A turbidity compensation method for fluorescent method of algal classification

Abstract

The present application belongs to the field of chemical analysis, and particularly relates to a turbidity compensation method for algae classification by fluorescence method, comprising the following steps: a) sequentially irradiating a water sample to be measured with multi-wavelength excitation light, and measuring the fluorescence intensity I i and the turbidity scattering light intensity I 浊 of the water sample after excitation at each wavelength; b) calculating the scattering light intensity Sca i corresponding to the fluorescence excitation light at each wavelength according to a pre-established relationship between the turbidity scattering light intensity and the fluorescence excitation light scattering intensity, and the I 浊 measured in step a); c) obtaining a first corrected fluorescence value I1 i by subtracting the Sca i calculated in step b) from the I i measured in step a); d) calculating a second corrected fluorescence value I2 i according to the I1 i and an extinction coefficient k; and e) calculating the algae classification concentration of the water sample to be measured according to the I2 i and a known fluorescence characteristic coefficient. The method provided by the present application can effectively improve the accuracy of the algae classification detection result, and is suitable for the detection of mixed algae, and has more practical significance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical analysis, and particularly relates to a turbidity compensation method for fluorescence method algae classification. BACKGROUND

[0002] Fast and accurate monitoring of algae concentration in water body is an important support for scientific and effective water bloom early warning and prevention. At present, the analysis of algae community is mainly based on the traditional analysis method of "field sampling-laboratory analysis", and the analysis method has long cycle, complicated steps, low measurement frequency and high cost, which cannot meet the needs of massive rapid data of water bloom prediction and early warning. The fluorescence method algae classification does not need sample pretreatment, has fast measurement speed and simple operation, and can provide a fast monitoring and early warning method for algae bloom outbreak.

[0003] At present, the fluorescence method algae classification monitoring mainly refers to the algae excitation fluorescence spectrum classification measurement method based on multi-wavelength LED. When the same kind of algae is excited by different wavelength unit intensity excitation light, the fluorescence intensity emitted is different. When different algae are excited by the same wavelength unit intensity excitation light, the fluorescence intensity emitted is also different. According to the known fluorescence characteristic coefficients of different algae, the fluorescence spectrum of the water sample collected during detection can be used to obtain the algae concentration of green algae, dinoflagellates, diatoms, blue-green algae and cryptophytes by using the non-negative least square method.

[0004] In addition to phytoplankton, there are many suspended particles in the water body, which are mainly derived from soil particles formed by ground erosion, and are usually quantified by "turbidity". The suspended particles have scattering or extinction effect on excitation light and fluorescence of living algae. The influence of turbidity on the detected fluorescence signal mainly includes: (1) in low turbidity water body, the scattering effect of particles on excitation light is stronger than the extinction effect of particles on excitation light, which causes the scattered light of excitation light to enter the detector, thereby increasing the detected signal; (2) in high turbidity water body, the extinction effect of particles on excitation light is stronger than the scattering effect of particles on excitation light, which causes the intensity of laser method to weaken, and the fluorescence intensity of living algae to weaken, thereby reducing the detected signal; (3) in high turbidity water body, the particles have absorption or extinction effect on the fluorescence of living algae, which causes the detected signal to decrease; (4) the fluorescence method algae classification is based on multi-wavelength excitation light, and the absorption and scattering of water body turbidity on different wavelengths of excitation light are different. In actual water body test, the particles have multiple effects on excitation light and fluorescence of living algae, which causes the detected fluorescence signal value to be high or low, and the detection result of algae classification concentration to have significant error.

[0005] At present, the fluorescence method algae classification method is affected by the turbidity of suspended solids in water body during detection, which causes low accuracy of the detection result of algae classification. SUMMARY

[0006] Therefore, the present application aims to provide a turbidity compensation method for fluorescence algae classification, which can effectively improve the accuracy of algae classification detection results.

[0007] The present application provides a turbidity compensation method for fluorescence algae classification, comprising the following steps:

[0008] a) sequentially irradiating a multi-wavelength excitation light to a water sample to be measured, and measuring the luminescence intensity of the water sample after excitation at each wavelength; wherein the multi-wavelength excitation light comprises a plurality of excitation lights with different wavelengths and in the range of 360-620 nm and one excitation light with a wavelength of 700-880 nm; the plurality of excitation lights with different wavelengths and in the range of 360-620 nm are used as fluorescence excitation light, and the measured luminescence intensity is defined as the fluorescence intensity of algae in the water body I i , wherein i represents the wavelength value; the excitation light with a wavelength of 700-880 nm is used as turbidity scattering light, and the measured luminescence intensity is defined as the turbidity scattering light intensity I 浊 ;

[0009] b) calculating the scattering light intensity Sca i corresponding to the fluorescence excitation light at each wavelength according to a previously established relationship between the turbidity scattering light intensity and the fluorescence excitation light scattering intensity, and the turbidity scattering light intensity I 浊 measured in step a);

[0010] c) subtracting the scattering light intensity Sca i corresponding to the fluorescence excitation light at each wavelength calculated in step b) from the fluorescence intensity I i of the algae in the water body after excitation at each wavelength measured in step a) to obtain a first corrected fluorescence value I1 i ;

[0011] d) calculating a second corrected fluorescence value I2 i corresponding to the fluorescence excitation light at each wavelength according to the first corrected fluorescence value I1 i and the extinction coefficient k;

[0012] e) calculating the algae classification concentration of the water sample to be measured by using a non-negative least square method according to the second corrected fluorescence value I2 i corresponding to the fluorescence excitation light at each wavelength calculated and the known fluorescence characteristic coefficient.

[0013] Preferably, the plurality of excitation lights with different wavelengths and in the range of 360-620 nm specifically comprises an excitation light with a wavelength of 440 nm, an excitation light with a wavelength of 470 nm, an excitation light with a wavelength of 530 nm, an excitation light with a wavelength of 570 nm, and an excitation light with a wavelength of 590 nm.

[0014] Preferably, the wavelength of the turbidity scattering light is 740 nm.

[0015] Preferably, the relationship between the intensity of turbidity-scattered light and the intensity of fluorescence-excited light scattering is established according to the following steps:

[0016] Prepare a gradient turbidity standard suspension free of algae;

[0017] Multiple wavelengths of excitation light were sequentially incident on a standard suspension, and the intensity of the scattered light Sca corresponding to each wavelength of fluorescence excitation light was measured. i The intensity of scattered light corresponding to turbidity scattered light I 浊 ;

[0018] Sca based on standard suspensions of different concentrations i and I 浊 The test results, and based on the equation Sca i =ai×I 浊 2 +bi×I 浊 +ci, and the relationship between the intensity of turbidity scattered light and the intensity of fluorescence excitation light scattered is obtained by fitting.

[0019] Preferably, the turbidity range of the gradient turbidity standard suspension is 0–105 NTU.

[0020] Preferably, the gradient turbidity standard suspension specifically includes a standard suspension with a turbidity of 0 NTU, a standard suspension with a turbidity of 15.3 NTU, a standard suspension with a turbidity of 36 NTU, a standard suspension with a turbidity of 63 NTU, and a standard suspension with a turbidity of 105 NTU.

[0021] Preferably, the extinction coefficient k is obtained according to the following steps:

[0022] Prepare gradient turbidity standard suspensions containing algal samples of the same concentration;

[0023] Multiple wavelengths of excitation light were sequentially incident on a standard suspension, and the fluorescence intensity I of the algae in the water corresponding to each wavelength of fluorescence excitation light was measured. i The intensity of scattered light corresponding to turbidity scattered light I 浊 ;

[0024] According to the I of standard suspensions of different concentrations i and I 浊 Based on the detection results, the attenuation rate of fluorescence intensity under different turbidities was calculated, and a turbidity scattered light intensity I was constructed. 浊 The linear relationship between the extinction coefficient k and the extinction coefficient k.

[0025] Preferably, the algal concentration of the gradient turbidity standard suspension is 1–100 μg / L; and the turbidity range of the gradient turbidity standard suspension is 0–105 NTU.

[0026] Preferably, the algal sample concentration of the gradient turbidity standard suspension is 20 μg / L; and the gradient turbidity standard suspension specifically comprises a standard suspension with a turbidity of 0 NTU, a standard suspension with a turbidity of 15.3 NTU, a standard suspension with a turbidity of 36 NTU, a standard suspension with a turbidity of 63 NTU and a standard suspension with a turbidity of 105 NTU.

[0027] Preferably, the detection device used comprises a light path system, a circuit system and a shell structure; the light path system comprises an excitation light source, a filter, a lens and a photodetector, wherein the excitation light source comprises a fluorescence excitation light source and a turbidity light source, the wavelength of the fluorescence excitation light source is 360-620 nm, and the wavelength of the turbidity light source is 700-880 nm; the circuit system comprises a light source driving control module and a signal acquisition and processing module.

[0028] Compared with the prior art, the present application provides a turbidity compensation method for fluorescence method algal classification, comprising the following steps: a) sequentially irradiating a plurality of wavelengths of excitation light into a water sample to be measured to measure the luminescence intensity of the water sample after excitation of each wavelength; wherein the plurality of wavelengths of excitation light comprises a plurality of excitation lights with different wavelengths and in the range of 360-620 nm and one excitation light with a wavelength of 700-880 nm; the plurality of excitation lights with different wavelengths and in the range of 360-620 nm are used as fluorescence excitation light, and the measured luminescence intensity is defined as the fluorescence intensity I i of the water body algae, wherein i represents the wavelength value; the excitation light with a wavelength of 700-880 nm is used as turbidity scattering light, and the measured luminescence intensity is defined as the turbidity scattering light intensity I 浊 ; b) according to a previously established relationship between the turbidity scattering light intensity and the fluorescence excitation light scattering intensity, and the turbidity scattering light intensity I 浊 measured in step a), the scattering light intensity Sca i corresponding to each wavelength of fluorescence excitation light is calculated; c) the fluorescence intensity I i of the water body algae after excitation of each wavelength measured in step a) is subtracted by the scattering light intensity Sca i corresponding to each wavelength of fluorescence excitation light calculated in step b), to obtain a first modified fluorescence value I1 i ; d) according to the first modified fluorescence value I1 i and the extinction coefficient k, the second modified fluorescence value I2 i corresponding to each wavelength of fluorescence excitation light is calculated; e) according to the second modified fluorescence value I2 i corresponding to each wavelength of fluorescence excitation light calculated and the known fluorescence characteristic coefficient, the non-negative least square method is used to calculate the algal classification concentration of the water sample to be measured. The method provided by the present application can effectively improve the accuracy of the algal classification detection result, is suitable for mixed algal detection, and has more practical significance in the actual algal classification detection of water bodies. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 The turbidity scattered light intensity I provided in Embodiment 1 of the present invention 740 Curves showing the variation of scattered light intensity Scai corresponding to different wavelengths of fluorescent excitation light;

[0031] Figure 2 This is a graph showing the relationship between the intensity of turbidity scattered light and the extinction coefficient k provided in Embodiment 1 of the present invention. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0033] This invention provides a turbidity compensation method for algal classification using fluorescence, comprising the following steps:

[0034] a) Multi-wavelength excitation light is sequentially incident on the water sample to be tested, and the luminescence intensity of the water sample after excitation at each wavelength is measured; wherein, the multi-wavelength excitation light includes multiple excitation lights of different wavelengths in the range of 360-620 nm and one excitation light with a wavelength of 700-880 nm; the multiple excitation lights of different wavelengths in the range of 360-620 nm are used as fluorescence excitation light, and the measured luminescence intensity is defined as the fluorescence intensity I of the algae in the water. i i represents the wavelength value; the excitation light with a wavelength of 700–880 nm is used as turbidity scattered light, and the measured luminescence intensity is defined as the turbidity scattered light intensity I. 浊 ;

[0035] b) Based on the pre-established relationship between the intensity of turbidity scattered light and the intensity of fluorescence excitation light scattering, and the turbidity scattered light intensity I measured in step a), 浊 Calculate the scattered light intensity Sca corresponding to each wavelength of fluorescence excitation light. i ;

[0036] c) The fluorescence intensity I of algae in the water after excitation at each wavelength, as measured in step a). iSubtracting the scattering light intensity Sca corresponding to each wavelength of fluorescence excitation light calculated in step b) i to obtain the primary corrected fluorescence value I1 i ;

[0037] d) According to the primary corrected fluorescence value I1 i and the extinction coefficient k, the secondary corrected fluorescence value I2 i corresponding to each wavelength of fluorescence excitation light is calculated.

[0038] e) According to the secondary corrected fluorescence value I2 i corresponding to each wavelength of fluorescence excitation light calculated and the known fluorescence characteristic coefficient, the algal classification concentration of the water sample to be measured is calculated by using the non-negative least square method.

[0039] In the method provided by the present application, the multiple wavelengths of excitation light different from each other and in the range of 360-620 nm preferably include excitation light with a wavelength of 440 nm, excitation light with a wavelength of 470 nm, excitation light with a wavelength of 530 nm, excitation light with a wavelength of 570 nm and excitation light with a wavelength of 590 nm.

[0040] In the method provided by the present application, the wavelength of the turbidity scattering light is preferably 740 nm.

[0041] In the method provided by the present application, the relationship between the turbidity scattering light intensity and the fluorescence excitation light scattering intensity is established according to the following steps:

[0042] A gradient turbidity standard suspension without algal sample is configured;

[0043] Multiple wavelengths of excitation light are sequentially incident on the standard suspension, and the scattering light intensity Sca i corresponding to each wavelength of fluorescence excitation light and the scattering light intensity I 浊 corresponding to turbidity scattering light are measured.

[0044] According to the Sca i and I 浊 detection results of the standard suspensions with different concentrations, and according to the equation Sca i = ai × I 浊 2 + bi × I 浊 + ci, the relationship between the turbidity scattering light intensity and the fluorescence excitation light scattering intensity is fitted.

[0045] In the method provided by the present application, the turbidity range of the gradient turbidity standard suspension without algae is preferably 0-105 NTU. In the specific embodiments of the present application, the gradient turbidity standard suspension with the same concentration of algae specifically can include a standard suspension with a turbidity of 0 NTU, a standard suspension with a turbidity of 15.3 NTU, a standard suspension with a turbidity of 36 NTU, a standard suspension with a turbidity of 63 NTU, and a standard suspension with a turbidity of 105 NTU.

[0046] In the method provided by the present application, the extinction coefficient k is specifically obtained according to the following steps:

[0047] A gradient turbidity standard suspension with the same concentration of algae is configured;

[0048] The multi-wavelength excitation light is sequentially incident on the standard suspension, and the fluorescence intensity I i of the algae in the water body corresponding to the fluorescence excitation light of each wavelength is measured. 浊 ;

[0049] According to the detection results of I i and I 浊 of the standard suspensions with different concentrations, the attenuation rate of the fluorescence intensity under different turbidities is calculated, and a linear relationship between the scattering light intensity I 浊 and the extinction coefficient k is constructed.

[0050] In the method provided by the present application, the concentration of algae in the gradient turbidity standard suspension with the same concentration of algae is preferably 1-100 μg / L, and more preferably 20 μg / L.

[0051] In the method provided by the present application, the turbidity range of the gradient turbidity standard suspension with the same concentration of algae is preferably 0-105 NTU. In the specific embodiments of the present application, the gradient turbidity standard suspension with the same concentration of algae specifically can include a standard suspension with a turbidity of 0 NTU, a standard suspension with a turbidity of 15.3 NTU, a standard suspension with a turbidity of 36 NTU, a standard suspension with a turbidity of 63 NTU, and a standard suspension with a turbidity of 105 NTU.

[0052] In the method provided by the present application, the detection device used preferably includes an optical system, a circuit system, and a shell structure. In the present application, the optical system preferably includes an excitation light source, a filter, a lens, and a photodetector; wherein the excitation light source includes a fluorescence excitation light source and a turbidity light source, the wavelength of the fluorescence excitation light source is preferably 360-620 nm, and the wavelength of the turbidity light source is preferably 700-880 nm. In the present application, the circuit system preferably includes a light source driving control module and a signal acquisition processing module.

[0053] The method provided by this invention can effectively improve the accuracy of algae classification and detection results, and is applicable to the detection of mixed algae, making it more practical in algae classification and detection in actual water bodies.

[0054] For clarity, the following examples and comparative models will be used to provide a detailed description.

[0055] Example 1

[0056] (1) Establishment of the relationship between the intensity of turbidity-scattered light and the intensity of fluorescence-excited light scattering

[0057] Standard suspensions with turbidity of 0 NTU, 15.3 NTU, 36 NTU, 63 NTU, and 105 NTU were prepared. Multi-wavelength excitation light (440 nm, 470 nm, 530 nm, 570 nm, 590 nm, and 740 nm) was sequentially incident on the standard suspension water samples. The intensity of the scattered light (Sca) after each wavelength of fluorescence excitation light (440 nm, 470 nm, 530 nm, 570 nm, and 590 nm) incident on the water sample was measured. 440 Sca 470 Sca 530 Sca 570 Sca 590 The intensity of the scattered light I after turbidity scattered light (wavelength 740nm) is incident on the water sample 740 As shown in the table below:

[0058] Table 1. Scattered light intensity measured from standard suspensions excited by different excitation lights.

[0059] Turbidity (NTU) value 440 value 470 value 530 value 570 value 590 value 740 0 0 0 14 0 0 291 15.3 2 1 45 36 303 4316 36 9 8 80 92 761 8610 63 19 17 126 170 1390 12617 105 34 30 200 300 2450 16792

[0060] Turbidity scattered light intensity I 740 The variation of the scattered light intensity Scai corresponding to each wavelength of fluorescence excitation light is as follows: Figure 1 As shown, the relationship between the intensity of turbidity-scattered light and the intensity of fluorescence-excited light scattering is established (1):

[0061] Sca 440 =1E-07×I 740 2 -8E-05×I 740 -0.0878;

[0062] Sca 470 =1E-07×I 740 2 +0.0001×I 740 -0.3364;

[0063] Sca 530 =4E-07×I 740 2 +0.0038×I 740+15.589;

[0064] Sca 570 =9E-07×I 740 2 +0.0026×I 740 +2.309;

[0065] Sca 590 =7E-06×I 740 2 +0.024×I 740 +18.832.

[0066] (2) Establishment of the relationship between turbidity scattered light intensity and extinction coefficient

[0067] Equal volumes of algal solution were added to standard suspensions with turbidities of 0 NTU, 15.3 NTU, 36 NTU, 63 NTU, and 105 NTU, respectively, to ensure an algal concentration of 20 μg / L in each solution. Multi-wavelength excitation light (440 nm, 470 nm, 530 nm, 570 nm, 590 nm, and 740 nm) was sequentially incident on the water samples, and the fluorescence intensity I after each wavelength of fluorescence excitation light (440 nm, 470 nm, 530 nm, 570 nm, and 590 nm) was measured. 440 I 470 I 530 I 570 I 590 The intensity of the scattered light I after turbidity scattered light (wavelength 740nm) is incident on the water sample 740 As shown in the table below:

[0068] Table 2. Detection light intensities measured for live algae standard suspensions excited by different excitation lights.

[0069] Turbidity (NTU) value 440 value 470 value 530 value 570 value 590 value 740 0 689 506 645 262 606 335 15.3 652 479 641 282 880 4234 36 577 419 616 314 1276 8588 63 465 357 595 357 1840 12436 105 451 314 613 464 2823 16410

[0070] According to the I measured in (2) i Subtract the Sca measured in (1) i The fluorescence values ​​of the algal solution at each excitation wavelength were calculated, and then the extinction coefficient k was obtained by dividing the fluorescence values ​​calculated at different turbidities by the fluorescence values ​​in a solution with a turbidity of 0 NTU.

[0071] Table 3. Extinction coefficients measured from standard suspensions containing live algae excited under different excitation lights.

[0072] Turbidity (NTU) value 440 value 470 value 530 value 570 value 590 0 1.00 1.00 1.00 1.00 1.00 15.3 0.94 0.94 0.94 0.94 0.95 36 0.82 0.81 0.85 0.85 0.85 63 0.65 0.67 0.74 0.72 0.74 105 0.61 0.56 0.65 0.63 0.61

[0073] like Figure 2 As shown, the relationship between the intensity of turbidity scattered light and the extinction coefficient k is established (2):

[0074] k = -3E-05 x I 740 + 1.0308.

[0075] (3) Fluorescence method of algae classification turbidity compensation

[0076] ① Configure different turbidity, different algae solution water sample, multi-wavelength excitation light (440 nm, 470 nm, 530 nm, 570 nm, 590 nm, 740 nm) incident water sample in turn, the fluorescence intensity I of algae in water body excited by each wavelength of fluorescence excitation light (440 nm, 470 nm, 530 nm, 570 nm, 590 nm) incident water sample is measured i (i is wavelength) and turbidity scattering light (wavelength 740 nm) incident water sample after the scattering light intensity I 浊 ;

[0077] Table 4 Detection light intensity measured by different excitation light excitation of living algae standard suspension

[0078] Water sample value 440 value 470 value 530 value 570 value 590 value 740 Water sample 1 3949 3712 667 399 2066 11793 Water sample 2 348 164 1419 1488 7452 12001 Water sample 3 1510 976 956 248 1474 11386 Water sample 4 552 527 836 450 1850 12244 Water sample 5 2062 1503 1792 698 3324 12355

[0079] ② According to the relationship between turbidity scattering light intensity and fluorescence excitation light scattering intensity (1), and the turbidity scattering light intensity of 740 nm, the scattering light intensity Sca corresponding to each wavelength of fluorescence excitation light is calculated i ;

[0080] ③ The fluorescence intensity I of algae in water body excited by each wavelength of fluorescence excitation light is detected i Subtract the scattering light intensity Sca corresponding to each wavelength of fluorescence excitation light calculated i , get the first modified fluorescence value I1 i ;

[0081] ④ According to the relationship between turbidity scattering light intensity and extinction coefficient k (2), and I1 i , the second modified fluorescence value I2 corresponding to each wavelength of fluorescence excitation light is calculated i ;

[0082] ⑤ According to the second modified fluorescence value I2 corresponding to each wavelength of fluorescence excitation light calculated i And the known fluorescence characteristic coefficient, the algae classification concentration is calculated by using non-negative least square method, and the calculation results are shown in table 5.

[0083] Comparative example 1

[0084] Referring to example 1, according to the fluorescence value I corresponding to each wavelength of fluorescence excitation light detected i And the known fluorescence characteristic coefficient, the algae classification concentration without turbidity compensation is calculated by using non-negative least square method, and the calculation results are shown in table 5.

[0085] Comparative example 2

[0086] (1) Turbidity interference coefficient determination: Configure standard suspensions with turbidity of 0 NTU, 15.3 NTU, 36 NTU, 63 NTU and 105 NTU, and multiple wavelength excitation light (440 nm, 470 nm, 530 nm, 570 nm and 590 nm) is incident on the standard suspension water sample in turn, and the scattering light intensity Sca 440 470 530 570 590 See Table 1.

[0087] (2) Calculate the linear relationship between the scattering light intensity and the turbidity concentration under different excitation wavelengths to obtain the turbidity interference coefficient, and the turbidity interference coefficient and the fluorescence characteristic coefficient of algae together constitute the fluorescence characteristic coefficient.

[0088] (3) According to the fluorescence value I i corresponding to each wavelength of the fluorescence excitation light detected and the known fluorescence characteristic coefficient, the non-negative least square method is used to calculate the algae classification concentration, and the calculation results are shown in Table 5.

[0089] Results comparison

[0090] Table 5 Comparison of calculation results of different turbidity compensation methods

[0091]

[0092]

[0093] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.​​​​

Claims

1. A turbidity compensation method for algal classification using fluorescence, characterized in that, Includes the following steps: a) Multi-wavelength excitation light is sequentially incident on the water sample to be tested, and the luminescence intensity of the water sample after excitation at each wavelength is measured; wherein, the multi-wavelength excitation light includes multiple excitation lights of different wavelengths in the range of 360-620 nm and one excitation light with a wavelength of 700-880 nm; the multiple excitation lights of different wavelengths in the range of 360-620 nm are used as fluorescence excitation light, and the measured luminescence intensity is defined as the fluorescence intensity I of the algae in the water. i , where i represents the wavelength value; The excitation light with a wavelength of 700–880 nm is used as turbidity scattered light, and the measured luminescence intensity is defined as the turbidity scattered light intensity I. 浊 ; b) Based on the pre-established relationship between the intensity of turbidity scattered light and the intensity of fluorescence excitation light scattering, and the turbidity scattered light intensity I measured in step a), 浊 Calculate the scattered light intensity Sca corresponding to each wavelength of fluorescence excitation light. i ; c) The fluorescence intensity I of algae in the water after excitation at each wavelength, as measured in step a). i Subtract the scattered light intensity Sca corresponding to each wavelength of fluorescence excitation light calculated in step b). i A corrected fluorescence value I1 was obtained. i ; d) Based on the first corrected fluorescence value I1 i Based on the extinction coefficient k, the second-corrected fluorescence value I2 corresponding to the fluorescence excitation light at each wavelength is calculated. i ; e) Based on the calculated secondary correction fluorescence value I2 corresponding to each wavelength of fluorescence excitation light. i Using known fluorescence characteristic coefficients, the algal classification concentration of the water sample to be tested was calculated using the non-negative least squares method.

2. The turbidity compensation method for algal classification using fluorescence as described in claim 1, characterized in that, The multiple excitation lights with different wavelengths and in the range of 360 to 620 nm specifically include excitation light with a wavelength of 440 nm, excitation light with a wavelength of 470 nm, excitation light with a wavelength of 530 nm, excitation light with a wavelength of 570 nm, and excitation light with a wavelength of 590 nm.

3. The turbidity compensation method for algal classification using fluorescence as described in claim 1, characterized in that, The wavelength of the turbidity-scattered light is 740 nm.

4. The turbidity compensation method for algal classification using fluorescence as described in claim 1, characterized in that, The relationship between the intensity of turbidity scattered light and the intensity of fluorescence excitation light scattered light is established according to the following steps: Prepare a gradient turbidity standard suspension free of algae; Multiple wavelengths of excitation light were sequentially incident on a standard suspension, and the intensity of the scattered light Sca corresponding to each wavelength of fluorescence excitation light was measured. i The intensity of scattered light corresponding to turbidity scattered light I 浊 ; Sca based on standard suspensions of different concentrations i and I 浊 The test results, and based on the equation Sca i =ai×I 浊 2 +bi×I 浊 +ci, and the relationship between the intensity of turbidity scattered light and the intensity of fluorescence excitation light scattered is obtained by fitting.

5. The turbidity compensation method for algal classification using fluorescence as described in claim 4, characterized in that, The turbidity range of the gradient turbidity standard suspension is 0–105 NTU.

6. The turbidity compensation method for algal classification by fluorescence method according to claim 5, characterized in that, The gradient turbidity standard suspensions specifically include standard suspensions with a turbidity of 0 NTU, 15.3 NTU, 36 NTU, 63 NTU, and 105 NTU.

7. The turbidity compensation method for algal classification by fluorescence method according to claim 1, characterized in that, The extinction coefficient k is obtained according to the following steps: Prepare gradient turbidity standard suspensions containing algal samples of the same concentration; Multiple wavelengths of excitation light were sequentially incident on a standard suspension, and the fluorescence intensity I of the algae in the water corresponding to each wavelength of fluorescence excitation light was measured. i The intensity of scattered light corresponding to turbidity scattered light I 浊 ; According to the I of standard suspensions of different concentrations i and I 浊 Based on the detection results, the attenuation rate of fluorescence intensity under different turbidities was calculated, and a turbidity scattered light intensity I was constructed. 浊 The linear relationship between the extinction coefficient k and the extinction coefficient k.

8. The turbidity compensation method for algal classification by fluorescence method according to claim 7, characterized in that, The algal concentration of the gradient turbidity standard suspension is 1–100 μg / L; the turbidity range of the gradient turbidity standard suspension is 0–105 NTU.

9. The turbidity compensation method for algal classification by fluorescence method according to claim 8, characterized in that, The algal sample concentration of the gradient turbidity standard suspension is 20 μg / L; the gradient turbidity standard suspension specifically includes a standard suspension with a turbidity of 0 NTU, a standard suspension with a turbidity of 15.3 NTU, a standard suspension with a turbidity of 36 NTU, a standard suspension with a turbidity of 63 NTU and a standard suspension with a turbidity of 105 NTU.

10. The turbidity compensation method for algal classification by fluorescence method according to claim 1, characterized in that, The detection device used includes an optical path system, a circuit system, and a housing structure; the optical path system includes an excitation light source, a filter, a lens, and a photodetector, wherein the excitation light source includes a fluorescent excitation light source and a turbidity light source, the wavelength of the fluorescent excitation light source is 360-620nm, and the wavelength of the turbidity light source is 700-880nm; the circuit system includes a light source drive control module and a signal acquisition and processing module.

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