CN116148200A - Water quality analyzer - Google Patents
Water quality analyzer Download PDFInfo
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- CN116148200A CN116148200A CN202310409175.7A CN202310409175A CN116148200A CN 116148200 A CN116148200 A CN 116148200A CN 202310409175 A CN202310409175 A CN 202310409175A CN 116148200 A CN116148200 A CN 116148200A
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
- G01N21/274—Calibration, base line adjustment, drift correction
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/061—Sources
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/062—LED's
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/20—Controlling water pollution; Waste water treatment
Abstract
The invention relates to a water quality analyzer, comprising: a broad spectrum light source; a light splitting unit comprisingN-1 beam splitter and one mirror for splitting the ultraviolet and visible spectrum of a broad spectrum light source intoNA plurality of discrete bands; wherein, the liquid crystal display device comprises a liquid crystal display device,Nis an integer greater than 1; a detector unit comprisingNThe absorption wavelengths of the narrow-band filters are in one-to-one correspondence with the discrete bands; the detection pool is distributed between the broad spectrum light source and the detector unit; the three-way valve is respectively connected with the pure water sample flow path, the water sample flow path to be detected and the detection tank; the signal analysis unit is used for carrying out spectral analysis according to the photoelectric signal of the photoelectric detector to obtain light intensity data, and utilizing the light intensity data of the pure water sample to obtain the light intensity of the water sample to be detectedAnd correcting the data to obtain the concentration of the water quality parameters of the water sample to be detected. According to the invention, the light intensity data of the pure water sample is utilized to correct the light intensity data of the water sample to be detected, so that the spectrum signal attenuation caused by window pollution or light source aging can be eliminated.
Description
Technical Field
The invention belongs to the technical field of water quality detection and analysis, and particularly relates to a water quality analyzer.
Background
The water quality monitoring technology based on the UV-Vis spectrometry is widely applied to the monitoring fields of industrial sewage, rivers, domestic sewage and the like due to the advantages of non-contact, corrosion resistance, quick response and the like, and the principle is that the ultraviolet-visible spectrum is utilized to carry out fingerprint analysis of characteristic absorption recognition on water quality pollutants.
The light source of the existing water quality analyzer mainly adopts a deuterium lamp and a tungsten lamp to combine or flash a xenon lamp, and absorbs signals through a broadband spectrometer to extract, but in the actual detection and analysis process, the following defects exist:
1. the light source is used as a core component, and has the defects of long stabilizing time (about 8-15 min) after power supply, short service life of the high-temperature radiation light source, high power and the like;
2. the output light intensity attenuation caused by long-term operation of the light source or the received light energy attenuation caused by water pollution of the window can cause measurement accuracy deviation;
3. the long-term operation of the light source and the broadband spectrometer can cause spectral shift, so that the measurement error is large and even the measurement is misdirected;
4. the system comprising the light source, the coupling optical fiber element, the optical fiber, the spectrometer and the like has overlarge volume and high cost, and can not meet the requirement of predicting the water quality change trend of the current distribution node type water quality monitoring.
Disclosure of Invention
Based on the above-mentioned drawbacks and deficiencies of the prior art, it is an object of the present invention to at least solve one or more of the above-mentioned problems of the prior art, in other words, to provide a water quality analyzer meeting one or more of the above-mentioned needs.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
a water quality analyzer, comprising:
a broad spectrum light source;
the light splitting unit comprises N-1 beam splitters and a reflecting mirror and is used for dividing ultraviolet and visible spectrums of the wide-spectrum light source into N discrete bands; wherein N is an integer greater than 1;
the detector unit comprises N narrow-band optical filters and photoelectric detectors, and the absorption wavelengths of the narrow-band optical filters are in one-to-one correspondence with the discrete bands;
the detection pool is distributed between the broad spectrum light source and the detector unit;
the three-way valve is respectively connected with the pure water sample flow path, the water sample flow path to be detected and the detection tank;
the signal analysis unit is used for carrying out spectrum analysis according to the photoelectric signal of the photoelectric detector to obtain light intensity data, and correcting the light intensity data of the water sample to be detected by utilizing the light intensity data of the pure water sample to obtain the concentration of the water quality parameter of the water sample to be detected.
Preferably, the broad spectrum light source is an LED light source combination.
As a preferable scheme, the LED light source combination comprises M LED light sources and a multi-surface reflecting cone, wherein M is an integer greater than 1; the multi-surface reflection cone is used for combining the light emitted by the M LED light sources to obtain a beam of light;
the quantity of the LED light sources is determined according to the quantity of water quality parameters to be detected in the water sample to be detected.
Preferably, the broad spectrum light source is a xenon lamp.
Preferably, the water quality analyzer further comprises:
the control unit is used for controlling the three-way valve to switch the pure water sample flow path or the water sample flow path to be detected to be communicated with the detection pool.
As a preferred scheme, the water quality analyzer also comprises a sampling pump, wherein the sampling pump is communicated with the detection tank and is positioned at the downstream of the detection tank along the water sample liquid inlet direction so as to perform up-sampling; wherein, the sampling pump is connected with the control unit in a control way.
As a preferred scheme, the spectrum analysis is performed according to the photoelectric signal of the photoelectric detector to obtain light intensity data, and the process includes:
the three-way valve is controlled to be switched to a pure water sample flow path to be communicated with the detection tank so as to sample the pure water sample, and light intensity data vectors of the pure water sample corresponding to different wavelengths are obtained;
and then, controlling the three-way valve to be switched to the water sample flow path to be detected to be communicated with the detection tank so as to sample the water sample to be detected, and obtaining light intensity data vectors of the water sample to be detected corresponding to different wavelengths.
As a preferred scheme, the correcting the light intensity data of the water sample to be detected by utilizing the light intensity data of the pure water sample comprises the following steps:
performing cross-correlation calculation on the light intensity data vector of the pure water sample corresponding to different wavelengths and a pre-stored reference light intensity data vector of different wavelengths to obtain the offset of the light intensity data vector;
performing spectrum calibration and light intensity adjustment according to the offset of the light intensity data vector to obtain a corrected spectrum function;
extracting light intensity data which does not absorb water quality based on light intensity data vectors corresponding to the water sample to be detected and different wavelengths, and fitting according to the corrected spectrum function to obtain compensation light intensity coefficients of different wavelengths;
extracting light intensity data of water quality absorption based on light intensity data vectors of the water sample to be detected corresponding to different wavelengths, and correcting the light intensity data according to compensation light intensity coefficients of the different wavelengths to obtain absorbance of the water sample to be detected corresponding to the different wavelengths;
and obtaining the concentration of the water quality parameters of the water sample to be detected according to the absorbance of the water sample to be detected corresponding to different wavelengths.
As a preferable scheme, the light intensity data vectors of the pure water sample corresponding to different wavelengths are as follows:
The pre-stored reference light intensity data vectors of different wavelengths are as follows:
the cross-correlation is calculated as:
； wherein ,/>
Is the wavelength offset;
taking the wavelength offset corresponding to the maximum amplitude point in the cross-correlation calculation result as the offset of the light intensity data vector
；
The corrected spectral function is:
the light intensity data vectors of the water sample to be measured corresponding to different wavelengths are as follows:
the light intensity data of no absorption to water quality are:
based on non-absorptive light intensity data z for water quality 1 According to the corrected spectral function
Fitting to obtain compensation light intensity coefficients of different wavelengths>
；
Light intensity data z of water quality absorption 2 Is the light intensity data vector z (k) and the light intensity data z without absorption to water quality 1 Is a difference set of (2):
the absorbance of the water sample to be measured corresponding to different wavelengths is as follows:
Preferably, the water quality parameter comprises at least one of nitrate, nitrite, soluble chemical oxygen demand, total suspended solids, chlorophyll a and turbidity.
Compared with the prior art, the invention has the beneficial effects that:
(1) According to the invention, the light intensity data of the pure water sample is utilized to correct the light intensity data of the water sample to be detected, so that the spectrum signal attenuation caused by window pollution or light source aging can be eliminated;
(2) According to the invention, the deviation amount of the light intensity data vector obtained by carrying out cross-correlation calculation on the light intensity data vector corresponding to different wavelengths of the pure water sample and the pre-stored reference light intensity data vector with different wavelengths is used for carrying out spectrum calibration and light intensity adjustment, so that the defect of large measurement error caused by spectrum deviation can be solved;
(3) The wide-spectrum light source provided by the invention adopts the LED light source combination, so that the light source is stable and the service life is long;
(4) The invention adopts an up-sampling mode, and can eliminate the influence of air bubbles and impurities in the detection cell on the scattering of the measurement light;
(5) The invention has simple hardware framework and low cost, and is suitable for distributed node type water quality monitoring.
Drawings
FIG. 1 is a schematic diagram showing the construction of a water quality analyzer according to example 1 of the present invention.
Detailed Description
In order to more clearly illustrate the embodiments of the present invention, specific embodiments of the present invention will be described below with reference to the accompanying drawings. It is evident that the drawings in the following description are only examples of the invention, from which other drawings and other embodiments can be obtained by a person skilled in the art without inventive effort.
Example 1:
as shown in fig. 1, the water quality analyzer of the present embodiment includes a broad spectrum light source 1, a detection cell 2, a three-way valve 3, a sampling pump 4, a pure water sample flow path 5, a water sample flow path 6 to be measured, a spectroscopic unit 7, a detector unit 8, a signal analysis unit 9, and a control unit 10.
The water quality analyzer of the present embodiment is for analyzing nitrate (NO 3- ) Nitrite (NO) 2- ) Dissolved chemical oxygen demand (soluble COD), total chemical oxygen demand (total COD), total Suspended Solids (TSS).
Specifically, the broad spectrum light source 1 comprises five different LED light sources, wherein the ultraviolet wave bands of the three LED light sources are respectively 210nm, 254nm and 345nm, and the visible light wave bands of the other two LED light sources are respectively 550nm and 650nm; and a beam of light is formed by adopting a pentahedral reflecting cone as a beam combiner and is emitted to the beam splitting unit 7. The number of the LED light sources is determined according to the number of the water quality parameters to be detected in the water sample to be detected, namely the number of the LED light sources is not smaller than the number of the water quality parameters to be detected in the water sample to be detected. In the embodiment, LED light sources of 210nm, 254nm, 345nm and 550nm are respectively used as measuring light sources of nitrate/nitrite, soluble COD, total COD and TSS, and 650nm is used as a reference light source.
The light splitting unit 7 of the present embodiment includes four beam splitters of different wavelength bands and one mirror for dividing the ultraviolet and visible spectrums of the wide-spectrum light source into five discrete bands. Specifically, the types of beam splitters include: 1. 210nm beam splitter, transmittance and reflectance 95/5, transmission band 200-220nm; 2. 254nm beam splitter, transmittance and reflectance 95/5, transmission wave band 240-260nm; 3. 345nm beam splitter, transmittance and reflectance 95/5, and transmission wave band 340-360nm; 4. 550nm beam splitter, transmittance and reflectance 95/5, and transmission band 450-650nm. In addition, the reflectivity of the reflecting mirror is 99.3%, the effective reflection band is 380-800nm, and 650nm is selected.
The detector unit 8 of the present embodiment includes five narrowband filters and photodetectors, and the absorption wavelengths of the narrowband filters correspond to discrete bands one by one. The narrow-band filter is designed based on the central wavelength of the beam splitter, has the bandwidth of 15nm and can effectively filter stray light. In addition, the photodetector captures the silicon-based sensor.
The detection cell 2 of the embodiment is distributed among the broad spectrum light source 1, the light splitting unit 7 and the detector unit 8, so that the light emitted by the broad spectrum light source 1 penetrates the detection cell 2 and is received by the detector unit 8 after being split by the light splitting unit 7.
Three interfaces of the three-way valve 3 in this embodiment are respectively connected with the pure water sample flow path 5, the water sample flow path 6 to be detected and the detection tank 2, and the pure water sample or the water sample to be detected can be controlled to enter the detection tank 2 through the three-way valve 3 so as to detect the pure water sample or the water sample to be detected. In addition, the sampling pump 4 is communicated with the detection tank 2 and is positioned downstream of the detection tank 2 along the water sample liquid inlet direction so as to perform up-sampling; the embodiment adopts an up-sampling mode to effectively eliminate the influence of air bubbles and large impurities on the scattering of measurement light. The three-way valve 3 and the sampling pump 4 are in control connection with the control unit 10, the control unit 10 controls the three-way valve 3 to switch the pure water sample flow path 5 or the water sample flow path 6 to be detected to be communicated with the detection tank 2, and controls the sampling pump 4 to realize automatic sampling.
The signal analysis unit of the embodiment is used for performing spectrum analysis according to the photoelectric signal of the photoelectric detector to obtain light intensity data, and correcting the light intensity data of the water sample to be detected by utilizing the light intensity data of the pure water sample to obtain the concentration of the water quality parameter of the water sample to be detected.
Specifically, spectrum analysis is performed according to a photoelectric signal of a photoelectric detector to obtain light intensity data, and the process comprises the following steps:
firstly, the three-way valve 3 is controlled to be switched to a pure water sample flow path 5 to be communicated with the detection tank 2, the sampling pump 4 is started to sample the pure water sample, and the obtained light intensity data vectors of the pure water sample corresponding to different wavelengths are as follows:
Then, the three-way valve 3 is controlled to be switched to the water sample flow path 6 to be detected to be communicated with the detection tank 2, the water sample to be detected is sampled, and the light intensity data vectors corresponding to the water sample to be detected and different wavelengths are obtained as follows:
the specific process of correcting the light intensity data of the water sample to be detected by utilizing the light intensity data of the pure water sample in the embodiment comprises the following steps:
(1) Performing cross-correlation calculation on the light intensity data vector of the pure water sample corresponding to different wavelengths and a pre-stored reference light intensity data vector of different wavelengths to obtain the offset of the light intensity data vector;
specifically, the pre-stored reference light intensity data vectors of different wavelengths are:
the cross-correlation is calculated as:
； wherein ,/>
Is the wavelength offset;
taking the wavelength offset corresponding to the maximum amplitude point in the cross-correlation calculation result as the offset of the light intensity data vector
；
(2) Based on the relation function among temperature, current and spectrum, carrying out spectrum calibration and light intensity adjustment according to the offset of the light intensity data vector, and obtaining a corrected spectrum function as follows:
(3) Extracting light intensity data which is not absorbed by water quality based on light intensity data vectors corresponding to different wavelengths of water samples to be detected
And according to the corrected spectral function->
Performing equal ratio fitting to obtain different wavelengths +.>
Is>
So as to eliminate light intensity attenuation caused by window pollution of the detection cell;
(4) Extracting light intensity data absorbed by water based on light intensity data vectors of the water sample to be detected corresponding to different wavelengths, namely light intensity data z absorbed by water 2 Is the light intensity data vector z (k) and the light intensity data z without absorption to water quality 1 Is a difference set of (2):
correcting the water sample to be detected according to the compensation light intensity coefficients of different wavelengths to obtain absorbance corresponding to different wavelengths of the water sample to be detected;
the absorbance of the water sample to be detected corresponding to different wavelengths is as follows:
(5) And obtaining the concentration of water quality parameters of the water sample to be detected, namely the concentration of nitrate/nitrite, soluble COD, total COD and TSS according to the absorbance of the water sample to be detected corresponding to different wavelengths.
Example 2:
the water quality analyzer of this embodiment is different from that of embodiment 1 in that:
the water quality analyzer of the embodiment is used for detecting and analyzing the water quality of the landscape water body. The evaluation system of the landscape water body is measured by chlorophyll a and turbidity, wherein the chlorophyll a is a main research object of planktonic algae and can characterize the pollution degree of eutrophication of the water body; turbidity is the comprehensive expression of water transparency, organic matters and non-organic matters suspended matters, and is an important index for evaluating the quality of landscape water.
The wide-spectrum light source of the embodiment adopts a flash xenon lamp light source, and is collimated by a self-focusing lens and then emitted to a light splitting unit;
the light splitting unit comprises five beam splitters with different wave bands and a reflecting mirror, and is used for dividing ultraviolet and visible spectrums of the wide-spectrum light source into six discrete bands. Specifically, the types of beam splitters include: 1. 237nm beam splitter, transmittance and reflectance 95/5, transmission band 200-250nm; 2. 337nm beam splitter, transmittance and reflectance 95/5, and transmission band 300-380nm; 3. 436nm beam splitter, transmittance and reflectance 95/5, and transmission band 400-480nm; 4. 550nm beam splitter, transmittance and reflectance of 95/5, and transmission wave band of 500-580nm; 5. 680nm beam splitter, 95/5 transmittance and reflectance, 620-700nm transmission band. In addition, the reflectivity of the reflecting mirror is 99.3%, the effective reflection band is 380-900nm, and 780nm is selected. Accordingly, the number of narrow band filters and photodetectors of the detector unit are adaptively adjusted.
In the embodiment, 237nm and 436nm are taken as measurement wavelengths of chlorophyll a, 680nm is taken as measurement wavelengths of turbidity, and 337nm, 550nm and 780nm are taken as reference wavelengths; correspondingly, performing partial least square fitting on the corrected spectrum function by using light intensity data corresponding to three reference wavelengths (namely light intensity data without absorption to water quality) to obtain compensation light intensity coefficients of different wavelengths; and then extracting light intensity data of water quality absorption so as to further realize the calculation of absorbance and the concentration calculation of water quality parameters, wherein the specific process can be referred to embodiment 1 and is not repeated herein.
The foregoing is only illustrative of the preferred embodiments and principles of the present invention, and changes in specific embodiments will occur to those skilled in the art upon consideration of the teachings provided herein, and such changes are intended to be included within the scope of the invention as defined by the claims.
Claims (10)
1. A water quality analyzer, comprising:
a broad spectrum light source;
the light splitting unit comprises N-1 beam splitters and a reflecting mirror and is used for dividing ultraviolet and visible spectrums of the wide-spectrum light source into N discrete bands; wherein N is an integer greater than 1;
the detector unit comprises N narrow-band optical filters and photoelectric detectors, and the absorption wavelengths of the narrow-band optical filters are in one-to-one correspondence with the discrete bands;
the detection pool is distributed between the broad spectrum light source and the detector unit;
the three-way valve is respectively connected with the pure water sample flow path, the water sample flow path to be detected and the detection tank;
the signal analysis unit is used for carrying out spectrum analysis according to the photoelectric signal of the photoelectric detector to obtain light intensity data, and correcting the light intensity data of the water sample to be detected by utilizing the light intensity data of the pure water sample to obtain the concentration of the water quality parameter of the water sample to be detected.
2. The water quality analyzer of claim 1, wherein the broad spectrum light source is a combination of LED light sources.
3. The water quality analyzer of claim 2, wherein the LED light source combination comprises M LED light sources and a multi-faceted reflecting cone, M being an integer greater than 1; the multi-surface reflection cone is used for combining the light emitted by the M LED light sources to obtain a beam of light;
the quantity of the LED light sources is determined according to the quantity of water quality parameters to be detected in the water sample to be detected.
4. The water quality analyzer of claim 1, wherein the broad spectrum light source is a xenon lamp.
5. The water quality analyzer of claim 1, further comprising:
the control unit is used for controlling the three-way valve to switch the pure water sample flow path or the water sample flow path to be detected to be communicated with the detection pool.
6. The water quality analyzer of claim 5, further comprising a sampling pump in communication with the detection cell and downstream of the detection cell in the water sample feed direction for upsampling; wherein, the sampling pump is connected with the control unit in a control way.
7. The water quality analyzer according to claim 5, wherein the process of performing spectral analysis based on the photoelectric signal of the photodetector to obtain the light intensity data comprises:
the three-way valve is controlled to be switched to a pure water sample flow path to be communicated with the detection tank so as to sample the pure water sample, and light intensity data vectors of the pure water sample corresponding to different wavelengths are obtained;
and then, controlling the three-way valve to be switched to the water sample flow path to be detected to be communicated with the detection tank so as to sample the water sample to be detected, and obtaining light intensity data vectors of the water sample to be detected corresponding to different wavelengths.
8. The water quality analyzer of claim 7, wherein the correcting the light intensity data of the water sample to be measured using the light intensity data of the pure water sample comprises:
performing cross-correlation calculation on the light intensity data vector of the pure water sample corresponding to different wavelengths and a pre-stored reference light intensity data vector of different wavelengths to obtain the offset of the light intensity data vector;
performing spectrum calibration and light intensity adjustment according to the offset of the light intensity data vector to obtain a corrected spectrum function;
extracting light intensity data which does not absorb water quality based on light intensity data vectors corresponding to the water sample to be detected and different wavelengths, and fitting according to the corrected spectrum function to obtain compensation light intensity coefficients of different wavelengths;
extracting light intensity data of water quality absorption based on light intensity data vectors of the water sample to be detected corresponding to different wavelengths, and correcting the light intensity data according to compensation light intensity coefficients of the different wavelengths to obtain absorbance of the water sample to be detected corresponding to the different wavelengths;
and obtaining the water quality parameters of the water sample to be detected according to the absorbance of the water sample to be detected corresponding to different wavelengths.
9. The water quality analyzer of claim 8, wherein the intensity data vectors of the pure water samples corresponding to different wavelengths are:
The pre-stored reference light intensity data vectors of different wavelengths are as follows:
the cross-correlation is calculated as:
； wherein ,/>
Is the wavelength offset;
taking the wavelength offset corresponding to the maximum amplitude point in the cross-correlation calculation result as the offset of the light intensity data vector
；
The corrected spectral function is:
the light intensity data vectors of the water sample to be measured corresponding to different wavelengths are as follows:
the light intensity data of no absorption to water quality are:
based on non-absorptive light intensity data z for water quality 1 According to the corrected spectral function
Fitting to obtain compensation light intensity coefficients of different wavelengths>
；
Light intensity data z of water quality absorption 2 Is the light intensity data vector z (k) and the light intensity data z without absorption to water quality 1 Is a difference set of (2):
the absorbance of the water sample to be measured corresponding to different wavelengths is as follows:
10. The water quality analyzer of any of claims 1-9, wherein the water quality parameter comprises at least one of nitrate, nitrite, soluble chemical oxygen demand, total suspended solids, chlorophyll a, turbidity.
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