CN111426641B - Method for detecting density distribution state of nano material - Google Patents
Method for detecting density distribution state of nano material Download PDFInfo
- Publication number
- CN111426641B CN111426641B CN201910019103.5A CN201910019103A CN111426641B CN 111426641 B CN111426641 B CN 111426641B CN 201910019103 A CN201910019103 A CN 201910019103A CN 111426641 B CN111426641 B CN 111426641B
- Authority
- CN
- China
- Prior art keywords
- density gradient
- gradient solution
- density
- detected
- detection
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000002086 nanomaterial Substances 0.000 title claims abstract description 148
- 238000000034 method Methods 0.000 title claims abstract description 46
- 238000001514 detection method Methods 0.000 claims abstract description 124
- 230000001678 irradiating effect Effects 0.000 claims abstract description 14
- XJHCXCQVJFPJIK-UHFFFAOYSA-M caesium fluoride Chemical compound [F-].[Cs+] XJHCXCQVJFPJIK-UHFFFAOYSA-M 0.000 claims description 48
- 238000012545 processing Methods 0.000 claims description 22
- 239000007788 liquid Substances 0.000 claims description 18
- 238000002835 absorbance Methods 0.000 claims description 17
- 230000008859 change Effects 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 12
- AIYUHDOJVYHVIT-UHFFFAOYSA-M caesium chloride Chemical compound [Cl-].[Cs+] AIYUHDOJVYHVIT-UHFFFAOYSA-M 0.000 claims description 5
- 238000005286 illumination Methods 0.000 claims description 4
- 239000004793 Polystyrene Substances 0.000 claims description 3
- 238000012937 correction Methods 0.000 claims description 3
- 239000005304 optical glass Substances 0.000 claims description 3
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims description 3
- 239000004926 polymethyl methacrylate Substances 0.000 claims description 3
- 229920002223 polystyrene Polymers 0.000 claims description 3
- 239000010453 quartz Substances 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- 239000000243 solution Substances 0.000 description 155
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 31
- 229910021389 graphene Inorganic materials 0.000 description 31
- 238000004062 sedimentation Methods 0.000 description 12
- 238000010586 diagram Methods 0.000 description 9
- 230000031700 light absorption Effects 0.000 description 8
- 230000003287 optical effect Effects 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000010365 information processing Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 235000013405 beer Nutrition 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 238000012634 optical imaging Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000008707 rearrangement Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
Abstract
The invention discloses a method for detecting a density distribution state of a nano material. The detection method comprises the following steps: providing a detection container; injecting a density gradient solution into the detection container; dispersing the nano material to be detected in a density gradient solution; irradiating the density gradient solution dispersed with the nano material to be detected by using a detection light beam, and carrying out first image acquisition on the whole formed by the detection container and the density gradient solution dispersed with the nano material to be detected to obtain a first image acquisition result; and obtaining the density distribution state of the nano material to be detected according to the first image acquisition result. According to the method for detecting the density distribution state of the nano material, the nano material to be detected is separated by using the density gradient solution, and the detection light beam is used for irradiating the density gradient solution which is formed by the detection container and the nano material to be detected, so that the method is simple and convenient to operate when the density distribution of the nano material to be detected is obtained, and can be applied to high-flux commercial detection application.
Description
Technical Field
The embodiment of the invention relates to the technical field of nano material detection, in particular to a method for detecting a density distribution state of a nano material.
Background
Since the concept of nanomaterials was proposed, various new nanomaterials have been layered endlessly, and by now, nanomaterials have been well known and widely used in various fields.
Some classical two-dimensional nanomaterials, such as graphene, have been commercially mass produced. However, commercial nanomaterials on the market have good quality, and the existing characterization method cannot realize efficient and convenient detection of the nanomaterials in large batches.
Disclosure of Invention
The invention provides a method for detecting the density distribution state of a nano material, which is used for detecting the density of the nano material in a large batch with high efficiency.
The embodiment of the invention provides a method for detecting a density distribution state of a nano material, which comprises the following steps:
providing a detection container;
injecting a density gradient solution into the detection container; the density gradient solution comprises a plurality of density gradient solution layers which are stacked, and the solutes of each density gradient solution layer are the same; the solute concentration of each density gradient solution layer is sequentially increased along the direction from the free liquid level of the density gradient solution to the bottom surface of the detection container;
dispersing the nano material to be detected in the density gradient solution; the density of the largest part of the density in the nano material to be detected is ρ1, the density of the density gradient solution layer with the largest solute concentration in the density gradient solution is ρ2, the density of the density gradient solution layer with the smallest solute concentration in the density gradient solution is ρ3, and ρ3 < ρ1 < ρ2;
irradiating the density gradient solution dispersed with the nano material to be detected by using a detection light beam, and acquiring a first image of the whole formed by the detection container and the density gradient solution dispersed with the nano material to be detected to obtain a first image acquisition result M1;
and obtaining the density distribution state of the nano material to be detected according to the first image acquisition result.
Further, the step of irradiating the density gradient solution in which the nanomaterial to be detected is dispersed with a detection beam, performing a first image acquisition on the whole formed by the detection container and the density gradient solution in which the nanomaterial to be detected is dispersed, and obtaining a first image acquisition result M1 is performed in a darkroom.
Further, the obtaining the density distribution state of the nanomaterial to be detected according to the first image acquisition result includes:
removing noise information in the first image acquisition result to obtain a first image processing result;
and obtaining the density distribution state of the nano material to be detected based on the first image processing result.
Further, before dispersing the nanomaterial to be detected in the density gradient solution, the method comprises:
under the condition of no illumination, carrying out second image acquisition on the whole formed by the detection container and the density gradient solution to obtain a second image acquisition result M2;
irradiating the density gradient solution by using the detection light beam, and carrying out third image acquisition on the whole formed by the detection container and the density gradient solution to obtain a third image acquisition result M3;
the removing the noise information in the first image acquisition result to obtain a first image processing result comprises the following steps:
according to m4=m1- (M3-M2) -M2, M4 is taken as the first image processing result.
Further, the obtaining the density distribution state of the nanomaterial to be detected based on the first image processing result includes:
extracting regional image information corresponding to each density gradient solution layer from the first image processing result;
obtaining the change relation of gray values along with the density gradient solution layer concentration according to the regional image information corresponding to the density gradient solution;
obtaining the change relation of absorbance along with the concentration of the density gradient solution layer based on the change relation of the gray value along with the concentration of the density gradient solution layer;
and obtaining the density distribution state of the nano material to be detected based on the change relation of the absorbance along with the density gradient solution layer concentration.
Further, the irradiating the density gradient solution with the nano material to be detected dispersed therein with a detection beam, performing a first image acquisition on an entirety formed by the detection container and the density gradient solution with the nano material to be detected dispersed therein, to obtain a first image acquisition result M1, including:
and irradiating the density gradient solution dispersed with the nano material to be detected by using the detection light beam, and performing first image acquisition on the whole formed by the detection container and the density gradient solution dispersed with the nano material to be detected by using a continuous shooting method to obtain a first image acquisition result M1.
Further, the method comprises the steps of, the detection container is a transparent centrifuge tube or cuvette.
Further, the material of the detection container comprises quartz, polystyrene, polymethyl methacrylate or optical glass.
Further, the solute of the density gradient solution is cesium chloride or cesium fluoride.
Further, the detection beam is generated by a laser generator.
According to the method for detecting the density distribution state of the nano material, the nano material to be detected is separated by utilizing the density gradient solution, and the detection light beam is adopted to irradiate the whole formed by the detection container and the density gradient solution for dispersing the nano material to be detected, so that the first image acquisition result is acquired and obtained, the density distribution state of the nano material to be detected is obtained according to the first image acquisition result, the operation is simple and convenient when the density distribution of the nano material to be detected is obtained, the detection result is accurate, and the method can be applied to commercial detection application in a large scale.
Drawings
FIG. 1 is a flow chart of a method for detecting a density distribution state of a nanomaterial provided by an embodiment of the present invention;
FIG. 2 is a flow chart of another method for detecting a density distribution state of a nanomaterial according to an embodiment of the present invention;
FIG. 3 is a flow chart of detecting a noise signal provided by an embodiment of the present invention;
FIG. 4 is a flowchart of a method for detecting a density distribution state of a nanomaterial according to an embodiment of the present invention;
fig. 5 is a physical diagram of a cesium fluoride solution and a detection container when sedimentation equilibrium is not reached and containing graphene provided by an embodiment of the present invention;
fig. 6 is a physical diagram of a cesium fluoride solution containing graphene after sedimentation equilibrium and a detection container provided in an embodiment of the present invention;
fig. 7 is a schematic diagram of a distribution of gray values of graphene according to an embodiment of the present invention;
fig. 8 is a schematic diagram of distribution of optical density of graphene according to an embodiment of the present invention;
fig. 9 is a schematic diagram of distribution of graphene with different densities according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
The invention relates to a method for separating nano particles with different densities by using a stepped or continuous density gradient liquid according to different sedimentation rates, which is characterized in that the density distribution of the nano material is treated by using the principle of a density gradient sedimentation method, and the layering of the nano material in different density gradients can be realized by using the method. The density gradient sedimentation method is a special density gradient centrifugal separation technology and has the advantages of simple and convenient operation and the like.
After layering the nano material by using a density gradient sedimentation method, the physicochemical properties of the nano material are analyzed by using an optical detection technology. Specifically, the optical measurement technology for measuring the nano material with the density gradient separation realized and determining the density distribution of the nano material by analyzing the gray scale of an image based on an optical imaging method.
Based on the principle, the embodiment of the invention provides a method for detecting the density distribution state of a nano material.
Fig. 1 is a flowchart of a method for detecting a density distribution state of a nanomaterial according to an embodiment of the present invention. Specifically, referring to fig. 1, the detection method includes:
step 10, providing a detection container.
Specifically, the detection container is used for containing a density gradient solution and nano materials to be detected dispersed in the density gradient solution.
Step 20, injecting a density gradient solution into a detection container; the density gradient solution comprises a plurality of density gradient solution layers which are stacked, and the solutes of each density gradient solution layer are the same; the solute concentration of each density gradient solution layer increases in sequence along the direction from the free liquid surface of the density gradient solution to the bottom surface of the detection container.
Specifically, the plurality of density gradient solution layers in the density gradient solution have the same solute but different concentrations of the solute, thereby forming a concentration gradient, and when the nanomaterial to be detected is placed in the density gradient solution, the nanomaterial to be detected having different densities can be distributed in the different density gradient solution layers. In addition, if necessary, the uppermost density gradient solution layer in the density gradient solution may be pure water, that is, the density gradient solution layer forming the free liquid surface may not contain a solute. Generally, the density of the solute is often greater than that of pure water, and the density of the solution containing the solute is also greater than that of pure water, so that the density range of the density gradient solution can be wider by arranging a density gradient solution layer which does not contain the solute, and the density gradient solution can detect more nano materials to be detected with different densities.
Step 30, dispersing the nano material to be detected in a density gradient solution; the density of the greatest part of the density in the nano material to be detected is ρ1, the density of the density gradient solution layer with the greatest solute concentration in the density gradient solution is ρ2, and the density of the density gradient solution layer with the smallest solute concentration in the density gradient solution is ρ3, wherein ρ3 < ρ1 < ρ2.
Specifically, when the nano material to be detected is dispersed in the density gradient solution, the nano material to be detected can be placed on a free liquid surface; since the plurality of density gradient solution layers in the density gradient solution can be quickly mixed into a single solution with uniform density when the plurality of density gradient solution layers are subjected to severe vibration, the standard of light placement is that the plurality of density gradient solution layers are prevented from being mixed due to vibration when the nano material to be detected is placed. It should be understood that in the experiment, the lighter the operation when placing the nanomaterial to be detected, the less the influence is exerted on the plurality of density gradient solution layers, the more the plurality of density gradient solution layers can be maintained in a layered state for a relatively long time.
The embodiment adopts the principle of gravity to enable the nano material to be detected to settle and separate; in a general state, the same nanomaterial comprises a plurality of components with different densities, the sedimentation rates of the components with different densities in the density gradient solution are different, if the density of the detected nanomaterial is higher, the sedimentation rate in the density gradient solution is higher, and finally the position in the density gradient solution is relatively closer to the bottom of the detection container. Since it is impossible for the nanomaterial to be detected to reach into the layer of the density gradient solution having a density greater than that of the nanomaterial, the nanomaterial to be detected eventually stops at the upper layer of the density gradient solution having a slightly greater density than that of the nanomaterial. And after a period of time, the nanomaterial to be detected of each density settles and stabilizes in a specific density gradient solution layer. If the density of a large amount of nano materials to be detected is larger than that of the density gradient solution layer with the largest solute concentration in the density gradient solution, a large amount of nano materials to be detected are deposited in the density gradient solution layer with the largest solute concentration, so that accurate detection results are difficult to obtain. Therefore, in order to ensure that a certain amount of nano-material to be detected exists in each layer of the density gradient solution layer, the density of the density gradient solution layer with the smallest solute concentration in the density gradient solution can be close to but slightly smaller than the component with the smallest density in the nano-material to be detected, and meanwhile, the density of the density gradient solution layer with the smallest solute concentration in the density gradient solution layer is close to but slightly larger than the component with the largest density in the nano-material to be detected. Before detection, the density distribution of the nano material to be detected can be estimated by a method of estimation judgment, so that the density of each layer of density gradient solution layer in the density gradient solution is determined.
And step 40, irradiating the density gradient solution dispersed with the nano material to be detected by using a detection light beam, and carrying out first image acquisition on the whole formed by the detection container and the density gradient solution dispersed with the nano material to be detected to obtain a first image acquisition result M1.
Specifically, since the nanomaterial to be detected interacts with light, such as light absorption, the more nanomaterial to be detected in the density gradient solution layer, the stronger the nanomaterial to be detected absorbs light, and the less light passes through the density gradient solution layer. In order to obtain the distribution of the band-detected nanomaterial in each density gradient solution layer, a first image acquisition result M1 may be obtained from the acquired first image acquisition.
And 50, obtaining the density distribution state of the nano material to be detected according to the first image acquisition result.
Specifically, according to the first image acquisition result, the light intensity of each layer of density gradient solution layer can be obtained, so that the quantity of the nano material to be detected in each layer of density gradient solution layer can be further determined, and the density distribution of the nano material to be detected can be further determined.
According to the method for detecting the density distribution state of the nano material, the nano material to be detected is separated by utilizing the density gradient solution, and the detection light beam is adopted to irradiate the whole formed by the detection container and the density gradient solution in which the nano material to be detected is dispersed, so that the first image acquisition result is acquired and obtained, the density distribution state of the nano material to be detected is obtained according to the first image acquisition result, the operation is simple and convenient when the density distribution of the nano material to be detected is obtained, the detection result is accurate, and the method can be applied to commercial detection application in a large scale.
Optionally, the step of irradiating the density gradient solution in which the nanomaterial to be detected is dispersed with the detection beam, performing first image acquisition on the whole formed by the detection container and the density gradient solution in which the nanomaterial to be detected is dispersed, and obtaining a first image acquisition result M1 is performed in a darkroom.
Specifically, since only the detection light beam exists in the darkroom, the interference of other light sources on the detection result can be avoided to the greatest extent. The camera is understood to be a camera in which no other light beam is present than the detection beam. In addition, when the density gradient solution in which the nanomaterial to be detected is dispersed is irradiated with the detection beam, the propagation direction of the detection beam may be made parallel to the free liquid surface of the density gradient solution, and in order to realize detection of the nanomaterial to be detected in each layer of the density gradient solution layer, the detection beam may be made capable of being irradiated to each layer of the detection solution layer.
Fig. 2 is a flowchart of another method for detecting a density distribution state of a nanomaterial according to an embodiment of the present invention. Optionally, referring to fig. 2, step 50, obtaining a density distribution state of the nanomaterial to be detected according to the first image acquisition result, including;
and 51, removing noise information in the first image acquisition result to obtain a first image processing result.
And step 52, obtaining the density distribution state of the nano material to be detected based on the first image processing result.
Specifically, in the first image acquisition result, certain noise information is often still present, so in order to obtain a more accurate detection result, the noise information in the first image acquisition result can be removed, a first image processing result is obtained, and according to the first image processing result, a more accurate density distribution state of the nano material to be detected is obtained.
Fig. 3 is a flowchart of detecting a noise signal according to an embodiment of the present invention. Optionally, referring to fig. 3, before dispersing the nanomaterial to be detected in the density gradient solution in step 30, the method includes:
step 31, under the condition of no illumination, the whole formed by the detection container and the density gradient solution is subjected to secondary image acquisition, and obtaining a second image acquisition result M2.
Specifically, the camera may be used for image acquisition, and due to the limitation of the current camera technology level, when the camera acquires an image, the camera itself often has a certain dark current, which has a certain interference on the final detection result, so that the interference signal generated by the camera itself can be detected under the condition of no illumination in the darkroom, and when the noise signal is removed, the signal can be removed.
And step 32, irradiating the density gradient solution by using the detection light beam, and carrying out third image acquisition on the whole formed by the detection container and the density gradient solution to obtain a third image acquisition result M3.
Specifically, since the detection vessel and the density gradient solution also interact with the detection beam to some extent, interference due to the detection vessel and the density gradient solution can be removed when the noise signal is removed.
Optionally, in step 51, removing noise information in the first image acquisition result to obtain a first image processing result, including: according to m4=m1- (M3-M2) -M2, M4 is taken as the first image processing result.
It should be noted that, since the camera acquires image information under various conditions such as light and no light, there are interference signals due to the camera itself, the third image acquisition result M3 actually includes two main interference signals, one from the camera itself and the other from the detection container and the density gradient solution. M3-M2 in the above formula represents the interference signal simply caused by the detection vessel and the density gradient solution.
Fig. 4 is a flowchart of a method for detecting a density distribution state of a nanomaterial according to an embodiment of the present invention. Optionally, referring to fig. 4, step 52, based on the result of the first image processing, obtaining the density distribution state of the nanomaterial to be detected includes:
step 521, extracting region image information corresponding to each density gradient solution layer from the first image processing result.
Specifically, when the detection light beam penetrates through each layer of the density gradient solution in a direction parallel to the free liquid surface, since there is also a certain difference in the amount of the nanomaterial to be detected in each layer of the density gradient solution layer, the detection result corresponding to each layer of the density gradient solution layer will also be different in the first image processing result, and therefore, the region image information corresponding to each layer of the density gradient solution layer can be extracted first before determining the density distribution of the nanomaterial to be detected.
And 522, obtaining the change relation of the gray value along with the concentration of the density gradient solution layer according to the region image information corresponding to the density gradient solution.
Specifically, in a general state, in order to improve the accuracy of detection, a density gradient solution and a detection container which absorb light poorly are generally used; since the absorption of light by the density gradient solution is very weak, the difference in absorbance of the density gradient solution layers of different solute concentrations is substantially negligible. Since the density, the number and the like of the nano materials to be detected in each layer of the density gradient solution layer are different, the same detection light beam has different light intensity after penetrating the density gradient solution layer containing the nano materials to be detected with different concentrations and densities, and the light intensity is reflected in the first image processing result, the gray values corresponding to the different density gradient solution layers are different, and therefore, the difference of the gray values can be utilized to reflect the difference of the densities and the concentrations of the nano materials to be detected in the different density gradient solution layers.
Step 523, obtaining the change relation of absorbance along with the density gradient solution layer concentration based on the change relation of the gray value along with the density gradient solution layer concentration.
Specifically, since the absorption of the nanomaterial to be detected to light is caused by different gray values, the change relation of absorbance with the density gradient solution layer concentration can be judged according to the change relation of the gray values with the density gradient solution layer concentration.
And step 524, obtaining the density distribution state of the nano material to be detected based on the change relation of the absorbance along with the density gradient solution layer concentration.
Specifically, when the density gradient solution layer contains the nanomaterial to be detected, the density gradient solution layer mainly depends on the amount of light absorption of the nanomaterial to be detected in the density gradient solution layer, so that the density distribution state of the nanomaterial to be detected can be obtained based on the change relation of absorbance with the concentration of the density gradient solution layer.
Optionally, irradiating a density gradient solution in which a nanomaterial to be detected is dispersed with a detection beam, and performing a first image acquisition on an entire body formed by a detection container and the density gradient solution in which the nanomaterial to be detected is dispersed, to obtain a first image acquisition result M1, including: the method comprises the steps of irradiating a density gradient solution in which nano materials to be detected are dispersed by using a detection light beam, and carrying out first image acquisition on the whole formed by a detection container and the density gradient solution in which the nano materials to be detected are dispersed by using a continuous shooting method to obtain a first image acquisition result M1.
Specifically, taking a two-dimensional nanomaterial to be detected as an example, which is generally a sheet-like structure, the relationship between the two-dimensional nanomaterial to be detected and the detection beam may be different at different times under the influence of molecular motion in the density gradient solution. For example, at some point, there may be a majority of two-dimensional planes of the nanomaterial to be detected that are parallel to the detection beam, at which time a majority of the detection beam is transmitted through the density gradient solution, but at other points, there may also be a majority of two-dimensional planes of the nanomaterial to be detected that are perpendicular to the detection beam, at which time a majority of the detection beam is not transmitted through the density gradient solution. In order to avoid such a phenomenon, a method of continuous shooting may be adopted, and by processing and averaging a plurality of shooting results, interference to the detection result due to accidental factors may be avoided.
Alternatively, the detection vessel is a transparent centrifuge tube or cuvette.
Specifically, the centrifuge tube and the cuvette have the advantages of transparency, thinness, low cost and the like, and are excellent detection containers. Furthermore, it should be understood that the test receptacles herein include, but are not limited to, the centrifuge tubes and cuvettes described above.
Alternatively, the material of the detection vessel comprises quartz, polystyrene, polymethyl methacrylate or optical glass.
In the case of the detection container, it should be ensured that the interaction between the detection container and the light is relatively weak, and the selection of the material of the detection container is not particularly limited in this embodiment when this condition is satisfied.
Alternatively, the solute of the density gradient solution is cesium chloride or cesium fluoride.
Specifically, in order to obtain accurate and reliable detection results, solutes with weak light absorption can be selected to be prepared into a density gradient solution. In a general state, cesium chloride and cesium fluoride solutions have weak absorption effect on visible light, thus ensuring that the detection light beams can pass through. The cesium chloride and cesium fluoride have relatively high solubility in water, and can be arranged as a density gradient solution layer having a plurality of concentration gradients. For example, at 291.15K, cesium fluoride can reach 367g in water solubility, and cesium fluoride can be used as a medium for preparing density gradients, can be prepared in a wider density range than other solutes, and is suitable for forming suspension dispersion systems in solutions of more inorganic nano materials. In addition, cesium fluoride aqueous solutions are stable and inactive for most inorganic materials. The solubility of cesium fluoride in methanol is also high and reaches 191g at 288.15K. It should be understood that other solute configuration density gradient solutions may be selected in a state where the effect with light is weak, solubility is large, and the aqueous solution is stable, and the like, which is not particularly limited in this embodiment.
Optionally, the detection beam is generated by a laser generator.
Optionally, the laser generator can generate laser beams, and the laser beams have the advantages of high brightness, high directivity, high monochromaticity, high coherence and the like, and can be widely applied to the detection of nano materials. In addition, if the nanomaterial to be detected is graphene, cesium fluoride can be selected as a solute of the density gradient solution, and visible light with a wavelength of 633nm can be selected as a detection beam, so that absorption of the nanomaterial to be detected to the detection beam is reduced to the greatest extent.
For example, to help the reader understand the technical solution of the present invention, the present embodiment further provides a method for detecting graphene nanomaterial by using a laser beam with a wavelength of 633nm and cesium fluoride solution, where the detection method is described in detail below:
first, a basic model is established, specifically as follows:
the cesium fluoride aqueous solutions with different mass fractions are prepared for standby as density gradient solutions, and the density gradient can be ranging from 1.00g/ml to 2.70g/ml by adjusting the mass fraction (cesium fluoride concentration) by using the cesium fluoride aqueous solution. In the cuvette, gradient liquids with different densities are sequentially prepared into gradient (i.e. discontinuous) density gradient liquids from bottom to top according to the density from large to small by adopting an upper paving method. After the density gradient solution is formed, the graphene to be detected may be placed in a cuvette. Fig. 5 is a physical diagram of a cesium fluoride solution and a detection container when the sedimentation balance is not reached immediately after graphene is put in the cesium fluoride solution and the detection container provided by the embodiment of the invention, and fig. 6 is a physical diagram of a cesium fluoride solution and a detection container containing graphene after sedimentation balance provided by the embodiment of the invention. It should be noted that the sedimentation balance is understood to be that, after graphene is deposited in cesium fluoride solution for a period of time, different densities of graphene are distributed in cesium fluoride solution layers of corresponding concentrations, and at this time, the cesium fluoride solution containing graphene is in a relatively stable state.
After the nano material reaches sedimentation equilibrium in a certain layer of density gradient liquid, a stable and uniform state can be formed. Irrespective of scattering of the material, the luminous flux Φ transmitted through the cuvette t ＝Φ 0 -Φ a Wherein Φ is 0 For the luminous flux of the detection beam before incidence on the cuvette, phi a Is the light flux absorbed by the graphene nanomaterial. The light transmittance of the detection beam through the sample isIt follows that the light flux through the cuvette is related to the light absorption capacity of the material.
According to the lambert beer law,wherein A is i Represents the absorbance epsilon of graphene in the i-th layer gradient liquid i Represents the light absorption coefficient of the graphene, c i And (3) representing the concentration of graphene in the i-th layer gradient liquid, wherein the subscript i is a positive integer.
After the detection light beam is collected by a camera and transmitted through cesium fluoride solution containing graphene, gray level images of graphene, gray of which can be obtained by software such as ImageJ and the likeMetric value the method meets the following conditions:wherein I represents a current obtained by photoelectric conversion, I m Current, P, at light saturation of photosensitive element 0 The light power irradiated to the photosensitive element when the photosensitive element is saturated; sign []As a rounding function, e.g. [3.5 ]]=3; 256 is related to the length of the data storage byte, and in a general state, the gray value can be in the range of 0-255 for 256 total.
It is possible to arrange the above formula in order,combined formula (I)>The method can obtain the following steps: a=lg256-lgY. Then, a change curve of the material concentration-Distance (c-Distance) can be obtained from a=k·α·c and a=lg 256-lgY, and we use a density gradient liquid, i.e. the same gradient, and the material concentration is uniform within a certain Distance, so that the distribution of the material content over the vertical Distance, i.e. the density gradient distribution of the material, is obtained.
It should be noted that the maximum value of the material concentration for effective measurement of the gray valueI.e. response current +.>When I takes 0, the above formula has no practical meaning, and therefore, an appropriate method can be selected to solve this problem.
Further, in consideration of the error influence of the optical train and the photoelectric signal conversion transmission, a correction term as shown below is introduced: a=k (α·c+b); wherein A represents absorbance obtained based on gray value, namely OD value; k represents a proportionality coefficient; alpha represents the absorbance coefficient of graphene; c represents the gradient of cesium fluoride solution; and B, error correction term.
Thus far, the basic model is established, and an image processing and analysis method will be discussed below.
Analysis and data processing.
Taking the average of the continuous shooting of images, i.e. the statistical average of absorbance based on gray values, then
Wherein,the statistical average of the OD values of n times of continuous shooting of images of the density gradient liquid without a sample and with the sample is adopted, and the value of n can be 20-30 times.
In the image information processing stage, optical information integration is carried out on each continuous shooting image through corresponding software, and the integrated density gradient liquid image information without sample is called M 0 The density gradient liquid image information of the sample is called M 1 The final image information is called M'. According to M' =M 1 -M 0 And performing image information processing to obtain a final image information result.
Formula M' =m 1 -M 0 Is embodied as
That is, the absorbance of the gray-scale image after the background is deducted and the statistical average is performed; the physical meaning of A is the statistical average of the light absorption of the material, which is reflected by taking average by continuous shooting to eliminate the possible flash phenomenon of the nano material.
FIG. 7 is a graph showing the gray value distribution of graphene according to an embodiment of the present inventionFig. 8 is a schematic diagram of distribution of optical density of graphene according to an embodiment of the present invention. Referring to fig. 7 and 8, the abscissa in fig. 7 represents the density of graphene, the ordinate represents the gray value of the nanomaterial to be detected obtained by detection, and the abscissa in fig. 8 represents the density of graphene, and the ordinate represents the optical density of the nanomaterial to be detected obtained by detection. In addition, the higher the light absorption density, the darker the image, i.e., the more the detection beam is absorbed by graphene, and the more the graphene in the density gradient solution. Therefore, as can be seen from comparing fig. 7 and 8, where the gradation value in fig. 7 is large, the optical density in fig. 8 is correspondingly smaller. As can be seen from FIG. 8, the density was 1.3g/cm 3 The amount of graphene is the largest from side to side.
Fig. 9 is a schematic diagram of distribution of graphene with different densities according to an embodiment of the present invention. Optionally, referring to fig. 9, after the density of graphene is obtained by using the method for detecting the density distribution state of the nanomaterial provided in this embodiment, the detection result may be drawn into a histogram, so as to obtain a clearer and clearer detection result. As can be seen from FIG. 9, the density of 72.73% graphene is 1.3g/cm 3 Left and right.
The embodiment provides a new measuring means for the commercial nanomaterial detection method, and has important significance for commercial nanomaterial quality detection, nanomaterial quantitative separation and purification and the like.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (6)
1. The method for detecting the density distribution state of the nano material is characterized by comprising the following steps of:
providing a detection container;
injecting a density gradient solution into the detection container; the density gradient solution comprises a plurality of density gradient solution layers which are stacked, and the solutes of each density gradient solution layer are the same; the solute concentration of each density gradient solution layer is sequentially increased along the direction from the free liquid level of the density gradient solution to the bottom surface of the detection container;
dispersing the nano material to be detected in the density gradient solution; the density of the largest part of the density in the nano material to be detected is ρ1, the density of the density gradient solution layer with the largest solute concentration in the density gradient solution is ρ2, the density of the density gradient solution layer with the smallest solute concentration in the density gradient solution is ρ3, and ρ3 < ρ1 < ρ2;
irradiating the density gradient solution in which the nano material to be detected is dispersed by using a detection light beam, and performing first image acquisition on the whole formed by the detection container and the density gradient solution in which the nano material to be detected is dispersed by using a continuous shooting method to obtain a first image acquisition result M1; the step of obtaining the first image acquisition result M1 is performed in a darkroom, wherein only the detection light beam exists in the darkroom, and the propagation direction of the detection light beam is parallel to the free liquid level of the density gradient solution, so that the detection light beam can irradiate each layer of detection solution layer, and the nano material to be detected in each layer of density gradient solution layer is detected;
removing noise information in the first image acquisition result to obtain a first image processing result;
extracting regional image information corresponding to each density gradient solution layer according to the first image processing result;
obtaining the change relation of gray values along with the density gradient solution layer concentration according to the regional image information corresponding to the density gradient solution;
converting the gray value into absorbance based on the change relation of the gray value with the density gradient solution layer concentration, and introducing an error correction term to obtain the change relation of the absorbance with the density gradient solution layer concentration; the absorbance and the gray value satisfy:
A＝lg256-lgY；
wherein A is the absorbance and Y is the gray value;
and obtaining the density distribution state of the nano material to be detected based on the change relation of the absorbance along with the density gradient solution layer concentration.
2. The method for detecting a density distribution state of a nanomaterial according to claim 1, characterized in that,
prior to said dispersing the nanomaterial to be detected in the density gradient solution, comprising:
under the condition of no illumination, carrying out second image acquisition on the whole formed by the detection container and the density gradient solution to obtain a second image acquisition result M2;
irradiating the density gradient solution by using the detection light beam, and carrying out third image acquisition on the whole formed by the detection container and the density gradient solution to obtain a third image acquisition result M3;
the removing the noise information in the first image acquisition result to obtain a first image processing result comprises the following steps:
according to m4=m1- (M3-M2) -M2, M4 is taken as the first image processing result.
3. The method for detecting a density distribution state of a nanomaterial according to claim 1, characterized in that,
the detection container is a transparent centrifuge tube or cuvette.
4. The method for detecting a density distribution state of a nanomaterial according to claim 3, wherein the material of the detection container comprises quartz, polystyrene, polymethyl methacrylate, or optical glass.
5. The method for detecting a density distribution state of a nanomaterial according to claim 1, wherein the solute of the density gradient solution is cesium chloride or cesium fluoride.
6. The method for detecting a density distribution state of a nanomaterial according to claim 1, wherein the detection beam is generated by a laser generator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910019103.5A CN111426641B (en) | 2019-01-09 | 2019-01-09 | Method for detecting density distribution state of nano material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910019103.5A CN111426641B (en) | 2019-01-09 | 2019-01-09 | Method for detecting density distribution state of nano material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111426641A CN111426641A (en) | 2020-07-17 |
| CN111426641B true CN111426641B (en) | 2024-04-09 |
Family
ID=71546034
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910019103.5A Active CN111426641B (en) | 2019-01-09 | 2019-01-09 | Method for detecting density distribution state of nano material |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111426641B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117585683A (en) * | 2023-03-22 | 2024-02-23 | 蚌埠学院 | Method for precisely separating nano-micro powder particles |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6593145B2 (en) * | 2001-03-07 | 2003-07-15 | The Texas A&M University System | Density gradient solutions of metal ion chelate complexes |
| JP2012145430A (en) * | 2011-01-12 | 2012-08-02 | Japan Aerospace Exploration Agency | Method and apparatus for visualizing density gradient |
| CN102890040A (en) * | 2012-10-17 | 2013-01-23 | 云南省烟草农业科学研究院 | Method for measuring pollen density by improved density gradient centrifugation method |
| CN104089851A (en) * | 2014-07-10 | 2014-10-08 | 中国工程物理研究院化工材料研究所 | Method for testing continuous distribution of crystal density based on density gradient light transmittance method |
| CN104091338A (en) * | 2014-07-10 | 2014-10-08 | 中国工程物理研究院化工材料研究所 | Method for testing crystalline density continuous distribution based on density gradient image processing method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9802818B2 (en) * | 2011-05-03 | 2017-10-31 | Northwestern University | Sorting process of nanoparticles and applications of same |
-
2019
- 2019-01-09 CN CN201910019103.5A patent/CN111426641B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6593145B2 (en) * | 2001-03-07 | 2003-07-15 | The Texas A&M University System | Density gradient solutions of metal ion chelate complexes |
| JP2012145430A (en) * | 2011-01-12 | 2012-08-02 | Japan Aerospace Exploration Agency | Method and apparatus for visualizing density gradient |
| CN102890040A (en) * | 2012-10-17 | 2013-01-23 | 云南省烟草农业科学研究院 | Method for measuring pollen density by improved density gradient centrifugation method |
| CN104089851A (en) * | 2014-07-10 | 2014-10-08 | 中国工程物理研究院化工材料研究所 | Method for testing continuous distribution of crystal density based on density gradient light transmittance method |
| CN104091338A (en) * | 2014-07-10 | 2014-10-08 | 中国工程物理研究院化工材料研究所 | Method for testing crystalline density continuous distribution based on density gradient image processing method |
Non-Patent Citations (2)
| Title |
|---|
| 纳米材料的密度梯度离心分离的研究进展(上);李鹏松等;《石油化工》;20160615(第06期);全文 * |
| 颗粒密度及密度分布定量表征技术;徐瑞娟等;《中国化学会第30届学术年会》;20160701;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111426641A (en) | 2020-07-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Reynolds et al. | Measurements and characterization of particle size distributions in coastal waters | |
| Hönisch et al. | The influence of symbiont photosynthesis on the boron isotopic composition of foraminifera shells | |
| Jerlov | Marine optics | |
| AU2019272066B2 (en) | Total protein measurement using whole blood refractometry | |
| Brown et al. | On the challenges of measuring interfacial characteristics of three‐phase fluid flow with x‐ray microtomography | |
| RU2014152326A (en) | SYSTEMS AND METHODS FOR DETECTING PARTICLES IN USEFUL AGENT | |
| CN111426641B (en) | Method for detecting density distribution state of nano material | |
| Giering et al. | The interpretation of particle size, shape, and carbon flux of marine particle images is strongly affected by the choice of particle detection algorithm | |
| Trentesaux et al. | Carbonate grain-size distribution in hemipelagic sediments from a laser particle sizer | |
| Price et al. | Determining the absolute abundance of dinoflagellate cysts in recent marine sediments III: Identifying the source of Lycopodium loss during palynological processing and further testing of the Lycopodium marker-grain method | |
| Stavn et al. | Biogeo-optics: particle optical properties and the partitioning of the spectral scattering coefficient of ocean waters | |
| Stavn et al. | Correcting the errors from variable sea salt retention and water of hydration in loss on ignition analysis: Implications for studies of estuarine and coastal waters | |
| Behrens | Use of the Goldberg refractometer as a salinometer for biological and geological field work | |
| Näykki et al. | Validation of a new measuring system for water turbidity field measurements | |
| Saliu et al. | A baseline assessment of the relationship between microplastics and plasticizers in sediment samples collected from the Barcelona continental shelf | |
| Kirk | Relationship between nephelometric turbidity and scattering coefficients in certain Australian waters | |
| US9914075B1 (en) | Turbidity measuring device | |
| JP4894491B2 (en) | Radiation transmission measuring apparatus and radiation transmission measuring method | |
| Sukigara et al. | Sinking dynamics of particulate matter in the subarctic and subtropical regions of the western North Pacific | |
| US20180106717A1 (en) | Measuring a size distribution of nucleic acid molecules in a sample | |
| CN104568848B (en) | A kind of surface plasma chip and preparation method thereof for biosensor | |
| WO2017109068A1 (en) | A method and a system for determinations of cell suspensions | |
| Barrett | Nonintrusive optical measurements of turbulence and mixing in a stably stratified fluid | |
| Antonenkov | The suspension characteristics determining method with the help of images processing | |
| Klyuvitkin et al. | Vertical particle fluxes in the Barents Sea on materials of short-time operation of automatic deep-water sedimentary observatory |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |