Method and device for adding a water quality detection item

Abstract

The present application belongs to the field of water quality online detection. The present application provides a method and device for adding a water quality detection item, which comprises the following steps: adding a water quality detection item in a water quality detection item adding module, editing corresponding characteristic wavelengths and characteristic coefficients and constant term coefficients corresponding to the characteristic wavelengths; receiving absorbance values of detection wave bands from a data acquisition and processing module by host computer software; calling absorbance values corresponding to the characteristic wavelengths, calling a template of a general measurement model, and calculating concentration values of the added water quality detection items according to the general calculation model. The method for adding a water quality detection item can add multiple water quality detection items, can select multiple characteristic wavelengths in the range of 190-1000 nm, and provides an open and editable general measurement model, so that quantitative detection of the added water quality detection items is realized.

Description

Technical Field

[0001] This invention belongs to the field of online water quality monitoring, and specifically relates to a method and apparatus for adding new water quality monitoring items. Background Technology

[0002] According to Lambert-Beer's law, a substance absorbs light of a "specific wavelength" (characteristic wavelength). The magnitude of absorption depends on the optical path length, the absorption coefficient, and the concentration of the substance, as shown in the following formula:

[0003]

[0004] in: Absorbance Let I be the light intensity of the incident water sample, I be the light intensity of the emitted water sample, and T be the transmittance. , Let λ be the absorption coefficient, b be the optical path length (the distance light travels in water), and c be the concentration of the substance. Therefore, measuring the absorbance at a characteristic wavelength can be used to calculate the concentration of a substance.

[0005] The full-spectrum water quality analyzer uses a scintillation xenon lamp as its light source, with a spectral range of 190nm-1000nm, covering wavelengths from deep ultraviolet to near-infrared. Both organic and inorganic substances in the water can absorb light within this spectral range. The full-spectrum water quality analyzer uses an ultraviolet-visible spectrometer as its detector, capable of detecting absorbance at various wavelengths with a resolution of 2nm or higher.

[0006] Therefore, by using a full-spectrum water quality analyzer to measure the absorbance of water samples in the 190nm-1000nm range, and establishing a metrological model between the analyte in the water sample and the absorbance at the characteristic wavelength, multiple components in the water sample can be detected simultaneously. The ability to perform real-time detection of multiple parameters is the greatest advantage of a full-spectrum water quality analyzer.

[0007] Currently available full-spectrum water quality analyzers on the market typically come with pre-set water quality testing items, ranging from 1 to 9 (common items include COD, turbidity, nitrate, and color). The price increases with the number of testing items, limiting users to only a fixed set of parameters. Whether users want to add more testing items or adapt the full-spectrum analyzer for specific water quality monitoring scenarios, they must contact the manufacturer and pay substantial customization fees, thus restricting the product's application scenarios.

[0008] Deficiencies of existing technology

[0009] Existing full-spectrum water quality analyzers require custom development by manufacturers to add water quality testing items. This not only increases the user's operating costs but also prevents users from fully exploring the detection potential of the full-spectrum water quality analyzer, thus hindering its widespread application.

[0010] The existing technology CN107179285A mainly focuses on hardware and optical innovations, enabling simultaneous measurement of absorption and fluorescence spectra, but it does not mention user-extended water quality items and parameters.

[0011] The water quality parameters that can be detected by the aforementioned prior art are fixed in the firmware and cannot be extended by the user. Summary of the Invention

[0012] To address the aforementioned technical problems, this invention provides a method and apparatus for adding new water quality testing items. The method allows users to add multiple water quality testing items, selecting multiple characteristic wavelengths within the range of 190-1000nm for each item. It provides an open, editable, and universal metrological model, enabling quantitative detection of the newly added water quality testing items.

[0013] The purpose of this invention is to provide a method for adding new water quality testing items, comprising the following steps:

[0014] (1) Add a water quality testing item in the new water quality testing item module of the host computer, and edit the characteristic wavelengths λ1, λ2, λ3, λ4 and the characteristic coefficients b1, b2, b3, b4 and constant coefficient b0 corresponding to the new water quality testing item;

[0015] (2) The host computer receives the absorbance value of the detection band from the data acquisition and processing module;

[0016] (3) Call the absorbance values ​​corresponding to the characteristic wavelengths λ1, λ2, λ3, and λ4, call the template of the general metrology model, and calculate the concentration values ​​of the newly added water quality detection items according to the general calculation model;

[0017] The template for a general econometric model is:

[0018] ,

[0019] in, The concentration of water quality testing items.

[0020] Here, is the coefficient of the constant term, and is the constant term in the calculation formula.

[0021] , , , The absorbance corresponds to the four characteristic wavelengths. At least one of the four characteristic wavelengths λ1, λ2, λ3, and λ4 is the maximum absorption wavelength of the newly added substance in the range of 190-1000nm, and the remaining wavelengths are the detection wavelengths of the interfering substances.

[0022] , , , These are the characteristic coefficients corresponding to the four characteristic wavelengths, which generally need to be determined based on on-site water sample testing.

[0023] This measurement method allows users to use an open, editable general metrology model to calculate and output test values ​​using a user-defined metrology model, enabling quantitative detection of new water quality testing items.

[0024] Furthermore, the data acquisition and processing module includes the following steps for obtaining the absorbance value of the detection band:

[0025] (1) The microprocessor controls and drives the pulse xenon lamp to emit pulses through the pulse triggering circuit, and controls the rotating electromagnet to drive the light shield to rotate through the rotating electromagnet driving circuit, thus blocking the measurement light and the reference light in a time-division manner;

[0026] (2) The ultraviolet-visible spectrometer performs spectral dispersion, acquisition and analog-to-digital conversion on the received light, stores spectral data, and the microprocessor receives the absorbance value of the detection band.

[0027] Preferably, if it is necessary to eliminate the interference of dissolved organic matter and counteract the interference of turbidity, then the characteristic coefficient , , , and constant term coefficients The determination method includes the following steps:

[0028] (1) Collect multiple different water samples from the site to be tested, and determine their properties using conventional testing methods. , and The concentration matrix X is obtained;

[0029] (2) The above method was used to determine the water sample from the test site in step (1) at the test site. , , , The absorbance at a given point is denoted as the absorbance matrix Y. According to the multi-component, multi-channel Lambert-Beer law, Y = XB. Least squares multiple linear regression is used to obtain the coefficient matrix. ;

[0030] (3) Take the average of the coefficients of each column of the coefficient matrix B obtained in step (2) to obtain the coefficients of the constant term. Characteristic coefficients , , , .

[0031] Furthermore, the absorbance at each wavelength is calculated using a UV-Vis spectrometer. The method and steps include:

[0032] (1) Convert each pixel to the corresponding wavelength using the wavelength correction formula. The light intensity of each pixel detected by the spectrometer is the light intensity of the corresponding wavelength, and the absorbance A of the corresponding wavelength λ is obtained.

[0033] The wavelength correction formula is:

[0034] ,

[0035] The wavelength corresponding to a certain pixel, in nm;

[0036] The number of pixels in the CCD;

[0037] , , , Wavelength calibration coefficients set for the spectrometer;

[0038] (2) The absorbance of the characteristic wavelength is calculated using the interpolation method. The interpolation formula is:

[0039]

[0040] in: Absorbance at a specific characteristic wavelength;

[0041] The characteristic wavelength is expressed in nm.

[0042] The wavelength of the neighboring pixel that has a smaller feature wavelength than the feature wavelength λ, in nm.

[0043] The wavelength corresponding to the neighboring pixel whose feature wavelength is larger than the feature wavelength λ, in nm;

[0044] The absorbance of neighboring pixels with smaller characteristic wavelengths;

[0045] This represents the absorbance of neighboring pixels with a larger characteristic wavelength.

[0046] Furthermore, the newly added water quality testing items were used as a new measurement model and downloaded to the solid-state storage.

[0047] The present invention also aims to provide a device, including a host computer and a data acquisition and processing module; the data acquisition and processing module is used to detect the absorbance value of a detection band; the host computer is used to receive the absorbance value of the detection band from the data acquisition and processing module;

[0048] The host computer includes a module for adding water quality testing items, which is used to add and edit water quality testing items, including editing the characteristic wavelength, characteristic coefficient, and constant coefficient corresponding to the added water quality testing item.

[0049] Furthermore, the data acquisition and processing module includes a microprocessor, a pulsed xenon lamp, a rotating electromagnet, and an ultraviolet-visible spectrometer;

[0050] The microprocessor is connected to the pulsed xenon lamp through a pulse generation circuit and a high-voltage discharge circuit to control and drive the pulsed xenon lamp to emit pulsed light.

[0051] The microprocessor controls the rotating electromagnet via a rotating electromagnet drive circuit. The rotating electromagnet is used to drive the light-shielding plate to rotate, blocking the measurement light and reference light in a time-division manner.

[0052] Ultraviolet-visible spectrometers are used to disperse, collect, and convert received light from analog to digital, and store spectral data in digital format.

[0053] The microprocessor is connected to the host computer.

[0054] Furthermore, after being excited by the high-voltage discharge circuit, the pulsed xenon lamp produces a flash with a duration of 1µs, and its spectral range is between 190nm and 1000nm.

[0055] Furthermore, the microprocessor adjusts the intensity of the pulsed xenon lamp light through the light intensity setting circuit and the high-voltage boost circuit.

[0056] Furthermore, the microprocessor is also connected to a solid-state memory, which is used to store historical data, measurement models, and new measurement models for newly added water quality testing items.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] (1) The method of adding water quality testing items in this invention allows users to add new metrological models for multiple water quality testing items and select multiple characteristic wavelengths in the range of 190-1000nm;

[0059] (2) This invention provides an open, editable general metrology model. Users can edit the general model to calculate and output detection values ​​using user-defined metrology models, thereby realizing the quantitative detection of new water quality testing items.

[0060] (3) Users can freely expand water quality testing items, allowing users to explore testing performance in depth at low cost. Attached Figure Description

[0061] Figure 1 This is a hardware connection diagram of the device in Example 1;

[0062] Figure 2 This is a schematic diagram of the corresponding wavelengths of the pixel linear array of an ultraviolet-visible spectrometer.

[0063] Figure 3 The flowchart shows the method for adding water quality testing items to this invention. Detailed Implementation

[0064] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0065] The purpose of this invention is to provide a novel full-spectrum multi-parameter water quality analysis device. This device allows users to freely expand the water quality detection items of the full-spectrum water quality analyzer, enabling users to deeply explore the detection performance of the full-spectrum water quality analyzer at low cost.

[0066] Example 1

[0067] 1. The full-spectrum multi-parameter water quality analysis device of the present invention has the following hardware system: Figure 1 As shown, it includes: 1. PC host computer; 2. USB-RS485 converter; 3. RS485 interface circuit SP3485EN-L / TR; 4. Microprocessor STM32U575VGT6; 5. Solid state memory W25Q256JVFIQ; 6. EEPROM memory BL24C512A-PARC; 7. Light intensity setting circuit DAC7311; 8. High voltage boost circuit UC3845; 9. Pulse generation circuit TLP2362; 10. High voltage discharge circuit; 11. Rotary electromagnet drive circuit DRV8833; 12. Rotary electromagnet; 13. Light blocking plate; 14. Ultraviolet-visible spectrometer; 15. Pulsed xenon lamp.

[0068] The functions of the above components are as follows.

[0069] (1) PC host computer: host computer software for running the full-spectrum water quality analysis device. This host computer software has functions such as adding water quality detection items, selecting characteristic wavelengths, editing measurement models and downloading models;

[0070] (2) USB-RS485 converter: connects the USB port of the PC to the RS485 interface of the full-spectrum water quality analyzer;

[0071] (3) RS485 interface circuit SP3485EN-L / TR: converts RS485 level to TTL level of microprocessor serial port;

[0072] (4) Microprocessor STM32U575VGT6: 32-bit Cortex-M33 high-performance microprocessor;

[0073] (5) Solid-state memory W25Q256JVFIQ: Stores historical measurement data, characteristic wavelengths, and metrology models, etc.;

[0074] (6) EEPROM memory BL24C512A-PARC: stores operating parameters such as measurement cycle, spectrometer integration time, xenon lamp trigger voltage, xenon lamp trigger interval, and averaging count;

[0075] (7) Light intensity setting circuit DAC7311: The pulsed xenon lamp emits light after high voltage pulse discharge. Adjusting the voltage value of the high voltage can change the flash intensity. A 12-bit DAC combined with a high voltage boost circuit UC3845 is used to change the xenon lamp intensity by changing the voltage value of the DAC.

[0076] (8) High voltage boost circuit UC3845: The UC3845 and the boost transformer together form a Boost power supply, so that the high voltage can be adjusted between 600V and 1000V. This high voltage is used to charge the main discharge capacitor.

[0077] (9) Pulse generation circuit TLP2362: The pulse width of the high-voltage discharge pulse of the pulse xenon lamp is required to be between 10uS and 100uS. A 20uS pulse is generated by the timer in the processor and then isolated by the high-speed optocoupler TLP2362 before being sent to the high-voltage discharge circuit.

[0078] (10) High-voltage discharge circuit: The high-voltage discharge circuit consists of a main discharge capacitor and a discharge switch. The pulse generation circuit triggers the discharge switch to discharge the main discharge capacitor, thereby generating a high-voltage pulse applied to the pulse xenon lamp.

[0079] (11) Rotary electromagnet drive circuit DRV8833: This circuit can make the electromagnet rotate clockwise or counterclockwise by applying a 5V / 1A current in different directions to the rotating electromagnet.

[0080] (12) Rotating electromagnet: After being subjected to current in different directions by 11, the rotating electromagnet will oscillate clockwise or counterclockwise with an oscillation angle of 60°. The rotating electromagnet is connected to the light-blocking plate through a coupling. The light-blocking plate oscillates to block the measuring light or reference light in time-division, so that the 14 spectrometer can integrate the measuring light or reference light in time-division.

[0081] (13) Light blocking plate: Driven by 12 rotating electromagnets, the light blocking plate can block the measurement light, pass through the reference light or block the reference light and pass through the measurement light in turn, and collect the measurement light and reference light respectively. The influence of xenon lamp intensity fluctuation on the measurement value can be offset by calculation through the reference light path.

[0082] (14) Ultraviolet-visible spectrometer: A spectrometer with a 512-pixel CMOS sensor that performs spectral dispersion, acquisition and analog-to-digital conversion on the received light and stores the spectral data in digital format;

[0083] (15) Pulsed xenon lamp: After being excited by the 10 high-voltage discharge circuit, the pulsed xenon lamp produces a flash with a duration of 1uS, and its spectral range is between 190nm and 1000nm.

[0084] 2. The software architecture of this invention is described as follows.

[0085] (1) The basic formula for calculating the concentration of water quality testing items is:

[0086]

[0087] in:

[0088] The concentration of water quality testing items;

[0089] is the coefficient of the constant term, and is the constant term in the calculation formula;

[0090] , , , These are the characteristic coefficients corresponding to the four characteristic wavelengths;

[0091] , , , The absorbance corresponds to the four characteristic wavelengths.

[0092] According to spectroscopy, when a solution contains multiple absorbing substances, at a given wavelength... The total absorbance is the sum of the absorbances of all substances. That is...

[0093] ,

[0094] in, , , The absorbance of substances x, y, and z at a certain wavelength;

[0095] , , Let x, y, and z be the absorption coefficients of three substances at a certain wavelength;

[0096] b is the optical path length;

[0097] , , Let x, y, and z be the concentrations of the three substances.

[0098] Therefore, to calculate the concentrations of substances x, y, and z, the absorbance of each substance must be subtracted from the absorbance of the others to accurately calculate the absorbance of the first substance, since the absorbances will be superimposed. For example, to measure the concentration of x, the characteristic absorption wavelength of x itself... In addition, the wavelengths of the y and z matter There is also absorption, so two additional wavelengths are needed to subtract the interference from substances y and z. Let's assume the wavelength that absorbs only substance y is... The wavelength at which only substance z absorbs is If the y substance is measured simultaneously... absorbance at wavelength Matter Z in absorbance at wavelength ,

[0099] but

[0100] in It is a constant;

[0101] For substance y in and The ratio of absorbance at two wavelengths is generally a constant and can be determined in advance;

[0102] For matter z in and The ratio of absorbance at two wavelengths is generally a constant and can be determined in advance.

[0103] (2) Characteristic wavelength groups: The firmware of the full spectrometer of this invention has 10 user-defined characteristic wavelength groups, each of which has , , , and There are 8 parameters, which are stored in solid-state memory and can be modified via a host computer.

[0104] (3) Input and storage of characteristic wavelength group parameters: When users want to expand a water quality testing item, such as dissolved ozone (O3), ozone is widely used for sterilization and disinfection in the water supply industry, and its content detection is very important.

[0105] Before establishing a characteristic wavelength group for ozone, users must first identify other "interfering substances" in the water sample. In addition to ozone, water samples from water supply plants generally contain suspended solids (turbidity) and dissolved organic matter. Turbidity is generally detected using an 880nm wavelength, while dissolved organic matter absorbs in the ultraviolet band of 190nm-300nm.

[0106] When a user wants to add O3 as a new detection item, they first select a wavelength group on the host computer software and name the detection item corresponding to that wavelength group O3. Ozone's absorption peak is at 253nm, but it does not absorb at 275nm and 880nm. Therefore, the first characteristic wavelength of ozone is selected as O3. 258nm is chosen because interference from dissolved organic matter needs to be eliminated. =275nm. Simultaneously, it's necessary to counteract turbidity interference, therefore, [the appropriate wavelength] is chosen. =880nm.

[0107] Next, we need to determine... , and Corresponding characteristic coefficients , , and Since only three characteristic wavelengths are used, therefore =0; Next, determine , , The process of determining the specific values ​​of the three wavelength coefficients:

[0108] a. Take samples of the on-site water to be tested and measure the concentration of organic matter and turbidity. For dissolved organic matter, determine its concentration in the laboratory according to the "HJ / T-2007 Determination of Chemical Requirements in Water - Rapid Digestion Spectrophotometric Method". For turbidity, the measured value was determined in the laboratory according to GB13200-91 Determination of Turbidity in Water. The ozone concentration was determined in the laboratory according to the iodometric method (GB / T 5701.11-2003). A total of 16 different water samples were collected, all of which needed to be tested. , and Finally, the concentration matrix was obtained. ;

[0109] b. Using the full-spectrum instrument of this invention, immerse 16 collected on-site water samples and measure the absorbance at 253 nm, 275 nm, and 880 nm, recording the absorbance matrix. According to the Lambert-Beer law for multi-component, multi-channel applications, we have: The coefficient matrix can be obtained by using least squares multiple linear regression. ;

[0110] c. To If the coefficients of each column are averaged, then , , , ;

[0111] (4) The full spectrometer calculates the newly added detection items: After the user inputs the parameters into the host computer, these parameters are written into the solid-state memory via the RS485 interface. When the full spectrometer is running, it will first call the existing detection data. When a new extended parameter O3 is detected, it will continue to call the O3 concentration calculation formula input in step (3). To calculate the concentration of O3;

[0112] (5) Calculation of absorbance at characteristic wavelength: (i.e., absorbance at 253nm) and The absorbance at these wavelengths is calculated through interpolation. The "ultraviolet-visible spectrometer" in the full spectrometer can read wavelengths across 512 pixels. The spectrometer's detector is a 512-pixel linear CCD array; therefore, when reading data acquired by the CCD, what is read is the light intensity of each pixel, such as... Figure 2 As shown, the wavelength range corresponding to pixels 1 to 512 of the spectrometer is 190-1000nm. In order to obtain the light intensity of each wavelength, it is also necessary to convert the number of pixels into the corresponding wavelength using a wavelength correction formula.

[0113] Wavelength correction formula:

[0114] The wavelength corresponding to a certain pixel is:

[0115]

[0116] in, The wavelength corresponding to a certain pixel, in nm;

[0117] This refers to the number of pixels in the CCD, ranging from 1 to 512.

[0118] , , , The wavelength calibration coefficients for the spectrometer are read from the spectrometer.

[0119] After obtaining the wavelength at each pixel, the light intensity of each pixel detected by the spectrometer is the light intensity of the corresponding wavelength, and the absorbance A of the corresponding wavelength λ is obtained.

[0120] The absorbance at a characteristic wavelength is calculated using an interpolation method. The interpolation formula is as follows:

[0121]

[0122] in:

[0123] Absorbance at a specific characteristic wavelength;

[0124] The characteristic wavelength is expressed in nm.

[0125] The wavelength of the neighboring pixel that has a smaller feature wavelength than the feature wavelength λ, in nm.

[0126] The wavelength corresponding to the neighboring pixel whose feature wavelength is larger than the feature wavelength λ, in nm;

[0127] The absorbance of neighboring pixels with smaller characteristic wavelengths;

[0128] This represents the absorbance of neighboring pixels with a larger characteristic wavelength.

[0129] 3. The specific steps for adding new water quality testing items are as follows, and the application flowchart is shown below. Figure 3 As shown.

[0130] (1) Open the host computer software: After connecting the PC and the full spectrum analyzer with a USB-RS485 converter, run the host computer software of the full spectrum water quality analyzer.

[0131] (2) Enter the name of the new water quality test item: In the host computer software interface, enter the name of the new water quality test item using English letters and characters, such as NO2. - (nitrite), O3 (ozone), etc.

[0132] (3) Select characteristic wavelength: Select characteristic wavelengths for the newly added water quality testing items. You can select 1-4 characteristic wavelengths. The input format is as follows: , … Taking ozone as an example, ozone has an absorption peak at 253 nm. To eliminate the influence of dissolved organic matter and turbidity on absorbance, it is necessary to select compensating wavelengths for organic matter and turbidity. Therefore, the characteristic wavelength of nitrite can be selected... , , ;

[0133] (4) Download new parameters and characteristic wavelengths to firmware: Download the new water quality detection items and their characteristic wavelengths to the solid-state memory of the full-spectrum water quality analyzer through the host computer software.

[0134] (5) Calling the template of the general measurement model: The user calls the template of the general measurement model in the host computer software. The simplest measurement model is the multivariate linear linear measurement model, and its formula is:

[0135]

[0136] in:

[0137] The concentration of the newly added water quality testing items;

[0138] The coefficient of the constant term is the constant term in the calculation formula;

[0139] , , , These are the absorption coefficients corresponding to the four characteristic wavelengths;

[0140] , , , The absorbance corresponds to the four characteristic wavelengths.

[0141] (6) Edit the metrological model for newly added parameters: The user inputs the spectral absorption characteristics of the newly added water quality testing items. Five coefficients.

[0142] The data in the table below are parameter values ​​for some of the testing items.

[0143]

[0144] (7) Download the new model to the firmware: Download the new water quality testing item measurement model formula to the solid-state memory of the full-spectrum water quality analyzer through the host computer software.

[0145] (8) Restart the full-spectrum water quality analyzer and calculate and output the detection values ​​of the new water quality test items: After restarting the full-spectrum water quality analyzer, the full-spectrum analyzer collects the spectrum and calculates the absorbance of each wavelength between 190-1000nm. The characteristic wavelength input by the user is calculated accurately using the interpolation method. The wavelength resolution can reach 0.7nm. Finally, the analyzer calculates the concentration of the new water quality test items in real time according to the test items, characteristic wavelengths, model parameters and absorbance of the collected characteristic wavelengths input by the user.

[0146] In summary, users can add water quality testing items, characteristic wavelengths, corresponding characteristic coefficients, and constant coefficients through the host computer software. They can select one or more characteristic wavelengths within the range of 190-1000nm. New items and characteristic wavelengths can be downloaded to the storage. Users can edit the metrological model of the added water quality testing items and download the new metrological model to the firmware. Detection values ​​can be calculated and output using the user-defined metrological model.

[0147] Water quality testing items can be defined and added by the user, which allows users to freely expand the water quality testing items of the full-spectrum water quality analyzer and enable users to apply the testing performance of the full-spectrum water quality analyzer at low cost.

[0148] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the scope of the invention and should be defined by the claims.

Claims

1. A method for adding new water quality testing items, characterized in that, Includes the following steps, (1) Add a water quality testing item in the upper computer’s new water quality testing item module, and edit the characteristic wavelengths λ1, λ2, λ3, λ4 and the characteristic coefficients b1, b2, b3, b4 and constant coefficient b0 corresponding to the new water quality testing item; (2) The host computer receives the absorbance value of the detection band from the data acquisition and processing module; (3) Call the absorbance values ​​corresponding to the characteristic wavelengths λ1, λ2, λ3, and λ4, call the template of the general metrology model, and calculate the concentration values ​​of the newly added water quality detection items according to the general calculation model; The template for a general econometric model is: ， in, The concentration of water quality testing items; is the coefficient of the constant term, and is the constant term in the calculation formula; , , , The absorbance corresponds to the four characteristic wavelengths. At least one of the four characteristic wavelengths λ1, λ2, λ3, and λ4 is the maximum absorption wavelength of the newly added substance in the range of 190-1000nm, and the remaining wavelengths are the detection wavelengths of the interfering substances. , , , These are the characteristic coefficients corresponding to the four characteristic wavelengths, determined by on-site water sample measurements.

2. The method according to claim 1, characterized in that, The data acquisition and processing module includes the following steps for obtaining the absorbance value of the detection band: (1) The microprocessor controls and drives the pulse xenon lamp to emit pulses through the pulse triggering circuit, and controls the rotating electromagnet to drive the light shield to rotate through the rotating electromagnet driving circuit, thus blocking the measurement light and the reference light in a time-division manner; (2) The ultraviolet-visible spectrometer performs spectral dispersion, acquisition and analog-to-digital conversion on the received light, stores spectral data, and the microprocessor receives the absorbance value of the detection band.

3. A method for adding a new water quality testing item to eliminate interference from dissolved organic matter and offset interference from turbidity, characterized in that, Includes the following steps, (1) Add a water quality testing item in the new water quality testing item module of the host computer, and edit the characteristic wavelengths λ1, λ2, λ3, λ4 and the characteristic coefficients b1, b2, b3, b4 and constant coefficient b0 corresponding to the new water quality testing item; (2) The host computer receives the absorbance value of the detection band from the data acquisition and processing module; (3) Call the absorbance values ​​corresponding to the characteristic wavelengths λ1, λ2, λ3, and λ4, call the template of the general metrology model, and calculate the concentration values ​​of the newly added water quality detection items according to the general calculation model; The template for a general econometric model is: ， in, The concentration of water quality testing items; is the coefficient of the constant term, and is the constant term in the calculation formula; , , , The absorbance corresponds to the four characteristic wavelengths. At least one of the four characteristic wavelengths λ1, λ2, λ3, and λ4 is the maximum absorption wavelength of the newly added substance in the range of 190-1000nm, and the remaining wavelengths are the detection wavelengths of the interfering substances. , , , These are the characteristic coefficients corresponding to the four characteristic wavelengths, determined by on-site water samples; In step (2), the data acquisition and processing module obtains the absorbance value of the detection band by means of the following steps: the microprocessor controls and drives the pulsed xenon lamp to emit pulses via a pulse triggering circuit, and controls the rotating electromagnet to rotate the light shield via a rotating electromagnet driving circuit to block the measurement light and reference light in a time-division manner; the ultraviolet-visible spectrometer performs spectral dispersion, acquisition and analog-to-digital conversion on the received light, stores the spectral data, and the microprocessor receives the absorbance value of the detection band. In step (3), the characteristic coefficients , , , and constant term coefficients The determination method includes the following steps: collecting multiple different water samples from the field to be tested, and determining their properties using conventional methods. , and The concentration matrix X is obtained; the absorbance of the water sample at λ1, λ2, λ3, and λ4 is determined using the method described in step (2). , , , Let Y be the absorbance matrix. Based on the multi-component, multi-channel Lambert-Beer law Y=XB, the coefficient matrix is ​​obtained by least squares multiple linear regression. The constant term coefficients are obtained by averaging the coefficients of each column of the coefficient matrix B. Characteristic coefficients , , , .

4. The method according to claim 2, characterized in that, The method for calculating absorbance at various wavelengths using a UV-Vis spectrometer includes the following steps: (1) Convert each pixel to the corresponding wavelength using the wavelength correction formula. The light intensity of each pixel detected by the spectrometer is the light intensity of the corresponding wavelength, and the absorbance A of the corresponding wavelength λ is obtained. The wavelength correction formula is: , The wavelength corresponding to a certain pixel, in nm; The number of pixels in the CCD; , , , Wavelength calibration coefficients set for the spectrometer; (2) The absorbance of the characteristic wavelength is calculated using the interpolation method. The interpolation formula is: ， in: Absorbance at a specific characteristic wavelength; The characteristic wavelength is expressed in nm. The wavelength of the neighboring pixel that has a smaller feature wavelength than the feature wavelength λ, in nm. The wavelength corresponding to the neighboring pixel whose feature wavelength is larger than the feature wavelength λ, in nm; The absorbance of neighboring pixels with smaller characteristic wavelengths; This represents the absorbance of neighboring pixels with a larger characteristic wavelength.

5. An apparatus, characterized in that, Includes a host computer and a data acquisition and processing module; The data acquisition and processing module is used to detect the absorbance value of the detection band; The host computer is used to receive the absorbance values ​​of the detection band from the data acquisition and processing module; The host computer includes a module for adding water quality testing items, which is used to add and edit water quality testing items, including editing the characteristic wavelength, characteristic coefficient, and constant coefficient corresponding to the added water quality testing item.

6. The apparatus according to claim 5, characterized in that, The data acquisition and processing module includes a microprocessor, a pulsed xenon lamp, a rotating electromagnet, and an ultraviolet-visible spectrometer; The microprocessor is connected to the pulse light source through a pulse generation circuit and a high-voltage discharge circuit to control and drive the pulse xenon lamp to emit pulses. The microprocessor controls the rotating electromagnet via a rotating electromagnet drive circuit. The rotating electromagnet is used to drive the light-shielding plate to rotate, blocking the measurement light and reference light in a time-division manner. Ultraviolet-visible spectrometers are used to disperse, collect, and convert received light from analog to digital, and store spectral data in digital format. The microprocessor is connected to the host computer.

7. The apparatus according to claim 6, characterized in that, The microprocessor adjusts the intensity of the pulsed xenon lamp through a light intensity setting circuit and a high-voltage boost circuit.

8. The apparatus according to claim 6, characterized in that, The microprocessor is also connected to a solid-state memory, which is used to store historical data, measurement models, and new measurement models for newly added water quality testing items.

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