CN109211847B - A method for analyzing the chemical composition of a single suspended particle using an analytical device - Google Patents

Abstract

The invention discloses a device for analyzing chemical components of single suspended particles, which comprises a pulse laser, a hollow beam particle capturing system, an atomic emission spectrum acquisition system, a Raman spectrum acquisition system and an imaging system, wherein the hollow beam particle capturing system is used for capturing particles; the hollow beam particle capturing system comprises a continuous laser, a hollow beam generating device, a beam expanding and collimating device, a high-reflection mirror, a first convergent lens and a sample cell, wherein sample particles are arranged in the sample cell; the atomic emission spectrum acquisition system comprises a first coupling lens and a laser-induced breakdown spectrometer; the Raman spectrum acquisition system comprises a second coupling lens and a Raman spectrometer. In addition, the invention also provides a method for analyzing the chemical composition of the single suspended particles by using the device. The invention captures sample particles by using hollow beams, ionizes the sample particles by using a pulse laser, and acquires atomic emission spectrum information and Raman spectrum information of the sample particles to realize in-situ analysis of element composition and material composition of single suspended particles.

Description

A method for analyzing the chemical composition of a single suspended particle using an analytical device

technical field

The invention belongs to the application field of nonlinear optics, and in particular relates to a method for analyzing the chemical composition of a single suspended particle by using an analysis device.

Background technique

At present, the detection methods for particulate matter in the air include: infrared absorption spectroscopy, ultraviolet absorption spectroscopy, ultraviolet fluorescence method, chemiluminescence method, turbidity method and scattering method, etc. However, these methods cannot detect fine particles in the air (aerosol, carbon The composition and structure of black, trace heavy metals, etc.) were detected. As an emerging in-situ measurement technology, laser-induced breakdown spectroscopy can analyze solid samples as well as liquid and gas samples. Analysis has been successfully used in many fields such as materials, metallurgy, combustion, environment, archaeology, space exploration, medicine and military.

Laser-Induced Breakdown Spectroscopy (LIBS) uses the plasma generated by a pulsed laser to ablate and excite the substances in the sample, and obtain the spectrum emitted by the atoms excited by the plasma through the spectrometer to identify The elemental composition of a sample, which in turn enables the identification, classification, qualitative and quantitative analysis of materials. Laser-induced breakdown Raman spectroscopy (LIBRAS) technology is an in-situ measurement spectroscopy technology that simultaneously acquires atomic and molecular spectra of substances at the same site through LIBS and Raman spectroscopy. Analytical processing can simultaneously complete the micro-area in-situ determination of atomic and molecular spectra, so as to quickly quantitatively analyze and identify the elemental and molecular composition of the sample. However, as far as the known reports are concerned, LIBS is only limited to online in-situ detection of sample particles attached to some solids, and the detection of particles suspended in fluids such as air or liquids is still unable to be carried out, and because the LIBS system can break down Objects and solids to which sample particles are attached will inevitably cause noise in the spectrometer, thereby affecting the accurate analysis of particle components.

In the field of optics, a hollow beam refers to a beam whose lateral amplitude distribution satisfies a higher-order Bessel function, and its lateral light intensity distribution appears as a series of concentric rings with a dark center. According to the principle of photophoresis, the hollow beam can capture the light-absorbing particles in its dark area. Using the hollow beam to capture the light-absorbing particles in the air is the most stable device known so far. At the same time, the particles can be realized by adjusting the size or power of the hollow beam. 3D operations. The unique light intensity distribution of the hollow beam makes it have important application value in the fields of particle manipulation and nonlinear optics.

At present, there is no report on the real-time in-situ analysis method for the composition of particles in the air. There are two main reasons: the currently known detection methods cannot analyze the chemical composition of particles in fluids (such as air, etc.); The laser capture technology has not been organically combined with the spectral analysis system.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method for analyzing the chemical composition of a single suspended particle by using an analysis device. The method converts the Gaussian beam generated by a continuous laser into a The hollow beam captures the sample particles in the sample cell, and at the same time, by setting a pulsed laser, the captured sample particles are ionized to achieve in-situ analysis of the elemental composition and material composition of single fine particles suspended in the air.

In order to solve the above-mentioned technical problems, the technical scheme adopted in the present invention is: a device for chemical composition analysis of a single suspended particle, including a pulsed laser, and characterized in that it also includes a hollow beam capturing particle system, an atomic emission spectrum acquisition system, Raman spectrum acquisition system and imaging system;

The hollow beam capturing particle system includes a continuous laser, a hollow beam generating device, a beam expanding and collimating device, a high reflection mirror capable of changing the direction of the hollow beam, a first condensing lens and a sample cell; the continuous laser, the hollow beam generating device, The beam expanding and collimating device, the high reflection mirror and the first condensing lens are sequentially arranged on the same optical path, and sample particles are arranged in the sample pool;

The atomic emission spectrum acquisition system includes a first coupling lens and a laser induced breakdown spectrometer connected to the first coupling lens, and a connection between the first coupling lens and the laser induced breakdown spectrometer is provided for connecting the first coupling lens and the laser The first fiber of the induced breakdown spectrometer;

The Raman spectrum acquisition system includes a second coupling lens and a Raman spectrometer connected to the second coupling lens, and a third coupling lens for connecting the second coupling lens and the Raman spectrometer is arranged between the second coupling lens and the Raman spectrometer. two optical fibers;

The pulsed light generated by the pulsed laser is perpendicular to the hollow beam reflected by the high reflection mirror;

The imaging system includes an imaging device and a microscope objective lens disposed between the imaging device and the sample cell.

The above-mentioned device for chemical composition analysis of a single suspended particle is characterized in that: the continuous laser is a 532 nm semiconductor continuous laser or an all-solid-state tunable Ti:sapphire dye continuous laser.

The above-mentioned device for chemical composition analysis of a single suspended particle is characterized in that: the hollow beam generating device comprises a self-phase spatial beam modulation system, a cross-phase spatial beam modulation system, a biconical lens, Spatial light modulator or phase plate.

The above-mentioned device for chemical composition analysis of a single suspended particle is characterized in that: the self-phase spatial beam modulation system includes a first convex lens and a nonlinear absorption medium sequentially arranged on the same optical path.

The above-mentioned device for chemical composition analysis of a single suspended particle is characterized in that: the beam expanding and collimating device comprises a second condensing lens and a third condensing lens located on the same optical path, and the second condensing lens is located on the same optical path. between the hollow beam generating device and the third condensing lens.

The above-mentioned device for chemical composition analysis of a single suspended particle is characterized in that: the imaging device includes a CCD camera, an ICCD camera or a CMOS camera.

The above-mentioned device for chemical composition analysis of a single suspended particle is characterized in that: the first condensing lens is located between the high reflection mirror and the sample cell.

The above-mentioned device for chemical composition analysis of a single suspended particle is characterized in that: the imaging device, the laser-induced breakdown spectrometer and the Raman spectrometer are respectively located on different sides of the sample cell.

In addition, the present invention also provides a method for analyzing the chemical composition of a single suspended particle using the above-mentioned device, which is characterized in that it includes the following steps:

Step 1: Obtain a continuous laser beam with a Gaussian distribution from the continuous laser, and shape the obtained continuous laser beam into a hollow beam through a hollow beam generating device;

Step 2: The hollow beam obtained in step 1 is incident on the high reflection mirror after passing through the beam expanding and collimating device, and the high reflection mirror is adjusted so that the reflected hollow beam is incident on the first condensing lens to form a condensing hollow beam. Incident into the sample cell;

Step 3, obtaining a convergent pulsed light from the pulsed laser and making the convergence center of the pulsed light coincide with the imaging center of the imaging device, and turning off the pulsed laser;

Step 4: injecting sample particles into the sample cell, the converging hollow beam incident on the sample cell captures the sample particles at the position of the optical trap, and adjusting the light intensity and size of the hollow beam to make the position of the optical trap coincide with the imaging center of the imaging device;

Step 5. The second coupling lens collects the scattered light generated by the sample particles, and the Raman spectrometer displays the Raman spectrum information;

Step 6: Turn on the pulsed laser so that the converging pulsed light will ionize the captured sample particles, and turn off the pulsed laser;

Step 7: The first coupling lens collects the atomic emission spectrum generated by the ionization of the sample particles, and the laser-induced breakdown spectrometer displays the information of the atomic emission spectrum.

Compared with the prior art, the present invention has the following advantages:

1. The present invention converts the Gaussian beam generated by the continuous laser into a hollow beam by setting a hollow beam generating device to capture the sample particles in the sample cell, and at the same time, by setting a pulsed laser, the captured sample particles are ionized to realize the ionization of the particles in the air. On-line in situ analysis of elemental composition and material composition of suspended single fine particles.

2. The present invention can obtain atomic emission spectrum information, Raman spectrum information and sample motion of ionized samples by setting up a spectrum acquisition system and an imaging device, so as to achieve the purpose of quantitative determination, and provide a new method for real-time online research of air pollution particles. ideas.

3. The analysis device of the present invention is simple in structure, reasonable in design, low in cost and easy to popularize.

4. The analysis method of the present invention is easy to operate, can capture suspended particles whose positions are constantly changing, and perform spectral analysis on the suspended particles, so as to realize the online detection of a single suspended solid.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

FIG. 1 is a schematic structural diagram of an apparatus for chemical composition analysis of a single suspended particle of the present invention.

2 is a schematic structural diagram of a pulsed laser, a hollow beam trapping particle system, an atomic emission spectrum acquisition system and an imaging system of the device for chemical composition analysis of a single suspended particle of the present invention.

FIG. 3 is a schematic structural diagram of the hollow beam generating device of the present invention.

FIG. 4 is a Raman spectrum diagram of single particle alumina measured by the present invention.

Figure 5 is a standard Raman spectrum of alumina.

Fig. 6 is the laser-induced breakdown spectrogram of the single particle alumina measured by the present invention.

FIG. 7 is a standard laser-induced breakdown spectrum of aluminum element.

Explanation of reference numbers:

1—continuous laser; 2—hollow beam generating device; 2-1—first convex lens;

2-2—non-linear absorption medium; 3—second condensing lens; 4—third condensing lens;

5—High reflection mirror; 6—First converging lens; 7—Sample cell;

8—sample particle; 9—pulse laser; 10—microscope objective lens;

11—imaging device; 12—first coupling lens; 13—first optical fiber;

14—laser induced breakdown spectrometer; 15—second coupling lens; 16—second optical fiber;

17—Raman spectrometer.

Detailed ways

Example 1

As shown in FIG. 1 and FIG. 2 , the device for chemical composition analysis of a single suspended particle in this embodiment includes a pulsed laser 9 , a hollow beam trapping particle system, an atomic emission spectrum acquisition system, a Raman spectrum acquisition system, and a imaging system;

The hollow beam capturing particle system includes a continuous laser 1, a hollow beam generating device 2, a beam expanding collimator, a high reflector 5 that can change the direction of the hollow beam, a first condensing lens 6 and a sample cell 7; the continuous laser 1 , the hollow beam generating device 2, the beam expanding and collimating device, the high reflection mirror 5 and the first condensing lens 6 are sequentially arranged on the same optical path, and the sample cell 7 is provided with sample particles 8;

The atomic emission spectrum acquisition system includes a first coupling lens 12 and a laser-induced breakdown spectrometer 14 connected to the first coupling lens 12, and a second coupling lens for connecting the first coupling lens 12 and the laser-induced breakdown spectrometer 14 is provided. a coupling lens 12 and the first optical fiber 13 of the laser-induced breakdown spectrometer 14;

The Raman spectrum acquisition system includes a second coupling lens 15 and a Raman spectrometer 17 connected to the second coupling lens 15, and a second coupling lens 15 is provided between the second coupling lens 15 and the Raman spectrometer 17 for connecting the second coupling lens 15. and the second optical fiber 16 of the Raman spectrometer 17;

The pulsed light generated by the pulsed laser 9 is perpendicular to the hollow beam reflected by the high-reflection mirror 5; the pulsed laser 9 is arranged at a direction perpendicular to the propagation direction of the hollow beam reflected by the high-reflection mirror 5 and is positioned on the same plane with the sample cell 7;

The imaging system includes an imaging device 11 and a microscope objective lens 10, and the microscope objective lens 10 is arranged between the imaging device 11 and the sample cell 7; in this embodiment, the microscope objective lens 10 has a magnification of 10. ×, microscope objective with N.A. of 0.25.

The CW laser 1 is a 532 nm semiconductor CW laser, which can also be replaced by an all-solid-state tunable Ti:sapphire dye CW laser.

The hollow beam generating device 2 includes a self-phase spatial beam modulation system, a cross-phase spatial beam modulation system, a biconical lens, a spatial light modulator or a phase plate that can generate a hollow beam.

As shown in FIG. 3 , the self-phase spatial beam modulation system includes a first convex lens 2-1 and a nonlinear absorption medium 2-2 sequentially arranged on the same optical path, and a CCD camera that can be used to detect the hollow beam, the CCD camera receives The light beam passes through the nonlinear absorption medium 2-2, and the activity is placed on the optical path.

In addition, a cross-phase spatial beam modulation system can also be used, and the cross-phase spatial beam modulation system is the application number "2016109453059" and the patent name is "A method and device for obtaining a Bessel beam based on cross-phase modulation". The device for obtaining Bessel beam disclosed in the invention patent, set the output wavelength of the laser to 780.2100nm to obtain a hollow beam;

In addition, hollow beams can be obtained by biconical lenses, spatial light modulators or phase plates.

The beam expanding and collimating device includes a second condensing lens 3 and a third condensing lens 4 located on the same optical path, and the second condensing lens 3 is located between the hollow beam generating device 2 and the third condensing lens 4; this In the embodiment, the focal length of the second condensing lens 3 is 100mm, and the focal length of the third condensing lens 4 is 200mm; Optical system for laser beam expansion and collimation.

The imaging device 11 includes a CCD camera, an ICCD camera or a CMOS camera; the imaging device in this embodiment is a CCD camera, which can also be replaced by an ICCD camera or a CMOS camera.

The first condensing lens 6 is located between the high-reflection mirror 5 and the sample cell 7. In this embodiment, the focal length of the first condensing lens 6 is 30mm. In addition, the magnification can be 10×, and the N.A. is 0.25 microscope objective and other replacement.

The imaging device 11 , the laser-induced breakdown spectrometer 14 and the Raman spectrometer 17 are respectively located on different sides of the sample cell 7 ; in this embodiment, the imaging device 11 , the laser-induced breakdown spectrometer 14 , the pulsed laser 9 , the sample The cell 7 and the Raman spectrometer 17 are in the same plane, which is perpendicular to the hollow beam reflected by the high reflector 5 .

Adopt the device of embodiment 1 to carry out the method for the chemical composition analysis of single suspended particle, the concrete steps include:

Step 1: Obtain a continuous laser beam with a Gaussian distribution from the continuous laser 1, and shape the obtained continuous laser beam into a hollow beam through the hollow beam generating device 2; 1 The obtained continuous laser beam with Gaussian distribution is first focused on the nonlinear absorption medium 2-2 through the first convex lens 2-1 to generate a hollow beam, which is detected by a CCD camera; the nonlinear absorption medium 2-2 is rubidium The atomic pool can also be replaced by lead glass or sodium atomic pool;

In step 2, the hollow beam obtained in step 1 is incident on the high reflection mirror 5 after passing through the beam expanding and collimating device, and the high reflection mirror 5 is adjusted so that the reflected hollow beam is incident on the first condensing lens 6 to form a converging hollow beam, which converges. The hollow beam is incident into the sample cell 7; the process of beam expansion and collimation is that the hollow beam obtained in step 1 first passes through the second condensing lens 3 and then passes through the third condensing lens 4 for beam expansion and collimation;

Step 3: Obtain a convergent pulsed light from the pulsed laser 9, adjust the pulsed laser 9 to make the convergence center of the pulsed light coincide with the imaging center of the imaging device 11, and turn off the pulsed laser 9;

Step 4: Spray the sample particles 8 into the sample cell 7, and the converging hollow beam incident on the sample cell 7 captures the sample particles 8 at the position of the optical trap, and adjusts the light intensity and size of the hollow beam so that the position of the optical trap matches that of the imaging device 11. The imaging centers are coincident; the sample particles 8 used in this embodiment are alumina with a particle size of 2-10 μm, which can also be replaced by other light-absorbing compounds; in this embodiment, a self-phase spatial beam modulation system is used to generate a hollow beam, and by adjusting the continuous laser 1 to adjust the light intensity of the obtained hollow beam, and change the size of the hollow beam by changing the focal length of the first convex lens 2-1, so that the obtained hollow beam captures the optical trap position of the sample particle 8 and the image displayed by the imaging device 11. The imaging center coincides;

The hollow beam is generated by the cross-phase spatial beam modulation system, and the light intensity and size of the hollow beam can be changed by rotating the angle of the half-wave plate;

The hollow beam is obtained through a biconical lens, and the light intensity of the hollow beam can be changed by setting a half-wave plate and a polarizing beam splitter; the size of the hollow beam can be changed by changing the vertex angle of the biconical lens;

The hollow beam is obtained through a spatial light modulator or a phase plate, and the light intensity and size of the hollow beam can be changed by adjusting the output current of the spatial light modulator or adjusting the phase information of the phase plate;

Adjust the imaging system so that the movement of the sample particles 8 is magnified by the microscope objective lens 10 and recorded on the imaging device 11; the imaging is captured by a CCD camera, which can also be replaced by an ICCD camera or a CMOS camera;

Step 5: Adjust the position of the second coupling lens 15, so that the second coupling lens 15 collects the scattered light generated by the sample particles 8, and the Raman spectrometer 17 connected to the second coupling lens 15 displays Raman spectrum information;

Step 6: Turn on the pulsed laser 9 so that the converged pulsed light ionizes the captured sample particles 8, and turn off the pulsed laser 9;

Step 7: Adjust the position of the first coupling lens 12 so that the first coupling lens 12 collects the atomic emission spectrum generated by the ionization of the sample particles 8 , and the laser-induced breakdown spectrometer 14 connected to the first coupling lens 12 displays the information of the atomic emission spectrum.

The sample particles are re-sprayed into the sample cell 7 for repeated detection, the spectra obtained multiple times are compared, and the determined spectra are compared with the standard spectra.

The above steps can be adjusted as needed.

According to Fig. 4 and Fig. 5, in the Raman spectrum of single particle alumina measured by the present invention (Fig. 4), the peak positions are 378cm ^-1 , 578 ^-1 and 645 ^-1 respectively, corresponding to the standard Raman of alumina 376.9 cm ^-1 , 575.9 cm ^-1 , and 643.9 cm ^-1 shown in the spectrum ( FIG. 5 ), from which it can be judged that the captured sample particles contain alumina species.

According to FIG. 6 and FIG. 7 , in the laser-induced breakdown spectrum (FIG. 6) of single-particle alumina measured by the present invention, there are peaks at wavelengths of 308.24 nm and 309.31 nm. Alignment of standard databases of laser-induced breakdown spectroscopy to determine the presence of aluminum in the captured samples.

The principle of the analytical method of the present invention is:

The present invention is based on the basic principle of optophoretic force optical tweezers. Specifically: when a beam of light is irradiated on the surface of light-absorbing particles, the temperature of the irradiated area on the surface of the particle will increase, and the thermal motion of the gas molecules attached to the surface will increase after the temperature of the irradiated area increases, and the gas molecules will bounce off the particles at a higher speed. On the surface, the thermal motion of the gas molecules on the irradiated surface is more intense than that of the molecules on the unirradiated surface. Under the combined action, the particles generate a net force from the irradiated surface to the unirradiated surface. According to the principle of aerodynamics, the pressure F of molecules acting on the surface of particles can be expressed as:

Among them, ρ _a is the density of air, kg/m ³ ; B is the universal air constant, J/(mol·K); T is the particle surface temperature, K; M is the molar mass of air molecules, kg/mol.

For a hollow beam, the force acting on the particle surface can be expressed as:

Among them, ρ _a is the density of air, kg/m ³ ; B is the universal air constant, J/(mol·K); T is the particle surface temperature, K; M is the molar mass of air molecules, kg/mol; S is the area of the light-irradiated area on the particle, m ² .

For irregular particles:

为空气分子的平均速度，m/s；γ＝c_p/c_v为比热比；P_l为入射空心光束的功率，W；P为环境气体压力，N/m²；P*为特征压力，N/m²；α为微粒表面的热适应系数，Δα＝α₁-α₂，

in,

is the average velocity of air molecules, m/s; γ=c _p /c _v is the specific heat ratio; P _l is the power of the incident hollow beam, W; P is the ambient gas pressure, N/m ² ; P* is the characteristic pressure , N/m ² ; α is the thermal adaptation coefficient of the particle surface, Δα=α ₁ -α ₂ ,

Under the action of gravity, F _ΔT and F _Δα , the particles can be trapped in the focal region, and the size of the F _ΔT force can be changed by adjusting the size of the hollow beam, and then the particles can be manipulated.

The captured particles are ionized by the pulsed light generated by the pulsed laser, and the spectrum of the electric particles is analyzed by LIBS technology and Raman spectroscopy, and the material composition information and element information of the particles are obtained at the same time.

The above are only preferred embodiments of the present invention and do not limit the present invention. Any simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still belong to the technology of the present invention. within the scope of the program.

Claims (6)

1. A method for single suspended particle chemical composition analysis using an analysis device comprising a pulsed laser (9), characterized in that: the analysis device also comprises a hollow beam particle capturing system, an atomic emission spectrum acquisition system, a Raman spectrum acquisition system and an imaging system;

the hollow beam particle capturing system comprises a continuous laser (1), a hollow beam generating device (2), a beam expanding and collimating device, a high reflecting mirror (5) capable of changing the direction of a hollow beam, a first converging lens (6) and a sample cell (7); the continuous laser (1), the hollow beam generating device (2), the beam expanding and collimating device, the high-reflection mirror (5) and the first convergent lens (6) are sequentially arranged on the same light path, and sample particles (8) are arranged in the sample cell (7); the hollow light beam generating device (2) is a self-phase space light beam modulation system capable of generating a hollow light beam, and the self-phase space light beam modulation system comprises a first convex lens (2-1), a nonlinear absorption medium (2-2) and a CCD (charge coupled device) camera, wherein the first convex lens and the nonlinear absorption medium are sequentially arranged on the same light path;

the atomic emission spectrum acquisition system comprises a first coupling lens (12) and a laser-induced breakdown spectrometer (14) connected with the first coupling lens (12), wherein a first optical fiber (13) used for connecting the first coupling lens (12) and the laser-induced breakdown spectrometer (14) is arranged between the first coupling lens (12) and the laser-induced breakdown spectrometer (14);

the Raman spectrum acquisition system comprises a second coupling lens (15) and a Raman spectrometer (17) connected with the second coupling lens (15), and a second optical fiber (16) used for connecting the second coupling lens (15) and the Raman spectrometer (17) is arranged between the second coupling lens (15) and the Raman spectrometer (17);

the pulse light generated by the pulse laser (9) is vertical to the hollow light beam reflected by the high reflector (5);

the imaging system comprises an imaging device (11) and a microscope objective (10), the microscope objective (10) being arranged between the imaging device (11) and the sample cell (7);

the method comprises the following steps:

step one, acquiring a continuous laser beam with Gaussian distribution from a continuous laser (1), and shaping the acquired continuous laser beam into a hollow beam through a hollow beam generating device (2);

step two, the hollow light beam obtained in the step one is incident to a high reflecting mirror (5) after passing through a beam expanding and collimating device, the high reflecting mirror (5) is adjusted, the reflected hollow light beam is incident to a first converging lens (6) to form a converged hollow light beam, and the converged hollow light beam is incident to a sample cell (7);

step three, obtaining a beam of convergent pulsed light from a pulse laser (9), enabling the convergence center of the pulsed light to coincide with the imaging center of an imaging device (11), and turning off the pulse laser (9);

step four, spraying sample particles (8) into the sample cell (7), capturing the sample particles (8) at the position of an optical trap by the converged hollow light beam incident into the sample cell (7), and adjusting the light intensity and the size of the hollow light beam to enable the position of the optical trap to coincide with the imaging center of the imaging device (11);

step five, collecting scattered light generated by the sample particles (8) by a second coupling lens (15), and displaying Raman spectrum information by a Raman spectrometer (17);

sixthly, turning on a pulse laser (9) to enable the converged pulse light to ionize the captured sample particles (8), and turning off the pulse laser (9);

and seventhly, acquiring an atomic emission spectrum generated by ionization of the sample particles (8) by using the first coupling lens (12), and displaying information of the atomic emission spectrum by using the laser-induced breakdown spectrometer (14).

2. A method for chemical composition analysis of individual suspended particles using an analytical device according to claim 1, wherein: the continuous laser (1) is a 532nm semiconductor continuous laser or an all-solid-state tunable titanium sapphire dye continuous laser.

3. A method for chemical composition analysis of individual suspended particles using an analytical device according to claim 1, wherein: the beam expanding and collimating device comprises a second converging lens (3) and a third converging lens (4) which are positioned on the same optical path, and the second converging lens (3) is positioned between the hollow light beam generating device (2) and the third converging lens (4).

4. A method for chemical composition analysis of individual suspended particles using an analytical device according to claim 1, wherein: the imaging device (11), the laser-induced breakdown spectrometer (14) and the Raman spectrometer (17) are respectively positioned on different sides of the sample cell (7).

5. A method for chemical composition analysis of individual suspended particles using an analytical device according to claim 1, wherein: the imaging device (11) comprises a CCD camera, an ICCD camera or a CMOS camera.

6. A method for chemical composition analysis of individual suspended particles using an analytical device according to claim 1, wherein: the first convergent lens (6) is positioned between the high reflection mirror (5) and the sample cell (7).

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