WO2019201086A1 - 一种体积排阻色谱联用型氮检测器及应用方法 - Google Patents

一种体积排阻色谱联用型氮检测器及应用方法 Download PDF

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WO2019201086A1
WO2019201086A1 PCT/CN2019/080919 CN2019080919W WO2019201086A1 WO 2019201086 A1 WO2019201086 A1 WO 2019201086A1 CN 2019080919 W CN2019080919 W CN 2019080919W WO 2019201086 A1 WO2019201086 A1 WO 2019201086A1
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nitrogen
size exclusion
exclusion chromatography
ultraviolet
oxidation
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PCT/CN2019/080919
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English (en)
French (fr)
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李文涛
蔡珉晖
叶大林
夏信群
李燕
李爱民
吴吉春
左延婷
吴亚萍
李大伟
宋海鸥
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南京大学
浙江泰林生物技术股份有限公司
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Priority to US17/042,196 priority Critical patent/US20210018476A1/en
Publication of WO2019201086A1 publication Critical patent/WO2019201086A1/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
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/33—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using ultraviolet light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/62—Detectors specially adapted therefor
    • G01N30/74—Optical detectors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N2030/022—Column chromatography characterised by the kind of separation mechanism
    • G01N2030/025—Gas chromatography
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/88—Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86
    • G01N2030/8809—Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86 analysis specially adapted for the sample
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
    • G01N30/02—Column chromatography
    • G01N30/88—Integrated analysis systems specially adapted therefor, not covered by a single one of the groups G01N30/04 - G01N30/86

Definitions

  • the invention relates to the field of water quality analysis and detection, in particular to a volume exclusion chromatography combined nitrogen detector and an application method thereof.
  • Dissolved organic matter is the main target of removal during drinking water and wastewater treatment. Analysis and characterization of the composition and properties of dissolved organic matter is an important means of research on the mechanism of water treatment technology. Molecular weight distribution is one of the important properties of dissolved organic matter, which affects the effects of physicochemical treatment technologies such as coagulation, membrane filtration, advanced oxidation, adsorption and ion exchange.
  • the analysis and characterization methods of molecular weight distribution characteristics mainly include series membrane separation method and size exclusion chromatography.
  • the former is affected by the pore size of the ultrafiltration membrane, and the molecular weight separation accuracy is poor.
  • the latter utilizes a size exclusion chromatography column and substances of different molecular weights.
  • the effluent time is different, the molecular weight separation effect is good, but the detectors configured by liquid chromatography are mainly ultraviolet absorption spectroscopy detector, fluorescence spectroscopy detector and evaporative light scattering detector. Due to the high heterogeneity of dissolved organic matter, the existing detection The device can only be used for relative quantification. Dissolved organic carbon is a comprehensive indicator of the total amount of dissolved organic matter in water in terms of carbon content.
  • the dissolved total nitrogen (TDN) in the water includes dissolved organic nitrogen (DON) and dissolved inorganic nitrogen (DIN).
  • soluble organic nitrogen comes from a variety of natural organic substances, such as proteins, humus and amino acids; inorganic nitrogen mainly includes ammonia nitrogen, nitrate nitrogen and nitrite nitrogen. Dissolved organic nitrogen has direct or indirect toxic effects on the human body.
  • organic nitrogen forms a nitrogen-containing disinfection by-product with a higher "triad effect" in the chlorination disinfection process of drinking water; on the other hand, organic nitrogen
  • the molecular weight distribution of substances also has an important impact on bioavailability and its eco-environmental effects.
  • the current method for determining organic nitrogen is mainly based on the subtractive method, that is, the determination of the dissolved total nitrogen concentration, minus the dissolved inorganic nitrogen (ie, the sum of the concentrations of NH 4 + , NO 3 - and NO 2 - respectively measured). Indirect measurement, there are accumulated errors in total nitrogen, NH 4 + , NO 3 - and NO 2 - , and the results are inevitably less accurate and reliable, and even negative values are calculated due to test errors.
  • the determination of total nitrogen was carried out by oxidative digestion of potassium persulfate in an aqueous solution above 60 ° C, and then the concentration of NO 3 - was determined by ultraviolet spectrophotometry.
  • the present invention provides a high-sensitivity and high-accuracy size exclusion chromatography-type nitrogen detector and an application method thereof, aiming at solving the qualitative and quantitative determination of dissolved organic nitrogen. Analyze the detection problem.
  • the analytical detection method of dissolved organic nitrogen has low sensitivity, large error and complicated test steps, and the like, and aims to provide a high-sensitivity and high-accuracy size exclusion chromatography type nitrogen detector and application thereof method.
  • the invention provides a volume exclusion chromatography combined nitrogen detector, comprising an oxidation system, a nitrate detection system, a power supply system, a signal processing and control system; and the sample to be detected is first separated by size exclusion chromatography and then enters the
  • the oxidation system is oxidized, the nitrogen in the sample is converted to nitrate and detected by a nitrate detection system; the power system supplies power to the detector; the signal processing and control system is used for signal processing of the oxidation system and the nitrate detection system. With control.
  • the oxidation system includes an ultraviolet oxidation module and an ultraviolet light intensity monitoring module.
  • the oxidation system includes a liquid leakage monitoring module and a vacuum negative pressure module for eliminating ozone and vacuuming in the oxidation system.
  • the ultraviolet oxidation module comprises an ultraviolet lamp tube, a quartz spiral tube flow path, a quartz adapter, a PEEK tube, a support holder and a quartz sleeve, and the support holder has an ultraviolet oxidation module.
  • the ultraviolet lamp tube is located inside the quartz sleeve, the quartz spiral tube flow path is spirally wound on the quartz sleeve, and the ends of the quartz spiral tube flow path are respectively connected with the quartz adapter One end is connected, and the other end of each quartz adapter is connected to the PEEK tube.
  • the ultraviolet oxidation module comprises an ultraviolet lamp tube and a microfluidic quartz chip, and the ultraviolet lamp is mounted on the surface of the microfluidic quartz chip; the microfluidic quartz chip is processed by etching technology
  • the microfluidic pipeline has a cross-sectional width of 0.10 to 1.0 mm, a depth of 0.05 to 0.50 mm, and a flow path length of 2 to 10 m.
  • the nitrate detecting system is an ultraviolet detector comprising a flow cell module and an ultraviolet absorption optical detecting module.
  • the power system includes a dedicated power source for the ultraviolet lamp and an AC-DC power conversion module; the dedicated power source for the ultraviolet lamp supplies power to the ultraviolet oxidation module, and the AC-DC power conversion module is nitric acid.
  • the root (NO 3 - ) detection system, signal processing and control system, and ultraviolet light intensity monitoring module supply power.
  • the signal processing and control system comprises a single chip microcomputer system, a display screen and a communication module; the single chip microcomputer system controls and processes signals, and the signals can be displayed through a display screen or transmitted by a communication module. Host computer.
  • the ultraviolet light intensity monitoring module uses a gallium nitride aluminum-based deep ultraviolet photodiode to monitor the light intensity of the ultraviolet oxidation module in real time.
  • the ultraviolet lamp tube is a low-pressure mercury lamp
  • the quartz spiral tube flow path is a capillary quartz tube having an inner diameter of 0.5 to 1.0 mm and an outer diameter of 1.5 to 3.0 mm.
  • the method for applying the size exclusion chromatography combined nitrogen detector is characterized in that the method comprises the following steps:
  • the sample is passed through the bypass and size exclusion column in a ratio of 1:10, and then detected by a nitrogen detector, wherein a rapid peak is formed due to the non-retention of the bypass.
  • the peak area is recorded as Area_TN; the peaks of organic nitrogen, NO 3 - and NH 4 + after separation by size exclusion chromatography are respectively integrated, and the peak areas are recorded as Area_TON, Area_NO 3 - _N and Area_NH 4 + _N;
  • a size exclusion chromatography-type nitrogen detector first oxidizes nitrogen in various compounds separated by size exclusion chromatography to nitrate by an oxidation system, and then detects nitrate Accurate and quantitative analysis of total nitrogen, nitrate nitrogen, nitrite nitrogen and ammonia nitrogen in various compounds, the results are accurate and reliable; overcoming the prior art organic nitrogen test using different methods for total nitrogen and nitrate Nitrogen, nitrite nitrogen and ammonia nitrogen are separately measured, and then the difference between total nitrogen and inorganic nitrogen is calculated, the operation steps are cumbersome, the test error is large, and the detector of the invention can be commonly used in the laboratory.
  • the combination of the autosampler and the size exclusion chromatography column is low in cost and convenient in system integration, which is conducive to promotion.
  • a size exclusion chromatography combined nitrogen detector wherein the oxidation system comprises an ultraviolet oxidation module and an ultraviolet light intensity monitoring module, and the ultraviolet oxidation module is used for oxidizing nitrogen in the compound to nitrate ions.
  • the ultraviolet light intensity monitoring module is used for real-time monitoring of the ultraviolet light intensity of the ultraviolet oxidation module, and the two modules cooperate with each other to ensure that the oxidation system has sufficient oxidation intensity to ensure a stable and effective oxidation effect.
  • a volume exclusion chromatography combined nitrogen detector wherein the oxidation system is further provided with a vacuum negative pressure module, which not only excludes ozone generated by ultraviolet irradiation air, but also evacuates it by vacuuming. Reduce the attenuation of ultraviolet light intensity to enhance the oxidation effect, and further ensure the stable and effective oxidation effect of the oxidation system.
  • the power supply system is provided with different power supply systems according to different characteristics of the ultraviolet oxidation module and other modules, which is beneficial to reducing energy consumption and further reducing operating costs.
  • a method for applying a size exclusion chromatography-type nitrogen detector according to the present invention by providing two different flow paths of a bypass and a size exclusion chromatography flow path; based on the non-retention effect of the bypass, The integral is recorded as Area_TN, and the peak areas such as TON, NO 3 - and NH 4 + separated by size exclusion chromatography are respectively integrated, and the ratio of Area_TON, Area_NO 3 - _N and Area_NH 4 + _N to Area_TN is calculated; to NO 3 - to establish a linear relationship between the standard solution Area_TN peak area of the nitrogen content, calculated final concentrations of various forms of nitrogen; provided in the bypass mode by the additional sample finalized various forms of nitrogen accurate quantitative detection
  • the method is simple and easy to operate, the cost is low, the result is accurate and reliable, the sensitivity is high, and the promotion is favorable.
  • a method for applying a size exclusion chromatography-type nitrogen detector according to the present invention which uses a size exclusion chromatography to separate different molecular weight substances, can qualitatively analyze the molecular weight distribution of organic nitrogen, and can provide more Characterization information, especially suitable for laboratory scientific research purposes.
  • Figure 1 is a plan view of a size exclusion chromatography combined nitrogen detector of the present invention
  • FIG. 2 is a front view of a spiral tube oxidation module of a size exclusion chromatography combined type nitrogen detector of the present invention
  • FIG. 3 is a top plan view of a spiral tube oxidation module of a size exclusion chromatography combined nitrogen detector according to the present invention
  • FIG. 4 is a schematic flow chart of a method for applying a nitrogen detector according to the present invention.
  • FIG. 6 is a chromatogram of the volume exclusion chromatography-type nitrogen detector of the present invention for detecting a biochemical secondary effluent water sample of a sewage treatment plant;
  • Figure 7 is a chromatogram of the volume exclusion chromatography-type nitrogen detector of the present invention for detecting water samples of the Yangtze River;
  • Figure 8 is a test chart showing the oxidation efficiency of the size exclusion chromatography-type nitrogen detector of the present invention.
  • FIG. 9 is a schematic view of a microfluidic chip oxidation module of a size exclusion chromatography combined nitrogen detector according to the present invention.
  • This embodiment provides a volume exclusion chromatography combined nitrogen detector, as shown in Figure 1, the detector includes an oxidation system 1, a nitrate detection system 2, a power supply system 3, a signal processing and control system 4;
  • the sample to be detected is first separated by size exclusion chromatography and then introduced into the oxidation system 1 for oxidation treatment, and the nitrogen in the sample is converted into nitrate and detected by the nitrate detection system 2;
  • the power supply system 3 supplies power to the detector;
  • the signal processing and control system 4 is used for signal processing and control of the oxidation system 1, the nitrate detection system 2.
  • the basic principle of the detector of the present invention is to convert the nitrogen contained in each compound after being subjected to size exclusion chromatography into NO 3 - by the oxidation system 1, and absorb the light according to the molar absorption coefficient or unit mass of NO 3 - at a specific ultraviolet wavelength. The coefficient is quantitatively detected.
  • the oxidation system 1 includes an ultraviolet oxidation module 101 and an ultraviolet light intensity monitoring module 103.
  • the ultraviolet oxidation module 101 oxidizes a compound by ultraviolet light oxidation to convert nitrogen contained in the compound into NO 3 - ultraviolet light.
  • the intensity monitoring module 103 is configured to monitor the intensity of the ultraviolet light generated by the ultraviolet oxidation module 101 in real time, and the signal processing and control system 4 is used to control the generated signal to ensure that the ultraviolet oxidation module 101 generates sufficient oxidation intensity.
  • the oxidation system 1 further includes a vacuum negative pressure module 104.
  • the vacuum negative pressure module 104 discharges ozone generated by ultraviolet irradiation of the air out of the detector, and vacuums to enhance the ultraviolet oxidation effect, and the micro vacuum pump is specifically used, and the micro vacuum pump is used.
  • An activated carbon filter element is arranged in front of the suction port of the vacuum pump to remove ozone.
  • the oxidation system 1 further includes a liquid leakage monitoring module 102 for monitoring system leakage and controlling by the signal processing and control system 4; the leakage monitoring module 102 adopts LeaKFilm
  • the sensor belt can respond quickly to liquid leakage, without false alarms, and can be quickly reset after liquid leakage cleaning and enter working condition.
  • the ultraviolet oxidation module 101 converts nitrogen in various types of compounds into NO 3 ⁇
  • the leakage monitoring module 102 is used for detecting leakage and leaking.
  • the liquid condition is displayed by the signal processing communication system 4; the ultraviolet light intensity monitoring module 103 displays the ultraviolet light intensity through the signal processing communication system 4.
  • This embodiment is basically the same as the embodiment, except that:
  • the nitrate detecting system 2 is an ultraviolet detector, including a flow cell module 201 and an ultraviolet absorption optical detecting module 202; the working principle is to emit a specific wavelength of ultraviolet light by using a continuous light source such as a xenon lamp or a UV_LED lamp, and detect the volume row.
  • a continuous light source such as a xenon lamp or a UV_LED lamp
  • the UV absorbance of the chromatographic mobile phase in the wavelength range of 215-230 nm and the optical path of 10-40 mm optical path, and the NO 3 - is quantified according to the molar absorptivity of NO 3 - or the absorbance coefficient per unit mass of the corresponding wavelength.
  • the nitrate detecting system 2 is an outlet of a flow path, wherein the flow cell module 201 quantitatively detects and emits an optical signal according to a molar absorption coefficient or a unit mass absorption coefficient of a specific ultraviolet wavelength of NO 3 -
  • the ultraviolet absorption optical detection module 202 converts the optical signal into an electrical signal and transmits it to the signal processing communication system 4.
  • the flow cell module 201 has a path length of 10 mm, and the NO 3 - is quantitatively detected by using an ultraviolet absorbance of 220 nm wavelength, and the unit mass absorption coefficient is 0.25 L / (mg * cm).
  • the signal processing and control system 4 includes a single chip microcomputer system 401, a display screen 402, and a communication module 403.
  • the single chip microcomputer system 401 controls and processes signals, and the signals can be displayed on the display screen 402 or transmitted to the upper position by the communication module 403. machine.
  • the electrical signal generated by the ultraviolet absorption optical detection module 202 generates a digital signal through an amplifying circuit and an analog-to-digital conversion circuit, and is sent to the single-chip microcomputer system 401; the single-chip microcomputer system 401 stores the digital signal to the single-chip microcomputer; the display 403 displays the digital number in real time.
  • the basic state of the signal and device is not limited to, but not limited to, but not limited to, but not limited to the ultraviolet absorption optical detection module 202 .
  • the single-chip microcomputer system 401 outputs a communication signal to the oxidation system 1, and controls the ultraviolet oxidation module 101 in the oxidation system 1 to operate in a continuous form.
  • This embodiment is basically the same as the embodiment, except that:
  • the ultraviolet light intensity monitoring module 103 uses a gallium nitride aluminum-based deep ultraviolet photodiode to monitor the light intensity of the ultraviolet oxidation module 101 in real time, which only responds to the ultraviolet light of the UVC band.
  • the power system 3 includes an ultraviolet lamp dedicated power supply 301 and an AC-DC power conversion module 302.
  • the ultraviolet lamp dedicated power supply 301 supplies power to the ultraviolet oxidation module 101
  • the AC-DC power conversion module 302 is a nitrate ( The NO 3 - ) detection system 2, the signal processing and control system 4, and the ultraviolet light intensity monitoring module 103 supply power.
  • the reason why the ultraviolet oxidation module 101 and other modules are powered by different power sources is that the ultraviolet lamp used in the ultraviolet oxidation module 101 belongs to a cold cathode lamp, and its power is small, so the power supply mode of alternating current DC and direct current alternating current is selected;
  • the hot cathode lamp required by the module has a large power supply, so the variable frequency voltage is used to connect the standard alternating current. Therefore, distinguishing the ultraviolet oxidation module 101 from the power supply system of other modules is beneficial to save power and further reduce operating costs.
  • This embodiment is basically the same as the embodiment, except that:
  • the ultraviolet oxidation module 101 includes an ultraviolet lamp tube 111, a quartz spiral tube flow path 112, a quartz adapter 113, a PEEK tube 114, a support fixture 115, and a quartz sleeve 116.
  • FIG. 2 is the ultraviolet oxidation module 101 of the present embodiment.
  • FIG. 3 is a top view of the ultraviolet oxidizing module 101 of the present embodiment. As shown in FIG. 2 and FIG. 3 , the supporting fixture 115 supports and fixes the ultraviolet oxidizing module 101 by using a plastic buckle with an inner diameter of 25 mm.
  • the ultraviolet lamp tube 111 is located inside the quartz sleeve 116, and the quartz sleeve 116 functions to protect the ultraviolet lamp tube 111 and the fixed quartz spiral tube 112.
  • the quartz spiral tube flow path 112 is melted and wound on the quartz sleeve 116 by a capillary quartz tube having an inner diameter of 1.0 mm and an outer diameter of 3.0 mm, and the two ends of the capillary quartz tube are respectively connected to the two quartz adapters 113 by fusion.
  • the other end of the quartz adapter has a 1/4-28 internal thread and can be connected to the PEEK joint 114 of the same specification; the PEEK tube to which the PEEK joint 114 is connected serves only to transport liquid, and Special role.
  • the separated sample was subjected to ultraviolet irradiation and oxidation in a quartz spiral tube.
  • the sample is recombined into one pass through the size exclusion chromatography column and bypassed, and then enters the quartz spiral tube through the PEEK through-wall joint and the quartz adapter in the Influent of the oxidation module, and is oxidized in this part, and then passed through the quartz adapter and PEEK.
  • the wall joint and the PEEK tube enter the detection module. After detection, the detector flows out of the detector at the Effluent port of the detector and is discharged through the waste liquid tube.
  • the ultraviolet lamp tube 111 adopts a low-pressure cold cathode mercury lamp having a diameter of 15 mm and a length of 150 mm.
  • the ultraviolet lamp 111 generates ultraviolet radiation containing two ultraviolet rays of 184.9 nm and 253.7 nm, of which 184.9 nm is ultraviolet.
  • the ray plays a major role in the oxidation of nitrogen.
  • FIG. 4 is a schematic flow chart. As shown in Figure 4, the steps of the entire process are as follows:
  • the sample enters the size exclusion chromatography combined nitrogen detector 12 through volume exclusion chromatography 9 and bypass PEEK tube 10 respectively; the size exclusion chromatography 9 is 250 mm long, the inner diameter is 20 mm, and the filler is used. Toyopearl HW-50S gel resin.
  • This embodiment also provides an application method for performing sample detection by the size exclusion chromatography combined nitrogen detector in Embodiment 1, comprising the following steps:
  • the sample is taken from the biochemical secondary effluent of the sewage plant, the volume is 500 ⁇ L, and the ratio is 1:10, respectively, through the bypass and size exclusion chromatography column, and then detected by a nitrogen detector, wherein the bypass has no retention effect, Rapid peak formation is formed, and the peak area is recorded as Area_TN. Due to the separation of size exclusion chromatography, the peaks of organic nitrogen, NO 3 - and NH 4 + can be integrated respectively, and the peak area is recorded as Area_TON, Area_NO 3 - _N and Area_NH 4 + _N, the unit is AU (Arbitrary Units);
  • FIG. 6 is a chromatogram of a sample of a mass exclusion type nitrogen detector for detecting a biochemical secondary effluent water sample of a sewage treatment plant according to the present invention, wherein Bypass represents a TN peak of the bypass; TON, Area_NO 3 - _N, Area_NH 4 + _N represents the peak of TON, NO 3 - _N, NH 4 + _N through the size exclusion column.
  • Table 1 shows the statistics of the final test results.
  • This embodiment is basically the same as the embodiment 5, except that the water sample is a Yangtze River water sample with a sampling amount of 500 ⁇ L, and the oxidation mode is only ultraviolet oxidation, and the oxidizing agent is not added using the syringe pump 11, and the nitrate (NO 3 ) is used.
  • the sum of -N) and ammonium (NH 4 + _N) is recorded as total inorganic nitrogen (TIN), and the obtained results, wherein TN, TON, NO 3 - _N, NH 4 + _N concentration calculation process and Example 5
  • Table 2 is the test result statistics in this embodiment.
  • FIG. 8 is a test chart of the oxidation efficiency of the size exclusion chromatography type nitrogen detector of the present invention, as shown in FIG. 8, wherein the injection volume is 25 ⁇ L and 50 ⁇ L.
  • the peak of the peak appeared in the middle of the chromatographic peak, indicating that the injection amount exceeded the oxidizing ability of the ultraviolet spiral tube, and the peak shape was better under the injection volume of 12.5 ⁇ L and 6.25 ⁇ L, and the peak area between the two was 2 times, indicating The ultraviolet oxidation module 101 is capable of sufficiently oxidizing the organic nitrogen TON under the injection amount.
  • the size exclusion chromatography column 9 and the bypass PEEK tube 10 are not used, and the TON_N, NO 3 - _N, NH 4 + _N solution 10 mg/L in N is prepared by using bovine serum albumin, NaNO 3 and NH 4 Cl. 5 injections, respectively, the relative standard deviation is less than 2%, in line with the accuracy requirements. Table 3 shows the statistics of the test results.
  • the numerical unit in this table is mg/L in addition to the relative standard deviation.
  • Example 6 using the size exclusion chromatography column 9 and the bypass PEEK tube 10, 10 mg/L of the prepared TON_N, NO 3 - _N, NH 4 + _N solution in N was injected.
  • the relative standard deviation is less than 2%, which meets the accuracy requirements.
  • Table 4 is a statistical analysis of the results of the method according to the invention.
  • This embodiment is basically the same as Embodiment 5 except that the flow ratio of the bypass 10 to the volume exclusion chromatography column 9 is 1:5.
  • the quartz spiral tube flow path 112 is a capillary quartz tube having an inner diameter of 0.5 mm and an outer diameter of 1.5 mm.
  • This embodiment is basically the same as Embodiment 5 except that the flow ratio of the bypass 10 to the volume exclusion chromatography column 9 is 1:15.
  • the ultraviolet oxidation module 101 includes an ultraviolet lamp tube 111 and a microfluidic quartz chip 117.
  • the ultraviolet lamp 111 is mounted on the surface of the microfluidic quartz chip 117.
  • the microfluidic quartz chip 117 is used.
  • the etching technique is processed with an S-type microfluidic pipeline having a cross-sectional width of 0.40 mm, a depth of 0.10 mm, and a flow path length of 4 m.

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Abstract

一种体积排阻色谱联用型氮检测器及应用方法，属于水质分析检测领域。检测器包括氧化系统（1）、硝酸根检测系统（2）、电源系统（3）、信号处理与控制系统（4）；将待检测样品首先经体积排阻色谱分离后进入氧化系统（1）氧化处理，样品中的氮转化为硝酸根后采用紫外吸光度法硝酸根检测系统（2）检测；电源系统（3）为检测器提供电源；信号处理与控制系统（4）负责氧化系统（1）、硝酸根检测系统（2）的信号处理与控制；检测器可实现总氮、有机氮、硝态氮和氨氮的定量分析，具有操作简便和信息丰富等优点，有效避免了传统有机氮分析方法中因差减计算所产生的较大误差和负值问题。

Description

一种体积排阻色谱联用型氮检测器及应用方法 技术领域
本发明涉及水质分析检测领域，具体涉及一种体积排阻色谱联用型氮检测器及应用方法。
背景技术
在饮用水和污水处理过程中，溶解性有机物是主要的去除对象。分析表征溶解性有机物的组成和性质，是水处理技术机理研究的重要手段。分子量分布特征是溶解性有机物的重要性质之一，影响着混凝、膜过滤、高级氧化、吸附与离子交换等物化处理技术的效果。
分子量分布特征的分析表征方法主要有系列膜分离法和体积排阻色谱法，前者受超滤膜孔径大小的影响，分子量分离准确度差；后者利用体积排阻色谱柱，不同分子量大小的物质流出时间不同，分子量分离效果好，但液相色谱所配置的检测器主要是紫外吸收光谱检测器、荧光光谱检测器以及蒸发光散射检测器，由于溶解性有机物具有高度异质性，现有检测器只能进行相对定量。溶解性有机碳是以碳的含量表示水体中溶解性有机物质总量的综合指标。近年来，美国GE公司所生产的基于薄膜电导检测技术的有机碳检测器，通过与体积排阻色谱的联用，将有机碳与酸混合并紫外氧化为CO 2，对透过薄膜的CO 2进行测定，从而对有机碳的分子量分布进行测定。
随着水体富营养化程度不断恶化，氮元素作为一种重要的营养元素，其在水中的存在和可利用形式成为重要的研究内容。水体中的溶解性总氮(total dissolved nitrogen，TDN)包括溶解性有机氮(dissolved organic nitrogen，DON)和溶解性无机氮(dissolved inorganic nitrogen，DIN)。其中，溶解性有机氮来自于各种各样的天然有机物，如蛋白质、腐殖质和氨基酸等；无机氮主要包括氨氮、硝态氮和亚硝态氮。溶解性有机氮对人体具有直接或间接的毒害作用，特别是，有机氮在饮用水氯化消毒工艺中会形成具有更高“三致效应”的含氮消毒副产物；另一方面，有机氮物质的分子量大小分布，对生物有效性及其生态环境效应也有重要影响。目前的有机氮测定方法主要基于差减法，即依赖于溶解性总氮浓度的测定，减去溶解性无机氮(即分别测定的NH 4 +，NO 3 -和NO 2 -浓度之和)。 这种间接测量，存在总氮、NH 4 +，NO 3 -和NO 2 -多方面测定的累加误差，结果难免不够精确和可靠，甚至会因为测试误差计算出负值。
基于上述缺陷，许多学者提出把DON与DIN分离后再测定，从而提高浓度测定的准确性，如中国专利申请号CN201010022653.1，公开日为2010.07.21的申请案公开了使用纳滤膜分离技术对DON分离后进行测定，但由于需要外加氮气控制跨膜压力，能耗大且对测试水样的需求量较大。而中国专利申请号CN201710048270.3，公开日为2017.05.31的申请案公开了使用透析预处理技术对DON分离后进行测定，由于需要通过初步测定结果判断后续测定方案，分离和测定步骤复杂，操作繁琐。此外，以上的溶解性有机氮测试方法仅限于定量分析方法，无法对溶解性有机氮的组成及其分子量分布进行深入的定性和定量分析。
中华人民共和国国家标准《GB 11894-89》，总氮的测定采用过硫酸钾在60℃以上水溶液中进行氧化消解，然后以紫外分光光度法测定NO 3 -的浓度。基于对总氮标准方法的改进与优化，本发明提供一种灵敏度高和准确性好的体积排阻色谱联用型氮检测器及其应用方法，旨在解决溶解性有机氮的定性和定量的分析检测难题。
发明内容
1.要解决的问题
现有技术中溶解性有机氮的分析检测方法灵敏度低、误差大和测试步骤复杂等问题，本发明旨在提供一种灵敏度高、准确性好的体积排阻色谱联用型氮检测器及其应用方法。
2.技术方案
为了解决上述问题，本发明所采用的技术方案如下：
本发明提供了一种体积排阻色谱联用型氮检测器，包括氧化系统、硝酸根检测系统、电源系统、信号处理与控制系统；将待检测样品首先经体积排阻色谱分离后进入所述的氧化系统氧化处理，样品中的氮转化为硝酸根后采用硝酸根检测系统检测；所述的电源系统为检测器提供电源；信号处理与控制系统用于氧化系统、硝酸根检测系统的信号处理与控制。
作为本发明更进一步的改进，所述的氧化系统包括紫外氧化模块和紫外光强 度监测模块。
作为本发明更进一步的改进，所述的氧化系统包括漏液监测模块和真空负压模块，所述的真空负压模块用于消除氧化系统内的臭氧和抽真空。
作为本发明更进一步的改进，所述的紫外氧化模块包括紫外灯管、石英螺旋管流路、石英转接头、PEEK管、支撑固定架和石英套管，所述的支撑固定架将紫外氧化模块承托并固定在基座上；所述的紫外灯管位于石英套管内部，石英螺旋管流路螺旋缠绕于石英套管上，所述的石英螺旋管流路两端分别与石英转接头的一端连接，每个石英转接头另一端与PEEK管连接。
作为本发明更进一步的改进，所述的紫外氧化模块包括紫外灯管和微流控石英芯片，紫外灯安装于微流控石英芯片的表面；所述的微流控石英芯片采用刻蚀技术加工有S型微流管路，优选地，微流管路的截面宽为0.10～1.0mm，深度为0.05～0.50mm，流路长度为2～10m。
作为本发明更进一步的改进，所述的硝酸根检测系统为紫外检测器，包括流通池模块和紫外吸收光学检测模块。
作为本发明更进一步的改进，所述的电源系统包括紫外灯专用电源和AC-DC电源转换模块；所述的紫外灯专用电源为紫外氧化模块供电，所述的AC-DC电源转换模块为硝酸根(NO 3 -)检测系统、信号处理与控制系统、紫外光强度监测模块供电。
作为本发明更进一步的改进，所述的信号处理与控制系统包括单片机系统、显示屏和通讯模块；所述的单片机系统控制和处理信号，所述信号可通过显示屏显示或由通讯模块传输到上位机。
作为本发明更进一步的改进，所述的紫外光强度监测模块采用氮化镓铝基深紫外光电二极管对所述紫外氧化模块的光强进行实时监测。
作为本发明更进一步的改进，所述的紫外灯管为低压汞灯，所述的石英螺旋管流路为内径0.5～1.0mm、外径1.5～3.0mm的毛细石英管。
作为本发明更进一步的改进，所述的体积排阻色谱联用型氮检测器的应用方法，其特征在于：包括以下步骤：
1)采用体积排阻色谱柱对样品中有机氮、硝酸盐氮(NO 3 -_N)和氨氮(NH 4 +_N)进行分离，流动相采用纯水或磷酸盐缓冲液，不能采用有机溶剂；
2)在体积排阻色谱柱两端并联一定长度的PEEK管形成PEEK管旁路，通过测试调整PEEK管长度，使形成PEEK管旁路与体积排阻色谱柱所产生的压力之比为n：1(n可以为5～15)，由此通过形成PEEK管旁路与通过体积排阻色谱柱的流量比为1：n；
3)自动进样器进样时，进样样品按照1：10的比例分别通过旁路与体积排阻色谱柱，然后经氮检测器检测，其中由于旁路无保留作用，形成快速出峰，其峰面积记为Area_TN；对经过体积排阻色谱的分离后有机氮、NO 3 -和NH 4 +的出峰分别进行积分，其峰面积记为Area_TON、Area_NO 3 -_N和Area_NH 4 +_N；
4)以NO 3 -标准溶液建立Area_TN峰面积与氮含量之间的线性关系，以样品旁路Area_TN计算出总氮(TN)，根据Area_TON、Area_NO 3 -_N和Area_NH 4 +_N占体积排阻色谱总峰面积的比例，分别计算出样品中有机氮(TON)、硝酸盐氮(NO 3 -_N)和氨氮(NH 4 +_N)的浓度。
3.有益效果
相比于现有技术，本发明的有益效果为：
(1)本发明所述的一种体积排阻色谱联用型氮检测器，首先采用氧化系统将经体积排阻色谱分离的各种化合物中的氮氧化为硝酸根，再对硝酸根进行检测，可以对各类化合物中的总氮、硝态氮、亚硝态氮和氨氮等进行准确定量分析，结果准确可靠；克服了现有技术中的有机氮测试采用不同方法对总氮、硝态氮、亚硝态氮和氨氮进行分别测定，然后计算总氮和无机氮的差值，操作步骤繁琐、测试误差较大的缺陷，且本发明的检测器可以和实验室普遍购置的恒流泵、自动进样器和体积排阻色谱柱进行联用，成本低廉、系统集成方便，利于推广。
(2)本发明所述的一种体积排阻色谱联用型氮检测器，其氧化系统包括紫外氧化模块和紫外光强度监测模块，紫外氧化模块用于将化合物中的氮氧化成硝酸根离子，紫外光强度监测模块用于对紫外氧化模块的紫外光强度进行实时监测，两个模块互相配合，保证氧化系统具有足够的氧化强度，从而保证稳定有效的氧化效果。
(3)本发明所述的一种体积排阻色谱联用型氮检测器，其氧化系统还设置真空负压模块，真空负压模块不仅将紫外照射空气产生的臭氧排除，而且通过抽真空来降低紫外光强的衰减从而增强氧化效果，进一步保证氧化系统稳定有效的 氧化效果。
(4)本发明所述的一种体积排阻色谱联用型氮检测器，电源系统根据紫外氧化模块和其他模块的不同特点设置不同的供电体系，有利于减少耗能，进一步降低运行成本。
(5)本发明的一种体积排阻色谱联用型氮检测器的应用方法，通过设置旁路和体积排阻色谱柱流路两种不同的流路；基于旁路的无保留作用，将其积分记为Area_TN，对经过体积排阻色谱的分离的TON、NO 3 -和NH 4 +等峰面积分别进行积分，并计算Area_TON、Area_NO 3 -_N和Area_NH 4 +_N占Area_TN的比例；再以NO 3 -标准溶液建立Area_TN峰面积与氮含量之间的线性关系，最终计算出各种形式存在的氮的浓度；通过额外设置旁路的方式最终完成样品中各种形式氮的准确定量检测，该方法简单易操作，成本低廉，结果准确可靠，灵敏度高，利于推广。
(6)本发明的一种体积排阻色谱联用型氮检测器的应用方法，其最终定量分析是根据总氮和以有机氮的出峰面积所占比例确定，不会出现负值，进一步保证结果的准确性，而现有技术中则是计算差值，误差较大。
(7)本发明的一种体积排阻色谱联用型氮检测器的应用方法，采用体积排阻色谱对不同分子量物质进行分离，可以对有机氮的分子量分布进行定性分析，可以提供更多的表征信息，特别适合于实验室科学研究用途。
附图说明
图1为本发明的体积排阻色谱联用型氮检测器的俯视图；
图2为本发明的体积排阻色谱联用型氮检测器螺旋管氧化模块的主视图；
图3为本发明的体积排阻色谱联用型氮检测器螺旋管氧化模块的俯视图；
图4为本发明的氮检测器的应用方法的流程示意图；
图5为NO 3 -标准溶液建立Area_TN峰面积与氮含量之间的线性关系图；
图6为本发明的体积排阻色谱联用型氮检测器检测污水厂生化二级出水水样的色谱图；
图7为本发明的体积排阻色谱联用型氮检测器检测长江水样的色谱图；
图8为本发明的体积排阻色谱联用型氮检测器氧化效率的测试图；
图9为本发明的体积排阻色谱联用型氮检测器微流控芯片氧化模块示意图。
图中：1、氧化系统；2、硝酸根检测模块；3、电源控制模块；4、信号处理 通讯系统；5、磷酸盐缓冲溶液；6、超纯水；7、恒流泵；8、自动进样器；9、体积排阻色谱柱；10、旁路PEEK管；11、注射泵；12、体积排阻色谱联用型氮检测器；101、紫外氧化模块；102、漏液监测模块；103、紫外灯光强检测模块；104、真空负压模块；201、流通池模块；202、紫外吸收光学检测模块；301、紫外灯专用电源；302、AC-DC电源转换模块；401、单片机系统；402、显示屏；403、通讯模块；111、紫外灯管；112、石英螺旋管流路；113、石英转接头；114、PEEK管；115、支撑固定架；116、石英管；117、微流控石英芯片。
具体实施方式
下面结合具体实施例对本发明进一步进行描述。
实施例1
本实施例提供了一种体积排阻色谱联用型氮检测器，如图1所示，该检测器包括氧化系统1、硝酸根检测系统2、电源系统3、信号处理与控制系统4；将待检测样品首先经体积排阻色谱分离后进入所述的氧化系统1氧化处理，样品中的氮转化为硝酸根后采用硝酸根检测系统2检测；所述的电源系统3为检测器提供电源；信号处理与控制系统4用于氧化系统1、硝酸根检测系统2的信号处理与控制。
本发明的检测器基本原理为采用氧化系统1将经过体积排阻色谱分离后各类化合物所含的氮转化为NO 3 -，根据NO 3 -在特定紫外波长下的摩尔吸光系数或单位质量吸光系数进行定量检测。
所述的氧化系统1包括紫外氧化模块101和紫外光强度监测模块103，所述的紫外氧化模块101通过紫外光氧化方式使化合物进行氧化，将化合物所含的氮转化为NO 3 -；紫外光强度监测模块103用于实时监测紫外氧化模块101所产生的紫外光强度，信号处理与控制系统4用于对产生的信号进行控制，从而保证紫外氧化模块101产生足够的氧化强度。
所述的氧化系统1还包括真空负压模块104，所述的真空负压模块104将可以紫外照射空气产生的臭氧排出检测器，并抽真空增强紫外氧化效果，其具体采用微型真空泵，且微型真空泵吸气口前设有活性炭滤芯去除臭氧。
所述的氧化系统1还包括漏液监测模块102，所述的漏液监测模块102用于监测系统漏液情况并通过信号处理与控制系统4进行控制；所述的漏液监测模块 102采用LeaKFilm传感带，对液体泄漏能够快速反应，没有误报警，且漏液清理后能够快速重新设置，并进入工作状态。
如图2、图3所示，所述的紫外氧化模块101将进入的各类化合物中的氮转化为NO 3 -，所述的漏液监测模块102用于漏液情况的检测，并将漏液情况经信号处理通讯系统4显示；所述的紫外光强度监测模块103将紫外光强经信号处理通讯系统4显示。
实施例2
本实施例基本与实施例相同，不同之处在于：
所述的硝酸根检测系统2为紫外检测器，包括流通池模块201和紫外吸收光学检测模块202；其工作原理为采用氘灯或UV_LED灯等连续光源发射特定波长的紫外光，并检测体积排阻色谱流动相在215～230nm波长范围和10～40mm光程流通池的紫外吸光度，并根据其对应波长下NO 3 -的摩尔吸光系数或单位质量吸光系数对NO 3 -进行定量。
所述的硝酸根检测系统2为流路的接出口，其中，所述的流通池模块201根据NO 3 -在特定紫外波长的摩尔吸光系数或单位质量吸光系数进行定量检测并发出光信号，所述的紫外吸收光学检测模块202将光信号转化为电信号并传入信号处理通讯系统4。
所述的流通池模块201光程选用10mm，采用220nm波长的紫外吸光度对NO 3 -进行定量检测，其单位质量吸光系数采用0.25L/(mg*cm)。
所述的信号处理与控制系统4包括单片机系统401、显示屏402和通讯模块403；所述的单片机系统401控制和处理信号，所述信号可通过显示屏402显示或由通讯模块403传输到上位机。
所述的紫外吸收光学检测模块202所产生的电信号经放大电路和模数转换电路产生数字信号，输送到单片机系统401；单片机系统401将数字信号储存到单片机；所述的显示器403实时显示数字信号和装置的基本状态。
所述的单片机系统401输出通讯信号给氧化系统1，控制氧化系统1中的紫外氧化模块101以连续形式进行工作。
实施例3
本实施例基本与实施例相同，不同之处在于：
所述的紫外光强度监测模块103采用氮化镓铝基深紫外光电二极管对所述紫外氧化模块101的光强进行实时监测，其仅对UVC波段的紫外产生响应。
所述的电源系统3包括紫外灯专用电源301和AC-DC电源转换模块302；所述的紫外灯专用电源301为紫外氧化模块101供电，所述的AC-DC电源转换模块302为硝酸根(NO 3 -)检测系统2、信号处理与控制系统4、紫外光强度监测模块103供电。
紫外氧化模块101和其他模块采用不同的电源进行供电的原因在于：紫外氧化模块101中采用的紫外灯属于冷阴极灯，其功率小，因此选择交流变直流、直流变交流的供电方式；而其他的模块需要的热阴极灯供电功率大，因此采用变频变压接标准交流电，因此将紫外氧化模块101与其他模块的供电体系进行区分有利于节省电源，进一步降低运行成本。
实施例4
本实施例基本与实施例相同，不同之处在于：
所述的紫外氧化模块101包括紫外灯管111、石英螺旋管流路112、石英转接头113、PEEK管114、支撑固定架115和石英套管116，图2为本实施例紫外氧化模块101的主视图；图3为本实施例紫外氧化模块101的俯视图，如图2，图3所示，所述的支撑固定架115采用内径为25mm的塑料扣环将紫外氧化模块101承托并固定在基座上；所述的紫外灯管111位于石英套管116内部，石英套管116起到保护紫外灯管111和固定石英螺旋管112的作用。所述的石英螺旋管流路112采用内径1.0mm、外径3.0mm的毛细石英管以熔融方式缠绕于石英套管116上，毛细石英管两端分别通过熔融方式连接于两个石英转接头113的一端，石英转接头另一端具有1/4-28规格内螺纹，可与相同规格的PEEK接头114连接；所述的PEEK接头114与之连接的PEEK管仅起到运输液体的作用，并无特殊作用。
分离后的样品在石英螺旋管中流动经受紫外照射并产生氧化。样品经体积排阻色谱柱以及旁路后重新合并为一路，之后在氧化模块的Influent经PEEK穿墙接头和石英转接头进入石英螺旋管，在此部分进行氧化，再经石英转接头、PEEK穿墙接头、PEEK管进入检测模块，经检测后在检测器的Effluent口流出检测器，经废液管排出。
所述的紫外灯管111采用低压冷阴极汞灯，其直径15mm，长度150mm；所述的紫外灯管111产生的紫外光谱中包含184.9nm和253.7nm的两条紫外射线，其中184.9nm的紫外射线在氮的氧化过程起主要作用。
实施例5
本实施例提供了实施例1中体积排阻色谱联用型氮检测器进行样品检测的流程，图4为流程示意图。如图4所示，整个流程的步骤如下：
a)采用自动采样器8将样品注射入多元恒流泵7驱动的流动相磷酸盐缓冲液5中；
b)样品分别经体积排阻色谱9和旁路PEEK管10两种流路进入体积排阻色谱联用型氮检测器12；所述的体积排阻色谱9长250mm，内径为20mm，填料采用Toyopearl HW-50S的凝胶树脂。
c)在进入体积排阻色谱联用型氮检测器12前通过注射泵11加入质量浓度为1％的过硫酸钾溶液作为氧化剂，其作用是对于高浓度水样，可以起到增强氧化的作用。
d)检测完成后，采用超纯水6清洗管路。
本实施例还提供了实施例1中体积排阻色谱联用型氮检测器进行样品检测的应用方法，包括以下步骤：
1)采用体积排阻色谱柱对样品中有机氮、NO 3 -和NH 4 +进行分离，流动相采用磷酸盐缓冲溶液，所述的磷酸盐缓冲液采用2.5g/L KH 2PO 4和1.5g/L Na 2HPO 4·2H 2O的混合溶液。
2)在体积排阻色谱柱两端通过三通并联一段PEEK管形成旁路，通过测试调整PEEK管长度，使旁路PEEK管10与体积排阻色谱柱所产生的的压力之比为10：1，由此通过旁路与通过体积排阻色谱柱的流量比为1：10；
3)进样样品取自污水厂生化二级出水，体积500μL，同样按照1：10的比例分别通过旁路与体积排阻色谱柱，然后经氮检测器检测，其中由于旁路无保留作用，形成快速出峰，其峰面积记为Area_TN；由于体积排阻色谱的分离作用，可对有机氮、NO 3 -和NH 4 +的出峰分别进行积分，其峰面积记为Area_TON、Area_NO 3 -_N和Area_NH 4 +_N，单位为AU(Arbitrary Units)；
4)以NO 3 -标准溶液建立Area_TN峰面积与氮含量之间的线性关系，以样品 旁路Area_TN计算出总氮(TN)，根据Area_TON、Area_NO 3 -_N和Area_NH 4 +_N占体积排阻色谱总峰面积的比例，分别计算出有机氮(TON)、硝酸根(NO 3 -_N)和铵根(NH 4 +_N)。
建立线性关系时，分别配制1mg/L、500μg/L、100μg/L、10μg/L、5μg/L的以N计的NO 3 -标准溶液并进样，建立Area_TN峰面积与氮含量的线性关系，图5为NO 3 -标准溶液建立Area_TN峰面积与氮含量之间的线性关系图，由图5可知，Area_TN峰面积与氮含量之间的线性方程中的R 2＝0.9995，满足线性标准。
图6为本发明即体积排阻色谱联用型氮检测器检测污水厂生化二级出水水样的色谱图，其中，Bypass代表旁路的TN出峰；TON、Area_NO 3 -_N、Area_NH 4 +_N代表经过体积排阻色谱柱的TON、NO 3 -_N、NH 4 +_N的出峰。
其中，TN、TON、NO 3 -_N、NH 4 +_N浓度的计算过程如下：
TN的浓度为：0.367AU×1.1mL/min×3.911mg·cm/L×11÷0.5mL＝34.735mg/L
TON的浓度为：34.735mg/L×(0.261÷0.367)÷10＝2.470mg/L
NO 3 -_N的浓度为：34.735mg/L×(1.338÷0.367)÷10＝12.636mg/L
NH 4 +_N的浓度为：34.735mg/L×(2.069÷0.367)÷10＝19.582mg/L
表1为最终测试结果统计。
表1测试结果
Figure PCTCN2019080919-appb-000001
实施例6
本实施例基本与实施例5相同，不同之处在于：所测水样为长江水样，取样量500μL，氧化方式为仅采用紫外氧化，不使用注射泵11添加氧化剂，将硝酸根(NO 3 -_N)和铵根(NH 4 +_N)之和记为总无机氮(TIN)，所获得结果，其中，TN、TON、NO 3 -_N、NH 4 +_N浓度的计算过程与实施例5相同，表2为本实施例中的测试结果统计。
表2测试结果
Figure PCTCN2019080919-appb-000002
实施例7
本实施例基本与实施例6相同，不同之处在于：本实施例中未采用体积排阻色谱柱9及旁路PEEK管10，采用100mg/L的牛血清蛋白水溶液进样25μL、50μL、12.5μL、6.25μL各两次，目的在于判断氧化效率，图8为本发明即体积排阻色谱联用型氮检测器氧化效率的测试图，如图8所示，其中进样体积为25μL和50μL的色谱峰中间出现倒叉峰，说明进样量超出紫外螺旋管的氧化能力，而12.5μL和6.25μL进样体积下，峰型较好，且二者之间峰面积为2倍关系，表明该进样量条件下紫外氧化模块101能够将有机氮TON充分氧化。
实施例8
本实施例中未采用体积排阻色谱柱9及旁路PEEK管10，采用牛血清蛋白、NaNO 3、NH 4Cl配制以N计的TON_N、NO 3 -_N、NH 4 +_N溶液10mg/L，分别进样5次，其相对标准差均小于2％，符合准确性要求。表3为测试结果统计。
表3测试结果
Figure PCTCN2019080919-appb-000003
本表格中除相对标准差外数字单位为mg/L。
同时，按照实施例6中的方法，采用体积排阻色谱柱9及旁路PEEK管10，对上述配制的以N计的TON_N、NO 3 -_N、NH 4 +_N溶液10mg/L进样，其相对标准差均小于2％，符合准确性要求。表4为按照本发明的方法的测试结果统计。
表4测试结果
Figure PCTCN2019080919-appb-000004
由表4的结果可知，本发明的方法准确可靠。
实施例9
本实施例基本与实施例5相同，不同之处在于：旁路10与通过体积排阻色谱柱9的流量比为1：5。
所述的石英螺旋管流路112采用内径0.5mm、外径1.5mm的毛细石英管。
实施例10
本实施例基本与实施例5相同，不同之处在于：旁路10与通过体积排阻色谱柱9的流量比为1：15。
如图9所示，所述的紫外氧化模块101包括紫外灯管111和微流控石英芯片117，紫外灯111安装于微流控石英芯片117的表面；所述的微流控石英芯片117采用刻蚀技术加工有S型微流管路，微流管路的截面宽为0.40mm,深度为0.10mm，流路长度为4m。
以上示意性的对本发明及其实施方式进行了描述，该描述没有限制性，附图中所示的也只是本发明的实施方式之一，实际的流程并不局限于此。所以，如果本领域的普通技术人员受其启示，在不脱离本发明创造宗旨的情况下，不经创造性的设计出与该技术方案相似的结构方式及实施例，均应属于本发明的保护范围。

Claims (11)

  1. 一种体积排阻色谱联用型氮检测器，其特征在于：包括氧化系统(1)、硝酸根检测系统(2)、电源系统(3)、信号处理与控制系统(4)；将待检测样品首先经体积排阻色谱分离后进入所述的氧化系统(1)氧化处理，样品中的氮转化为硝酸根后采用硝酸根检测系统(2)检测；所述的电源系统(3)为检测器提供电源；信号处理与控制系统(4)用于氧化系统(1)、硝酸根检测系统(2)的信号处理与控制。
  2. 根据权利要求1所述的体积排阻色谱联用型氮检测器，其特征在于：所述的氧化系统(1)包括紫外氧化模块(101)和紫外光强度监测模块(103)。
  3. 根据权利要求1或2所述的体积排阻色谱联用型氮检测器，其特征在于：所述的氧化系统(1)包括漏液监测模块(102)和真空负压模块(104)，所述的真空负压模块(104)用于消除氧化系统(1)内的臭氧和抽真空。
  4. 根据权利要求3所述的体积排阻色谱联用型氮检测器，其特征在于：所述的紫外氧化模块(101)包括紫外灯管(111)、石英螺旋管流路(112)、石英转接头(113)、PEEK管(114)、支撑固定架(115)和石英套管(116)，所述的支撑固定架(115)将紫外氧化模块(101)承托并固定在基座上；所述的紫外灯管(111)位于石英套管(116)内部，石英螺旋管流路(112)螺旋缠绕于石英套管(116)上，所述的石英螺旋管流路(112)两端分别与石英转接头(113)的一端连接，每个石英转接头(113)另一端与PEEK管(114)连接。
  5. 根据权利要求1所述的体积排阻色谱联用型氮检测器，其特征在于：所述的硝酸根检测系统(2)为紫外检测器，包括流通池模块(201)和紫外吸收光学检测模块(202)。
  6. 根据权利要求2所述的体积排阻色谱联用型氮检测器，其特征在于：所述的电源系统(3)包括紫外灯专用电源(301)和AC-DC电源转换模块(302)；所述的紫外灯专用电源(301)为紫外氧化模块(101)供电，所述的AC-DC电源转换模块(302)为硝酸根(NO 3 -)检测系统(2)、信号处理与控制系统(4)、紫外光强度监测模块(103)供电。
  7. 根据权利要求4或5所述的体积排阻色谱联用型氮检测器，其特征在于：所述的信号处理与控制系统(4)包括单片机系统(401)、显示屏(402)和通讯模块(403)；所述的单片机系统(401)控制和处理信号，所述信号可通过显示屏(402)显示或由通讯模块(403)传输到上位机。
  8. 根据权利要求1或2所述的体积排阻色谱联用型氮检测器，其特征在于：所述的紫外光强度监测模块(103)采用氮化镓铝基深紫外光电二极管对所述紫外氧化模块(101)的光强进行实时监测。
  9. 根据权利要求4或5所述的体积排阻色谱联用型氮检测器，其特征在于：所述的紫外灯管(111)为低压汞灯，所述的石英螺旋管流路(112)为内径0.5～1.0mm、外径1.5～3.0mm 的毛细石英管。
  10. 权利要求1所述的体积排阻色谱联用型氮检测器的应用方法，其特征在于：包括以下步骤：
    1)采用体积排阻色谱柱(9)对样品中有机氮、硝酸盐氮(NO 3 -_N)和氨氮(NH 4 +_N)进行分离；
    2)在体积排阻色谱柱(9)两端并联一定长度的PEEK管形成PEEK管旁路(10)，通过测试调整PEEK管长度，使PEEK管旁路(10)与体积排阻色谱柱(9)所产生的压力之比为n：1；
    3)自动进样器(8)进样时，进样样品按照1：10的比例分别通过PEEK管旁路(10)与体积排阻色谱柱(9)，然后经体积排阻色谱联用型氮检测器(12)检测，旁路峰面积记为Area_TN；经过体积排阻色谱的分离作用后有机氮、NO 3 -和NH 4 +的出峰分别进行积分，其峰面积记为Area_TON、Area_NO 3 -_N和Area_NH 4 +_N；
    4)以NO 3 -标准溶液建立Area_TN峰面积与氮含量之间的线性关系，以样品旁路Area_TN计算出总氮(TN)，根据Area_TON、Area_NO 3 -_N和Area_NH 4 +_N占体积排阻色谱总峰面积的比例，分别计算出样品中有机氮(TON)、硝酸盐氮(NO 3 -_N)和氨氮(NH 4 +_N)的浓度。
  11. 根据权利要求2所述的体积排阻色谱联用型氮检测器，其特征在于：所述的紫外氧化模块(101)包括紫外灯管(111)和微流控石英芯片(117)，紫外灯(111)安装于微流控石英芯片的表面(117)；所述的微流控石英芯片(117)采用刻蚀技术加工有S型微流管路，优选地，微流管路的截面宽为0.10～1.0mm,深度为0.05～0.50mm，流路长度为2～10m。
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