WO2020228507A1 - 基于集成阀岛装置的高精度海水pH原位测量系统及方法 - Google Patents

基于集成阀岛装置的高精度海水pH原位测量系统及方法 Download PDF

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WO2020228507A1
WO2020228507A1 PCT/CN2020/086451 CN2020086451W WO2020228507A1 WO 2020228507 A1 WO2020228507 A1 WO 2020228507A1 CN 2020086451 W CN2020086451 W CN 2020086451W WO 2020228507 A1 WO2020228507 A1 WO 2020228507A1
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seawater
solenoid valve
indicator
integrated valve
pipeline
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English (en)
French (fr)
Inventor
曹璐
张云燕
张颖颖
张天鹏
褚东志
王婧茹
王小红
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Oceanographic Instrumentation Research Institute Shandong Academy of Sciences
Institute of Oceanographic Instrumentation
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Oceanographic Instrumentation Research Institute Shandong Academy of Sciences
Institute of Oceanographic Instrumentation
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Priority to EP20806137.4A priority Critical patent/EP3819631B1/en
Publication of WO2020228507A1 publication Critical patent/WO2020228507A1/zh
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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
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
    • G01N21/80—Indicating pH value
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/38—Diluting, dispersing or mixing samples
    • 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
    • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
    • 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
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/85—Investigating moving fluids or granular solids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/18—Water
    • G01N33/1893—Water using flow cells
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/02—Devices for withdrawing samples
    • G01N1/10—Devices for withdrawing samples in the liquid or fluent state
    • 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
    • G01N2021/0193—Arrangements or apparatus for facilitating the optical investigation the sample being taken from a stream or flow to the measurement cell
    • 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
    • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
    • G01N2021/3148—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths using three or more wavelengths
    • 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
    • G01N21/314—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths
    • G01N2021/3181—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry with comparison of measurements at specific and non-specific wavelengths using LEDs
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N35/00—Automatic analysis not limited to methods or materials provided for in any single one of groups G01N1/00 - G01N33/00; Handling materials therefor
    • G01N2035/00465—Separating and mixing arrangements
    • 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
    • G01N21/03—Cuvette constructions
    • G01N21/05—Flow-through cuvettes
    • 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
    • G01N2201/0627—Use of several LED's for spectral resolution
    • 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
    • G01N2201/08—Optical fibres; light guides
    • 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
    • G01N2201/12—Circuits of general importance; Signal processing
    • G01N2201/127—Calibration; base line adjustment; drift compensation
    • G01N2201/12746—Calibration values determination

Definitions

  • the invention belongs to the technical field of marine monitoring, and specifically relates to a high-precision seawater pH in-situ measurement system and method based on an integrated valve island device capable of multi-reagent detection.
  • the pH of the surface seawater continues to decrease at a rate of 0.002/a.
  • the seawater pH measurement technology based on the photometric method has the advantages of high accuracy (up to 0.001) and good stability. It has become the mainstream method that needs to accurately observe the pH in the current research on seawater acidification and carbon cycle.
  • High-precision seawater pH in-situ measurement systems are mostly based on photometry and flow injection analysis technology.
  • the pH value of seawater can be obtained by measuring the absorbance of different forms of indicators after mixing the sample and the indicator.
  • Flow path composition and control, flow cell selection, light source coupling module, signal acquisition and detection, and indicator calibration are the core technologies for constructing a high-precision seawater pH in-situ measurement system, as well as the key to determining whether the entire system is accurate and stable.
  • the flow path design of the existing in-situ pH sensor mostly adopts three-way valve combination or multi-position selection valve, etc., which has disadvantages such as large volume and high power consumption; the light source and signal detection mostly use the combination of LED lamp and photodiode, and only a single The indicator is measured, and there are disadvantages such as low resolution and poor accuracy, which directly affect the measurement precision and measurement range of the instrument.
  • the present invention provides a high-precision seawater pH in-situ measurement system and method based on an integrated valve island device capable of multi-reagent detection; the flow path structure of the high-precision seawater pH in-situ measurement system is based on the integrated valve island device, which is deadlocked Small size and good stability; and the optical path structure uses LED coupled light source and micro spectrometer as light source and detector, which can use a variety of indicators for measurement, which broadens the measurement range and improves measurement accuracy.
  • High-precision seawater pH in-situ measurement system based on integrated valve island including: flow path module, optical path module and circuit module;
  • the flow path module includes an integrated valve island, a flow cell, and a reagent bag connected to the integrated valve island through a pulse pump; one end of the flow cell is connected to the integrated valve island through a peristaltic pump, and the other end is connected to the integrated valve island.
  • the valve island is connected; the integrated valve island is also provided with a seawater sampling pipeline, a seawater waste liquid discharge pipeline, and an indicator waste liquid discharge pipeline;
  • the optical path module is used to measure the absorbance of a sample at a characteristic wavelength; it includes a light source coupling module, a miniature spectrometer, and an optical fiber, and the light source coupling module includes three LED lights with different wavelengths arranged in a light source coupler. Three LED lamps with different wavelengths form a coupled light source, the light emitted by the coupled light source is transmitted through an optical fiber, and enters the miniature spectrometer to detect the signal intensity after passing through the flow cell;
  • the peristaltic pump, the pulse pump, the integrated valve island, and the micro spectrometer are all connected to the circuit module; the circuit module is used to control the peristaltic pump, the pulse pump, and the integrated valve island , The micro-spectrometer is turned on or off and used for data collection.
  • the integrated valve island includes four two-position three-way solenoid valves: a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve; the first solenoid valve, the second solenoid valve, and the fourth solenoid valve
  • the three solenoid valves and the fourth solenoid valve each include a normally closed port a, a normally open port b, and a third port, a total of three ports;
  • the seawater sampling pipeline is connected to the normal opening b of the first solenoid valve, and the third interface of the first solenoid valve is connected to the normal opening b of the second solenoid valve.
  • the normally closed port a and the reagent bag are connected through a pulse pump, the third port of the second solenoid valve is connected to the third port of the third solenoid valve, and the normally open port b of the third solenoid valve is connected through a peristaltic pump and One end of the flow cell is connected, the normally closed port a of the third solenoid valve is connected to the indicator waste liquid discharge pipeline, and the normally closed port a of the fourth solenoid valve is connected to the normally closed port of the first solenoid valve a connection, the normal opening b of the fourth solenoid valve is connected with the seawater waste liquid discharge pipeline, and the third interface of the fourth solenoid valve is connected with the other end of the flow cell.
  • the integrated valve island further includes a valve island, the valve island includes a base plate and a bottom plate; the base plate is arranged at the lower part of the base plate, and the four solenoid valves are all arranged at the lower part of the base plate;
  • the substrate and the bottom plate are made of highly transparent acrylic material, and are seamlessly bonded by adhesive bonding in a dust-free and clean environment; a liquid channel is provided inside the substrate and the bottom plate, and the liquid channel is used to communicate with a solenoid valve And an external fluid pipeline connected to the integrated valve island;
  • the external fluid pipeline connected to the integrated valve island includes the fluid pipeline between the peristaltic pump and the integrated valve island, the fluid pipeline between the pulse pump and the integrated valve island, and the indicator waste liquid discharge Pipeline, the seawater waste liquid discharge pipeline, the seawater sampling pipeline, the fluid pipeline between the flow cell and the integrated valve island, and the third interface of the first solenoid valve and the first Two fluid pipelines between the normally opening b of the solenoid valve;
  • the liquid channel is also used between the first solenoid valve and the fourth solenoid valve, and used for the connection between the second solenoid valve and the third solenoid valve;
  • the inner diameter of the liquid channel inside the base plate and the bottom plate is the same as the inner diameter of the external fluid pipeline connected to the integrated valve island, so as to prevent the flow rate state of fluid from changing after the fluid enters the integrated valve island and ensure measurement accuracy.
  • the flow cell is made of plastic material and has a cross-shaped structure.
  • the fluid flows from bottom to top, the light signal is transmitted in the horizontal direction, and the bubbles generated in the fluid can rise to the top of the flow cell to avoid the accumulation of bubbles.
  • the optical path length of the flow cell is 0.5-4 cm, and the flow cell is placed in the seawater outside the instrument compartment to keep the sample in the flow cell and the seawater temperature consistent; a temperature probe is also set next to the flow cell for real-time measurement of the seawater temperature.
  • the three LED lamps with different wavelengths include: a warm white LED lamp with a center wavelength of 580nm, an LED lamp with a center wavelength of 435nm and an LED lamp with a center wavelength of 490nm;
  • the spectrum detection range of the miniature spectrometer is 300nm-800nm, is equipped with a 25 ⁇ m slit, and the wavelength resolution is 1.5nm; the miniature spectrometer is a miniature spectrometer on the market with small volume and power consumption, and is suitable for in-situ pH sensors .
  • the flow path is controlled by the integrated valve island.
  • seawater pH is measured in situ
  • seawater is first injected into the flow path to determine the blank light intensity, and then the indicator is injected into the flow path, and the flow path is closed. Synthesize a loop, mix the seawater and the indicator in the loop, detect the light intensity of the mixed solution after the mixing is complete, calculate the absorbance, and then calculate the seawater pH.
  • a high-precision in-situ measurement method of seawater pH based on an integrated valve island device capable of multi-reagent detection, using the measurement system includes:
  • Seawater sampling control the first solenoid valve, the second solenoid valve, the third solenoid valve and the fourth solenoid valve to be in the normally open position b, turn on the peristaltic pump, and the seawater sample enters from the seawater sampling pipeline and fills the flow path.
  • the sample is discharged from the seawater waste liquid discharge pipeline;
  • Blank light intensity detection turn off the peristaltic pump, turn on the coupled light source composed of LED lights, and use a micro-spectrometer to detect the blank light intensity of the seawater blank sample at the characteristic wavelength of the selected indicator, the characteristic wavelength of the selected indicator includes the maximum absorption of the acid state The wavelength at the peak, the wavelength at the maximum absorption peak in the alkali state, and the wavelength at the absorption peak in the acid state and the alkali state; the recorded optical signal is ⁇ I0, and ⁇ is the wavelength;
  • the wavelength at the maximum absorption peak in the acid state, the wavelength at the maximum absorption peak in the basic state, and the wavelengths at the absorption peaks in the acid state and basic state are 435nm, 596nm and 494nm respectively, and the optical signal is recorded as ⁇ 435I0, respectively. , ⁇ 596I0, ⁇ 494I0.
  • Reagent sampling switch the second solenoid valve and the third solenoid valve to the normally closed position a, turn on the pulse pump, draw the indicator from the reagent bag into the reagent flow path, and discharge the excess indicator from the indicator waste liquid discharge line. Turn off the pulse pump;
  • Sample mixing switch the second solenoid valve and the third solenoid valve to the normally open position b, and the first solenoid valve and the fourth solenoid valve to the normally closed position a to form a closed loop, turn on the peristaltic pump, seawater sample and indicator Fully mix, the mixing time is 20-180s, the mixing time is selected according to the pump speed and pipeline, after the mixing is uniform, turn off the peristaltic pump;
  • the pH of seawater is determined by the secondary dissociation equilibrium reaction of the acid-base indicator.
  • the calculation formula is:
  • pHT is expressed as the pH value under the scale of total hydrogen ion
  • K2T is the secondary dissociation constant of the indicator
  • [I2-] and [HI-] are the concentrations of the indicator in the alkaline state and acid state
  • [HI-] and [I2-] Measure the absorbance ⁇ 1A and ⁇ 2A of the sample at the maximum absorption wavelength ⁇ 1 and ⁇ 2 respectively;
  • K2T determines the measurement range of the indicator, and the pH measurement of seawater can be carried out by using the applicable seawater pH measurement indicator;
  • e1, e2, e3 are the ratios of the molar absorption coefficients of different forms of the indicator at different wavelengths, which are related to temperature and salinity; R is the absorbance ratio; ⁇ 1 ⁇ I2- and ⁇ 2 ⁇ I2- are the absorption coefficients of I2- at the wavelengths of ⁇ 1 and ⁇ 2, ⁇ 1 ⁇ HI- and ⁇ 2 ⁇ HI- are the absorbance coefficients of HI- at ⁇ 1 and ⁇ 2.
  • the method further includes the step of indicator calibration, specifically:
  • the first solenoid valve and the fourth solenoid valve are switched to the normally open position b, the peristaltic pump is turned on, the seawater sample enters the pipeline, and the indicator in the pipeline is continuously diluted.
  • the absorbance value on the x-axis for multiple times at the absorption wavelengths of the acid state and the alkali state, and the corresponding pH value is a straight line on the y-axis.
  • the y value obtained is the pH value of the sea water itself after the interference of the indicator is eliminated.
  • the flow path structure of the high-precision seawater pH in-situ measurement system provided by the present invention is based on an integrated valve island device, has the characteristics of small dead volume, compact structure, and low power consumption, can achieve complete mixing of seawater and indicator, and can improve instrument measurement The stability.
  • the optical path structure of the high-precision seawater pH in-situ measurement system uses an LED coupled light source and a miniature spectrometer as a light source and a detector, and can use a variety of indicators for measurement, broadens the measurement range and improves the measurement accuracy.
  • Figure 1 is a structural composition and flow path diagram of a high-precision seawater pH in-situ measurement system based on an integrated valve island in an embodiment of the present invention
  • Figure 2 is a three-dimensional schematic diagram of the structure of the integrated valve island device in the embodiment of the present invention
  • the three-way valve combination or multi-position selection valve is mostly used, which has the disadvantages of large volume and high power consumption; the light source and signal detection mostly use the combination of LED lights and photodiodes, which can only be used
  • a single indicator is used for measurement, and there are disadvantages such as low resolution and poor accuracy, which directly affect the measurement precision and measurement range of the instrument.
  • the embodiment of the present invention provides a high-precision seawater pH in-situ measurement system based on an integrated valve island device that can detect multiple reagents; it is based on photometry and circulation analysis, and the measurement principle is that the absorbance changes after the indicator is completely mixed with seawater. ⁇ pH value.
  • the measurement system includes: a flow path module, an optical path module and a circuit module;
  • the flow path module includes an integrated valve island, a flow cell, and a reagent bag connected to the integrated valve island through a pulse pump; one end of the flow cell is connected to the integrated valve island through a peristaltic pump, and the other end is connected to the integrated valve island.
  • the valve island is connected; the integrated valve island is also provided with a seawater sampling pipeline, a seawater waste liquid discharge pipeline, and an indicator waste liquid discharge pipeline; wherein, the flow path module also includes a flow path pipeline, the Between the reagent bag and the pulse pump, between the pulse pump and the integrated valve island, between the peristaltic pump and the integrated valve island, between the peristaltic pump and the flow cell, and between the flow cell and the integrated valve island, all are connected by flow path pipelines ;
  • the optical path module is used to measure the absorbance of a sample at a characteristic wavelength; it includes a light source coupling module, a miniature spectrometer, and an optical fiber, and the light source coupling module includes three LED lights with different wavelengths arranged in a light source coupler. Three LED lamps with different wavelengths form a coupled light source, and the light emitted by the coupled light source is transmitted through an optical fiber, passes through a flow cell, and enters the miniature spectrometer to detect signal intensity.
  • the peristaltic pump, the pulse pump, the integrated valve island, and the spectrometer are all connected to the circuit module; the circuit module is used to control the peristaltic pump, the pulse pump, the integrated valve island, The spectrometer is turned on or off and used for data collection.
  • the circuit system adopts a modular design concept, and the corresponding circuit module is turned on or off according to the work flow during the measurement process, thereby reducing static working power consumption.
  • a leakage detection circuit was designed to protect some parts of the system from leakage and to upload leakage warning information.
  • the integrated valve island includes four two-position three-way solenoid valves: a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve; the first solenoid valve, the second solenoid valve The valve, the third solenoid valve and the fourth solenoid valve all include a normally closed port a, a normally open port b, and a third port, a total of three ports;
  • the seawater sampling pipeline is connected to the normal opening b of the first solenoid valve, and the third interface of the first solenoid valve is connected to the normal opening b of the second solenoid valve.
  • the normally closed port a and the reagent bag are connected through a pulse pump, the third port of the second solenoid valve is connected to the third port of the third solenoid valve, and the normally open port b of the third solenoid valve is connected through a peristaltic pump and One end of the flow cell is connected, the normally closed port a of the third solenoid valve is connected to the indicator waste liquid discharge pipeline, and the normally closed port a of the fourth solenoid valve is connected to the normally closed port of the first solenoid valve a connection, the normal opening b of the fourth solenoid valve is connected with the seawater waste liquid discharge pipeline, and the third interface of the fourth solenoid valve is connected with the other end of the flow cell.
  • the integrated valve island further includes a valve island, the valve island includes a base plate and a bottom plate; the base plate is arranged on the lower part of the base plate, and the four solenoid valves are all arranged on the lower part of the base plate;
  • the substrate and the bottom plate are made of highly transparent acrylic material, and are seamlessly bonded by adhesive bonding in a dust-free and clean environment; a liquid channel is provided inside the substrate and the bottom plate, and the liquid channel is used to communicate with a solenoid valve And an external fluid pipeline connected to the integrated valve island;
  • the external fluid pipeline connected to the integrated valve island includes the fluid pipeline between the peristaltic pump and the integrated valve island, the fluid pipeline between the pulse pump and the integrated valve island, and the indicator waste liquid discharge Pipeline, the seawater waste liquid discharge pipeline, the seawater sampling pipeline, the fluid pipeline between the flow cell and the integrated valve island, and the third interface of the first solenoid valve and the first Two fluid pipelines between the normally opening b of the solenoid valve;
  • the liquid channel is also used between the first solenoid valve and the fourth solenoid valve, and used for the connection between the second solenoid valve and the third solenoid valve;
  • the inner diameter of the liquid channel inside the base plate and the bottom plate is the same as the inner diameter of the external fluid pipeline connected to the integrated valve island, so as to prevent the flow rate state of fluid from changing after the fluid enters the integrated valve island and ensure measurement accuracy.
  • the inner diameter of the liquid channel inside the base plate and the bottom plate and the inner diameter of the external fluid pipeline connected to the integrated valve island are both 0.1-3 mm.
  • the specific structure of the integrated valve island is:
  • the liquid channels provided inside the base plate and the base plate include base plate liquid channels 3-10, base plate liquid channels 3-9 and valve island internal liquid channels 3-11,
  • the bottom plate is provided with a bottom plate liquid channel connected to the solenoid valve through the bottom plate, and three solenoid valve normal opening b3-3, third interface 3-4, and normally closed port a3-5 are provided above each solenoid valve.
  • Bottom liquid channels that is, there are 12 bottom liquid channels on the valve island;
  • the upper part of the base plate is provided with threaded holes 3-8, the fluid pipeline between the peristaltic pump and the integrated valve island, the fluid pipeline between the pulse pump and the integrated valve island, and the indicator waste liquid is discharged Pipeline, the seawater waste liquid discharge pipeline, the seawater sampling pipeline, and the fluid pipeline between the flow cell and the integrated valve island, and the third interface of the first solenoid valve and the first
  • the fluid pipelines between the normal openings b of the two solenoid valves are both connected to the threaded holes on the integrated valve island substrate.
  • the number of threaded holes is 8;
  • a substrate liquid channel 3-9 is provided at the lower part of the substrate, and the substrate liquid channel corresponds to the threaded hole 3-8 one-to-one, and the number of substrate liquid channels is also 8; and the upper end of the substrate liquid channel and The threaded holes are connected, and the lower end of the substrate liquid channel 3-9 is connected with the corresponding bottom plate liquid channel 3-10 on the bottom plate, thereby realizing the connection between the external fluid pipeline of the integrated valve island and the solenoid valve.
  • each threaded hole is provided with a joint for clamping and fixing the fluid pipeline; specifically, the threaded hole is a flat-bottomed threaded hole.
  • the lower end surface of the base plate and the upper end surface of the bottom plate are simultaneously grooved and bonded to form an internal liquid channel 3-11 of the valve island, and the internal liquid channel of the valve island includes a first internal liquid channel and a second internal liquid channel;
  • Both ends of the first internal liquid passage are respectively connected to the bottom plate liquid passage corresponding to the third interface of the second solenoid valve and the third interface of the third solenoid valve, so as to realize the third interface of the second solenoid valve and the The connection of the third interface of the third solenoid valve;
  • the two ends of the second internal liquid channel are respectively connected to the bottom plate liquid channel corresponding to the fourth solenoid valve normally closed port a and the first solenoid valve normally closed port a to realize the The connection between the normally closed port a of the fourth solenoid valve and the normally closed port a of the first solenoid valve;
  • the solenoid valve 8 can be a commercially available two-position three-way valve, and the material is made of PEEK, which can prevent high salt and acid-base corrosion.
  • the fluid is driven by a peristaltic pump or pulse pump, enters the liquid channel in the valve island through the external fluid pipeline connected to the integrated valve island, and then enters the solenoid valve, thereby controlling the fluid flow direction.
  • the entire integrated valve island device makes the flow path system compact and reduces the dead volume of the flow path and the power consumption of the instrument.
  • the flow cell is made of plastic material and has a cross-shaped structure.
  • the fluid flows from bottom to top, the light signal is transmitted in the horizontal direction, and the bubbles generated in the fluid can rise to the top of the flow cell to avoid The influence of bubble accumulation on absorbance measurement;
  • the optical path length of the flow cell is 0.5-4 cm, and the flow cell is placed in the seawater outside the instrument compartment to keep the sample in the flow cell and the seawater temperature consistent; a temperature probe is also set beside the flow cell for real-time measurement of the seawater temperature.
  • the three LED lamps with different wavelengths include: a warm white LED lamp with a center wavelength of 580nm and a wider peak width, an LED lamp with a center wavelength of 435nm and an LED lamp with a center wavelength of 490nm;
  • the spectrum detection range of the spectrometer is 300nm-800nm, equipped with a 25 ⁇ m slit, and the wavelength resolution is 1.5nm;
  • the selection of the LED lamp depends on the characteristic wavelength of the indicator used, including the wavelength at the maximum absorption peak in the acid state, the wavelength at the maximum absorption peak in the alkali state, and the wavelength at the absorption peak in the acid state and the alkali state.
  • the commonly used indicators in the pH measurement of seawater are m-cresol purple, thymol blue and cresol red. These three indicators have a wavelength of 430-440nm at the maximum absorption peak of the acid state, and the maximum absorption peak of the alkali state.
  • the wavelength is 550-600nm, and the isoabsorption peak wavelength changes with temperature mostly at 480-500nm.
  • the use of the above three LED lamps with different wavelengths to form a coupled light source in the present invention can simultaneously meet the measurement requirements of the three indicators of m-cresol purple, thymol blue and cresol red, and can complete the seawater of the three indicators. pH measurement.
  • a miniature spectrometer with a small size and low power consumption is selected as the signal detection unit, the spectrum detection range is 300nm-800nm, it is equipped with a 25 ⁇ m slit, and the wavelength resolution is 1.5nm.
  • the wavelength resolution of the signal detection unit selected by the measurement system is higher than 2nm, the pH can be calculated according to the published indicator related data. If it is lower than 2nm, in order to ensure the measurement accuracy, it is necessary to determine the characteristic coefficients of the indicator by yourself .
  • the miniature spectrometer can accurately measure the absorbance at the characteristic wavelength of the indicator, and can measure the absorbance at multiple wavelengths at the same time. It is not interfered by other circuits during use and has stable performance. While meeting the requirements of high-precision detection, it can achieve multiple Indicator measurement, thereby broadening the scope of instrument use.
  • the range of the indicator for measuring the pH of seawater is mainly determined by the second-order dissociation constant K 2 and is also affected by the molar absorption coefficient.
  • the best measurement range is PK 2 -1 ⁇ pH ⁇ pK 2 .
  • Commonly used indicators for measuring seawater are m-cresol purple, thymol blue and cresol red. According to the prior art, the measurement range of m-cresol purple is 7.2-8.2, and the measurement range of thymol blue is 7.6-8.6. The measurement range of phenol red is 6.8-7.8.
  • m-cresol purple is suitable for profile and offshore seawater
  • thymol blue is suitable for ocean surface seawater
  • cresol red is suitable for seawater in low pH areas.
  • the integrated valve island controls the flow path.
  • seawater pH is measured in situ
  • the seawater is first injected into the flow path to determine the blank light intensity, and then the indicator is injected into the flow path.
  • the flow path is closed into a loop, the seawater and the indicator are mixed in the loop. After the mixing is complete, the light intensity of the mixed solution is detected, the absorbance is calculated, and the seawater pH is calculated.
  • the structure in which the flow path is closed into a loop has the characteristics of small dead volume, compact structure, and low power consumption, which can achieve complete mixing of seawater and indicator, and can improve the stability of instrument measurement.
  • the fluid pipe material is polytetrafluoroethylene with an inner diameter of 0.1-3mm;
  • the reagent bag is made of aluminum foil material, which is light-proof and airtight;
  • the indicator concentration is 0.1-5mmol/L;
  • pulse The pump is a micro pump with a pulse volume of 10-500 ⁇ L.
  • the embodiment of the present invention also provides a high-precision in-situ measurement method of seawater pH based on an integrated valve island device capable of multi-reagent detection, using the measurement system in the foregoing embodiment, and the method includes:
  • Seawater sampling control the first solenoid valve 4, the second solenoid valve 5, the third solenoid valve 6 and the fourth solenoid valve 7 to be in the normally open position b, turn on the peristaltic pump, and the seawater sample enters the seawater sample pipeline 8
  • the flow path is filled, and the excess sample is discharged from the seawater waste liquid discharge pipe 9;
  • Blank light intensity detection turn off the peristaltic pump, turn on the LED light, and use a spectrometer to detect the blank light intensity of the seawater blank sample at the characteristic wavelength of the selected indicator.
  • the selected indicator characteristic wavelength includes the wavelength at the maximum absorption peak of the acid state, alkali The wavelength at the maximum absorption peak of the state and the wavelength at the absorption peaks of the acid state and alkali state; the recorded optical signal is ⁇ I 0 , ⁇ is the wavelength;
  • the wavelength at the maximum absorption peak of the acid state, the wavelength of the maximum absorption peak of the alkali state, and the wavelengths of the absorption peaks of the acid state and the alkali state are 435nm, 596nm and 494nm respectively, and the optical signal is recorded as ⁇ . 435 I 0 , ⁇ 596 I 0 , ⁇ 494 I 0 .
  • Reagent sampling switch the second solenoid valve 5 and the third solenoid valve 6 to the normally closed position a, turn on the pulse pump 2, the indicator is drawn from the reagent bag into the reagent flow path, and the excess indicator is discharged from the indicator waste liquid discharge pipe Route 10 is discharged and the pulse pump is turned off;
  • Sample mixing switch the second solenoid valve 5 and the third solenoid valve 6 to the normally open position b, and the first solenoid valve 4 and the fourth solenoid valve 7 to the normally closed port a position to form a closed loop, integrating the valve island and
  • the peristaltic pump, flow cell and other pipelines form a circulation system. Turn on the peristaltic pump, and the seawater sample and indicator are fully mixed.
  • the mixing time is 20-180s. The mixing time is selected according to the pump speed and pipeline. After the mixing is uniform, turn off the peristaltic pump;
  • the pH of seawater is determined by the secondary dissociation equilibrium reaction of the acid-base indicator.
  • the calculation formula is:
  • pH pH value T is expressed as the total scale hydrogen ion, K 2 T dissociation constant of two of the indicator solution, [I 2-] and [HI -] is a state indicator base and acid concentration state; in [ HI -] and [I 2-] ⁇ 1 maximum absorption wavelength [lambda], respectively measuring the absorbance of the sample 1 a and ⁇ 2 a, the [lambda] 2;
  • K 2 T determines the measurement range of the indicator, and the pH measurement of seawater can be carried out by using the applicable seawater pH measurement indicator;
  • e 1 , e 2 , e 3 are the ratios of molar absorption coefficients of different forms of indicator at different wavelengths, and R is the ratio of absorbance; with Is the absorption coefficient of I 2- at wavelengths of ⁇ 1 and ⁇ 2 , with Is HI - the absorbance coefficient at ⁇ 1 and ⁇ 2 , which is related to temperature and salinity.
  • the method further includes the step of indicator correction, specifically:
  • the indicator is a dibasic acid, and its addition will interfere with the seawater pH measurement.
  • the concentration change and the pH value of the mixed solution during the dilution of the indicator are used to estimate the seawater pH value and realize real-time correction.
  • the method also includes the steps of pipeline flushing: switching the first solenoid valve 4 and the fourth solenoid valve 7 to the normally open position a, the peristaltic pump is reversed, the reversal time is 1-10s, and the first solenoid valve 4 is normally closed A position is connected to the normally closed port a of the fourth solenoid valve 7 and the sample in the pipeline is flushed out between the fourth solenoid valve 7 and the flow cell.
  • the reversal time needs to be controlled reasonably. It is necessary to flush out the sample completely and avoid flowing into the flow Pool; switch the first solenoid valve 4 and the fourth solenoid valve 7 to the normally open position b, turn on the peristaltic pump to continue flushing the pipeline, and the flushing time is 20-180s.
  • the method provided by the embodiment of the present invention completes the interference correction of the indicator during the mixing process of the seawater and the indicator.
  • the indicator itself is a dibasic acid, and its addition will cause a change in seawater pH.
  • the traditional calibration method is applied to the calculation of seawater pH after the calibration model is obtained in the laboratory. The accuracy of this calibration needs to be improved.
  • the method of the present invention adopts a method that can quickly correct indicator interference in situ, and can perform indicator interference correction for each seawater pH measurement. The method is very suitable for in-situ instruments and improves the accuracy of correction.
  • the following example analyzes the process of determining the pH of seawater, using the seawater pH in-situ measuring device in the above embodiment of the present invention, and the indicator is thymol blue (but the present invention is not limited to this indicator).
  • Preparation of indicator Weigh 0.1954g of thymol blue sodium salt and dissolve in 200mL of high-purity water, after completely dissolved, adjust the pH of the solution to 7.9 ⁇ 0.1 with 1.0mol/L hydrochloric acid and sodium hydroxide solution. Among them, the concentration of thymol blue sodium salt is 2mmol/L.
  • T represents the pH at a pH scale total hydrogen ions
  • K 2 T dissociation constant of two of thymol blue indicator solution, [I 2-] and [HI -] thymol blue as indicator in The concentration of alkali and acid states.
  • e1, e2, and e3 are the ratios of molar absorption coefficients of different forms of thymol blue at different wavelengths:
  • ⁇ 435 A and ⁇ 596 A are the sample absorbance measured at wavelengths of 435nm and 596nm, with Is I 2- absorption coefficient at wavelengths of 435nm and 596nm, with HI - the absorbance coefficient at wavelengths of 435nm and 596nm. Since the wavelength resolution of the spectrometer used for the measurement in this embodiment is 1.5 nm, it can directly use the published literature values in the prior art for calculation. The prior art has the secondary dissociation indicator thymol blue.
  • the constant and molar absorption coefficient formula are as follows:
  • T temperature
  • S salinity
  • the method also includes the following steps of indicator calibration and pipeline cleaning:
  • Indicator calibration switch the first solenoid valve and the fourth solenoid valve to the normally open position b, turn on the peristaltic pump, the seawater sample enters the pipeline, the indicator thymol blue is continuously diluted, the dilution time is 60s, and the spectrometer is used During the continuous collection and dilution process, the mixed solution light intensity ⁇ 435 I i , ⁇ 596 I i , ⁇ 494 I i , calculate the absorbance ⁇ 435 A i , ⁇ 596 A i , and ⁇ 494 A i .
  • Pipeline cleaning switch the first solenoid valve 4 and the fourth solenoid valve 7 to the normally closed port a, the peristaltic pump reverses, and the reversal time is 5s; turn off the peristaltic pump, and turn the first solenoid valve 4 normally closed again And the fourth solenoid valve 7 is always open at position b. Start the peristaltic pump to continue flushing the pipeline. The flushing time is 60s to complete the pipeline cleaning.

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Abstract

本发明属于海洋监测技术领域，具体涉及基于集成阀岛装置可多试剂检测的高精度海水pH原位测量系统及方法。所述测量系统包括流路模块、光路模块和电路模块；所述流路模块中包括控制流路方向的集成阀岛，所述流路模块用于进行海水样品进样、试剂进样、混合；通过所述集成阀岛控制流路，在海水pH原位测量时，首先将海水进样至流路中测定空白光强，然后将指示剂进样至流路中，将流路闭合成一个环路，在环路中将海水和指示剂混合，混合完全后检测混合溶液的光强，计算吸光度，进而计算获得海水pH。本发明中的流路结构采用阀岛装置，具有死体积小、结构紧凑、功耗低的特点，能够实现海水和指示剂的完全混合，可提高仪器测量的稳定性。

Description

基于集成阀岛装置的高精度海水pH原位测量系统及方法 技术领域
本发明属于海洋监测技术领域，具体涉及基于集成阀岛装置可多试剂检测的高精度海水pH原位测量系统及方法。
背景技术
目前表层海水pH以0.002/a的速度持续下降，海洋碳酸盐体系的深入研究对pH测量技术提出了更高的要求，亟需稳定可靠的高精度pH测量仪器。基于光度法的海水pH测量技术具备精度高(可达0.001)、稳定性好等优点，已成为当前研究海水酸化和碳循环等领域需准确观测pH的主流方法。高精度海水pH原位测量系统多基于光度法和流动注射分析技术，通过测定样品和指示剂混合后不同形态指示剂的吸光值，可得出海水pH值。
流路组成及控制、流通池选择、光源耦合模块、信号采集检测和指示剂校正等是构建高精度海水pH原位测量系统的核心技术，也是决定整个系统是否准确稳定的关键。
现有的原位pH传感器的流路设计多采用三通阀组合或多位选择阀等，存在体积大、功耗高等缺点；光源及信号检测多选用LED灯和光电二极管组合，仅可使用单一指示剂进行测定，且存在分辨率较低、准确性较差等缺点，直接影响仪器测定精密度和测量范围。
发明内容
针对上述技术问题，本发明提供基于集成阀岛装置可多试剂检测的高精度海水pH原位测量系统及方法；所述高精度海水pH原位测量系统的流路结构基于集成阀岛装置，死体积小，稳定性好；并且光路结构以LED耦合光源和微型光谱仪作为光源和检测器，可使用多种指示剂进行测量，拓宽了测量范围，提高了测量准确性。
本发明是通过以下技术方案实现的：
基于集成阀岛的高精度海水pH原位测量系统，包括：流路模块、光路模块和电路模块；
所述流路模块包括集成阀岛、流通池、通过脉冲泵和所述集成阀岛连接的试剂袋；所述流通池的一端通过蠕动泵和所述集成阀岛连接，另一端和所述集成阀岛连接；所述集成阀岛上还设置有海水进样管路、海水废液排出管路以及指示剂废液排出管路；
所述光路模块，用于测量样品在特征波长处的吸光度；包括光源耦合模块、微型光谱仪和光纤，所述光源耦合模块包括设置于光源耦合器中的三个具有不同波长的LED灯，所述三个具有不同波长的LED灯组成耦合光源，耦合光源发出的光通过光纤传输，经过流通池后进入所述微型光谱仪检测信号强度；
所述蠕动泵、所述脉冲泵、所述集成阀岛、所述微型光谱仪均和所述电路模块连接；所述电路模块用于控制所述蠕动泵、所述脉冲泵、所述集成阀岛、所述微型光谱仪的开启或者关闭以及用于数据采集。
进一步地，所述集成阀岛包括第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀四个两位三通电磁阀；所述第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀均包括一个常闭口a、一个常开口b和一个第三接口共三个接口；
所述海水进样管路和所述第一电磁阀的常开口b连接，所述第一电磁阀的第三接口和所述第二电磁阀的常开口b连接，所述第二电磁阀的常闭口a和所述试剂袋通过脉冲泵连接，所述第二电磁阀的第三接口和所述第三电磁阀的第三接口连接，所述第三电磁阀的常开口b通过蠕动泵和所述流通池的一端连接，所述第三电磁阀的常闭口a和所述指示剂废液排出管路连接，所述第四电磁阀的常闭口a和所述第一电磁阀的常闭口a连接，所述第四电磁阀的常开口b和海水废液排出管路连接，所述第四电磁阀的第三接口和所述流通池的另一端连接。
进一步地，所述集成阀岛还包括阀岛，所述阀岛包括基板和底板；所述底板设置在所述基板的下部，四个电磁阀均设置于所述底板的下部；
所述基板和所述底板均采用高透明的亚克力材质，在无尘洁净环境下采用胶接无缝键合；在所述基板和底板内部均设置液体通道，所述液体通道用于连通电磁阀和接入所述集成阀岛的外部流体管路；
所述接入集成阀岛的外部流体管路包括所述蠕动泵和集成阀岛之间的流体管路、所述脉冲泵和集成阀岛之间的流体管路、所述指示剂废液排出管路、所述海水废液排出管路、所述海水进样管路、所述流通池和所述集成阀岛之间的流体管路、以及第一电磁阀的第三接口和所述第二电磁阀的常开口b之间的流体管路；
所述液体通道还用于所述第一电磁阀和第四电磁阀之间，以及用于所述第二电磁阀和所述第三电磁阀之间的连接；
所述基板和所述底板内部的液体通道的内径和所述接入集成阀岛的外部流体管路的内径相同，以避免流体进入集成阀岛后流速状态改变，保证了测量精度。
进一步地，所述流通池采用塑料材质加工，为十字形结构，流体自下而上流动，光信号在水平方向传输，流体中产生的气泡能够上浮至所述流通池顶部，以避免气泡积存对吸光度测量的影响；
所述流通池光路长度为0.5-4cm，流通池置于仪器舱外部的海水中，以保持 流通池内样品和海水温度一致；在流通池旁边还设置温度探头，用于对海水温度进行实时测量。
进一步地，所述三个具有不同波长的LED灯包括：中心波长为580nm的暖白光LED灯、中心波长为435nm的LED灯和中心波长为490nm的LED灯；
所述微型光谱仪的光谱检测范围为300nm-800nm，配备25μm狭缝，波长分辨率为1.5nm；所述微型光谱仪为市场在售微型光谱仪，体积和功耗均很小，适用于原位pH传感器。
采用三个具有不同波长的LED灯组成耦合光源作为光源以及采用所述微型光谱仪作为检测器，能够适用于间甲酚紫、百里酚蓝和甲酚红三种指示剂的海水pH测量，pH测量范围为6.8-8.6。
进一步地，通过所述集成阀岛控制流路，在海水pH原位测量时，首先将海水进样至流路中测定空白光强，然后将指示剂进样至流路中，将流路闭合成一个环路，在环路中将海水和指示剂混合，混合完全后检测混合溶液的光强，计算吸光度，进而计算获得海水pH。
基于集成阀岛装置可多试剂检测的高精度海水pH原位测量方法，采用所述测量系统，包括：
海水进样：控制第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀均处于常开口b位，开启蠕动泵，海水样品从海水进样管路进入并充满流路，多余样品从海水废液排出管路排出；
空白光强检测：关闭蠕动泵，开启LED灯组成的耦合光源，采用微型光谱仪检测海水空白样品在所选指示剂特征波长处的空白光强，所述所选指示剂特征波长包括酸态最大吸收峰处波长、碱态最大吸收峰处波长以及酸态和碱态等吸收峰处波长；记录光信号为λI0，λ为波长；
以百里酚蓝为例，其在酸态最大吸收峰处波长、碱态最大吸收峰处波长以及酸态和碱态等吸收峰处波长分别为435nm，596nm和494nm，光信号分别记录为λ435I0，λ596I0，λ494I0。
试剂进样：将第二电磁阀和第三电磁阀切换至常闭口a位，开启脉冲泵，指示剂从试剂袋抽入试剂流路中，多余指示剂从指示剂废液排出管路排出，关闭脉冲泵；
样品混合：将第二电磁阀和第三电磁阀切换至常开口b位，将第一电磁阀和第四电磁阀切换至常闭口a位，形成闭合回路，开启蠕动泵，海水样品和指示剂充分混合，混合时间为20-180s，根据泵速和管路选择混合时间，混合均匀后，关闭蠕动泵；
检测混合溶液的光强，计算吸光度：混合完全后，开启LED灯，检测混合 溶液的光强，记录光信号为λI，计算吸光度λA＝-log10(λI/λI0)；根据吸光度计算海水pH。
进一步地，海水pH计算的方法具体为：
采用光度法，利用酸碱指示剂的二级解离平衡反应测定海水pH，计算公式为：
Figure PCTCN2020086451-appb-000001
pHT表示为总氢离子标度下的pH值，K2T为指示剂的二级解离常数，[I2-]和[HI-]为指示剂碱态和酸态的浓度；在[HI-]和[I2-]的最大吸收波长λ1，λ2下分别测定样品的吸光度λ1A和λ2A；
根据朗伯比尔定律，计算公式可写成：
Figure PCTCN2020086451-appb-000002
K2T决定了指示剂的测量范围，采用适用海水pH测量指示剂即可对海水进行pH测量；
其中：
Figure PCTCN2020086451-appb-000003
e1，e2，e3为指示剂不同形态在不同波长的摩尔吸光系数的比值，与温度和盐度相关；R为吸光度比值；λ1εI2-和λ2εI2-为I2-在λ1和λ2波长时的吸光系数，λ1εHI-和λ2εHI-为HI-在λ1和λ2时的吸光系数。
进一步地，所述方法还包括指示剂校正的步骤，具体为：
检测混合溶液的光强，计算吸光度的步骤完成后，将第一电磁阀和第四电磁阀切换至常开口b位，开启蠕动泵，海水样品进入管路，管路中指示剂不断被稀释，采用微型光谱仪连续采集稀释过程中混合溶液的光强度，计算吸光度和pH值，稀释时间为20-180s；指示剂在酸态和碱态等吸收波长处吸光度仅与指示剂浓度相关，以指示剂在酸态和碱态等吸收波长处多次测定吸光度值为x轴，相应pH值为y轴做直线，当x＝0时得到的y值即为消除指示剂干扰后海水本身pH值。
本发明的有益技术效果：
本发明提供的高精度海水pH原位测量系统的流路结构基于集成阀岛装置，具有死体积小、结构紧凑、功耗低的特点，能够实现海水和指示剂的完全混合， 可提高仪器测量的稳定性。
本发明提供的高精度海水pH原位测量系统的光路结构以LED耦合光源和微型光谱仪作为光源和检测器，可使用多种指示剂进行测量，拓宽了测量范围，提高了测量准确性。
附图说明
图1为本发明实施例中基于集成阀岛的高精度海水pH原位测量系统的结构组成及流路图；
图2为本发明实施例中集成阀岛装置结构立体示意图
附图标记：1.试剂袋；2.脉冲泵；3.集成阀岛；4.第一电磁阀；5.第二电磁阀；6.第三电磁阀；7.第四电磁阀；8.海水进样管路；9.海水废液排出管路；10.指示剂废液排出管路；11.蠕动泵；12.光源耦合模块；13.流通池；14.微型光谱仪；3-1.基板基体；3-2.底板基体；3-3.常开口b；3-4.第三接口；3-5.常闭口a；3-6.电磁阀光洁孔；3-7.固定螺孔；3-8.螺纹孔；3-9.基板液体通道；3-10.底板液体通道；3-11.阀岛内部液体通道。
具体实施方式
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细描述。应当理解，此处所描述的具体实施例仅仅用于解释本发明，并不用于限定本发明。
相反，本发明涵盖任何由权利要求定义的在本发明的精髓和范围上做的替代、修改、等效方法以及方案。进一步，为了使公众对本发明有更好的了解，在下文对本发明的细节描述中，详尽描述了一些特定的细节部分。对本领域技术人员来说没有这些细节部分的描述也可以完全理解本发明。
针对现有技术中原位pH传感器的流路设计多采用三通阀组合或多位选择阀等，存在体积大、功耗高等缺点；光源及信号检测多选用LED灯和光电二极管组合，仅可使用单一指示剂进行测定，且存在分辨率较低、准确性较差等缺点，直接影响仪器测定精密度和测量范围。本发明实施例提供一种基于集成阀岛装置可多试剂检测的高精度海水pH原位测量系统；以光度法和环流分析为基础，测定原理为通过指示剂和和海水完全混合后吸光度变化得出pH值。
如图1所示，所述测量系统包括：流路模块、光路模块和电路模块；
所述流路模块包括集成阀岛、流通池、通过脉冲泵和所述集成阀岛连接的试剂袋；所述流通池的一端通过蠕动泵和所述集成阀岛连接，另一端和所述集成阀 岛连接；所述集成阀岛上还设置有海水进样管路、海水废液排出管路以及指示剂废液排出管路；其中，所述流路模块还包括流路管路，所述试剂袋和所述脉冲泵之间、脉冲泵和集成阀岛之间、蠕动泵和集成阀岛之间、蠕动泵和流通池之间、流通池和集成阀岛之间均采用流路管路连接；
所述光路模块，用于测量样品在特征波长处的吸光度；包括光源耦合模块、微型光谱仪和光纤，所述光源耦合模块包括设置于光源耦合器中的三个具有不同波长的LED灯，所述三个具有不同波长的LED灯组成耦合光源，耦合光源发出的光通过光纤传输，经过流通池后进入所述微型光谱仪检测信号强度。
所述蠕动泵、所述脉冲泵、所述集成阀岛、所述光谱仪均和所述电路模块连接；所述电路模块用于控制所述蠕动泵、所述脉冲泵、所述集成阀岛、所述光谱仪的开启或者关闭以及用于数据采集。优选地，所述电路系统采用模块化设计思路，在测量过程内根据工作流程开启或者关闭相应电路模块，从而减小静态工作功率消耗。基于对本测定系统工作环境的考虑，设计了漏液检测电路，用于对本系统一些部件的漏液断电保护和上传漏液预警信息。
在本实施例中，所述集成阀岛包括第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀四个两位三通电磁阀；所述第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀均包括一个常闭口a、一个常开口b和一个第三接口共三个接口；
所述海水进样管路和所述第一电磁阀的常开口b连接，所述第一电磁阀的第三接口和所述第二电磁阀的常开口b连接，所述第二电磁阀的常闭口a和所述试剂袋通过脉冲泵连接，所述第二电磁阀的第三接口和所述第三电磁阀的第三接口连接，所述第三电磁阀的常开口b通过蠕动泵和所述流通池的一端连接，所述第三电磁阀的常闭口a和所述指示剂废液排出管路连接，所述第四电磁阀的常闭口a和所述第一电磁阀的常闭口a连接，所述第四电磁阀的常开口b和海水废液排出管路连接，所述第四电磁阀的第三接口和所述流通池的另一端连接。
在本实施例中，所述集成阀岛还包括阀岛，所述阀岛包括基板和底板；所述底板设置在所述基板的下部，四个电磁阀均设置于所述底板的下部；
所述基板和所述底板均采用高透明的亚克力材质，在无尘洁净环境下采用胶接无缝键合；在所述基板和底板内部均设置液体通道，所述液体通道用于连通电磁阀和接入所述集成阀岛的外部流体管路；
所述接入集成阀岛的外部流体管路包括所述蠕动泵和集成阀岛之间的流体管路、所述脉冲泵和集成阀岛之间的流体管路、所述指示剂废液排出管路、所述海水废液排出管路、所述海水进样管路、所述流通池和所述集成阀岛之间的流体管路、以及第一电磁阀的第三接口和所述第二电磁阀的常开口b之间的流体管路；
所述液体通道还用于所述第一电磁阀和第四电磁阀之间，以及用于所述第二电磁阀和所述第三电磁阀之间的连接；
所述基板和所述底板内部的液体通道的内径和所述接入集成阀岛的外部流体管路的内径相同，以避免流体进入集成阀岛后流速状态改变，保证了测量精度。在本实施例中，所述基板和所述底板内部的液体通道的内径和所述接入集成阀岛的外部流体管路的内径均为0.1-3mm。
具体地，如图2所示，所述集成阀岛的具体结构为：
在所述基板和底板内部设置的液体通道包括底板液体通道3-10、基板液体通道3-9和阀岛内部液体通道3-11，
在所述底板上贯穿设置和电磁阀连通的底板液体通道，在每个电磁阀上方均设置分别和电磁阀常开口b3-3、第三接口3-4、常闭口a3-5连接的三个底板液体通道，即在阀岛上共设置12个底板液体通道；
所述基板的上部设有螺纹孔3-8，所述蠕动泵和集成阀岛之间的流体管路、所述脉冲泵和集成阀岛之间的流体管路、所述指示剂废液排出管路、所述海水废液排出管路、所述海水进样管路、及所述流通池和所述集成阀岛间的流体管路、以及第一电磁阀的第三接口和所述第二电磁阀的常开口b之间的流体管路均和集成阀岛基板上的所述螺纹孔连接，在本实施例中，螺纹孔的数量共8个；
在所述基板的下部设有基板液体通道3-9，所述基板液体通道和所述螺纹孔3-8一一对应，基板液体通道数量也为8个；且所述基板液体通道的上端和所述螺纹孔连通，所述基板液体通道3-9的下端和所述底板上的相应的底板液体通道3-10连接，进而实现集成阀岛外部流体管路和电磁阀的连接。其中，每个螺纹孔上设置用于夹持固定夹持固定流体管路的接头；具体地，其中螺纹孔为平底螺纹孔。
在所述基板下端面和所述底板上端面同时开槽键合后形成阀岛内部液体通道3-11，所述阀岛内部液体通道包括第一内部液体通道和第二内部液体通道；
所述第一内部液体通道的两端分别和第二电磁阀第三接口、所述第三电磁阀第三接口对应的底板液体通道连接，以实现所述第二电磁阀第三接口和所述第三电磁阀第三接口的连接；所述第二内部液体通道的两端分别和第四电磁阀常闭口a、所述第一电磁阀常闭口a对应的底板液体通道连接，以实现所述第四电磁阀常闭口a和所述第一电磁阀常闭口a的连接；
具体地，在底板下端设置用于安装固定四个电磁阀的4组光洁孔3-6；底板下端同时设有用于固定整个集成阀岛装置固定螺孔3-7。电磁阀8均可以选用市 售两位三通阀，材质选用PEEK材质，能够防止高盐及酸碱侵蚀。流体在蠕动泵或脉冲泵驱动下，通过接入集成阀岛的外部流体管路进入阀岛内的液体通道后进入电磁阀，进而控制流体流向。
整个集成阀岛装置使得流路系统结构紧凑，降低了流路死体积和仪器功耗。
在本实施例中，所述流通池采用塑料材质加工，为十字形结构，流体自下而上流动，光信号在水平方向传输，流体中产生的气泡能够上浮至所述流通池顶部，以避免气泡积存对吸光度测量的影响；
所述流通池光路长度为0.5-4cm，流通池置于仪器舱外部的海水中，以保持流通池内样品和海水温度一致；在流通池旁边还设置温度探头，用于对海水温度进行实时测量。
在本实施例中，所述三个具有不同波长的LED灯包括：中心波长为580nm的峰宽较宽的暖白光LED灯、中心波长为435nm的LED灯和中心波长为490nm的LED灯；
所述光谱仪的光谱检测范围为300nm-800nm，配备25μm狭缝，波长分辨率为1.5nm；
采用三个具有不同波长的LED灯组成耦合光源作为光源以及采用所述光谱仪作为检测器，能够适用于间甲酚紫、百里酚蓝和甲酚红三种指示剂的海水pH测量，测量范围为6.8-8.6。
在本实施例中，LED灯的选择取决于所用指示剂的特征波长，包括在酸态最大吸收峰处波长、在碱态最大吸收峰处波长以及在酸态和碱态等吸收峰处波长。目前海水pH测定中常用的指示剂有间甲酚紫、百里酚蓝和甲酚红等，这三种指示剂在酸态最大吸收峰处波长为430-440nm，在碱态最大吸收峰处波长550-600nm，等吸收峰波长随温度变化多集中于480-500nm。因此，本发明中采用上述三个具有不同波长的LED灯组成耦合光源能够同时满足间甲酚紫、百里酚蓝和甲酚红三种指示剂的测定需求，能够完成三种指示剂的海水pH测量。
并且，在本发明实施例中，选用体积小、功耗低的微型光谱仪作为信号检测单元，光谱检测范围为300nm-800nm，配备25μm狭缝，波长分辨率为1.5nm。当测量系统选用的信号检测单元波长分辨率高于2nm时，可以根据已发表的指示剂相关数据进行pH计算，若低于2nm时，为保证测量精度，需自行测定指示剂的各项特征系数。微型光谱仪可以精确测定指示剂特征波长处吸光度，且可同时测定多个波长处吸光度值，在使用过程中不受其他电路的干扰，性能稳定，在满足高精度检测要求的同时，可实现多种指示剂的测量，从而拓宽仪器使用范围。
指示剂测量海水pH的范围主要由二级解离常数K 2决定，同时也受摩尔吸收系数的影响，其最佳测定范围为PK 2-1≤pH≤pK 2。常用的测量海水的指示剂为间甲酚紫、百里酚蓝和甲酚红，根据现有技术，间甲酚紫测量范围为7.2-8.2，百里酚蓝测量范围为7.6-8.6，甲酚红测量范围为6.8-7.8，根据目前海水pH分布，间甲酚紫适用于剖面和近岸海水，百里酚蓝适用于大洋表层海水，甲酚红适应于低pH区域海水。
在本实施例中，通过所述集成阀岛控制流路，在海水pH原位测量时，首先将海水进样至流路中测定空白光强，然后将指示剂进样至流路中，将流路闭合成一个环路，在环路中将海水和指示剂混合，混合完全后检测混合溶液的光强，计算吸光度，进而计算获得海水pH。
其中，流路闭合成一个环路的结构具有死体积小、结构紧凑、功耗低的特点，能够实现海水和指示剂的完全混合，可提高仪器测量的稳定性。在本实施例中，流体管路材料为聚四氟乙烯，内径为0.1-3mm；试剂袋选用铝箔材料，具有避光和不透气的特征；所述指示剂浓度为0.1-5mmol/L；脉冲泵选用微量泵，脉冲体积为10-500μL。
本发明实施例还提供一种基于集成阀岛装置可多试剂检测的高精度海水pH原位测量方法，采用上述实施例中的测量系统，所述方法包括：
海水进样：控制第一电磁阀4、第二电磁阀5、第三电磁阀6和第四电磁阀7均处于常开口b位，开启蠕动泵，海水样品从海水进样管路8进入并充满流路，多余样品从海水废液排出管路9排出；
空白光强检测：关闭蠕动泵，开启LED灯，采用光谱仪检测海水空白样品在所选指示剂特征波长处的空白光强，所述所选指示剂特征波长包括酸态最大吸收峰处波长、碱态最大吸收峰处波长以及酸态和碱态等吸收峰处波长；记录光信号为λI 0，λ为波长；
以百里酚蓝为例，其在酸态最大吸收峰处波长、碱态最大吸收峰处波长以及酸态和碱态等吸收峰处波长分别为435nm，596nm和494nm，光信号分别记录为λ 435I 0，λ 596I 0，λ 494I 0。
试剂进样：将第二电磁阀5和第三电磁阀6切换至常闭口a位，开启脉冲泵2，指示剂从试剂袋抽入试剂流路中，多余指示剂从指示剂废液排出管路10排出，关闭脉冲泵；
样品混合：将第二电磁阀5和第三电磁阀6切换至常开口b位，将第一电磁阀4和第四电磁阀7切换至常闭口a位，形成闭合环路，集成阀岛和蠕动泵、流 通池和其他管路构成环流体系，开启蠕动泵，海水样品和指示剂充分混合，混合时间为20-180s，根据泵速和管路选择混合时间，混合均匀后，关闭蠕动泵；
检测混合溶液的光强，计算吸光度：混合完全后，开启LED灯，检测混合溶液光强，记录光信号为λI，计算吸光度λA＝-log 10(λI/λI 0)；光谱仪能够精确测定整个测量范围内各波长光强，该光谱仪可以测定300-800nm波长内的光强，输出时选择需要输出波长即可。当更换指示剂时选择合适的输出波长即可，根据光谱仪的测量结果计算pH。
具体地，pH计算的方法具体为：
采用光度法，利用酸碱指示剂的二级解离平衡反应测定海水pH，计算公式为：
Figure PCTCN2020086451-appb-000004
pH T表示为总氢离子标度下的pH值，K 2 T为指示剂的二级解离常数，[I 2-]和[HI -]为指示剂碱态和酸态的浓度；在[HI -]和[I 2-]的最大吸收波长λ1，λ2下分别测定样品的吸光度λ 1A和λ 2A；
根据朗伯比尔定律，计算公式可写成：
Figure PCTCN2020086451-appb-000005
K 2 T决定了指示剂的测量范围，采用适用海水pH测量指示剂即可对海水进行pH测量；
其中：
Figure PCTCN2020086451-appb-000006
e 1，e 2，e 3为指示剂不同形态在不同波长的摩尔吸光系数的比值，R为吸光度比值；
Figure PCTCN2020086451-appb-000007
和
Figure PCTCN2020086451-appb-000008
为I 2-在λ 1和λ 2波长时的吸光系数，
Figure PCTCN2020086451-appb-000009
和
Figure PCTCN2020086451-appb-000010
为HI -在λ 1和λ 2时的吸光系数，与温度和盐度相关。
在本实施例中，所述方法还包括指示剂校正的步骤，具体为：
指示剂作为一种二元酸，其加入会对海水pH测定产生干扰，为消除指示剂干扰采用指示剂稀释过程中浓度变化和混合溶液pH值的变化推算海水pH值， 实现实时校正。
检测混合溶液的光强，计算吸光度的步骤完成后，将第一电磁阀4和第四电磁阀7切换至常开口b位，开启蠕动泵，海水样品进入管路，管路中指示剂不断被稀释，采用光谱仪连续采集稀释过程中混合溶液的光强度，计算吸光度和pH值，稀释时间为20-180s；指示剂在酸态和碱态等吸收波长处吸光度仅与指示剂浓度相关，以指示剂在酸态和碱态等吸收波长处多次测定吸光度值为x轴，相应pH值为y轴做直线，当x＝0时得到的y值即为消除指示剂干扰后海水本身pH值。
所述方法还包括管路冲洗的步骤：将第一电磁阀4和第四电磁阀7切换至常开口a位，蠕动泵反转，反转时间为1-10s，第一电磁阀4常闭口a位和第四电磁阀7常闭口a位连接，管路内样品冲出至第四电磁阀7和流通池之间，反转时间需合理控制，既要将样品完全冲出又要避免流入流通池；将第一电磁阀4和第四电磁阀7切换至常开口b位，开启蠕动泵继续冲洗管路，冲洗时间为20-180s。
本发明实施例提供的方法在海水和指示剂的混合过程中完成对指示剂进行干扰校正。指示剂本身是一种二元酸，它的加入会引起海水pH的改变。传统的校正方法是在实验室得到校正模型后，应用于海水pH的计算中，这种校正准确性有待提高。本发明所述方法采用一种可快速原位校正指示剂干扰的方法，能够针对每次海水pH的测量进行指示剂干扰校正，该方法非常适用于原位仪器，提高了校正的准确度。
以下实施例分析测定海水pH的过程，使用本发明上述实施例中的海水pH原位测量装置，指示剂选用百里酚蓝(但本发明不限于该指示剂)流通池光程为1cm。测定方法包括：
指示剂的配制：称取0.1954g百里酚蓝钠盐溶于200mL高纯水中，完全溶解后用1.0mol/L的盐酸和氢氧化钠溶液将溶液pH值调至7.9±0.1。其中，百里酚蓝钠盐浓度2mmol/L。
海水pH的测定：
a.控制第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀均处于常开口b位，开启蠕动泵，海水样品从海水进样管路进入并充满流路，多余样品从海水废液排出管路排出，完成海水进样；
b.关闭蠕动泵，开启LED耦合光源，使用光谱仪检测流通池中空白样品光强，记录百里酚蓝特征波长处(包括酸态最大吸收峰处波长(435nm)、碱态最大吸收峰处波长(596nm)和酸态和碱态等吸收峰处波长(494nm))的空白光强， 分别为λ 435I 0，λ 596I 0，λ 494I 0；
c.将第二电磁阀和第三电磁阀切换至常闭口a位，开启脉冲泵，指示剂进入流路，指示剂从试剂袋抽入试剂流路中，多余指示剂从指示剂废液排出管路排出，完成指示剂进样，关闭脉冲泵；
d.将第二电磁阀5和第三电磁阀6切换至常开口b位，将第一电磁阀4和第四电磁阀7切换至常闭口a位，形成闭合回路，开启蠕动泵，海水样品和指示剂充分混合，混合时间为60s，关闭蠕动泵；
e.使用微型光谱仪检测流通池中混合溶液光强，记录百里酚蓝特征波长处光强，分别为λ 435I，λ 596I，λ 494I；吸光度计算公式为λA＝-log(λI/λI 0)，记录吸光度分别为λ 435A，λ 596A，λ 494A；
海水pH的计算：
海水pH计算公式为：
Figure PCTCN2020086451-appb-000011
其中pH T表示为总氢离子标度下的pH值，K 2 T为指示剂百里酚蓝的二级解离常数，[I 2-]和[HI -]为指示剂百里酚蓝在碱态和酸态的浓度。
根据朗伯比尔定律，公式可写作：
Figure PCTCN2020086451-appb-000012
其中e1，e2，e3为百里酚蓝不同形态在不同波长的摩尔吸光系数的比值：
Figure PCTCN2020086451-appb-000013
λ 435A和λ 596A为在435nm和596nm波长下测定的样品吸光度，
Figure PCTCN2020086451-appb-000014
和
Figure PCTCN2020086451-appb-000015
为I 2-在波长435nm和596nm的吸光系数，
Figure PCTCN2020086451-appb-000016
和
Figure PCTCN2020086451-appb-000017
为HI -在波长435nm和596nm时的吸光系数。由于本实施例中用于测定的光谱仪的波长分辨率为1.5nm，能够直接使用现有技术中已发表的文献值进行计算，现有技术中已有指示剂百里酚蓝的二级解离常数和摩尔吸收系数公式如下：
-log 10(K T 2)＝4.706S/T+26.3300-7.17218logT-0.017316×S
e 1＝-0.00132+1.600×10 -5T
e 2＝7.2326-0.0299717T+4.600×10 -5T 2
e 3＝0.0223+0.0003917T
其中温度(T)和盐度(S)的适用范围分别为：278.15≤T≤308.15K，20≤S≤40。
所述方法还包括以下指示剂校正及管路清洗的步骤：
f.指示剂校正：将第一电磁阀和第四电磁阀切换至常开口b位，开启蠕动泵，海水样品进入管路，指示剂百里酚蓝不断被稀释，稀释时间为60s，采用光谱仪连续采集稀释过程中混合溶液光强λ 435I i，λ 596I i，λ 494I i，计算吸光度λ 435A i，λ 596A i，λ 494A i。
根据海水pH计算公式分别计算指示剂百里酚蓝稀释过程中混合溶液的pH值，记为pH i；以混合溶液测定吸光度λ 494A为x轴，相应pH值为y轴做直线，当x＝0时，得到的y值即为消除百里酚蓝干扰后海水pH值。
g.管路清洗：将第一电磁阀4和第四电磁阀7切换至常闭口a位，蠕动泵反转，反转时间为5s；关闭蠕动泵，再次将第一电磁阀4常闭口a位和第四电磁阀7常开口b位，启动蠕动泵继续冲洗管路，冲洗时间为60s，完成管路清洗。

Claims (9)

  1. 基于集成阀岛装置的高精度海水pH原位测量系统，其特征在于，包括：流路模块、光路模块和电路模块；
    所述流路模块包括集成阀岛、流通池、通过脉冲泵和所述集成阀岛连接的试剂袋；所述流通池的一端通过蠕动泵和所述集成阀岛连接，另一端和所述集成阀岛连接；所述集成阀岛上还设置有海水进样管路、海水废液排出管路以及指示剂废液排出管路；
    所述光路模块，用于测量样品在特征波长处的吸光度；包括光源耦合模块、微型光谱仪和光纤，所述光源耦合模块包括设置于光源耦合器中的三个具有不同波长的LED灯，所述三个具有不同波长的LED灯组成耦合光源，耦合光源发出的光通过光纤传输，经过流通池后进入所述微型光谱仪检测信号强度；
    所述蠕动泵、所述脉冲泵、所述集成阀岛、所述微型光谱仪均和所述电路模块连接；所述电路模块用于控制所述蠕动泵、所述脉冲泵、所述集成阀岛、所述微型光谱仪的开启或者关闭以及用于数据采集。
  2. 根据权利要求1所述基于集成阀岛装置的高精度海水pH原位测量系统，其特征在于，所述集成阀岛包括第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀四个两位三通电磁阀；所述第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀均包括一个常闭口a、一个常开口b和一个第三接口共三个接口；
    所述海水进样管路和所述第一电磁阀的常开口b连接，所述第一电磁阀的第三接口和所述第二电磁阀的常开口b连接，所述第二电磁阀的常闭口a和所述试剂袋通过脉冲泵连接，所述第二电磁阀的第三接口和所述第三电磁阀的第三接口连接，所述第三电磁阀的常开口b通过蠕动泵和所述流通池的一端连接，所述第三电磁阀的常闭口a和所述指示剂废液排出管路连接，所述第四电磁阀的常闭口a和所述第一电磁阀的常闭口a连接，所述第四电磁阀的常开口b和海水废液排出管路连接，所述第四电磁阀的第三接口和所述流通池的另一端连接。
  3. 根据权利要求2所述基于集成阀岛装置的高精度海水pH原位测量系统，其特征在于，所述集成阀岛还包括阀岛，所述阀岛包括基板和底板；所述底板设置在所述基板的下部，四个电磁阀均设置于所述底板的下部；
    所述基板和所述底板均采用高透明的亚克力材质，在无尘洁净环境下采用胶接无缝键合；在所述基板和底板内部均设置液体通道，所述液体通道用于连通电磁阀和接入所述集成阀岛的外部流体管路；
    所述接入集成阀岛的外部流体管路包括所述蠕动泵和集成阀岛之间的流体管路、所述脉冲泵和集成阀岛之间的流体管路、所述指示剂废液排出管路、所述 海水废液排出管路、所述海水进样管路、所述流通池和所述集成阀岛之间的流体管路、以及第一电磁阀的第三接口和所述第二电磁阀的常开口b之间的流体管路；
    所述液体通道还用于所述第一电磁阀和第四电磁阀之间，以及用于所述第二电磁阀和所述第三电磁阀之间的连接；
    所述基板和所述底板内部的液体通道的内径和所述接入集成阀岛的外部流体管路的内径相同，以避免流体进入集成阀岛后流速状态改变，保证了测量精度。
  4. 根据权利要求1所述基于集成阀岛装置的高精度海水pH原位测量系统，其特征在于，所述流通池采用塑料材质加工，为十字形结构，流体自下而上流动，光信号在水平方向传输，流体中产生的气泡能够上浮至所述流通池顶部，以避免气泡积存对吸光度测量的影响；
    所述流通池光路长度为0.5-4cm，流通池置于仪器舱外部的海水中，以保持流通池内样品和海水温度一致；在流通池旁边还设置温度探头，用于对海水温度进行实时测量。
  5. 根据权利要求1所述基于集成阀岛装置的高精度海水pH原位测量系统，其特征在于，所述三个具有不同波长的LED灯包括：中心波长为580nm的暖白光LED灯、中心波长为435nm的LED灯和中心波长为490nm的LED灯；
    所述微型光谱仪的光谱检测范围为300nm-800nm，配备25μm狭缝，波长分辨率为1.5nm；
    采用三个具有不同波长的LED灯组成耦合光源作为光源以及采用所述微型光谱仪作为检测器，能够适用于间甲酚紫、百里酚蓝和甲酚红三种指示剂的海水pH测量，pH测量范围为6.8-8.6。
  6. 根据权利要求2所述基于集成阀岛装置的高精度海水pH原位测量系统，其特征在于，通过所述集成阀岛控制流路，在海水pH原位测量时，首先将海水进样至流路中测定空白光强，然后将指示剂进样至流路中，将流路闭合成一个环路，在环路中将海水和指示剂混合，混合完全后检测混合溶液的光强，计算吸光度，进而计算获得海水pH。
  7. 基于集成阀岛装置可多试剂检测的高精度海水pH原位测量方法，采用权利要求1-6任一项所述测量系统，其特征在于，包括：
    海水进样：控制第一电磁阀、第二电磁阀、第三电磁阀和第四电磁阀均处于常开口b位，开启蠕动泵，海水样品从海水进样管路进入并充满流路，多余样品从海水废液排出管路排出；
    空白光强检测：关闭蠕动泵，开启LED灯组成的耦合光源，采用微型光谱仪检测海水空白样品在所选指示剂特征波长处的空白光强，所述所选指示剂特征波长包括酸态最大吸收峰处波长、碱态最大吸收峰处波长以及酸态和碱态等吸收峰处波长；记录光信号为λI 0，λ为波长；
    试剂进样：将第二电磁阀和第三电磁阀切换至常闭口a位，开启脉冲泵，指示剂从试剂袋抽入试剂流路中，多余指示剂从指示剂废液排出管路排出，关闭脉冲泵；
    样品混合：将第二电磁阀和第三电磁阀切换至常开口b位，将第一电磁阀和第四电磁阀切换至常闭口a位，形成闭合回路，开启蠕动泵，海水样品和指示剂充分混合，混合时间为20-180s，根据泵速和管路选择混合时间，混合均匀后，关闭蠕动泵；
    检测混合溶液的光强，计算吸光度：混合完全后，开启LED灯，检测混合溶液的光强，记录光信号为λI，计算吸光度λA＝-log 10(λI/λI 0)；根据吸光度计算海水pH。
  8. 根据权利要求7所述基于集成阀岛装置可多试剂检测的高精度海水pH原位测量方法，其特征在于，海水pH计算的方法具体为：
    采用光度法，利用酸碱指示剂的二级解离平衡反应测定海水pH，计算公式为：
    Figure PCTCN2020086451-appb-100001
    pH T表示为总氢离子标度下的pH值，K 2 T为指示剂的二级解离常数，[I 2-]和[HI -]为指示剂碱态和酸态的浓度；在[HI -]和[I 2-]的最大吸收波长λ1，λ2下分别测定样品的吸光度λ 1A和λ 2A；
    根据朗伯比尔定律，计算公式可写成：
    Figure PCTCN2020086451-appb-100002
    K 2 T决定了指示剂的测量范围，采用适用海水pH测量指示剂即可对海水进行pH测量；
    其中：
    Figure PCTCN2020086451-appb-100003
    e 1，e 2，e 3为指示剂不同形态在不同波长的摩尔吸光系数的比值，与温度和盐度相关；R为吸光度比值；λ 1ε I 2-和λ 2ε I 2-为I 2-在λ 1和λ 2波长时的吸光系数，λ 1ε HI-和λ 2ε HI-为HI -在λ 1和λ 2时的吸光系数。
  9. 根据权利要求7所述基于集成阀岛装置可多试剂检测的高精度海水pH原位测量方法，其特征在于，所述方法还包括指示剂校正的步骤，具体为：检测混合溶液的光强，计算吸光度的步骤完成后，将第一电磁阀和第四电磁阀切换至常开口b位，开启蠕动泵，海水样品进入管路，管路中指示剂不断被稀释，采用微型光谱仪连续采集稀释过程中混合溶液的光强度，计算吸光度和pH值，稀释时间为20-180s；指示剂在酸态和碱态等吸收波长处吸光度仅与指示剂浓度相关，以指示剂在酸态和碱态等吸收波长处多次测定吸光度值为x轴，相应pH值为y轴做直线，当x＝0时得到的y值即为消除指示剂干扰后海水本身pH值。
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