particle scattering, or non-specific light attenuation.

[0107] The formula for calculating the absorbance ratio Q is:

[0108] Q = (A 616 - A 740 ) / (A 444 - A 740 ).

[0109] S6. Based on the absorbance ratio Q, combined with the dissociation equilibrium of the colorimetric reagent, temperature, salinity, and relevant molar absorptivity parameters, calculate the pH of the colorimetric solution of the seawater sample to be tested.

[0110] Specifically, the colorimetric reagent exists in an acid-base dissociation equilibrium in aqueous solution: HL <=> H + + L - dissociation constant K a Regulated by temperature and ionic strength (salinity); HL is in protonated form, L- As deprotonated forms, the two forms have different molar absorptivity. At a selected characteristic wavelength, the total absorbance of the mixture is contributed by both forms. The absorbance ratio Q is defined as the ratio of the absorbance corresponding to the characteristic absorption of the two forms at a specified wavelength. The expression for hydrogen ion concentration can be obtained by combining the Lambert-Beer law with the dissociation equilibrium relationship, and then correcting the ion activity coefficient for seawater salinity and the apparent dissociation constant K for temperature. a The effects of salt and temperature on dissociation equilibrium were eliminated. The absorbance ratio Q, the molar absorptivity of each form, and the optical path parameters were substituted into the formula to calculate the hydrogen ion activity, and finally the pH value of the seawater sample was obtained.

[0111] The technical solution of the present invention has the following technical effects compared with the prior art:

[0112] This invention splits light emitted from the same light source into a measurement light and a reference light. Both are from the same source and are influenced by it. The measurement light is detected by the photoelectric detection module via a flow cell, while the reference light is directly detected by the same module. The system simultaneously acquires photoelectric signals from both optical paths and normalizes the results using the ratio of the measurement photoelectric signal to the reference photoelectric signal, thereby eliminating the influence of light source intensity fluctuations, circuit drift, and environmental disturbances on the absorbance measurement results. Simultaneously, a non-absorption reference wavelength is added to monitor the flow cell status and serves as a background correction wavelength to compensate for detector fluctuations, sample particle scattering, or non-specific light attenuation.

[0113] Example 2, refer to Figure 3 and Figure 4 As shown, a dual-optical-path detection device 100 and electronic device 200 for analyzing total alkalinity in seawater are provided.

[0114] For the dual-optical-path detection device 100, refer to Figure 3 As shown, it includes:

[0115] Light source module 110 is used to provide light sources of different wavelengths;

[0116] The measurement module 120 is connected to the light source module 110 via a beam splitter 121; the measurement module 120 includes a measurement branch 122 and a reference branch 123; the measurement branch 123 is provided with a flow detection cell 124 for the sample to be tested, and the reference branch 123 does not pass through the flow detection cell 124.

[0117] The signal acquisition module 130 includes a measurement photoelectric detection unit and a reference photoelectric detection unit, which correspond to the measurement branch 122 and the reference branch 123 respectively, and are used to acquire the measurement branch signal and the reference branch signal;

[0118] The data processing module 140 is used to calculate the pH of the sample to be tested based on the measurement branch signal and the reference branch signal.

[0119] In some embodiments of the present invention, the light source module 110 includes an LED light source 111, a narrowband filter 112, and a light source housing 113; the LED light source 111 is selected with a center wavelength of 444nm, 616nm, and 740nm; wherein 444nm and 616nm are used for the detection of bromocresol green in acidic and basic states, respectively, and 740nm is a non-absorption reference wavelength used to monitor the state of the flow cell and as a background correction wavelength to compensate for detector fluctuations, sample particle scattering, or non-specific light attenuation.

[0120] In some embodiments, the diameter of the LED light source 111 is 5 mm.

[0121] In some embodiments, the narrowband filter 112 is disposed in the light-emitting direction of the LED light source to further limit the spectral bandwidth of the emitted light from the LED, thereby improving the monochromaticity and wavelength selectivity of the detection light. The center wavelength of the narrowband filter is matched with the corresponding LED light source, preferably including narrowband filters around 444 nm, 616 nm, and 740 nm. Taking the 616 nm detection channel as an example, its filter center wavelength can be 616.65 nm, with a transmittance of 96.03% and a half-bandwidth of 8.32 nm. Other wavelength channels can use narrowband filters 112 that match the center wavelength of the corresponding LED.

[0122] In some embodiments, the light source housing 113 serves to fix the LED light source 111 and the narrowband filter 112, and to connect to the downstream beam splitter. If the light source is not encapsulated and exposed to natural light, the light entering the beam splitter will be impure and subject to changes in the external environment. The light source housing 113 mainly includes screws, an encapsulation shell, and a collimating lens. The screws are mainly used to fix the LED light source 111 and the narrowband filter 112, and the collimating lens is used to receive the light source signal and connect to the beam splitter.

[0123] In some embodiments, the central light source is placed horizontally, and the other two light sources are placed at a 17-degree angle to the central light source.

[0124] In some embodiments of the present invention, the measurement module 120 includes a beam splitter 121 and two branches, the main function of which is to split the beam of the same source light to form a measurement branch 122 and a reference branch 123.

[0125] In some embodiments, the beam splitter 121 preferentially uses a Y-type beam splitting fiber.

[0126] Specifically, the input end of the Y-type beam splitter is connected to the light source module 110 through a collimating lens, and one output branch of the Y-type beam splitter is a measurement branch 122, and the other output branch is a reference branch 123.

[0127] The measurement module 120 also includes a flow detection cell 124, which is disposed in the measurement branch 122 and used to realize optical detection of the seawater to be tested. The flow detection cell 124 includes an inlet, an outlet, and a detection window. The seawater to be tested enters the detection chamber of the flow cell through the inlet, and the measurement beam enters the signal acquisition module 130 through one of the detection windows of the flow cell and the other detection window. The absorbed light signal is detected, and after the detection is completed, the liquid is discharged from the outlet.

[0128] In some embodiments, the flow detection cell 124 is made of quartz glass, the detection window has good light transmittance, and the optical path is 1 cm.

[0129] The signal acquisition module 130 adopts a photoelectric detection module, which is an integrated module that integrates analog-to-digital conversion, amplification and noise reduction, and communication functions. The communication protocol is RS485, and the communication interface is USB to TTL to establish communication with the host computer.

[0130] In some embodiments, the flow detection cell 124 and the signal acquisition module 130 are fixed together inside the flow cell housing.

[0131] In some embodiments, the optical path structure of the dual-path detection device is a co-source dual-branch reference structure. The detection light is emitted from an LED light source 111, obtains its characteristic wavelength after passing through a narrow-band filter 112, and then enters a Y-shaped beam splitter. The Y-shaped beam splitter divides the detection light into a measurement branch 122 and a reference branch 123. The measurement branch 122 is one output branch of the Y-shaped beam splitter; the measurement light output from this branch enters a flow-through detection cell 124, passes through the liquid to be tested within the flow-through detection cell 124, and reaches the measurement photoelectric detection module. The reference branch 123 is the other output branch of the Y-shaped beam splitter; the reference light output from this branch bypasses the colorimetric absorption region of the mixed solution to be tested, directly passes through a fixed reference channel, and reaches the reference photoelectric detection module. The reference branch signal mainly reflects the current output intensity of the light source and the transmission status of the reference branch. Since the measurement branch and the reference branch originate from the same light source, both signals will be affected simultaneously when the light source experiences brightness fluctuations, output attenuation, or power supply disturbances. By comparing the measured branch signal with the reference branch signal, the influence of the common light source fluctuation term on the measurement results can be reduced.

[0132] It should be understood that the dual-optical-path detection device 100 here is embodied in the form of a functional module. The term "module" here can refer to application-specific integrated circuits (ASICs), electronic circuits, processors (e.g., shared processors, proprietary processors, or group processors, etc.) and memories for executing one or more software or firmware programs, integrated logic circuits, and / or other suitable components supporting the described functions. In an alternative example, those skilled in the art will understand that the dual-optical-path detection device 100 can be specifically the electronic device 200 in the above embodiments, or the functions of the electronic device 200 in the above embodiments can be integrated into the dual-optical-path detection device 100. The dual-optical-path detection device 100 can be used to execute the various processes and / or steps corresponding to the electronic device 200 in the above method embodiments; to avoid repetition, these will not be described again here.

[0133] The aforementioned dual-optical-path detection device 100 has the function of implementing the corresponding steps performed by the electronic device 200 of the dual-optical-path detection method in Embodiment 1; the aforementioned function can be implemented by hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the aforementioned function. For example, the aforementioned acquisition module can be a communication interface, such as a transceiver interface.

[0134] In the embodiments of this application, Figure 3 The dual-optical-path detection device 100 can also be a chip or a chip system, such as a system on chip (SoC).

[0135] Reference Figure 4 As shown, in this embodiment, an electronic device 200 is provided, including:

[0136] Processor 210, and memory 220 and transceiver 230 communicatively connected to said processor;

[0137] The memory 220 stores computer-executed instructions; the transceiver 230 is used for sending and receiving data.

[0138] The processor 210 executes the computer execution instructions stored in the memory 220 to implement the detection method in Embodiment 1.

[0139] It should be understood that the electronic device 200 can be used to perform the corresponding steps and / or processes in the above method embodiments. Optionally, the memory 220 may include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the memory 220 may also include non-volatile random access memory. For example, the memory 220 may also store device type information. The processor 210 can be used to execute instructions stored in the memory 220, and when the processor 210 executes the instructions, the processor 210 can perform the corresponding steps and / or processes in the above method embodiments.

[0140] It should be understood that, in the embodiments of this application, the processor 210 may be a central processing unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0141] In implementation, each step of the above method can be completed by the integrated logic circuitry of the hardware in the processor 210 or by instructions in software form. The steps of the method disclosed in the embodiments of this application can be directly embodied in the execution by the hardware processor, or by a combination of hardware and software modules in the processor 210. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory, and the processor executes the instructions in the memory, combining them with its hardware to complete the steps of the above method. To avoid repetition, detailed descriptions are not provided here.

[0142] Example 3: In this example, a computer-readable storage medium is provided, which stores computer-executable instructions. When executed by a processor, the computer-executable instructions are used to implement the dual-optical-path detection method in Example 1.

[0143] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0144] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0145] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0146] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0147] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0148] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dual-optical-path detection method for total alkalinity analysis in seawater, characterized in that, Includes the following steps: S1. Turn off the LED light source and collect the dark current signal of the measurement branch and the dark current signal of the reference branch; S2. With the seawater sample in a blank state, turn on the light sources of the first, second, and third wavelengths in sequence, and collect the raw signals I of the measurement branch under each wavelength light source. sig,blank,λ The original signal I of the reference branch ref,blank,λ ; S3. Subtract and preprocess the corresponding dark current from the original signal in step S2 to obtain the effective signal I' of each wavelength light source in the measurement branch under the blank state of the seawater sample to be tested. sig,blank,λ The effective signal I' of the reference branch ref,blank,λ Then, the blank normalized transmission signal R is calculated based on the effective signal. blank,λ ; S4. With the seawater sample under color development state, repeat steps S2 and S3 to obtain the effective signal I of each wavelength light source in the measurement branch under the color development state of the seawater sample. sig,sample,λ The effective signal I of the reference branch ref,sample,λ Then, the colorimetric normalized transmission signal R is calculated based on the effective signal. sample,λ ; S5. Calculate the net absorbance for each wavelength, and then calculate the absorbance ratio Q based on the net absorbance. S6. Based on the absorbance ratio Q, combined with the dissociation equilibrium of the colorimetric reagent, temperature, salinity, and relevant molar absorptivity parameters, calculate the pH of the colorimetric solution of the seawater sample to be tested.

2. The dual-optical-path detection method for total alkalinity analysis of seawater according to claim 1, characterized in that, The formula for calculating the net absorbance is as follows: A λ =lg(R blank,λ / R sample,λ ); Among them, R blank,λ For blank normalized transmission signal, the calculation formula is: R blank,λ =I' sig,blank,λ / I' ref,blank,λ ; R sample,λ The normalized transmission signal for color development is calculated using the following formula: R sample,λ =I' sig, sample,λ / I' ref, sample,λ .

3. The dual-optical-path detection method for total alkalinity analysis of seawater according to claim 2, characterized in that, The formula for calculating the absorbance ratio Q is: Q=(A λ2 - A λ3 ) / (A λ1 - A λ3 ); Among them, A λ1 The first net absorbance, A λ2 For the second net absorbance, A λ3 The third net absorbance; the first wavelength is less than the second wavelength, and the third wavelength is a non-absorption reference wavelength.

4. The dual-optical-path detection method for total alkalinity analysis of seawater according to claim 1, characterized in that, The blank state refers to blank seawater and seawater samples before the addition of titration colorimetric reagent. The colorimetric state refers to seawater samples mixed with titration colorimetric reagent containing acid and bromocresol green in a set ratio.

5. The dual-optical-path detection method for total alkalinity analysis of seawater according to claim 1, characterized in that, The measurement branch is equipped with a flow detection pool, which is used to hold the seawater sample to be tested.

6. A dual-optical-path detection device for analyzing total alkalinity in seawater, characterized in that, To achieve a dual-optical-path detection method for total alkalinity analysis of seawater as described in any one of claims 1-5, comprising: Light source module, used to provide light sources of different wavelengths; A measurement module is connected to the light source module via a beam splitter; the measurement module includes a measurement branch and a reference branch; the measurement branch is equipped with a flow detection cell for the sample to be tested, and the reference branch does not pass through the flow detection cell; The signal acquisition module includes a measurement photoelectric detection unit and a reference photoelectric detection unit, which correspond to the measurement branch and the reference branch, respectively, and are used to acquire the measurement branch signal and the reference branch signal; The data processing module is used to calculate the pH of the sample to be tested based on the measurement branch signal and the reference branch signal.

7. A dual-optical-path detection device for seawater total alkalinity analysis according to claim 6, characterized in that, The light source module includes an LED light source and a narrowband filter; the LED light source uses LEDs with center wavelengths of 444nm, 616nm, and 740nm; the narrowband filter is disposed in the light emission direction of the LED light source, and the center wavelength of the narrowband filter matches the wavelength of the LED light source.

8. A dual-optical-path detection device for seawater total alkalinity analysis according to claim 6, characterized in that, The measurement module includes a beam splitter, a measurement branch, and a reference branch; the beam splitter is a Y-type optical fiber, one output branch of the Y-type optical fiber is the measurement branch, and the other output branch is the reference branch.

9. An electronic device, characterized in that, include: A processor, and a memory and a transceiver communicatively connected to the processor; The memory stores computer-executed instructions; the transceiver is used for sending and receiving data. The processor executes the computer execution instructions stored in the memory to implement a dual-optical-path detection method for total alkalinity analysis of seawater as described in any one of claims 1-5.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement a dual-optical-path detection method for total alkalinity analysis of seawater as described in any one of claims 1-5.

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