A wide-band high-resolution inductively coupled plasma emission spectrometer

Abstract

The present invention discloses a wide-band high-resolution inductively coupled plasma emission spectrometer, which belongs to the technical field of spectral instruments. The emission spectrometer includes a sample introduction system, an excitation light source, a dispersion system, a control and detection system, and a data processing system, wherein the sample introduction system, the excitation light source, the dispersion system, and the data processing system are connected in sequence, and the control and detection system is connected to the sample introduction system, the excitation light source, and the data processing system, respectively, wherein the dispersion system adopts a back-to-back double grating scanning design, and also includes a double filter and a double PMT design, and its transmission system adopts a whole turbine disc design. The wide-band high-resolution inductively coupled plasma emission spectrometer provided by the present invention, by improving the dispersion system, broadens the wavelength range of the instrument, reduces matrix interference, and improves system sensitivity under the premise of ensuring spectral resolution, and can realize the analysis of trace and constant elements in multiple fields.

Description

Technical Field

[0001] The invention relates to the technical field of spectral instruments, and in particular to a wide-band high-resolution inductively coupled plasma emission spectrometer. Background Art

[0002] The most mature and widely used plasma emission spectrometer is the inductively coupled plasma emission spectrometer (ICP-AES, referred to as ICP spectrometer). ICP spectrometer is one of the most commonly used analytical instruments in the field of element detection. It has the advantages of simultaneous, rapid and direct determination of multiple elements, high spectral resolution and a wide wavelength application range (infrared to far ultraviolet region), fast testing speed and wide wavelength coverage, making it an ideal testing method for solving material composition testing.

[0003] ICP spectrometers are divided into multi-channel simultaneous type, sequential scanning type and full spectrum direct reading type. Among them, the multi-channel simultaneous ICP spectrometer is an instrument with multiple wavelength channels for simultaneous single spectrum detection. The test spectrum generally does not exceed 20, and the wavelength is fixed. Therefore, this type of instrument has been eliminated; the sequential scanning ICP spectrometer is an instrument that obtains spectrum lines by rotating the dispersion element (usually a grating). Its spectroscopic mechanism determines that the spectral resolution and wavelength range of this type of instrument cannot be achieved at the same time, which greatly limits the application field of sequential scanning ICP spectrometers. Summary of the invention

[0004] The purpose of the present invention is to provide a wide-band high-resolution inductively coupled plasma emission spectrometer, which can broaden the spectral range while ensuring the spectral resolution.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A wide-band high-resolution inductively coupled plasma emission spectrometer, comprising a sample introduction system, an excitation light source, a dispersion system, a control and detection system and a data processing system, wherein the sample introduction system, the excitation light source, the dispersion system and the data processing system are connected in sequence, and the control and detection system is connected to the sample introduction system, the excitation light source and the data processing system respectively; the sample introduction system is used to atomize a sample to be tested and bring it into a central channel of an inductively coupled plasma; the excitation light source is a radio frequency power generator, which generates radio frequency excitation power of an inductively coupled plasma for a spectrometer, and is used to excite the sample to be tested to generate an emission spectrum; the dispersion system adopts a scanning back-to-back double grating spectrometer, which is used to collect, transmit, split and detect the emission spectrum generated by the sample to be tested being excited in the inductively coupled plasma; the data processing system is used to perform data processing on the spectrum information output by the dispersion system; the control and detection system is used to control the working sequence between various components of the spectrometer and the data exchange between various components;

[0007] Wherein, the dispersion system includes an optical chamber and components, a transmission system and a photoelectric detector. The optical chamber and components include an optical chamber and a double slit component, a grating component and a double reflector component arranged in the optical chamber. The double slit component includes an incident slit component and an exit slit component, which are respectively arranged at the light inlet and the light outlet of the optical chamber. The incident slit component includes a front optical path and a double filter. The grating component adopts a back-to-back double grating design. The back-to-back double gratings are two plane gratings with different parameters, including grating A and grating B. The structural parameters of grating A and grating B are the same, but the line density is different. The double reflector component includes a first spherical reflector and a second spherical reflector. The first spherical reflector is used to reflect the light transmitted by the incident slit component to the grating component, and the second spherical reflector is used to reflect the light emitted by the grating component to the exit slit component.

[0008] The transmission system is arranged at the bottom of the optical chamber, and the transmission system includes a whole turbine disc, a turbine shaft, a turbine worm, a coupling, and a transmission motor. The whole turbine disc is designed according to the material matching of a copper ring inlaid outside an aluminum block. The transmission motor is fixed to the bottom of the optical chamber through a motor positioning plate. The transmission motor is driven and connected to the turbine worm through the coupling. The turbine worm drives the whole turbine disc and the turbine shaft to rotate. The turbine shaft passes through the bottom of the optical chamber and is connected to the grating assembly.

[0009] The photoelectric detector is arranged at the exit slit assembly, and is used to convert the light signal of the emission spectrum emitted by the exit slit assembly into an electrical signal, and transmit it to the data processing system.

[0010] Furthermore, a rectangular support frame is arranged at the bottom end of the light chamber, the interior of the light chamber is sprayed with plastic, the light chamber is mounted on the rectangular support frame, and the transmission system is mounted on the light chamber.

[0011] Furthermore, the photodetector includes two photomultiplier tubes, namely photomultiplier tube A and photomultiplier tube B. The exit slit assembly is provided with a plane mirror and a cylinder for driving the plane mirror to flip. The light beam is deflected by flipping the plane mirror. When the plane mirror is in the light path, photomultiplier tube B is in a working state. When the plane mirror exits the light path, photomultiplier tube A is in a working state.

[0012] Furthermore, the transmission system also includes three limit switches and limit blocks. The three limit switches are installed at the bottom of the optical chamber by screws and adapters. The limit block is arranged on the whole turbine disk. The limit switch sends a signal to the upper computer by touching the limit block to limit and protect the rotation of the grating assembly. The three limit switches are respectively a mechanical zero limit switch, a long-wave edge wavelength limit protection limit switch and an extreme zero protection limit switch. The mechanical zero limit switch is the initial position of the grating assembly, that is, the starting point before the emission spectrometer starts working; the long-wave edge wavelength limit protection limit switch is the limited protection position of the rotation angle of the whole turbine disk when the grating assembly works to the longest wavelength; the extreme zero protection limit switch is the extreme secondary protection of the mechanical zero limit switch. When the mechanical zero limit switch fails, the extreme zero protection limit switch plays a protective role.

[0013] Furthermore, the dispersion system also includes a constant temperature system, which uses a PTC heater and is arranged at the bottom of the optical chamber to provide a constant temperature working environment for the dispersion system.

[0014] Furthermore, the excitation light source includes a power amplifier circuit module, an impedance matching network module, a water cooling component and a power control circuit. The power amplifier circuit module is used to amplify the RF excitation power, the impedance matching network module is used to achieve maximum efficiency transmission of the RF excitation power, the water cooling component is used to cool the excitation light source, and the power control circuit is used to collect the output power signal amplitude and perform power control by comparing the size of the set signal and the output signal.

[0015] Furthermore, the power amplifier circuit module adopts a 4-stage amplifier circuit, including: a first-stage amplifier circuit, a second-stage amplifier circuit, a third-stage amplifier circuit and a fourth-stage amplifier circuit connected in sequence, the first-stage amplifier circuit is a crystal oscillator, used to provide a radio frequency signal source with a high Q value; the second-stage amplifier circuit is a linear amplifier device, used to receive and amplify the drive signal emitted by the crystal oscillator, and increase the driving ability of the output radio frequency signal; the third-stage amplifier circuit is used to amplify the voltage of the radio frequency signal to meet the drive signal input requirement of the fourth-stage amplifier circuit; the four-stage amplifier circuit includes a transformer, a high-power MOS tube and a synthesizer. After the drive signal is converted by the transformer, it is divided into an in-phase end and an inverting end. The in-phase end is amplified by n parallel high-power MOS tubes, and the inverting end is amplified by n parallel high-power MOS tubes. The synthesizer realizes the synthesized output of high-power in-phase and inverting end signals; the water cooling component is used to dissipate heat and cool the high-power MOS tube.

[0016] Furthermore, the impedance matching network module includes an air capacitor, a vacuum capacitor, a servo motor M1, a servo motor M2, a phase amplitude detection circuit, a coil and an automatic matching circuit. The air capacitor serves as the load capacitor of the power amplifier circuit module, and adjusts the appropriate capacitance value to perform impedance matching to reduce the power loss of the power amplifier; the vacuum capacitor and the coil form a frequency selection network, and by adjusting the vacuum capacitance value, a tuning state is achieved at the frequency point corresponding to the radio frequency signal, and the power transmission efficiency is the highest; the servo motor is respectively connected to the rotating shafts of the air capacitor and the vacuum capacitor, and the phase amplitude detection circuit is used to detect the matching state, and the phase amplitude signal enters the automatic matching circuit, and the automatic matching circuit is used to collect the amplitude and phase of the matching network, and the rotating shafts of the air capacitor and the vacuum capacitor are respectively driven by controlling the servo motor M1 and the servo motor M2 to adjust to achieve the best matching state and ensure the maximum efficient power output.

[0017] Furthermore, the control and detection system includes a main control board, a peristaltic pump assembly, a gas circuit control assembly and a two-dimensional automatic adjustment platform assembly, the main control board and the peristaltic pump assembly, the gas circuit control assembly and the two-dimensional automatic adjustment platform assembly are interconnected through a CAN bus, the power amplifier circuit module is connected to the main control board through a radio frequency power supply control line, and the impedance matching network module is connected to the main control board through a matching control line;

[0018] The peristaltic pump assembly includes a roller pump head, a reduction mechanism, a stepper motor and a stepper motor drive control circuit board, and the peristaltic pump assembly is used to control the introduction of liquid samples into the injection system; the gas circuit control assembly includes a flow control circuit board and three mass flow controllers electrically connected to the flow control circuit board, and the three mass flow controllers are arranged between the gas source and the injection system, and are used to control the gas flow introduced into the injection system; the two-dimensional automatic adjustment platform assembly is connected to the impedance matching network module, and is used to adjust the height of the impedance matching network module so that the height of the coil in the impedance matching network module is appropriate relative to the plasma position.

[0019] Furthermore, the data processing system is connected to the dispersion system and the control and detection system via network cables for data transmission.

[0020] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: the wide-band high-resolution inductively coupled plasma emission spectrometer provided by the present invention adopts a scanning back-to-back double grating spectrometer as the dispersion system of the wide-band high-resolution inductively coupled plasma emission spectrometer, and on the premise of ensuring the spectral resolution, the wavelength range of the instrument is broadened, thereby achieving the purpose of taking into account both the spectral resolution and the wavelength range, further expanding the wavelength range of the instrument, reducing matrix interference, improving system sensitivity, and being able to achieve the analysis of trace and constant elements in multiple fields; in the dispersion system, a whole-disk turbine disk design method is adopted, which avoids the instability of the grating turntable caused by the unbalanced counterweight relationship compared to the traditional fan-shaped turbine disk, and ensures the rotation stability of the grating component; considering the weight reduction factor, the turbine disk is designed according to the material matching method of the copper ring embedded outside the aluminum block to reduce the load of the motor and the transmission system, and further improve the stability of the emission spectrometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 This is a structural block diagram of a wide-band high-resolution inductively coupled plasma optical emission spectrometer according to an embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of the structure of the optical chamber and components in the dispersion system of an embodiment of the present invention;

[0024] Figure 3 A schematic diagram of the connection between the excitation light source and the control and detection system according to an embodiment of the present invention;

[0025] Figure 4 It is a structural schematic diagram of a transmission system according to an embodiment of the present invention;

[0026] Figure 5 It is a schematic diagram of the structure of the optical chamber and the transmission system in the dispersion system of an embodiment of the present invention from a bottom view;

[0027] Figure 6 It is a schematic diagram of the structure of a limit switch and a limit block in a transmission system according to an embodiment of the present invention;

[0028] Figure 7 This is a structural block diagram of an excitation light source according to an embodiment of the present invention;

[0029] Figure 8 It is a structural schematic diagram of an impedance matching network module according to an embodiment of the present invention;

[0030] Fig. 9 It is a structural schematic diagram of a sample injection system according to an embodiment of the present invention;

[0031] Description of reference numerals: 1. injection system; 2. excitation light source; 3. dispersion system; 4. control and detection system; 5. data processing system;

[0032] 201. Power amplifier circuit module; 202. Impedance matching network module; 203. Water cooling component; 204. Power control circuit;

[0033] 21. Air capacitor; 22. Vacuum capacitor; 23. Servo motor M1; 24. Servo motor M2; 25. Phase amplitude detection circuit; 26. Coil; Automatic matching circuit 27;

[0034] 301. Optical chamber and components; 302. Transmission system; 303. Constant temperature system; 304. Photoelectric detector;

[0035] 31. Optical chamber; 32. Pre-optical path; 33. Entrance slit assembly; 34. Double filter; 35. Exit slit assembly; 36. Grating assembly; 37. First spherical reflector; 38. Second spherical reflector; 39. Photomultiplier tube A; 40. Photomultiplier tube B; 41. Plane reflector;

[0036] 401, main control board; 402, peristaltic pump assembly; 403, gas circuit control assembly; 404, two-dimensional automatic adjustment platform assembly;

[0037] 11. RF power control line; 12. Matching control line; 13. CAN bus;

[0038] 50. Whole turbine disc; 51. Turbine shaft; 52. Turbine worm; 53. Coupling; 54. Transmission motor; 55. Rectangular support frame; 56. Limit switch; 57. Limit block;

[0039] 5601, mechanical zero limit switch;

[0040] 5602, limit switch for zero position protection;

[0041] 5603, long wave edge wavelength limit protection limit switch;

[0042] 110. plasma; 111. torch; 112. cooling gas inlet; 113. auxiliary gas inlet; 114. carrier gas inlet; 115. nebulizer; 116. spray chamber; 117. peristaltic pump; 118. sample to be tested; 119. waste liquid barrel. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The purpose of the present invention is to provide a wide-band high-resolution inductively coupled plasma emission spectrometer, which can broaden the spectral range while ensuring the spectral resolution.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] like Figures 1 to 4 As shown, the wide-band high-resolution inductively coupled plasma emission spectrometer provided in an embodiment of the present invention comprises: a sample injection system 1, an excitation light source 2, a dispersion system 3, a control and detection system 4 and a data processing system 5, wherein the sample injection system 1, the excitation light source 2, the dispersion system 3 and the data processing system 5 are connected in sequence, and the control and detection system 4 is connected to the sample injection system 1, the excitation light source 2 and the data processing system 5 respectively;

[0047] The sample introduction system 1 is used to atomize the sample to be tested and bring it into the central channel of the inductively coupled plasma; the excitation light source 2 is a radio frequency power generator, which generates radio frequency excitation power of the inductively coupled plasma for the spectrometer, and is used to excite the sample to be tested to produce an emission spectrum; the dispersion system 3 adopts a scanning back-to-back double grating spectrometer and a whole-disk turbine disk design transmission system, which is used to collect, transmit, split and detect the emission spectrum generated by the sample to be tested being excited in the inductively coupled plasma; the data processing system 5 is used to perform data processing on the spectral information output by the dispersion system 3; the control and detection system 4 is used to control the working timing between the various components of the spectrometer and the data exchange between the various components.

[0048] Among them, the dispersion system 3 is the key improved structure of the present invention, specifically including an optical chamber and components 301, a transmission system 302 and a photodetector 304. The optical chamber and components 301 include an optical chamber 31 and a double slit component, a grating component 36, and a double reflector component arranged in the optical chamber 31. The double slit component includes an incident slit component 33 and an exit slit component 35, which are respectively arranged at the light inlet and the light outlet of the optical chamber 31. The incident slit component 33 includes a front optical path 32 and a double filter 34. The front optical path 32 includes a front lens, and the distance ratio of the front lens object distance to the image distance is 1.5:1. The double filter 34 adopts a gas The cylinder switches the filter accurately, and the dual filter 34 can effectively avoid the interference of the second-order and above diffraction orders of the grating on the signal; the grating component 36 adopts a back-to-back dual grating design, and the back-to-back dual gratings are two plane gratings with different parameters, including grating A and grating B. The structural parameters of grating A and grating B are consistent, but the line density is different; the dual reflector component includes a first spherical reflector 37 and a second spherical reflector 38, the first spherical reflector 37 is used to reflect the light transmitted by the incident slit component 33 to the grating component 36, and the second spherical reflector 38 is used to reflect the light emitted by the grating component 36 to the exit slit component 35;

[0049] The transmission system 302 is arranged at the bottom of the optical chamber 31, and the transmission system 302 includes a whole turbine disc 50, a turbine shaft 51, a turbine worm 52, a coupling 53, and a transmission motor 54. The whole turbine disc 50 is designed according to the material matching of an aluminum block inlaid with a copper ring. The transmission motor 54 is fixed to the bottom of the optical chamber 31 through a motor positioning plate. The transmission motor 54 is connected to the turbine worm 52 through the coupling 53. The turbine worm 52 drives the whole turbine disc 50 and the turbine shaft 52 to rotate. The turbine shaft 51 passes through the bottom of the optical chamber 31 and is connected to the grating assembly 36;

[0050] The photoelectric detector 304 is disposed at the exit slit assembly 35 , and the photoelectric detector 304 is used to convert the optical signal of the emission spectrum emitted by the exit slit assembly 36 into an electrical signal, and transmit the electrical signal to the data processing system 5 .

[0051] like Figure 5 As shown, a rectangular support frame 55 is provided at the bottom end of the optical chamber 31, which is convenient for the separate debugging of the optical chamber and the installation of the transmission system 302. The interior of the optical chamber 31 is sprayed with plastic to prevent stray light from entering the photoelectric detector; the optical chamber 31 is installed on the rectangular support frame 55, and the transmission system 302 is installed on the optical chamber. The optical chamber 31 adopts a design method of integrally processing the mounting brackets of the optical chamber 31 and the transmission system 302, so as to avoid the introduction of installation deviation due to the separate installation of the transmission system, and further improve the stability and consistency of the transmission system.

[0052] The photodetector 304 includes two photomultiplier tubes, namely, photomultiplier tube A-39 and photomultiplier tube B-40. The exit slit assembly 35 is provided with a plane reflector 41 and a cylinder for driving the plane reflector 41 to move. The light beam is deflected by the movement of the plane reflector 41. When the plane reflector 41 is in the optical path, the photomultiplier tube B-40 is in a working state. When the plane reflector 41 exits the optical path, the photomultiplier tube A-39 is in a working state. Photomultiplier tube A has a higher sensitivity in the ultraviolet region, and photomultiplier tube B has a higher sensitivity in the visible light to infrared range. Depending on the test wavelength, the plane reflector 41 automatically switches between being in the optical path or exiting the optical path. The design of the two photomultiplier tubes ensures that a better signal-to-noise ratio can be obtained in a wide spectral range. The photodetector 304 converts the optical signal of the emission spectrum into an electrical signal, and then obtains the signal data through a preamplifier, a filter, and an A / D converter, stores it inside the FPGA, and finally transmits the data to the data processing system 5 after being processed through an Ethernet communication circuit.

[0053] In the dispersion system 3, the grating assembly 36 adopts a back-to-back double grating design. The back-to-back double gratings are two plane gratings with different parameters. By combining the two gratings with different parameters, the wavelength range of the instrument is broadened while ensuring the spectral resolution, thereby achieving the purpose of taking into account both the spectral resolution and the wavelength range, and further expanding the application field of the instrument.

[0054] The optical path transmission mode of the dispersion system 3 is specifically manifested as follows: the emission spectrum light beam generated by the inductively coupled plasma RF source system is transmitted to the dispersion system 3 through the incident slit component 33, the light beam is dispersed by the incident slit and irradiated to the first spherical reflector 37, after being collimated by the first spherical reflector 37, it is irradiated to the grating A or grating B of the back-to-back double grating component, after being diffracted by the grating, the diffracted light beam is irradiated to the second spherical reflector 38, and after being reflected by the second spherical reflector 38, it is focused to the exit slit component 35, and a photomultiplier tube PMT receives the photoelectric signal.

[0055] like Figure 5 and Figure 6As shown, the transmission system 302 adopts a whole-disc turbine disk, and the turbine disk is designed according to the material combination of an aluminum block inlaid with a copper ring. The motor and the turbine worm are connected together through a coupling, and a motor positioning plate is designed at the position where the motor is installed on the optical chamber to accurately position the motor on the optical chamber, effectively ensuring the coaxiality of the motor and the turbine worm, and improving the transmission performance of the spectrometer; after the transmission system 302 is installed, a transmission sealing plate is used to seal the exposed part of the transmission system to prevent dust and other pollutants in the air from contaminating the transmission system and affecting the performance of the spectrometer; the transmission system 302 also includes three limit switches 56 and limit blocks 57, the three limit switches 56 are installed at the bottom of the optical chamber 31 by screws and adapters, the limit blocks 57 are arranged on the whole-disc turbine disk 50, and the limit switches 5 By touching the limit block 57, a signal is sent to the upper computer to limit and protect the rotation of the grating component 36; the three limit switches 56 are respectively a mechanical zero limit switch 5601, a long-wave edge wavelength limit protection limit switch 5603 and an extreme zero protection limit switch 5602; the mechanical zero limit switch 5601 is the initial position of the grating component 36, that is, the starting point before the emission spectrometer starts working; the long-wave edge wavelength limit protection limit switch 5603 is the limited protection position of the rotation angle of the entire turbine disk 50 when the grating component 36 works to the longest wavelength; the extreme zero protection limit switch 5602 is the extreme secondary protection of the mechanical zero limit switch 5601, and when the mechanical zero limit switch 5601 fails, the extreme zero protection limit switch 5602 plays a protective role.

[0056] The extreme secondary protection is that when the long-wave edge wavelength extreme protection limit switch 5603 and the mechanical zero position limit switch 5601 fail, the extreme zero position protection limit switch 5602 can protect the system, which is designed for protection redundancy.

[0057] The photoelectric detector 304 controls the rotation of the turbine disk. After receiving the command and data information from the computer, the FPGA processor on the acquisition circuit obtains accurate position information, stepper motor acceleration information and stepper motor deceleration information through the built-in stepper motor S-curve acceleration and deceleration algorithm, thereby controlling the start-up, acceleration and deceleration process of the stepper motor and accurately controlling the rotation position of the turbine disk.

[0058] The dispersion system 3 also includes a constant temperature system 303. The constant temperature system 303 uses a PTC heater to ensure that the light chamber and the component 301 work at a constant temperature. The constant temperature circuit controls the output power of the PTC heater according to the temperature of the light chamber. The constant temperature system 303 ensures that the dispersion system 3 works at a constant temperature, ensuring the stability of the instrument. The constant temperature system 303 can set a target temperature through a temperature controller, usually between 30°C and 38°C.

[0059] like Figure 7 As shown, the excitation light source 2 is a high-power, high-stability RF power generator with automatic matching function, including a power amplifier circuit module 201, an impedance matching network module 202, a water cooling component 203 and a power control circuit 204. The power amplifier circuit module 201 is used to amplify the RF excitation power, the impedance matching network module 202 is used to achieve the maximum efficiency transmission of the RF excitation power, the water cooling component 203 is used to cool the excitation light source 2, and the power control circuit 204 is used to collect the output power signal amplitude, and perform power control by comparing the size of the set signal and the output signal. The power amplifier circuit module 201 adopts a 4-stage amplifier circuit, including: a first-stage amplifier circuit, a second-stage amplifier circuit, a third-stage amplifier circuit and a fourth-stage amplifier circuit connected in sequence, the first-stage amplifier circuit is a crystal oscillator, used to provide a radio frequency signal source with a high Q value; the second-stage amplifier circuit is a linear amplifier device, used to receive and amplify the drive signal sent by the crystal oscillator, and increase the drive capability of the output radio frequency signal; the third-stage amplifier circuit is used to amplify the voltage of the radio frequency signal to meet the drive signal input requirement of the fourth-stage amplifier circuit; the four-stage amplifier circuit includes a transformer, a high-power MOS tube and a synthesizer. After the drive signal is converted by the transformer, it is divided into an in-phase end and an inverting end. The in-phase end is amplified by n parallel high-power MOS tubes, and the inverting end is amplified by n parallel high-power MOS tubes. The synthesizer realizes the synthesized output of high-power in-phase and inverting end signals; the water cooling component 203 is used to dissipate heat and cool the high-power MOS tube.

[0060] like Figure 8 As shown, the impedance matching network module 202 includes an air capacitor 21, a vacuum capacitor 22, a coil 26, a servo motor M1-23, a servo motor M2-24, a phase amplitude detection circuit 25 and an automatic matching circuit 27. The air capacitor 21 serves as the load capacitor of the power amplifier circuit module 201, and adjusts the appropriate capacitance value for impedance matching to reduce the power loss of the power amplifier; the vacuum capacitor 22 and the coil 26 form a frequency selection network, and by adjusting the vacuum capacitance value, a tuning state is achieved at the frequency point corresponding to the radio frequency signal, and the power transmission efficiency is the highest; the servo motors M1-23 and the servo motors M2-24 are respectively connected to the rotating shafts of the air capacitors 21 and the vacuum capacitors 22, the phase amplitude detection circuit 25 is used to detect the matching state, and the phase amplitude signal enters the automatic matching circuit 27, and the automatic matching circuit 27 is used to collect the amplitude and phase of the matching network, and the servo motors M1-23 and the servo motors M2-24 are respectively driven to adjust the rotating shafts of the air capacitors 21 and the vacuum capacitors 22 to achieve the best matching state, ensuring the maximum efficiency of power output.

[0061] The control and detection system 4 is a multi-component interactive system based on a CAN bus communication method, including a main control board 401, a peristaltic pump assembly 402, a gas circuit control assembly 403 and a two-dimensional automatic adjustment platform assembly 404. The main control board 401 and the peristaltic pump assembly 402, the gas circuit control assembly 403 and the two-dimensional automatic adjustment platform assembly 404 are interconnected through a CAN bus 13, the power amplifier circuit module 201 is connected to the main control board 401 through a radio frequency power supply control line 11, and the impedance matching network module 202 is connected to the main control board 401 through a matching control line 12;

[0062] The peristaltic pump assembly 402 includes a 4-channel 12-roller pump head, a reduction mechanism with a reduction ratio of 3.3:1, a stepper motor and a stepper motor drive control circuit board. The peristaltic pump assembly 402 is used to control the introduction of liquid samples into the injection system 1; the gas path control assembly 403 includes a flow control circuit board and three mass flow controllers electrically connected to the flow control circuit board. The three mass flow controllers are arranged between the gas source and the injection system 1 to control the gas flow introduced into the injection system 1; the two-dimensional automatic adjustment platform assembly 404 is connected to the impedance matching network module 202, and is used to adjust the height of the impedance matching network module 202 so that the height of the coil 26 in the impedance matching network module 202 is suitable relative to the plasma position.

[0063] The gas path control component 403 is connected to the main control board 401 via the CAN bus to perform data exchange, receive data in real time, and regularly upload the three-path gas flow data at certain time intervals.

[0064] The gas source (pipeline gas or cylinder gas) is supplied to the gas circuit control component 403 after passing through the pressure regulating valve. Under the action of three mass flow controllers, three expected stable gas flow rates are respectively obtained and output to the torch tube 111 and the nebulizer 115 in the sampling system 1 for use. Fig. 9 As shown, the sample injection system 1 also includes a plasma 110, a torch 111, a cooling gas inlet 112, an auxiliary gas inlet 113, a carrier gas inlet 114, an atomizer 115, a spray chamber 116, a peristaltic pump 117, a sample to be tested 118, and a waste liquid barrel 119.

[0065] The two-dimensional automatic adjustment platform assembly 404 is connected to the impedance matching network module 202, and the height of the impedance matching network module is adjusted so that the height of the torch coil in the impedance matching network module is appropriate relative to the ICP torch position. The two-dimensional automatic adjustment platform assembly 404 adopts the structure disclosed in patent ZL 201510314333.6.

[0066] The two-dimensional automatic adjustment platform component 404 is connected to the main control board 401 via the CAN bus to perform data exchange, receive data in real time, and upload two-dimensional position data at regular intervals.

[0067] The data processing system 5 is connected to the dispersion system 3 and the control and detection system 4 via a network cable to perform data transmission.

[0068] In the embodiment of the present invention, the wavelength range designed for the wide-band high-resolution inductively coupled plasma optical emission spectrometer is 165 nm to 820 nm, but is not limited to this wavelength range.

[0069] The selected grating A and grating B have a line density of 4320l / mm and 2400l / mm respectively, the wavelength range of grating A is 165nm~450nm, and the wavelength range of grating B is 450nm~820nm. The double grating setting ensures the spectral resolution of the short-wave band, while also broadening the wavelength range of the spectrometer, thereby broadening the application field of the instrument.

[0070] The selected dual filters are a 310nm high pass filter and a 510nm high pass filter.

[0071] The two photomultiplier tubes in the photodetector 304 are respectively: PMT1, model Hamamatsu R7447; PMT2, model Hamamatsu R928.

[0072] like Figure 4 As shown, the turbine disk selected by the present invention adopts a whole disk design, and the turbine disk is designed according to the material matching method of an aluminum block inlaid with a copper ring to reduce the weight of the motor and the transmission system.

[0073] The invention provides a wide-band high-resolution inductively coupled plasma emission spectrometer, which adopts a scanning back-to-back double-grating spectrometer as a dispersion system of the wide-band high-resolution inductively coupled plasma emission spectrometer. The dispersion system adopts a back-to-back double-grating scanning design, and also includes a double filter and a double PMT design. The transmission system adopts a whole turbine disk design, which broadens the wavelength range of the instrument under the premise of ensuring the spectral resolution, thereby achieving the purpose of taking both the spectral resolution and the wavelength range into consideration, further expanding the wavelength range of the instrument, reducing matrix interference, improving system sensitivity, and realizing the analysis of trace and constant elements in multiple fields. In the dispersion system, a whole turbine disk design is adopted, which avoids the instability of a grating turntable caused by an unbalanced counterweight relationship compared with a traditional fan-shaped turbine disk. Considering the weight reduction factor, the turbine disk is designed according to the material matching method of an aluminum block inlaid with a copper ring, so as to reduce the weight of a motor and a transmission system, and further improve the stability of the emission spectrometer.

[0074] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A wide-band high-resolution inductively coupled plasma optical emission spectrometer, characterized in that: The invention comprises a sample introduction system (1), an excitation light source (2), a dispersion system (3), a control and detection system (4) and a data processing system (5), wherein the sample introduction system (1), the excitation light source (2), the dispersion system (3) and the data processing system (5) are connected in sequence, and the control and detection system (4) is respectively connected to the sample introduction system (1), the excitation light source (2) and the data processing system (5); the sample introduction system (1) is used to atomize the sample to be tested and bring it into the central channel of the inductively coupled plasma; the excitation light source (2) is a radio frequency power generator, which generates radio frequency excitation power of the inductively coupled plasma for the spectrometer, and is used to excite the sample to be tested to generate an emission spectrum; the dispersion system (3) adopts a scanning back-to-back double grating spectrometer, which is used to collect, transmit, split and detect the emission spectrum generated by the sample to be tested being excited in the inductively coupled plasma; the data processing system (5) is used to perform data processing on the spectrum information output by the dispersion system (3); the control and detection system (4) is used to control the working sequence between the various components of the spectrometer and the data exchange between the various components; The dispersion system (3) comprises an optical chamber and components (301), a transmission system (302) and a photodetector (304); the optical chamber and components (301) comprise an optical chamber (31) and a double slit component, a grating component (36) and a double reflector component arranged in the optical chamber (31); the double slit component comprises an incident slit component (33) and an exit slit component (35), which are arranged at the light inlet and the light outlet of the optical chamber (31) respectively; the incident slit component (33) comprises a front optical path (32) and a double filter (34); the grating component (36) comprises a front optical path (32) and a double filter (34); The component (36) adopts a back-to-back double grating design. The back-to-back double gratings are two plane gratings with different parameters, including grating A and grating B. The structural parameters of grating A and grating B are consistent, but the line density is different. The double reflector component includes a first spherical reflector (37) and a second spherical reflector (38). The first spherical reflector (37) is used to reflect the light transmitted by the incident slit component (33) to the grating component (36), and the second spherical reflector (38) is used to reflect the light emitted by the grating component (36) to the exit slit component (35). The transmission system (302) is arranged at the bottom of the optical chamber (31), and the transmission system (302) comprises a whole turbine disc (50), a turbine shaft (51), a turbine worm (52), a coupling (53), and a transmission motor (54). The whole turbine disc (50) is designed according to the material combination of an aluminum block and a copper ring embedded outside. The transmission motor (54) is fixed to the bottom of the optical chamber (31) through a motor positioning plate. The transmission motor (54) is connected to the turbine worm (52) through the coupling (53). The turbine worm (52) drives the whole turbine disc (50) and the turbine shaft (51) to rotate. The turbine shaft (51) passes through the bottom of the optical chamber (31) and is connected to the grating assembly (36). The photoelectric detector (304) is arranged at the exit slit assembly (35), and the photoelectric detector (304) is used to convert the light signal of the emission spectrum emitted by the exit slit assembly (35) into an electrical signal, and transmit it to the data processing system (5).

2. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 1, characterized in that: A rectangular support frame is arranged at the bottom end of the light chamber (31), the interior of the light chamber (31) is sprayed with plastic, the light chamber (31) is mounted on the rectangular support frame, and the transmission system (302) is mounted on the light chamber.

3. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 1, characterized in that: The photodetector (304) comprises two photomultiplier tubes, namely a photomultiplier tube A (39) and a photomultiplier tube B (40). The exit slit assembly (35) is provided with a plane reflector (41) and a cylinder for driving the plane reflector (41) to move. The light beam is deflected by the movement of the plane reflector (41). When the plane reflector (41) is in the light path, the photomultiplier tube B (40) is in a working state. When the plane reflector (41) exits the light path, the photomultiplier tube A (39) is in a working state.

4. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 1, characterized in that: The transmission system (302) further comprises three limit switches (56) and a limit block (57). The three limit switches (56) are mounted on the bottom of the optical chamber (31) by means of screws and adapters. The limit block (57) is arranged on the whole turbine disc (50). The limit switch (56) sends a signal to the upper computer by touching the limit block (57) to limit the position and protect the rotation of the grating assembly (36). The three limit switches (56) are respectively a mechanical zero position limit switch (5601), a long-wave edge wavelength limit protection limit switch (5603) and a limit zero position protection limit switch (5604). Limit switch (5602); the mechanical zero limit switch (5601) is the initial position of the grating assembly (36), that is, the starting point before the emission spectrometer starts working; the long-wave edge wavelength limit protection limit switch (5603) is the limited protection position of the rotation angle of the entire turbine disk (50) when the grating assembly (36) works to the longest wavelength; the extreme zero protection limit switch (5602) is the extreme secondary protection of the mechanical zero limit switch (5601), and when the mechanical zero limit switch (5601) fails, the extreme zero protection limit switch (5602) plays a protective role.

5. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 1, characterized in that: The dispersion system also includes a constant temperature system (303), which uses a PTC heater and is arranged at the bottom of the light chamber (31) to provide a constant temperature working environment for the dispersion system (3).

6. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 1, characterized in that: The excitation light source (2) comprises a power amplifier circuit module (201), an impedance matching network module (202), a water cooling component (203) and a power control circuit (204); the power amplifier circuit module (201) is used to amplify radio frequency excitation power; the impedance matching network module (202) is used to achieve maximum efficiency transmission of radio frequency excitation power; the water cooling component (203) is used to cool the excitation light source (2); and the power control circuit (204) is used to collect the output power signal amplitude and perform power control by comparing the size of the set signal and the output signal.

7. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 6, characterized in that: The power amplifier circuit module (201) adopts a four-stage amplifier circuit, comprising: a first-stage amplifier circuit, a second-stage amplifier circuit, a third-stage amplifier circuit and a fourth-stage amplifier circuit connected in sequence, wherein the first-stage amplifier circuit is a crystal oscillator for providing a radio frequency signal source with a high Q value; the second-stage amplifier circuit is a linear amplifier device for receiving and amplifying a driving signal emitted by the crystal oscillator to increase the driving capability of the output radio frequency signal; the third-stage amplifier circuit is used to amplify the voltage of the radio frequency signal to meet the driving signal input requirement of the fourth-stage amplifier circuit; the four-stage amplifier circuit comprises a transformer, a high-power MOS tube and a synthesizer; the driving signal is divided into an in-phase end and an inverting end after being converted by the transformer; the in-phase end is amplified by n parallel high-power MOS tubes, and the inverting end is amplified by n parallel high-power MOS tubes; the synthesizer realizes the synthesized output of high-power in-phase and inverting end signals; the water cooling component (203) is used to dissipate heat and cool the high-power MOS tube.

8. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 6, characterized in that: The impedance matching network module (202) comprises an air capacitor (21), a vacuum capacitor (22), a servo motor M1 (23), a servo motor M2 (24), a phase amplitude detection circuit (25), a coil (26) and an automatic matching circuit (27); the air capacitor (21) serves as a load capacitor of the power amplifier circuit module (201); a suitable capacitance value is adjusted to perform impedance matching, thereby reducing power loss of the power amplifier; the vacuum capacitor (22) and the coil (26) form a frequency selection network; by adjusting the vacuum capacitor value, a tuning state is achieved at a frequency point corresponding to a radio frequency signal, and the power amplifier circuit module (201) is automatically matched to the power amplifier circuit module (201); The transmission efficiency is the highest; the servo motor M1 (23) and the servo motor M2 (24) are respectively connected to the rotating shafts of the air capacitor (21) and the vacuum capacitor (22); the phase amplitude detection circuit (25) is used to detect the matching state; the phase amplitude signal enters the automatic matching circuit (27); the automatic matching circuit (27) is used to collect the amplitude and phase of the matching network; the servo motor M1 (23) and the servo motor M2 (24) are controlled to drive the rotating shafts of the air capacitor (21) and the vacuum capacitor (22) to adjust so as to achieve the best matching state and ensure the maximum efficiency output of power.

9. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 8, characterized in that: The control and detection system (4) comprises a main control board (401), a peristaltic pump assembly (402), a gas path control assembly (403) and a two-dimensional automatic adjustment platform assembly (404); the main control board (401) and the peristaltic pump assembly (402), the gas path control assembly (403) and the two-dimensional automatic adjustment platform assembly (404) are interconnected via a CAN bus (13); the power amplifier circuit module (201) is connected to the main control board (401) via a radio frequency power supply control line (11); and the impedance matching network module (202) is connected to the main control board (401) via a matching control line (12); The peristaltic pump assembly (402) comprises a roller pump head, a speed reduction mechanism, a stepper motor and a stepper motor drive control circuit board, and the peristaltic pump assembly (402) is used to control the introduction of liquid samples into the injection system (1); the gas circuit control assembly (403) comprises a flow control circuit board and three mass flow controllers electrically connected to the flow control circuit board, and the three mass flow controllers are arranged between the gas source and the injection system (1) and are used to control the gas flow introduced into the injection system (1); the two-dimensional automatic adjustment platform assembly (404) is connected to the impedance matching network module (202) and is used to adjust the height of the impedance matching network module (202) so that the height of the coil (26) in the impedance matching network module (202) is appropriate relative to the plasma position.

10. The wide-band high-resolution inductively coupled plasma optical emission spectrometer according to claim 1, characterized in that: The data processing system (5) is connected to the dispersion system (3) and the control and detection system (4) via network cables for data transmission.

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