Mercury form analysis system and mercury form analysis method thereof

Abstract

The invention discloses a mercury form analysis system in the technical field of mercury form analysis. The mercury form analysis system comprises a trapping pipe (containing argon and Tenax filler), a pretreatment device, an automatic sample injector and a mercury form analyzer. The trapping tube receives the sample from which the interferent is removed. The mercury form analyzer comprises a shell, a first controller, a power supply and the like, and the thermal desorption module fixes a trapping pipe by using a first spiral nickel heating wire and is connected with the gas chromatographic separation unit through a gas guide pipe. The pyrolysis module comprises a quartz tube and a second spiral nickel heating wire, and is connected with the gas chromatographic separation unit and the cold atomic fluorescence detector. The first spiral nickel heating wire, the electronic flowmeter, the first electromagnetic valve and the like are all connected with a power source and are in electric signal connection with the first controller through the PWM control circuit. The first controller is used for controlling the operation of the gas chromatography separation unit and the cold atomic fluorescence detector and the heating temperature of the heating wire. The system can analyze the mercury form in the sample with high precision and high sensitivity.

Description

Technical Field

[0001] The invention belongs to the technical field of mercury form analysis, and in particular relates to a mercury form analysis system and a method for analyzing mercury forms. Background Art

[0002] Mercury is widely present in the environment. It is a harmful element that is not necessary for organisms and is one of the key heavy metals to be controlled. Mercury exists in the environment mainly in the form of elemental mercury, inorganic mercury and organic mercury. The toxicity of organic mercury is far greater than that of elemental mercury and inorganic mercury. The main organic mercury forms are methylmercury, ethylmercury, dimethylmercury, diethylmercury, propylmercury and phenylmercury. Among them, methylmercury and ethylmercury are the most common organic mercury. Methylmercury is the most toxic form of organic mercury. Methylmercury is bioaccumulative and biotoxic, while ethylmercury has not been found to be bioaccumulative, but relies on simple diffusion to enter the brain. Exposure experiments have found that compared with methylmercury, ethylmercury can cause less brain damage and greater kidney damage.

[0003] The analysis methods of mercury forms generally include gas chromatography, liquid chromatography + atomic spectroscopy technology and liquid chromatography + inductively coupled plasma mass spectrometry (LC + ICP-MS). Among them, gas chromatography is currently an obsolete detection method due to its insufficient sensitivity, high detection limit, low recovery rate of actual sample spikes, and instability. LC-ICPMS and liquid chromatography-atomic fluorescence method have complex pre-treatment when detecting alkyl mercury (methylmercury, ethylmercury). After long-term analysis, it will be enriched in the chromatographic column and pipeline, and gold sol cleaning is required, which is very troublesome. When doing low-concentration samples, the sensitivity response to mercury is not enough. For the current common sewage and natural water samples, they do not meet the ultra-low concentration detection requirements. Summary of the invention

[0004] The present invention aims to provide a mercury speciation analysis system and a method for analyzing mercury speciation, so as to achieve high-precision and high-sensitivity analysis of mercury speciation in a sample.

[0005] A mercury speciation analysis system in the present scheme comprises a capture tube, a preprocessor, an automatic sample injector and a mercury speciation analyzer, wherein the preprocessor is used to remove interferences in a sample; the mercury speciation analyzer comprises a housing and a first controller arranged in the housing, a power supply, a thermal desorption module, an electronic flow meter, a first solenoid valve, a gas chromatography separation unit, a pyrolysis module and a cold atomic fluorescence detector, wherein the thermal desorption module comprises a capture tube and a first spiral nickel heating wire wound on the capture tube, wherein a filler Tenax is arranged in the capture tube, wherein the gas outlet end of the capture tube is connected to an air guide tube, and the other end of the air guide tube is connected to the injection end of the gas chromatography separation unit through the electronic flow meter and the first solenoid valve; the automatic sample injector is used to automatically purge the sample after the interferences are removed to the gas inlet end of the capture tube; the pyrolysis module comprises a quartz tube and a second spiral nickel heating wire coated on the quartz tube, The sample outlet end of the gas chromatography separation unit is connected to one end of the quartz tube, and the other end of the quartz tube is connected to the sample inlet end of the cold atomic fluorescence detector; the first spiral nickel heating wire, the electronic flow meter, the first solenoid valve, the gas chromatography separation unit, the second spiral nickel heating wire, and the cold atomic fluorescence detector are all connected to a power supply, and the first spiral nickel heating wire and the second spiral nickel heating wire are connected to the power supply through a PWM control circuit, and the PWM control circuit, the electronic flow meter, the first solenoid valve, the gas chromatography separation unit and the cold atomic fluorescence detector are all connected to the first controller by electrical signals, and the first controller is used to control the on and off of the gas chromatography separation unit and the cold atomic fluorescence detector, control the sample injection and sample outlet speed of the gas chromatography separation unit, and control the heating temperature of the first spiral nickel heating wire and the second spiral nickel heating wire through the PWM control circuit.

[0006] The beneficial effects of this solution are as follows: the first controller flexibly adjusts parameters such as thermal desorption and pyrolysis temperature, gas chromatography separation conditions, and injection speed, which can meet the mercury form analysis tasks of a variety of complex samples and achieve high-precision and high-sensitivity analysis of the mercury form in the sample.

[0007] Furthermore, the housing is provided with a touch screen, which is connected to the first controller, the gas chromatography separation unit and the cold atomic fluorescence detector. The entire mercury speciation analyzer can be conveniently controlled through the touch screen, the separation state of the gas chromatography separation unit and the detection data of the cold atomic fluorescence detector can be monitored in real time, and instructions can be conveniently issued to the first controller to adjust the analysis parameters, which greatly improves the convenience and intuitiveness of operation, reduces operational errors, and improves work efficiency.

[0008] Furthermore, the housing is provided with an air inlet and an air outlet, and a fan is installed at the air outlet to promote air circulation inside the housing, timely remove the heat generated during the analysis process, and ensure that the electronic components inside the instrument are in a suitable working temperature environment.

[0009] Furthermore, a notch is provided on the top of the housing, and an inspection panel is provided on the notch for opening and closing the notch, so as to facilitate the inspection, maintenance and replacement of internal components.

[0010] Furthermore, the quartz tube and the second spiral nickel heating wire are provided with a same heat-insulating shell, which can reduce the heat loss of the pyrolysis module and enable the pyrolysis reaction in the quartz tube to proceed in a stable high-temperature environment.

[0011] Furthermore, the pre-processor includes a box body, an aluminum block is provided on the box body, a heating device for heating the aluminum block is provided in the box body, and a plurality of placement holes for placing a distillation bottle are evenly distributed on the aluminum block; the box body is also provided with a plurality of cooling water tanks for placing receiving bottles, the cooling water tanks are located below the placement tanks, and a cooling device for cooling the cooling water tanks is provided in the box body. During the pre-processing process, the heating device heats the aluminum block, thereby causing the sample in the distillation bottle to be heated and distilled, and the impurities and the target mercury form are separated. The cooling water tank cooperates with the cooling device to quickly cool the gaseous substance after distillation, so that it is condensed and collected in the receiving bottle. This design realizes efficient distillation and condensation collection of samples, effectively removes interferences, and provides a pure sample basis for subsequent high-precision analysis.

[0012] Furthermore, the number of the cooling water tanks and the placement holes is the same, a distillation flask is placed in the placement hole, a receiving flask is placed in the cooling water tank, and the receiving flask is connected to the corresponding distillation flask through a connecting pipe. This ensures that the distillation and condensation collection process proceeds in an orderly manner, and the processed samples in each distillation flask can be accurately collected by the corresponding receiving flask to avoid cross contamination.

[0013] Furthermore, the automatic sampler includes a base and an XYZ three-axis module installed on the top of the base, a second controller is provided in the base, a sample rack for placing a receiving bottle is provided on the base, and an injection assembly is provided on the Z axis of the XYZ three-axis module for injecting inert gas into the receiving bottle and bringing the gaseous sample after gas-liquid separation into the capture tube; the injection assembly and the XYZ three-axis module are both connected to the second controller by electrical signals, and the second controller is used to control the operation of the XYZ three-axis module and the injection assembly; the inert gas is selected from nitrogen or argon. Under the control of the second controller, the XYZ three-axis module can realize the precise positioning of the injection assembly in three-dimensional space, and cooperate with the injection assembly to ensure the efficiency and stability of the injection process.

[0014] Furthermore, the injection assembly includes an injection needle detachably connected to the Z axis of the XYZ three-axis module. The injection needle adopts a double-layer design. The double-layer sleeve needle is assembled from a double-layer stainless steel sleeve. There is a gap between the double-layer sleeve needles. The bottom of the first layer needle is a needle head that is convenient for puncturing the septum of the receiving bottle. At the same time, a hole is opened on the side for blowing out air. The upper part of the second layer connected to the first layer is provided with a small hole connected to the gap. The small hole is connected to the air inlet end of the capture tube through the gap. The first layer is connected to an external inert gas source, and a second solenoid valve is provided on the connecting path. The second solenoid valve is electrically connected to the second controller. The second controller is used to control the on and off of the second solenoid valve. The setting of the injection needle can ensure that the gaseous sample after gas-liquid separation can be brought into the capture tube. The second solenoid valve is controlled by the second controller, and the amount of inert gas entering can be accurately controlled.

[0015] The method for analyzing mercury forms using the mercury form analysis system comprises the following steps:

[0016] Step 1: Sample pretreatment: Place the sample to be analyzed in the distillation bottle of the pretreatment device, add hydrochloric acid and copper sulfate, start the heating device, heat the sample to distill and form water vapor, the water vapor enters the receiving bottle through the connecting pipe, and is condensed and collected in the receiving bottle under the action of the cooling device;

[0017] Step 2, automatic injection: inject the buffer solution and sodium tetrapropylborate into the receiving bottle storing the pre-treated sample, then place the receiving bottle on the sample rack, the second controller controls the XYZ three-axis module to move the injection needle to the top of the receiving bottle, the second controller controls the Z axis of the XYZ three-axis module to move downward until the injection needle is inserted into the receiving bottle, and then the second controller controls the second solenoid valve to open and supply air, and the hole opened at the bottom of the first layer of the injection needle starts to supply air, and the elemental mercury, alkyl mercury derivatives, and divalent mercury derivatives in the sample of the receiving bottle are purged and come out from the small hole opened at the upper part of the second layer of the injection needle connected to the first layer into the capture tube;

[0018] Step 3, thermal desorption and transmission: the first controller controls the first spiral nickel heating wire to heat the sample in the capture tube through the PWM control circuit, so that the capture filler Tenax heats and desorbs the captured mercury vapor, and at the same time, the argon gas in the capture tube carries the alkyl mercury derivatives into the gas chromatography separation unit through the gas guide tube, the electronic flow meter, and the solenoid valve. The first controller synchronously controls the operation of the electronic flow meter, the solenoid valve, and the gas chromatography separation unit to control the flow rate of mercury vapor entering the gas chromatography separation unit;

[0019] Step 4: Gas chromatography separation: The gas chromatography separation unit separates the mercury forms into individual components according to their physical and chemical properties and outputs them in sequence;

[0020] Step 5, pyrolysis and detection: The separated mercury components enter the quartz tube, and the first controller controls the second spiral nickel heating wire through the PWM control circuit to pyrolyze the mercury components in the quartz tube into atomic mercury. The atomic mercury enters the cold atomic fluorescence detector, generates a fluorescent signal to be detected, and then the mercury form and content are obtained.

[0021] Beneficial effects of this application:

[0022] 1. High-precision analysis: Through the precise separation of the gas chromatography separation unit and the high-sensitivity detection of the cold atomic fluorescence detector, combined with the effective pretreatment of mercury forms by the thermal desorption and pyrolysis modules, the content and distribution of various mercury forms in the sample can be accurately determined, and ultra-low concentration mercury samples can also be accurately analyzed, meeting the stringent requirements for high-precision analysis of mercury forms in current environmental monitoring, biological sample testing and other fields.

[0023] 2. High-sensitivity response: The cold atomic fluorescence detector has extremely high sensitivity to mercury atoms and can keenly capture the fluorescence signals produced by extremely low concentrations of mercury. Combined with the system's optimized pre-treatment, transmission and separation links, it improves the overall detection sensitivity of mercury forms, effectively solving the problem of insufficient sensitivity of traditional methods when detecting low-concentration samples.

[0024] 3. Stability and reliability: The layout of the system components is reasonable. The first controller combines with the PWM control circuit to accurately control the key components. The heat dissipation and maintenance design of the casing and the precise connection of each component ensure that the instrument has stable performance and reliable data during long-term operation, reduces the probability of failure, and has low maintenance costs.

[0025] 4. Efficient pretreatment: The preprocessor uses a combination of distillation and condensation to quickly and efficiently remove interferences in the sample, provide pure samples for subsequent high-precision analysis, avoid the influence of interferences on the analysis results, and improve the accuracy and reliability of the entire analysis process.

[0026] 5. Strong adaptability: According to different sample characteristics and analysis requirements, the first controller can flexibly adjust parameters such as thermal desorption and pyrolysis temperature, gas chromatography separation conditions, injection speed, etc. It has a wide range of adaptability and can meet the mercury form analysis tasks of various complex samples.

[0027] The mercury speciation analysis system of the present application can accurately quantify and characterize methylmercury and ethylmercury in a sample, and can also characterize and roughly quantify elemental mercury and divalent mercury. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a three-dimensional diagram of a pre-processor in a mercury speciation analysis system according to Example 1 of the present invention;

[0029] Figure 2 for Figure 1Another perspective stereogram after removing the cover;

[0030] Figure 3 for Figure 1 Schematic diagram of the workflow of the preprocessor;

[0031] Figure 4 A three-dimensional diagram of an automatic sample injector in a mercury speciation analysis system in Example 1 of the present invention;

[0032] Figure 5 A three-dimensional diagram of a mercury speciation analyzer in a mercury speciation analysis system according to Embodiment 1 of the present invention;

[0033] Figure 6 for Figure 5 Another perspective of the mercury speciation analyzer;

[0034] Figure 7 for Figure 6 A three-dimensional image of the mercury speciation analyzer with part of the casing removed;

[0035] Figure 8 for Figure 7 Another perspective stereogram;

[0036] Fig. 9 Schematic diagram of the working process of the mercury speciation analyzer.

[0037] Figures 10 to 21 Performance analysis report for mercury speciation analysis systems. DETAILED DESCRIPTION

[0038] The following is further described in detail through specific implementation methods:

[0039] The figure marks in the drawings of the specification include: preprocessor A, box body A1, cover A2, aluminum block A3, placement hole A4, refrigeration plate A5, refrigeration water tank A6, automatic sampler B, base B1, XYZ three-axis module B2, sample rack B3, injection assembly B4, mercury form analyzer C, casing C1, maintenance panel C2, fan C3, air inlet C4, touch screen C5, first controller C6, pyrolysis module C7, partition C8, cold atomic fluorescence detector C9, gas chromatography separation unit C10, power supply C11, fixing plate C12, electronic flow meter box C13, thermal desorption assembly C14, mounting bracket C15, first solenoid valve C16.

[0040] Example 1: A mercury speciation analysis system, comprising a capture tube, a preprocessor A, an automatic sampler B and a mercury speciation analyzer C, wherein the capture tube contains a filler Tenax;

[0041] Preprocessor A as attached Figures 1-2As shown, it includes a box body A1, an aluminum block A3 is arranged on the box body A1, a heating device for heating the aluminum block A3 is arranged in the box body A1, and a heating rod is selected as the heating device. Twelve placement holes A4 for placing a distillation bottle are evenly distributed on the aluminum block A3, and a side wall of the aluminum block A3 is provided with through grooves connected with the placement holes A4. The through grooves are equal in number to the placement holes A4 and are correspondingly connected. The through grooves are used for connecting pipes to pass through. A cover plate A2 for covering the placement holes A4 is hingedly connected to the top of the aluminum block A3; a refrigeration plate A5 is also installed on the box body A1, and twelve refrigeration water tanks A6 for placing receiving bottles are arranged on the refrigeration plate A5, and the refrigeration water tank A6 is located below the placement tank, and the through grooves are located between the refrigeration water tank A6 and the placement tank. A cooling device for cooling the refrigeration water tank A6 is arranged in the box body A1, and the cooling device is located directly below the refrigeration plate A5. The cooling device adopts a compressor refrigeration method.

[0042] Automatic sampler B as attached Figure 4 As shown, it includes a second controller, a base B1 and an XYZ three-axis module B2 installed on the top of the base B1, the second controller is arranged in the base B1, the base B1 is provided with a sample rack B3 for placing a receiving bottle, the sample rack B3 is located below the XYZ three-axis module B2, and the Z axis of the XYZ three-axis module B2 is provided with an injection assembly B4 for injecting a sample into a collecting tube; the Z axis of the XYZ three-axis module B2 is provided with an injection assembly B4 for injecting an inert gas into the receiving bottle and bringing a gaseous sample after gas-liquid separation into the collecting tube, the injection assembly B4 includes an injection needle detachably connected to the Z axis of the XYZ three-axis module B2, and the injection needle adopts a double-layer Design, the double-layer trocar is assembled from a double-layer stainless steel sleeve, there is a gap between the double-layer trocars, the bottom of the first-layer needle is a needle head that is convenient for puncturing the septum of the receiving bottle, and a hole is opened on the side for blowing air out, and a small hole connected to the gap is opened on the upper part of the second layer connected to the first layer, and the small hole is connected to the air inlet end of the capture tube through the gap; the first layer is connected to an external inert gas source, and a second solenoid valve is provided on the communication path, the second solenoid valve is electrically connected to the second controller, and the second controller is used to control the on and off of the second solenoid valve, the first layer refers to the inner layer trocar, the second layer refers to the outer layer trocar, and the two ends of the second layer trocar are tightly connected to the outer wall of the first layer trocar through a sealing ring.

[0043] Mercury speciation analyzer C as attached Figures 5 to 8As shown, it includes a housing C1 and a first controller C6, a power supply C11, a thermal desorption component C14, an electronic flow meter box C13, a mounting bracket C15, a gas chromatography separation unit C10, a pyrolysis module C7 and a cold atomic fluorescence detector C9 arranged in the housing C1. A notch is provided on the top of the housing C1, and an inspection plate C2 for opening and closing the notch is detachably connected to the notch by screws; a touch screen C5 is provided on the front of the housing C1, and the touch screen C5 is connected to the first controller C6, the gas chromatography separation unit C10 and the cold atomic fluorescence detector C9. A fixing plate C12 for mounting the touch screen C5 is provided on the inner wall of the housing C1; an air inlet C4 and an air outlet are provided on the back of the housing C1, and there are two air outlets and both are equipped with fans C3. An air inlet C4 is also provided on the bottom of the housing C1, and the air inlet C4 is located directly below the mounting bracket C15.

[0044] A "T"-shaped partition C8 is provided in the casing C1, and the partition C8 divides the interior of the casing C1 into three areas. The cold atomic fluorescence detector C9 is located in one of the areas and is close to the fixed plate C12. The first controller C6, the gas chromatography separation unit C10 and the power supply C11 are located in another area. The pyrolysis module C7, the electronic flowmeter box C13, the thermal desorption component C14 and the mounting bracket C15 are located in the third area. The electronic flowmeter box C13 is provided with an electronic flowmeter; the electronic flowmeter box C13 is installed on the wall of the partition C8, the mounting bracket C15 is detachably connected to the bottom of the casing C1 and the side is detachably connected to the partition C8, the first solenoid valve C16 is installed on the bottom layer of the mounting bracket C15, and the pyrolysis module C7 and the thermal desorption component C14 are installed on the top layer of the mounting bracket C15.

[0045] The thermal desorption assembly C14 includes an installation box and a thermal desorption module located inside the installation box, the thermal desorption module is composed of the aforementioned capture tube and a first spiral nickel heating wire wound on the capture tube, the gas outlet end of the capture tube is connected to an air guide tube, and the other end of the air guide tube is connected to the injection end of the gas chromatography separation unit C10 through an electronic flow meter and a first solenoid valve C16; the pyrolysis module C7 includes a quartz tube and a second spiral nickel heating wire coated on the quartz tube, and the quartz tube and the second spiral nickel heating wire are provided with a same insulation shell; the sample outlet end of the gas chromatography separation unit C10 is connected to one end of the quartz tube, and the other end of the quartz tube is connected to the injection end of the cold atomic fluorescence detector C9; the first spiral nickel heating wire, the electronic flow meter, the first solenoid valve C16, the gas chromatography separation unit C 10. The second spiral nickel heating wire and the cold atomic fluorescence detector C9 are both connected to the power supply C11. The first spiral nickel heating wire and the second spiral nickel heating wire are both connected to the power supply C11 through a PWM control circuit. The PWM control circuit, the electronic flow meter, the first solenoid valve C16, the gas chromatography separation unit C10 and the cold atomic fluorescence detector C9 are all electrically connected to the first controller C6. The first controller C6 is used to control the on and off of the gas chromatography separation unit C10 and the cold atomic fluorescence detector C9, receive the analysis information of the cold atomic fluorescence detector C9 and display it on the touch screen C5, control the injection and output speeds of the gas chromatography separation unit C10, and control the heating temperature of the first spiral nickel heating wire and the second spiral nickel heating wire through the PWM control circuit.

[0046] In Example 1, the first controller can be selected from the Inovance H3U series small PLC controller, the second controller can be selected from the Weihong NK105 motion controller, the power supply C11 can be selected from a battery; and the inert gas can be selected from nitrogen or argon.

[0047] The method for analyzing mercury forms by the mercury form analysis system of Example 1 comprises the following steps:

[0048] Step 1: Sample pretreatment: The process is as follows Figure 3 As shown, water is added to the cooling water tank A6, the sample to be analyzed is placed in the distillation bottle of the preprocessor A, hydrochloric acid and copper sulfate are added, and the heating device is started to heat the sample to distill and form water vapor, and the water vapor enters the receiving bottle through the connecting pipe, and is condensed and collected in the receiving bottle under the action of the cooling device to obtain the sample after the interference is removed; the cooling process is specifically: the cooling device transmits the cooling to the cooling water tank A6 through the copper tube, water is added to the cooling water tank A6, the copper tube is placed in the water, and the water is cooled for the sample distilled by the heating device. The heated sample is vapor, and a certain amount of water is added to the receiving bottle in advance and placed in the cooling water tank A6. The vapor is collected in the receiving bottle and liquefied when cooled to obtain the pre-treated sample.

[0049] The workflow of steps 2 to 5 is as attached. Fig. 9 shown.

[0050] Step 2, automatic injection: inject the buffer solution and sodium tetrapropylborate into the receiving bottle storing the pre-treated sample, and then place the receiving bottle on the sample rack B3. The second controller controls the XYZ three-axis module B2 to move the injection needle to the top of the receiving bottle. The second controller controls the Z axis of the XYZ three-axis module B2 to move downward until the injection needle is inserted into the receiving bottle. Then the second controller controls the second solenoid valve to open and supply air. The hole at the bottom of the first layer of the injection needle starts to supply air to purge the elemental mercury, alkyl mercury derivatives, and divalent mercury derivatives in the sample in the receiving bottle, and enter the capture tube through the small hole opened at the upper part where the second layer of the injection needle is connected to the first layer.

[0051] Step 3, thermal desorption and transmission: The first controller C6 controls the first spiral nickel heating wire to heat the sample in the capture tube through the PWM control circuit, so that the capture filler Tenax heats and desorbs the captured mercury vapor. At the same time, the argon gas in the capture tube carries the alkyl mercury derivatives through the air guide tube, the electronic flow meter, and the first solenoid valve C16 into the gas chromatography separation unit C10. The first controller C6 synchronously controls the electronic flow meter, the first solenoid valve C16 and the gas chromatography separation unit C10 to control the flow of mercury vapor entering the gas chromatography separation unit C10.

[0052] Step 4: Gas chromatography separation: The gas chromatography separation unit C10 separates different mercury forms into individual components according to their different physical and chemical properties and outputs them in sequence.

[0053] Step 5, pyrolysis and detection: the separated mercury components enter the quartz tube, and the first controller C6 controls the second spiral nickel heating wire through the PWM control circuit to pyrolyze the mercury components in the quartz tube into atomic mercury. The atomic mercury enters the fluorescence detection cell of the cold atomic fluorescence detector C9, absorbs the 253.7nm wavelength emitted by the mercury lamp, and is excited to produce resonant 253.7nm fluorescence. The photoelectric amplifier measures the generated resonant fluorescence, and the fluorescence intensity is proportional to the concentration of mercury atoms. The fluorescence signal is converted into an electrical signal through the photoelectric amplifier and amplified and processed. Finally, the first controller C6 receives the processed data (qualitative and quantitative mercury form) and displays the results on the touch screen C5.

[0054] To test the performance of the mercury speciation analysis system, Figures 10 to 21 This is a performance analysis report for the mercury speciation analysis system; specifically, its precision test data is attached. Figures 10 to 13 (The test results of some samples / standards are not shown), and the accuracy test data is attached. Figures 14 to 17 (The test results of some samples / standard products are not shown in the graphs). The stability test data are attached. Figures 18 to 21 (The test result graphs of some samples / standards are not shown).

[0055] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A mercury speciation analysis system, characterized in that: The invention comprises a trapping tube, a preprocessor, an automatic sample injector and a mercury form analyzer, wherein the preprocessor is used for removing interferences in a sample; the mercury form analyzer comprises a casing and a first controller arranged in the casing, a power supply, a thermal desorption module, an electronic flow meter, a first electromagnetic valve, a gas chromatography separation unit, a pyrolysis module and a cold atomic fluorescence detector, the thermal desorption module comprises a trapping tube and a first spiral nickel heating wire wound on the trapping tube, a filler Tenax is arranged in the trapping tube, an air outlet end of the trapping tube is connected with an air guide tube, and the other end of the air guide tube is connected with the injection end of the gas chromatography separation unit through the electronic flow meter and the first electromagnetic valve; the automatic sample injector is used for automatically blowing the sample after removing interferences to the air inlet end of the trapping tube; the pyrolysis module comprises a quartz tube and a second spiral nickel heating wire coated on the quartz tube, the gas chromatography separation unit The sample outlet is connected to one end of the quartz tube, and the other end of the quartz tube is connected to the sample inlet of the cold atomic fluorescence detector; the first spiral nickel heating wire, the electronic flow meter, the first solenoid valve, the gas chromatography separation unit, the second spiral nickel heating wire, and the cold atomic fluorescence detector are all connected to a power supply, and the first spiral nickel heating wire and the second spiral nickel heating wire are both connected to the power supply through a PWM control circuit, and the PWM control circuit, the electronic flow meter, the first solenoid valve, the gas chromatography separation unit, and the cold atomic fluorescence detector are all connected to the first controller by electrical signals, and the first controller is used to control the on and off of the gas chromatography separation unit and the cold atomic fluorescence detector, control the sample injection and sample outlet speed of the gas chromatography separation unit, and control the heating temperature of the first spiral nickel heating wire and the second spiral nickel heating wire through the PWM control circuit.

2. A mercury speciation analysis system according to claim 1, characterized in that: The housing is provided with a touch screen, which is connected to the first controller, the gas chromatography separation unit and the cold atomic fluorescence detector.

3. A mercury speciation analysis system according to claim 2, characterized in that: The casing is provided with an air inlet and an air outlet, and a fan is installed at the air outlet.

4. A mercury speciation analysis system according to claim 3, characterized in that: A notch is arranged on the top of the casing, and an inspection plate for opening and closing the notch is arranged on the notch.

5. A mercury speciation analysis system according to claim 4, characterized in that: The quartz tube and the second spiral nickel heating wire are provided with a same heat-insulating shell.

6. A mercury speciation analysis system according to any one of claims 1 to 5, characterized in that: The pre-processor includes a box body, an aluminum block is provided on the box body, a heating device for heating the aluminum block is provided in the box body, and a plurality of placement holes for placing distillation bottles are evenly distributed on the aluminum block; the box body is also provided with a plurality of cooling water tanks for placing receiving bottles, the cooling water tanks are located below the placement tanks, and a cooling device for cooling the cooling water tanks is provided in the box body.

7. A mercury speciation analysis system according to claim 6, characterized in that: The number of the cooling water tanks and the placement holes is the same, distillation flasks are placed in the placement holes, and receiving bottles are placed in the cooling water tanks. The receiving bottles are connected to the corresponding distillation flasks through connecting pipes.

8. A mercury speciation analysis system according to claim 7, characterized in that: The automatic sampler includes a base and an XYZ three-axis module installed on the top of the base, a second controller is arranged in the base, a sample rack for placing a receiving bottle is arranged on the base, and an injection assembly is arranged on the Z axis of the XYZ three-axis module for injecting inert gas into the receiving bottle and bringing the gaseous sample after gas-liquid separation into the capture tube; the injection assembly and the XYZ three-axis module are both connected to the second controller by electrical signals, and the second controller is used to control the operation of the XYZ three-axis module and the injection assembly.

9. A mercury speciation analysis system according to claim 8, characterized in that: The injection assembly includes an injection needle detachably connected to the Z axis of the XYZ three-axis module. The injection needle adopts a double-layer design. The double-layer sleeve needle is assembled from a double-layer stainless steel sleeve. There is a gap between the double-layer sleeve needles. The bottom of the first layer needle is a needle head that is convenient for puncturing the septum of the receiving bottle. At the same time, a hole is opened on the side for blowing out air. A small hole connected to the gap is opened on the upper part of the second layer connected to the first layer, and the small hole is connected to the air inlet end of the capture tube through the gap; the first layer is connected to an external inert gas source, and a second solenoid valve is provided on the communication path. The second solenoid valve is electrically connected to the second controller, and the second controller is used to control the on and off of the second solenoid valve.

10. A method for analyzing mercury forms using a mercury form analysis system according to claim 9, characterized in that: The following steps are involved: Step 1: Sample pretreatment: Place the sample to be analyzed in the distillation bottle of the pretreatment device, add hydrochloric acid and copper sulfate, start the heating device, heat the sample to distill and form water vapor, the water vapor enters the receiving bottle through the connecting pipe, and is condensed and collected in the receiving bottle under the action of the cooling device; Step 2, automatic injection: inject the buffer solution and sodium tetrapropylborate into the receiving bottle storing the pre-treated sample, then place the receiving bottle on the sample rack, the second controller controls the XYZ three-axis module to move the injection needle to the top of the receiving bottle, the second controller controls the Z axis of the XYZ three-axis module to move downward until the injection needle is inserted into the receiving bottle, and then the second controller controls the second solenoid valve to open and supply air, and the hole opened at the bottom of the first layer of the injection needle starts to supply air, and the elemental mercury, alkyl mercury derivatives, and divalent mercury derivatives in the sample of the receiving bottle are purged and come out from the small hole opened at the upper part of the second layer of the injection needle connected to the first layer into the capture tube; Step 3, thermal desorption and transmission: the first controller controls the first spiral nickel heating wire to heat the sample in the capture tube through the PWM control circuit, so that the capture filler Tenax heats and desorbs the captured mercury vapor, and at the same time, the argon gas in the capture tube carries the alkyl mercury derivatives into the gas chromatography separation unit through the gas guide tube, the electronic flow meter, and the solenoid valve. The first controller synchronously controls the operation of the electronic flow meter, the solenoid valve, and the gas chromatography separation unit to control the flow rate of mercury vapor entering the gas chromatography separation unit; Step 4: Gas chromatography separation: The gas chromatography separation unit separates the mercury forms into individual components according to their physical and chemical properties and outputs them in sequence; Step 5, pyrolysis and detection: The separated mercury components enter the quartz tube, and the first controller controls the second spiral nickel heating wire through the PWM control circuit to pyrolyze the mercury components in the quartz tube into atomic mercury. The atomic mercury enters the cold atomic fluorescence detector, generates a fluorescent signal to be detected, and then the mercury form and content are obtained.

Images