CN109030842B - A kind of nutrients in sea water in-situ study device - Google Patents

Abstract

The invention discloses an in-situ analysis device for seawater nutrient salts, which includes a measurement control and photoelectric conversion module, a sampling module, a power supply module, an underwater in-situ filtration module, a reagent and standard sample storage module, and a colorimetric analysis and measurement module; The underwater in-situ filtration module and plunger pump are installed in the first cabin, the colorimetric analysis measurement module, automatic selection valve head, reagent and standard sample storage module are installed in the second cabin, the power supply module, measurement control and photoelectric conversion The module is installed in the third cabin, and the two adjacent cabins are isolated and sealed from each other, and all the liquid flow paths and joints are placed outside the cabin. This device clearly divides the optical, electromechanical and hydraulic system. The optical, electrical and mechanical rotating parts are all sealed and assembled, and the hydraulic part is all placed in the water environment. Leakage, the optomechanical part of the main body of the instrument is still very safe.

Description

A device for in-situ analysis of seawater nutrients

technical field

The invention relates to a seawater analysis device, in particular to a seawater nutrient salt in-situ analysis device.

Background technique

Nutrients such as N, P, and Si in seawater are the basis of the marine food chain, and the study of nutrient content or distribution characteristics in seawater is the basis for studying marine biogeochemical cycle processes.

At present, the detection of seawater nutrients mainly adopts on-site sampling, which is brought back to the ship or shore station laboratory for pretreatment and measurement. This method has low work efficiency, samples are easily polluted, and it is difficult to realize long-term serial monitoring of nutrients in seawater. , especially for deep-sea ecological environment monitoring and time-series early warning and forecasting, the above detection methods are even more powerless. In recent years, with the continuous development and progress of marine monitoring technology, the detection technology of nutrient salts in seawater is gradually moving from the laboratory to on-site online to in-situ measurement. In my country, the research on in-situ detection technology of nutrient salts is still at the stage In the initial stage, the mature technology is still blank. With the continuous deepening of ocean understanding, China has begun to pay attention to the in-situ measurement technology of seawater nutrients, but the technology is still immature.

Patent document CN206863042U discloses "a portable seawater nutrient salt automatic analysis device". The device is based on the national standard wet chemical colorimetric measurement method. Or reagent leakage can cause catastrophic damage to the instrument. In addition, traditional cuvettes are mostly used for colorimetric measurement sample cells at present, which consumes a lot of reagents and samples, has strong light attenuation, and has low detection sensitivity.

Contents of the invention

The object of the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a kind of seawater nutrient salt in-situ analysis device with high safety in use

For realizing the above object, technical scheme of the present invention is:

An in-situ analysis device for seawater nutrients, including a measurement control and photoelectric conversion module, a sample selection module, a power supply module, an underwater in-situ filtration module, a reagent and standard sample storage module, and a colorimetric analysis and measurement module; wherein,

The power supply module is electrically connected to the measurement control and photoelectric conversion module and the sampling module respectively, so as to provide power for the work of the measurement control and photoelectric conversion module and the sampling module;

The measurement control and photoelectric conversion module includes a measurement control unit and a photoelectric conversion unit;

The underwater in-situ filtration module is used to filter the collected seawater;

The sampling module is connected with the underwater in-situ filtration module for sampling the filtered seawater; the sampling module is also connected with the measurement control unit, and the measurement control unit controls the sampling the work of the module;

The reagent and standard sample storage module is composed of a plurality of reagent boxes and standard sample boxes, and the sample selection module is connected with the kits and standard sample boxes with a liquid path to transfer the reagents and samples to the sample selection module;

The colorimetric analysis measurement module is connected with the sample selection module with a phase liquid path for measuring and analyzing the sample collected by the sample selection module; the photoelectric conversion unit is connected with the colorimetric analysis measurement module for colorimetric analysis measurement The work of the module provides the amount of light;

The sampling module includes a plunger pump and a fully automatic selection valve head, and the plunger pump is used to pump the filtered seawater, reagents, standard samples, etc. in the kit to the fully automatic selection valve head, and the automatic selection There are several liquid joints outside the valve head.

The underwater in-situ filtration module and the plunger pump are installed in the first cabin, the colorimetric analysis measurement module, the fully automatic selection valve head and the reagent and standard sample storage module are installed in the second cabin, and the power supply module, measurement control and The photoelectric conversion module is installed in the third cabin; the first cabin, the second cabin, and the third cabin are arranged vertically from low to high, and the adjacent two cabins are isolated and sealed from each other, and all the liquid flow paths and The joints are all placed outside the cabin body.

A watertight cable connector for power supply and communication with the upper computer is installed on the upper end cover of the third cabin; an optical fiber or signal cable sealing joint group for transmitting photoelectric signals is installed in the lower end cover of the third cabin, The power supply cable watertight connector group of the sampling module is also installed in the lower end cover of the three-chamber body.

The liquid outlets of the kit and the standard sample box are connected through the male and female through-the-plate buckle joints and the external liquid joints of the automatic valve selection head; It is connected with the liquid outlet of the standard sample box, and the female/male end of the male-female plate-through buckle joint is connected through a corrosion-resistant hose to the liquid joint outside the fully automatic selection valve head, and the male and female through-plate buckle is disconnected. , the liquid path is cut off, the kit and the standard sample box are in a closed state, connected to the male and female plate-through buckles, the liquid path is connected, the reagent in the kit is connected to the fully automatic selection valve head; the kit and the standard sample box are composed of It is made of blackout material and the surface color is different.

The lower ends of the kit and the standard sample box are provided with a joint mounting plate, and the joint mounting plate is provided with male and female through-plate sleeve buckle joint mounting screw holes, mounting fixing rods, automatic sampling module fixing holes and cables. Via.

The colorimetric analysis measurement module includes a colorimetric measurement sample cell; the colorimetric measurement sample cell is composed of a liquid core waveguide and a "Z" type optical-liquid coupling joint assembled at both ends of the liquid core waveguide, and the liquid core waveguide The length can be adjusted arbitrarily according to needs, and the diameter of the liquid core waveguide is adjustable within the range of 1500um; the optical-liquid coupling port of the optical-liquid coupling joint is designed with a watertight structure.

The photoelectric conversion unit is composed of an optical fiber, a light source power supply control subunit, and an optical fiber input type spectrum monitoring subunit. The optical fiber is inserted into the optical output port of the optical liquid coupling joint, and the colorimetric photometric signal is connected to the optical fiber input type through optical communication. In the spectrum monitoring subunit; an optical fiber is inserted into the optical input port of the optical-liquid coupling joint, so that the output optical energy of the optical fiber is introduced into the colorimetric measurement sample cell through the optical fiber.

The photoelectric conversion unit is composed of a light source power supply control subunit and an analog electrical signal processing subunit; a photodetector is installed at the light output port of the optical liquid coupling joint, and the photoelectric detection is carried out by comparing the color photometric signal, and the photoelectric detection signal is electrically connected Connecting to the analog electrical signal processing subunit; installing a light source at the optical input port of the light-liquid coupling joint, and electrically connecting the power supply control between the light source and the light source power supply control subunit.

The power supply control module is a magnetic control switch to control the power supply process through an external magnet in a non-contact manner.

The underwater in-situ filtration module is composed of an outer filter and an inner filter core. The outer filter is sintered from titanium powder or 316 stainless steel powder. The inner filter core is composed of a sintered rod with a pore size. The aperture of the mesh is larger than that of the sintered rod; the sintered rod is titanium powder or 16 stainless steel powder or copper powder sintered rod.

The liquid input joint of the Z-type light-liquid coupling joint in the water inlet of the colorimetric measurement sample pool is connected to one of the several joints outside the fully automatic selection valve head in a watertight connection through a corrosion-resistant pipeline. The colorimetric measurement sample The liquid output joint of the Z-type light-liquid coupling joint at the pool outlet is watertightly connected to the waste liquid collection bag through a corrosion-resistant waste discharge pipeline. The waste liquid collection bag is higher than the colorimetric analysis and measurement module to achieve smooth exhaust and waste discharge.

Compared with the prior art, the present invention has the beneficial effects of:

1. The seawater nutrient in-situ measurement device of the present invention clearly divides the optical, electromechanical and liquid circuit systems. The optical, electrical and mechanical rotating parts are all sealed and assembled, and the liquid circuit parts are all placed outside the water environment. Even if an accident occurs In the event of pipeline rupture and loose joints leading to liquid leakage, the optical, electromechanical and electrical parts of the instrument are still very safe, which is an added advantage and breakthrough for wet chemical analysis.

2. The structure design of the present invention is compact and flexible, easy to disassemble and assemble, and the measurement process can be completed automatically in situ in combination with the physical and chemical environment of the sample, and only need to replace the light source; it can be used for in situ of various heavy metals, nutrient salts and other environmental parameters Measurement has a broad application market and good application prospects.

3. The sample cell used in the present invention has high sensitivity, wide application range, and small amount of samples and reagents. It is very suitable for underwater long-term in-situ monitoring and early warning. By adjusting the length of the sample cell, extremely low concentration and wide dynamic range can be realized. High sensitivity detection of chemical elements such as range nutrients.

Description of drawings

Fig. 1 is the structural schematic diagram of the seawater nutrient salt in-situ analysis device provided by the embodiment of the present invention;

Fig. 2 is the structural representation of colorimetric measurement sample cell;

Fig. 3 is a schematic diagram of the structure of the joint installed over the board;

Fig. 4 is the structural representation of the upper end cover of the third cabin;

Fig. 5 is the structural representation of the lower end cover of the third cabin;

In the figure: 1. Measurement control and photoelectric conversion module; 2. Sample selection module; 3. Underwater in-situ filtration module; 4. Reagent and standard sample storage module; 5. Colorimetric analysis measurement module; 6. Connector installed 7, the first cabin body; 8, the second cabin body; 9, the third cabin body; 51, the colorimetric measurement sample pool; 61, the installation screw hole; 62, the reagent and the standard sample storage box installation fixing hole; 91 , Communication and power supply watertight cable joint; 91. Cable sealing joint group; 93. Power supply cable watertight joint group; 511. Liquid core waveguide; 512. Light-liquid coupling joint; 5120. Optical output port; 5121. Optical input port; 5122 , Liquid input connector; 5123, Liquid output connector.

Detailed ways

The content of the present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Example:

Referring to Figures 1-5, a device for in-situ analysis of seawater nutrients provided by this embodiment includes a measurement control and photoelectric conversion module 1, a sampling module 2, a power supply module (not shown), and an underwater in-situ filter module 3 , a reagent and standard sample storage module 4 , and a colorimetric analysis measurement module 5 .

Wherein, the power supply module is electrically connected with the measurement control and photoelectric conversion module 1 and the sampling module 2 respectively, so as to provide power for the work of the measurement control and photoelectric conversion module 1 and the sampling module 2. Specifically, the power supply module mainly It is a magnetic control switch, which can control the power supply process in a non-contact manner through an external magnet, so as to facilitate the adjustment and control of the power supply process, and the measurement control and photoelectric conversion module 1 is mainly composed of two parts: a measurement control unit and a photoelectric conversion unit.

The underwater in-situ filtration module 3 is used to filter the collected seawater. The underwater in-situ filtration module provided by the application is a miniature multi-stage filtration device. In order to reduce the volume of the instrument, the filtration device is patented The document CN102553325B discloses "an underwater in-situ filtration device" which is optimized on the basis of an external filter and an inner filter core. In order to ensure the reliability of in-situ filtration, the external filter is made of titanium Powder or 316 stainless steel powder sintered, with good rigidity, pressure without deformation, and the inner filter element is composed of sintered rod with a certain aperture, the sintered rod can choose titanium powder, 316 stainless steel powder or copper powder sintered rod, in addition , In order to increase the corrosion resistance of the filter device, the sintered rod is made of copper sintered rod, and the pore size of the outer filter is larger than that of the inner filter rod.

The sample selection module 2 is mainly composed of a high-precision plunger pump and its electromechanical drive device for sample pumping and mixing, and a fully automatic selection valve head and its electromechanical drive device for sample and reagent selection. There are M (M>1) liquid joints outside the valve head, and the underwater in-situ filtration module 3 communicates with one of the M joints outside the fully automatic selection valve head through a corrosion-resistant pipe fitting to realize the The filtered seawater is sampled; in addition, in order to adapt to different sea areas and different sample filtration requirements, more than N (N ≥ 1) filter modules 3 can be installed, and the work of the sample selection module 2 is mainly controlled by the control unit of.

The reagent and standard sample storage module 4 is composed of a plurality of reagent boxes and standard sample boxes. In order to ensure the long-term reliability of the reagents, the reagent and standard sample boxes are made of light-shielding materials. The fluid connection between the liquid path joints is to increase the safety of the instrument and avoid leakage of the standard sample and reagent in the kit. Preferably, a joint with a cut-off function is connected to the liquid outlet of the kit and the standard sample box. The cut-off function joint is Male and female through-plate buckle structure, the male/female end of the joint is connected to the liquid outlet of the kit, and the other end of the joint, the female/male joint through the plate, is connected to the fully automatic selection valve head through a corrosion-resistant hose, disconnect the buckle , the liquid path is cut off, the reagent kit and the standard sample box are in a closed state, the sleeve button is connected, the liquid path is connected, and the reagents and standard samples in the kit and the standard sample box are connected to the fully automatic selection valve. Furthermore, in order to improve the safety of the instrument and avoid misconnection, the reagent and standard sample boxes are designed in different colors. At the same time, in order to increase the safety and flexibility of the use of the reagent box and the standard sample box, as shown in Figure 3, a cut-off function connector is designed at the lower end of the reagent and standard sample box to install the overboard 6, and the overboard is designed with a cutoff function Mounting screw holes 61 for the through-board connector, mounting and fixing holes 62 for reagent and standard sample storage boxes, fixing holes for the automatic sample selection module and cable through holes. One end connected to the automatic sample selection module in the cut-off function joint of the passing board is fixed on the passing board through the mounting screw hole 61 .

The colorimetric analysis and measurement module 5 is mainly composed of a colorimetric measurement sample pool 51. As shown in Figure 2, the colorimetric measurement sample pool 51 is composed of a total reflection AF-2400 liquid core waveguide 511 and a liquid core waveguide assembled on both sides of the liquid core waveguide. The length of the liquid core waveguide 511 can be adjusted arbitrarily according to the needs, and the diameter of the liquid core waveguide 511 can be adjusted within the range of 1500um; in order to be safe and suitable for in-situ measurement, the " The light-liquid coupling port 512 of the Z" type light-liquid coupling joint is designed with a watertight structure. In addition, in order to expand the use range of the colorimetric measurement sample cell and increase the flexibility of its use; the photoelectric conversion unit has two designs: the first one, the photoelectric conversion unit is composed of an optical fiber output light source, a light source power supply control subunit and an optical fiber input type Spectrum monitoring sub-units; the second type, the photoelectric conversion unit is composed of a light source power supply control sub-unit and an analog electrical signal processing sub-unit; and the optical output port 5120 in the optical-liquid coupling joint 512 has two designs: the first type is, A photodetector is directly installed at the light output port 5120 to perform photoelectric detection against the color photometric signal, and the photoelectric detection signal is connected to the analog electrical signal processing subunit through an electrical connection. The second is to insert an optical fiber into the optical output port 5120, and connect the colorimetric photometric signal to the optical fiber input spectrum monitoring subunit in the measurement and photoelectric conversion unit through optical connection. Correspondingly, there are two designs of the light input port 5121 in the light-liquid coupling joint 512: the first one is that the light source is directly installed on the light input port 5121, and the light source is connected to the corresponding light source power supply control subunit in the measurement control and photoelectric conversion module. Electrically connected to supply control. The second is to connect the optical fiber to the optical input port 5121 in the optical-liquid coupling connector, and introduce the optical fiber output type optical energy provided in the measurement control and photoelectric conversion module into the colorimetric measurement sample cell through the optical fiber, and the colorimetric measurement sample cell The liquid input joint 5122 of the "Z" type light-liquid coupling joint at the water inlet is connected with one of the M joints outside the automatic selection valve head in a watertight connection through a corrosion-resistant pipeline, and the "Z" at the water outlet of the sample cell is measured colorimetrically. The liquid output joint 5123 of the "type light-liquid coupling joint is connected watertightly with the waste liquid collection bag through a corrosion-resistant waste discharge pipeline, and the waste liquid collection bag is hung slightly above the upper part of the measurement through the waste liquid bag hook to ensure the exhaust of the sampling system Waste discharge is smooth.

The above-mentioned underwater in-situ filtration module 3 and the plunger pump are installed in the first cabin 7, the colorimetric analysis measurement module 5, the fully automatic selection valve head and the reagent and standard sample storage module 4 are installed in the second cabin 8, The power supply module, measurement control and photoelectric conversion module 1 are installed in the third cabin 9; the first cabin 7, the second cabin 8, and the third cabin 9 are vertically arranged in sequence from low to high, and the adjacent two cabins They are isolated and sealed from each other, and all liquid flow paths and joints are placed outside the cabin. That is to say, all electronic systems, optical systems and mechanical moving parts of the device are sealed in the airtight cabin, and all liquid flow paths and joints are placed outside the water body to ensure that the liquid flow paths are in harmony with light, machinery, and electricity. The components are completely isolated to avoid fatal damage to key components such as optical, electromechanical, etc. due to leakage of the liquid pipeline of the instrument or damage to the joint. At the same time, the device is designed into a three-layer structure, which is convenient for installation, disassembly and safe and effective work in situ .

In addition, in order to further improve the safe use of the device, a communication and power supply watertight cable connector 91 for power supply and communication with the upper computer is installed on the upper end cover of the third cabin; An optical fiber or a signal cable sealing connector group 92 for transmitting photoelectric signals is installed in the middle, and a power supply cable watertight connector group 93 of the sampling module is also installed in the lower end cover of the three cabins.

The usage method of the seawater nutrient salt in-situ measurement device is as follows:

S1. Connect the cut-off function joint of the liquid outlet of the kit and the standard sample box with the through-plate joint to ensure that the reagent pure water and standard solution are connected to the fully automatic selection valve; at the same time, the kit and the standard sample box pass through the reagent and standard sample The storage box is fixed with a fixing rod.

S2. Connect the liquid line joint of the waste liquid bag bottle to the "Z" type light-liquid coupling joint at the water outlet of the colorimetric measurement sample cell through a watertight connection of the corrosion-resistant waste discharge pipeline, and hang it on the upper end of the instrument;

S3. Control the power on of the instrument through the magnetic control switch, and the analyzer enters the state of waiting for user instructions. At this time, it can receive the operation instructions of the host computer, and the user can control the automatic sampling and colorimetric analysis through the host computer user interface as required. Cleaning and other work; if no specific instruction or automatic data collection instruction is received within a fixed period of time, it will enter the automatic nutrient salt sampling analysis and in-situ storage of information.

S4. After the work is over, the magnetic control switch controls the power off of the instrument. If it is not used for a long time, take out the reagent bag box and the standard sample box from the instrument, remove the waste liquid bag, clean the pipeline and store it in ventilation

It can be seen that the seawater nutrient in-situ analysis device provided by the present invention has the following technical advantages:

1. The seawater nutrient in-situ measurement device of the present invention clearly divides the optical, electromechanical and liquid circuit systems. The optical, electrical and mechanical rotating parts are all sealed and assembled, and the liquid circuit parts are all placed outside the water environment. Even if an accident occurs In the event of pipeline rupture and loose joints leading to liquid leakage, the optomechanical part of the instrument is still very safe, which is a great advantage and breakthrough for wet chemical analysis.

2. The structure design of the present invention is compact and flexible, easy to disassemble and assemble, and the measurement process can be completed automatically in situ in combination with the physical and chemical environment of the sample, and only need to replace the light source; it can be used for in situ of various heavy metals, nutrient salts and other environmental parameters Measurement has a broad application market and good application prospects.

3. The sample cell used in the present invention has high sensitivity, wide application range, and small amount of samples and reagents. It is very suitable for underwater long-term in-situ monitoring and early warning. By adjusting the length of the sample cell, extremely low concentration and wide dynamic range can be realized. High sensitivity detection of chemical elements such as range nutrients.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention, and its purpose is to enable those of ordinary skill in the art to understand the content of the present invention and implement it accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the essence of the present invention shall fall within the protection scope of the present invention.

Claims (10)

1. An in-situ analysis device for seawater nutrients, characterized in that it includes a measurement control and photoelectric conversion module, a sample selection module, a power supply module, an underwater in-situ filtration module, a reagent and a standard sample storage module, and a colorimetric analysis measurement module; among them, The power supply module is electrically connected with the measurement control and photoelectric conversion module and the sampling module respectively, so as to provide power for the work of the measurement control and photoelectric conversion module and the sampling module; The measurement control and photoelectric conversion module includes a measurement control unit and a photoelectric conversion unit; The underwater in-situ filtration module is used to filter the collected seawater; The sample selection module is connected with the underwater in-situ filtration module in a liquid path for sampling the filtered seawater; the sample selection module is also connected to the measurement control unit with signals, and is controlled by the measurement control unit. The work of the sample selection module; The reagent and standard sample storage module is composed of a plurality of reagent boxes and standard sample boxes, and the sampling and selection module is connected to the liquid path of the kits and standard sample boxes, so as to transfer the reagents and standard samples to the sampling and selection module; The colorimetric analysis measurement module is connected with the sample selection module with a phase liquid path for measuring and analyzing the sample collected by the sample selection module; the photoelectric conversion unit is connected with the colorimetric analysis measurement module for colorimetric analysis measurement The work of the module provides the amount of light; The sampling module includes a plunger pump and a fully automatic selection valve head, the plunger pump is used to pump filtered seawater, reagents and standard samples in the reagent box and standard sample box to the fully automatic selection valve head, There are several liquid joints outside the fully automatic selection valve head; The underwater in-situ filtration module and the plunger pump are installed in the first cabin, the colorimetric analysis measurement module, the fully automatic selection valve head and the reagent and standard sample storage module are installed in the second cabin, and the power supply module, measurement control and The photoelectric conversion module is installed in the third cabin; the first cabin, the second cabin, and the third cabin are arranged vertically from low to high, and the adjacent two cabins are isolated and sealed from each other, and all the liquid flow paths and The joints are all placed outside the cabin body. 2. The in-situ analysis device for seawater nutrients as claimed in claim 1, wherein a watertight cable joint for power supply and communication with the upper computer is installed on the upper end cover of the third cabin body; The lower end cover of the cabin body is installed with an optical fiber or signal cable sealing joint group for transmitting photoelectric signals, and a power supply cable watertight joint group for the sampling module is also installed in the lower end cover of the third cabin body. 3. The in-situ analysis device for seawater nutrient salts as claimed in claim 2, wherein the liquid outlets of the test kit and the standard sample box are externally placed through a male and female plate-through buckle joint and a fully automatic valve head. The liquid circuit joints are connected; the male/female ends of the male and female through-plate buckle joints are connected with the liquid outlets of the reagent box and the standard sample box, and the female/male ends of the male and female through-plate buckle joints pass through corrosion-resistant hoses and full-body Automatically select the connection between the external liquid joints of the valve head, disconnect the male and female piercing buckles, the liquid road is cut off, the reagent box and the standard sample box are in a closed state, connect the male and female piercing buckles, the liquid road is connected, and the kit The reagent in the kit is connected to the fully automatic selection valve head; the kit and the standard sample box are both made of light-shielding materials and have different surface colors. 4. The in-situ analysis device for seawater nutrient salts as claimed in claim 3, characterized in that, the lower ends of the kit and the standard sample box are provided with a joint mounting plate, and the joint mounting plate is provided with male and female threading plates. Mounting screw holes for plate sleeve buckle joints, mounting and fixing rods, fixing holes for automatic sampling and selection modules, and cable through holes. 5. The seawater nutrient in-situ analysis device as claimed in claim 1, wherein the colorimetric analysis measurement module includes a colorimetric measurement sample pool; the colorimetric measurement sample pool is composed of a liquid core waveguide and assembled in The liquid-core waveguide is composed of "Z" optical-liquid coupling joints at both ends. The length of the liquid-core waveguide can be adjusted arbitrarily according to the needs, and the diameter of the liquid-core waveguide can be adjusted within the range of 1500um; The coupling ports are designed with watertight structure. 6. The in-situ analysis device for seawater nutrients as claimed in claim 5, wherein the photoelectric conversion unit is composed of an optical fiber, a light source power supply control subunit and an optical fiber input type spectrum monitoring subunit, and the light-liquid coupling The optical output port of the connector is plugged with optical fiber, and the colorimetric photometric signal is connected to the optical fiber input type spectrum monitoring subunit through optical connection; the optical input port of the optical liquid coupling connector is plugged with optical fiber, so that the optical fiber output type light energy is introduced through the optical fiber Colorimetric measurement sample cell. 7. The in-situ analysis device for seawater nutrients as claimed in claim 5, wherein the photoelectric conversion unit is composed of a light source power supply control subunit and an analog electrical signal processing subunit; A photodetector is installed at the output port to perform photoelectric detection against the color photometric signal, and the photoelectric detection signal is connected to the analog electrical signal processing subunit through an electrical connection; a light source is installed at the optical input port of the optical liquid coupling joint, and the light source and the light source power supply control subunit The units are electrically connected for power supply control. 8 . The in-situ analysis device for seawater nutrients according to claim 1 , wherein the power supply control module is a magnetic control switch to control the power supply process through an external magnet in a non-contact manner. 9. The seawater nutrient in-situ analysis device according to claim 1, wherein the underwater in-situ filtration module is composed of an outer filter and an inner filter core, and the outer filter is made of titanium powder or Sintered 316 stainless steel powder, the inner filter core is made of sintered rods with apertures, the outer filter has a larger aperture than the sintered rods; the sintered rods are titanium powder or 16 stainless steel powder or copper powder sintered rods. 10. The in-situ analysis device for seawater nutrients as claimed in claim 5, wherein the liquid input joint of the Z-type light-liquid coupling joint in the water inlet of the colorimetric measurement sample pool and the fully automatic selection valve head are externally placed One of the several joints is watertightly connected through a corrosion-resistant pipeline, and the liquid output joint of the Z-type light-liquid coupling joint at the outlet of the colorimetric measurement sample cell is connected watertightly with the waste liquid collection bag through a corrosion-resistant waste discharge pipeline. , The waste liquid collection bag is higher than the colorimetric analysis measurement module to achieve smooth exhaust and waste discharge.