Multi-channel automatic sampling system for measuring mercury in water

Abstract

The utility model belongs to the technical field of environmental science, and particularly relates to a multi-channel automatic sampling system for measuring mercury in water, which is used for measuring mercury in water and comprises a plurality of sample bottles, a reagent bottle, an oxidation bottle, two multi-way valves, an injection pump, a reduction bottle, a mercury detector and a carrier gas system. The water sample of each sample bottle is connected by the first multi-way valve through a sample feeding pipe, and each reagent bottle and each oxidation bottle are connected by the second multi-way valve. The injection pump is connected with the second multi-way valve through the sampling pipe, and the sample outlet pipe feeds the mixture into the reduction bottle. The mercury detector is connected with the reduction bottle through a sample detection pipe, the carrier gas system is conveyed to the reduction bottle through a gas sample feeding pipe, a pre-treated water sample in the reduction bottle is purged, and reduced elemental mercury is brought out and enters the mercury detector. The system reliably realizes automatic sampling analysis and on-line monitoring of the total mercury and the form of the total mercury in water.

Description

Technical Field

[0001] The utility model belongs to the technical field of environmental science, and in particular relates to a multi-channel automatic sampling system for measuring water quality mercury. Background Art

[0002] Mercury is a toxic and harmful heavy metal element that is liquid at room temperature and pressure, and will volatilize into the atmosphere at very low temperatures (above -38°C). Various processes from human and natural sources, including the mining and burning of fossil fuels, the production of industrial materials, forest fires, volcanic eruptions, etc., can emit mercury into the atmosphere, where it stays in the atmosphere for a long time, migrates over long distances with atmospheric activities, and then enters the soil and water bodies on the surface through dry and wet deposition. Part of the mercury in the soil will also enter the water body through surface runoff and be converted by microorganisms into highly toxic alkyl mercury, which is enriched in the food chain, thus posing huge risks to the ecological environment and human health. Excessive mercury concentration in water can lead to serious environmental and health risks. Some areas have even experienced regional mercury poisoning incidents, such as the horrific Minamata disease incident in Japan. Therefore, the efficient and rapid measurement of mercury concentration and distribution in water bodies, especially the real-time and in-situ online measurement of water quality mercury, is a technical problem that needs to be solved in environmental mercury monitoring. In addition, total mercury analysis in water quality is also an important project in water pollution monitoring. With the entry into force and better implementation of the International Mercury Convention (Minamata Convention), the country has paid more and more attention to the prevention and control of environmental mercury pollution in recent years, and the monitoring of total mercury in water quality is bound to become more and more normalized. However, the occurrence form of mercury in water bodies is extremely complex, and the form and distribution of mercury in different water qualities are also different. In addition, the concentration of mercury in water bodies is generally low. The concentration of total mercury in most natural water bodies is ppt (ngL -1 ) level, which brings great challenges to the research and development of rapid measurement of water quality mercury. The existing traditional analysis methods require manual sampling and preservation, chemical oxidation digestion, stannous chloride reduction and purging enrichment. The process is relatively cumbersome and requires a large number of manual processing steps. It is not only easy to introduce human errors but also difficult to achieve online analysis. These shortcomings determine that traditional analysis methods will be difficult to meet the increasingly frequent monitoring needs of total mercury in water quality. In addition, if the form of water quality mercury (including dissolved gaseous mercury and active mercury) is analyzed, different analysis methods need to be used for pretreatment and sampling. The analysis process is more complicated. At present, there is no technical method that can automatically pretreat and sample. Therefore, in order to quickly measure water quality mercury and reduce the interference and errors of human operation, the pretreatment of samples must be automated, and combined with the purging and trapping of samples and a high-sensitivity mercury analyzer to meet the requirements of fully automatic analysis of water quality mercury. To this end, it is a very urgent and important technology to develop a multi-channel automatic sampling device and method for water quality mercury measurement that can meet the rapid measurement of total mercury and mercury form concentrations of all surface waters.

[0003] Existing water quality mercury measurement and analysis techniques involve manual sampling, pretreatment, and injection. First, samples need to be manually collected by humans, transported to the laboratory, and the water samples are preserved. When measuring the mercury concentration in water quality, prepared bromine chloride oxidation is added to the water sample to convert all forms of mercury in the water into oxidized mercury (Hg 2+ ). Then, the prepared hydroxylamine hydrochloride solution is added to the water sample to remove the excess bromine chloride in the water sample. Subsequently, the prepared stannous chloride solution is manually added to reduce Hg 2+ in the water sample to elemental mercury (Hg 0 ). Finally, Hg 0 is purged and separated from the water sample by the carrier gas and then introduced into the mercury detector for the analysis and measurement of the mercury concentration. In addition, some water quality mercury analyzers are equipped with an automatic sampler. The automatic sampler of this technical method consists of mechanisms such as a hollow purge needle, a locator, a rotor gear, and a transmission belt. When measuring a water sample, the locator identifies the position of the sample bottle. The purge needle moves above the sample bottle under the action of the gear and the transmission belt. The purge needle moves down and pierces into the water sample in the sample bottle. Then, the carrier gas purges the sample that has been pretreated with reagents manually added to the bottle through the hollow pipe of the purge needle, blows out the reduced elemental mercury, and then introduces it into the mercury detector for measurement.

[0004] The existing manual analysis process of water quality mercury requires manual sampling and the addition of various chemical reagents, and various reagents need to be manually added to each sample, which is very easy to introduce human contamination and errors. Due to the relatively cumbersome sample pretreatment steps, only trained chemical laboratory technicians can be competent for the relevant work; the structure and control method of the traditional automatic sampler are relatively complex. In previous experiments, it has been found that in the case of long-term use, mechanical mechanisms such as gears, belts, and purge needles are prone to failures due to wear. Moreover, all samples are purged and injected through the same purge needle, which is likely to cause cross-contamination of samples. These disadvantages are not conducive to the rapid injection and accurate analysis and determination of water quality mercury, let alone in-situ real-time online measurement of water quality mercury. Moreover, it is time-consuming and laborious, increasing the cost of analysis. In addition, the existing automatic injection method for water quality mercury analysis can only be used for the measurement of total mercury in water quality and cannot meet the measurement requirements of mercury forms in water quality, which is not conducive to the comprehensive monitoring and research of water quality mercury. Summary of the Utility Model

[0005] (1) Technical Problems to be Solved

[0006] The present utility model mainly aims at the above problems and proposes a multi-channel automatic sampling system for water quality mercury measurement, aiming to solve the complex problems in sample injection and the problems of human-caused contamination and errors in traditional water quality mercury analysis techniques.

[0007] (2) Technical Solutions

[0008] To achieve the above object, the present utility model provides a multi-channel automatic sampling system for mercury measurement in water quality, comprising:

[0009] A plurality of sample bottles, a plurality of reagent bottles and an oxidation bottle, wherein the sample bottles are used for storing water samples; the reagent bottles are used for storing specific reagents, and the oxidation bottle is used for carrying out chemical reactions;

[0010] A first multi-way valve and a second multi-way valve, which are connected by a sampling tube between the first multi-way valve and the second multi-way valve. Different channels of the first multi-way valve are respectively inserted into the water samples in each sample bottle through sampling tubes, and different channels of the second multi-way valve are respectively inserted into the reagents in each reagent bottle and into the oxidation bottle through sampling tubes;

[0011] An injection pump, which is connected to the second multi-way valve through a sampling tube and is used for extracting the water sample or reagent to be measured;

[0012] A reduction bottle, the second multi-way valve is inserted into the liquid in the reduction bottle through a sample outlet tube, and a first stop valve is arranged on the sample outlet tube between the reduction bottle and the second multi-way valve;

[0013] A mercury detector, the mercury detector is connected to the reduction bottle through a sample inspection tube and is used for detecting the mercury content in the gas. A second stop valve is arranged on the sample inspection tube between the mercury detector and the reduction bottle;

[0014] A carrier gas system, which is inserted into the liquid in the reduction bottle through a gas sampling tube and is used for transporting the carrier gas.

[0015] Further, the reagent bottles are respectively a bromine chloride solution bottle, a hydroxylamine hydrochloride solution bottle and a stannous chloride solution bottle.

[0016] Further, a drying tube is also arranged on the sample inspection tube between the second stop valve and the mercury detector.

[0017] Further, the bottom of the reduction bottle is connected to a waste liquid bottle through a discharge tube, and a third stop valve is arranged on the discharge tube.

[0018] Further, it also includes an ultrapure water storage sample bottle, and the channel of the first multi-way valve is inserted into the liquid in the ultrapure water storage sample bottle through a sampling tube.

[0019] Further, it also includes a mercury standard solution storage sample bottle, and the channel of the first multi-way valve is inserted into the liquid in the mercury standard solution storage sample bottle through a sampling tube.

[0020] Further, it further includes a sedimentation tank. The channel of the first multi-way valve is inserted into the liquid in the sedimentation tank through a sampling pipeline. The bottom of the sedimentation tank is connected to a peristaltic pump through a sampling pipeline. The peristaltic pump is connected to a switching valve through a sampling pipeline. One channel of the switching valve is connected to a moving water sample through a sampling pipeline, and the other channel is connected to the water outlet of a filter through a sampling pipeline. The water inlet of the filter is connected to the moving water sample.

[0021] Further, an overflow port is provided at the upper end of the sedimentation tank.

[0022] Further, a mass flow controller is provided on the gas sampling tube.

[0023] Further, the sample bottle, reagent bottle, oxidation bottle, ultrapure water storage sample bottle, mercury standard solution storage sample bottle, reduction bottle, and waste liquid bottle are all made of borosilicate glass or Teflon.

[0024] (III) Beneficial effects

[0025] Compared with the prior art, a multi-channel automatic sampling system for mercury measurement in water quality provided by the present utility model realizes the full-process automatic processing of water body samples and other liquid samples by integrating a first multi-way valve and a second multi-way valve, an injection pump and a peristaltic pump, including automatic sampling, reagent addition (including the addition of oxidant bromine chloride and reductant stannous chloride), sample digestion, sample purging, and mercury element injection analysis. The system uses high-purity carrier gas (nitrogen or argon) to purge and carry the pre-treated mercury sample into the mercury detector for concentration determination, ensuring that there is no manual intervention in the whole process, fundamentally eliminating the possible human errors and pollution problems in traditional manual operations. In addition, the system can automatically process multiple samples, support on-site real-time online monitoring, greatly simplifies the process of mercury analysis in water quality, improves the detection efficiency and accuracy, and at the same time reduces the contact with harmful reagents, which is more environmentally friendly. Description of the drawings

[0026] Figure 1 It is a schematic diagram of a multi-channel automatic sampling system for mercury measurement in water quality disclosed in this application.

[0027] Figure 2 It is a response test result diagram of a multi-channel automatic sampling system for mercury measurement in water quality disclosed in this application.

[0028] Reference numerals shown in the figures: 1, sample bottle; 2, reagent bottle; 3, oxidation bottle; 4, first multi-way valve; 5, second multi-way valve; 6, syringe pump; 7, reduction bottle; 8, mercury detector; 9, first stop valve; 10, second stop valve; 11, bromine chloride solution bottle; 12, hydroxylamine hydrochloride solution bottle; 13, stannous chloride solution bottle; 14, drying tube; 15, waste liquid bottle; 16, third stop valve; 17, ultrapure water storage sample bottle; 18, mercury standard solution storage sample bottle; 19, sedimentation tank; 20, peristaltic pump; 21, switching valve; 22, filter; 23, overflow port. Detailed implementation mode

[0029] The present utility model will be described in detail below with reference to the accompanying drawings. The technical solutions in the embodiments of the present utility model will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0030] It should be noted that when a component is referred to as "fixed to" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present utility model belongs. The terms used in the description of the present utility model herein are only for the purpose of describing specific embodiments, and are not intended to limit the present utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0032] Please refer to Figure 1 As shown, it is a schematic structural diagram of a multi-channel automatic sampling system for water quality mercury measurement provided by a preferred embodiment of the present application. In Figure 1 the embodiment shown, the system includes:

[0033] a plurality of sample bottles 1, a plurality of reagent bottles 2 and an oxidation bottle 3. The sample bottle 1 is used to store water samples; the reagent bottle 2 is used to store specific reagents, and the oxidation bottle 3 is used to carry out chemical reactions;

[0034] A first multi-way valve 4 and a second multi-way valve 5, the first multi-way valve 4 and the second multi-way valve 5 are connected by a sampling tube, different channels of the first multi-way valve 4 are respectively inserted into the water samples in each sample bottle 1 through sampling tubes, and different channels of the second multi-way valve 5 are respectively inserted into the reagents in each reagent bottle 2 and into the oxidation bottle 3 through sampling tubes;

[0035] An injection pump 6, which is connected to the second multi-way valve 5 through a sampling tube and is used to extract the water sample or reagent to be tested;

[0036] A reduction bottle 7, the second multi-way valve 5 is inserted into the liquid in the reduction bottle 7 through a sample outlet tube, and a first stop valve 9 is provided on the sample outlet tube between the reduction bottle 7 and the second multi-way valve 5;

[0037] A mercury detector 8, the mercury detector 8 is connected to the reduction bottle 7 through a sample inspection tube and is used to detect the mercury content in the gas, and a second stop valve 10 is provided on the sample inspection tube between the mercury detector 8 and the reduction bottle 7;

[0038] A carrier gas system, which is inserted into the liquid in the reduction bottle 7 through a gas sampling tube and is used to transport the carrier gas.

[0039] In this embodiment, the system integrates multiple sample bottles 1, reagent bottles 2 and oxidation bottles 3 to store water samples and specific reagents, and to carry out chemical reactions. Through the configuration of the first multi-way valve 4 and the second multi-way valve 5, the system can connect different channels to the sample bottle 1 and the reagent bottle 2 respectively, so as to carry out automatic sampling and chemical treatment. The injection pump 6 is used to extract the water sample or reagent into the oxidation bottle 3, and then further process it through the reduction bottle 7. The system also includes a mercury detector 8, which is connected through the second stop valve 10 and is used to detect the mercury content in the processed sample. In addition, the carrier gas system is responsible for transporting the carrier gas throughout the process to help purge the gaseous mercury to be detected from the reduction bottle 7. The automated design of the entire system greatly reduces the complexity and error of manual operation, improves the detection efficiency and accuracy, and is suitable for the measurement of mercury in water quality and its automated analysis.

[0040] The reagent bottle 2 includes three types: a bromine chloride solution bottle 11, a hydroxylamine hydrochloride solution bottle 12, and a stannous chloride solution bottle 13, which are respectively used to store bromine chloride solution, hydroxylamine hydrochloride solution and stannous chloride solution. These three reagents are respectively used in the chemical reaction process of the sample, where bromine chloride is used to oxidize mercury in the water sample, hydroxylamine hydrochloride is used to neutralize excess bromine chloride and acid radicals, and stannous chloride is used to reduce mercuric oxide to elemental mercury.

[0041] On the sample tube between the second shut-off valve 10 and the mercury detector 8, a drying tube 14 is configured to remove moisture from the gas purged from the reduction bottle 7, ensuring that the gas fed into the mercury detector 8 is dry, thereby improving the detection accuracy.

[0042] The bottom of the reduction bottle 7 is connected to a waste liquid bottle 15 through a discharge pipe to safely dispose of the waste liquid after the chemical reaction. To control the flow and prevent accidental leakage, a third shut-off valve 16 is installed on the discharge pipe.

[0043] The system also has an ultrapure water sample storage bottle 17 and a mercury standard solution sample storage bottle 18 for storing ultrapure water and mercury standard solution respectively. Specific channels of the first multi-way valve 4 are directly connected to these two sample storage bottles through sampling tubes, allowing the system to automatically sample ultrapure water for the blank test of the system or sample mercury standard solution for accuracy verification when needed. This design effectively integrates the test process of the system, ensuring the reliability and accuracy of the measurement results.

[0044] The system also includes a sedimentation tank 19, which is connected to the sampling tube through the channel of the first multi-way valve 4. The bottom of the sedimentation tank 19 is connected to a peristaltic pump 20, and the peristaltic pump 20 is further connected to a switching valve 21 through the sampling tube. The switching valve 21 is designed with two channels: one directly draws water samples from the active water sample, and the other is connected to the water outlet of a filter 22, and the water inlet of the filter 22 also comes from the active water sample. Such a configuration allows the system to select whether to filter the water sample as needed. In addition, an overflow port 23 is installed at the upper end of the sedimentation tank 19, which can automatically drain the excess water, ensuring that the water sample in the sedimentation tank 19 is always fresh, thereby guaranteeing the accuracy of water quality analysis.

[0045] On the gas sampling tube, the system is equipped with a mass flow controller. The main function of the mass flow controller is to precisely adjust the carrier gas flow rate to ensure that the gas flows through the entire system at a stable and constant speed.

[0046] The schematic diagram of the technical solution of this embodiment is as Figure 1 shown. The entire analysis system mainly consists of three units: automatic sampling, automatic pretreatment, and automatic purge injection. The analysis process and steps are as follows:

[0047] Automatic sampling: When analyzing the mercury concentration of different water samples, first use a pipette to take 10 - 1000 milliliters of different water samples (determined according to the mercury concentration of different water samples and experimental requirements) and add them to the corresponding headspace sample bottles 1 (borosilicate glass bottles or Teflon bottles, with Teflon headspace lids, or Teflon sample bags) corresponding to water samples A, B, C, until water sample N. After the sample addition is completed, insert the Teflon sampling tubes of different channels of the first multi-way valve 4 into the water samples in the sample bottles 1.

[0048] When on-site water quality mercury online measurement is required, the peristaltic pump 20 is started. According to the water quality situation, the water samples are divided into two cases: those that need to be filtered and those that do not need to be filtered. If the measured water sample needs to be filtered, the switching valve 21 conducts one end of the filter 22, and a filter membrane is provided inside the filter 22. After the peristaltic pump 20 extracts the water sample and filters it through the filter membrane (the pore size of the filter membrane is 1-10 microns), the water sample is transported by the peristaltic pump 20 to the sedimentation tank 19. If the measured water sample does not need to be filtered, the switching valve 21 conducts the end without a filter membrane, and the peristaltic pump 20 directly pumps the water sample into the sedimentation tank 19. After the water in the sedimentation tank 19 is full, the Teflon sampling tube of a channel in the first multi-way valve 4 is inserted into the water sample in the sedimentation tank 19. An overflow port 23 is opened on the outer wall at the top of the sedimentation tank 19. After the water is full, it can be discharged through the overflow port 23 to ensure that the water sample in the sedimentation tank 19 is fresh, so as to ensure that the mercury concentration measured online is the real-time water quality mercury concentration at the monitoring site.

[0049] Automatic pre - treatment: The sampling tube of one channel of the second multi - way valve 5 is connected to one channel of the first multi - way valve 4, and one channel of the second multi - way valve 5 is connected to the injection pump 6. The other channels are respectively inserted into the bromine chloride solution bottle 11 ((BrCl)), hydroxylamine hydrochloride solution bottle 12 (NH3OHCl), stannous chloride solution bottle 13 (SnCl2) and oxidation bottle 14 through Teflon tubes. When it is necessary to digest the water sample A, the first multi - way valve 4 is turned on to the first sample bottle of the water sample A, and the channels of other sample bottles are closed. The injection pump 6 extracts a certain volume (10 - 1000 ml, set according to the measurement requirements) of the water sample A into the injection pump 6. Then the second multi - way valve 5 turns on the channel to the oxidation bottle 3, and the other channels are closed. The injection pump 6 injects the extracted water sample A into the oxidation bottle 3. After that, the second multi - way valve 5 turns on one end of the bromine chloride solution bottle 11, and the other channels are closed. The injection pump 6 extracts a certain volume (0.1 - 1 ml, set according to the sample situation and measurement requirements) of the bromine chloride solution into the injection pump 6. Then the second multi - way valve 5 turns on the channel to the oxidation bottle 3, and the other channels are closed. The injection pump 6 injects the extracted bromine chloride solution into the oxidation bottle 3, and the bromine chloride oxidizes various forms of mercury in the water sample A into mercury oxide. In addition to this extraction method, it is also possible to turn on the first multi - way valve 4 to the first sample bottle of the water sample A, close the channels of other sample bottles, extract a certain volume (10 - 1000 ml, set according to the measurement requirements) of the water sample A into the injection pump 6 by the injection pump 6. Then turn on one end of the bromine chloride solution bottle 11 by the second multi - way valve 5, close the other channels, extract a certain volume (0.1 - 1 ml, set according to the sample situation and measurement requirements) of the bromine chloride solution into the injection pump 6 by the injection pump 6. After mixing the water sample A and the bromine chloride solution in the injection pump 6, turn on the channel to the oxidation bottle 3 by the second multi - way valve 5, close the other channels, and inject the mixed water sample into the oxidation bottle 3 by the injection pump 6, so that the bromine chloride further oxidizes various forms of mercury in the water sample A into mercury oxide. These two injection methods can be used in the subsequent steps of mixing water samples and reagents in this embodiment, that is, the water sample can be injected into the oxidation bottle 3 or the reduction bottle 7 first, and then the oxidation reagent or the reduction reagent can be injected into the oxidation bottle 3 or the reduction bottle 7, or the water sample and the oxidation reagent or the reduction reagent can be extracted into the injection pump 6 for mixing first, and then injected into the oxidation bottle 3 or the reduction bottle 7.

[0050] After completing the above operation steps, after the mercury in water sample A is fully oxidized in the oxidation bottle 3 (10 - 600 minutes, set according to the sample situation and measurement requirements), the second multi-way valve 5 conducts the end of the hydroxylamine hydrochloride solution bottle 12, and other channels are closed. The injection pump 6 extracts a certain volume (0.1 - 1 ml, set according to the sample situation and measurement requirements) of hydroxylamine hydrochloride solution into the injection pump 6. Then the second multi-way valve 5 conducts the channel to the oxidation bottle 3, and other channels are closed. The injection pump 6 injects the extracted hydroxylamine hydrochloride solution into the oxidation bottle 3. Hydroxylamine hydrochloride can neutralize the excess bromine chloride and acid radicals. For some water samples with clean water quality (few particles and few interfering impurities), since less bromine chloride solution is added, it is not necessary to add hydroxylamine hydrochloride solution.

[0051] After the hydroxylamine hydrochloride solution is injected into the oxidation bottle 3 for 5 - 60 minutes (set according to the sample situation and measurement requirements), or for water samples that do not require the addition of hydroxylamine hydrochloride, it can directly enter the next analysis step: The second multi-way valve 5 conducts the channel to the oxidation bottle 3, and other channels are closed. The injection pump 6 extracts the digested water sample in the oxidation bottle 3 into the injection pump 6. Then the first cut-off valve 9 is opened, the second cut-off valve 10 and the third cut-off valve 16 are closed. The second multi-way valve 5 conducts the channel to the reduction bottle 7, and the injection pump 6 injects the digested water sample into the reduction bottle 7. After that, the second multi-way valve 5 conducts the end of the stannous chloride solution bottle 13, and other channels are closed. The injection pump 6 extracts a certain volume (0.1 - 1 ml, set according to the sample situation and measurement requirements) of stannous chloride solution into the injection pump 6. The second multi-way valve 5 then conducts the channel to the reduction bottle 7, and the injection pump 6 injects the stannous chloride solution into the reduction bottle 7. Stannous chloride reduces the mercury oxide in the water sample to elemental mercury.

[0052] Automatic purge injection: After the system completes the addition of stannous chloride, the first cut-off valve 9 is closed, the second cut-off valve 10 is opened. After the carrier gas (high-purity nitrogen or argon) is stabilized to a certain flow rate (300 - 400 ml / min) through the mass flow controller (MFC), it purges the pre-treated water sample in the reduction bottle 7 to carry out the reduced elemental mercury. After removing the moisture through the soda lime desiccant, it is introduced into the mercury detector 8 for concentration analysis.

[0053] After the mercury concentration of water sample A is measured, the first multi-way valve 4 will automatically conduct to the second sample bottle of water sample B, and the system will automatically digest and inject the sample according to the above analysis steps. In this way, the automatic digestion and injection of other water samples will be completed one by one. If it is the real-time on-line analysis and measurement of mercury in water quality at the monitoring site, the first multi-way valve 4 conducts to the sedimentation tank 19, and the automatic digestion and injection of the water sample are completed according to the same analysis steps as described above. If it is the measurement of mercury species in water quality, the first multi-way valve 4 conducts to the sample bottle 1, the second multi-way valve 5 conducts the channel of the first multi-way valve 4, and other channels are closed. The first cut-off valve 9 is opened, and the injection pump 6 pumps the water sample into the reduction bottle 7. Then the first cut-off valve 9 is closed. First, the carrier gas is passed to purge the dissolved gaseous mercury for enrichment and measurement. Then the first cut-off valve 9 is opened again. The second multi-way valve 5 conducts to the stannous chloride solution bottle 13, and the injection pump 6 sobs the stannous chloride solution and injects it into the reduction bottle 7. Then the carrier gas is passed again to purge the reactive mercury in the water sample for enrichment and measurement.

[0054] System blank and recovery rate test: To prevent sample cross-contamination and reduce the blank, when the injection of each water sample is completed, the system will automatically close the carrier gas and the second cut-off valve 10, and open the third cut-off valve 16. The waste liquid in the reduction bottle 7 can be discharged through the outlet at the bottom and flow into the waste liquid bottle 15. Then the first multi-way valve 4 conducts to the ultrapure water storage sample bottle 17 (blank water sample), and the system will complete the automatic digestion and injection of the blank water sample according to the same analysis steps as described above, and then test the blank of the system by measuring the mercury concentration of the blank water sample. When the recovery rate of the system needs to be measured, the first multi-way valve 4 conducts to the channel of the mercury standard solution storage sample bottle 18, and the injection and analysis of the mercury standard solution are completed according to the same analysis steps, and then the recovery rate of the system is tested.

[0055] The operation of each device of this system is controlled and coordinated by an embedded control circuit board, realizing automatic sampling, digestion and injection, without the need for personnel on duty, and only regular maintenance and replacement of necessary consumables are required. In addition, all sample bottles 1, reagent bottles 2, oxidation bottles 3, sample bags, pipe fittings and connectors are made of borosilicate glass or Teflon to prevent the adsorption of mercury in the sample.

[0056] To verify the effectiveness and practicability of this system, the developed system device was combined with a cold atomic fluorescence mercury detector, and mercury standard solutions with mercury concentrations of 0, 5, 10, 20, and 50 ppt (ng / L) were used to conduct response tests on the system. Each mercury standard solution with a concentration was tested 3 times, and the linear analysis of the detection results is as Figure 2 shown. There is a very good gradient response relationship between the mercury standard solution concentration and the peak area of the mercury detector, and the square value of the correlation coefficient (R2) is greater than 0.999. The response results show that the multi-channel automatic injection system for water quality mercury measurement in this embodiment can very effectively inject and measure and analyze the mercury concentration in water quality, and has good application potential and prospects.

[0057] The technical solution of this embodiment has revolutionized the traditional water quality mercury analysis method by automatically processing the mercury concentration in water samples and other liquid samples. This system eliminates the need for manual sample pretreatment, thereby eliminating human errors and potential pollution problems, and realizing the automatic injection measurement and on-line analysis of the total mercury and mercury species concentration of multiple samples and on-site monitoring samples. This automated processing method greatly simplifies the analysis process, significantly improves the analysis speed and efficiency. At the same time, the system is easy to maintain, suitable for long-term water quality monitoring and environmental analysis, effectively reduces costs, reduces the direct contact between operators and harmful reagents, and greatly improves the environmental protection performance. These advantages make this embodiment have great application potential and practical value in the field of water quality mercury analysis.

[0058] Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of this application is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in this application. Any reference signs in the claims should not be construed as limiting the claims concerned. In addition, it is obvious that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. The multiple units or devices stated in the device claims can also be implemented by the same unit or device through software or hardware. The words such as "first" and "second" are used to indicate names and do not indicate any specific order.

[0059] The above embodiments are only used to illustrate the technical solutions of this application and not to limit them. Although this application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of this application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A multi-channel automatic sampling system for water quality mercury measurement, characterized in that Comprising: Multiple sample bottles, multiple reagent bottles and an oxidation bottle, where the sample bottles are used to store water samples; The reagent bottles are used to store specific reagents, and the oxidation bottle is used to conduct chemical reactions; A first multi-way valve and a second multi-way valve, which are connected by a sampling tube between the first multi-way valve and the second multi-way valve. Different channels of the first multi-way valve are respectively inserted into the water samples in each sample bottle through sampling tubes, and different channels of the second multi-way valve are respectively inserted into the reagents in each reagent bottle and into the oxidation bottle through sampling tubes; An injection pump, which is connected to the second multi-way valve through a sampling tube and is used to extract the water sample or reagent to be measured; A reduction bottle, the second multi-way valve is inserted into the liquid in the reduction bottle through a sampling tube, and a first stop valve is provided on the sampling tube between the reduction bottle and the second multi-way valve; A mercury detector, the mercury detector is connected to the reduction bottle through a sample detection tube and is used to detect the mercury content in the gas, and a second stop valve is provided on the sample detection tube between the mercury detector and the reduction bottle; A carrier gas system, which is inserted into the liquid in the reduction bottle through a gas sampling tube and is used to transport the carrier gas.

2. The multi-channel automatic sampling system for water quality mercury measurement according to claim 1, characterized in that, The reagent bottles are respectively a bromine chloride solution bottle, a hydroxylamine hydrochloride solution bottle, and a stannous chloride solution bottle.

3. The multi-channel automatic sampling system for water quality mercury measurement according to claim 2, characterized in that, A drying tube is also provided on the sample detection tube between the second stop valve and the mercury detector.

4. A multi-channel automatic sampling system for water quality mercury measurement according to claim 3, characterized in that, The bottom of the reduction bottle is connected to a waste liquid bottle through a discharge pipe, and a third stop valve is provided on the discharge pipe.

5. A multi-channel automatic sampling system for water quality mercury measurement according to claim 4, characterized in that, It also includes an ultrapure water storage sample bottle, and the channel of the first multi-way valve is inserted into the liquid in the ultrapure water storage sample bottle through a sampling tube.

6. The multi-channel automatic sampling system for water quality mercury measurement according to claim 5, characterized in that, It also includes a mercury standard solution storage sample bottle, and the channel of the first multi-way valve is inserted into the liquid in the mercury standard solution storage sample bottle through a sampling tube.

7. A multi-channel automatic sampling system for water quality mercury measurement according to claim 1, characterized in that, It also includes a sedimentation tank. The channel of the first multi-way valve is inserted into the liquid in the sedimentation tank through a sampling pipeline. The bottom of the sedimentation tank is connected to a peristaltic pump through a sampling pipeline. The peristaltic pump is connected to a switching valve through a sampling pipeline. One channel of the switching valve is connected to the mobile water sample through a sampling pipeline, and the other channel is connected to the water outlet of a filter through a sampling pipeline. The water inlet of the filter is connected to the mobile water sample.

8. A multi-channel automatic sampling system for water quality mercury measurement according to claim 7, characterized in that, An overflow port is provided at the upper end of the sedimentation tank.

9. A multi-channel automatic sampling system for water quality mercury measurement according to claim 1, characterized in that, A mass flow controller is provided on the gas sampling tube.

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