Glass bead standard sample combination and application thereof in method for measuring sensitivity of laser diffraction particle size analyzer

Abstract

The invention provides a glass bead standard sample combination applied to laser diffraction particle size analysis and a method for measuring the sensitivity of a laser diffraction particle size analyzer by adopting the standard sample combination. The inventor makes a large number of attempts, the specific glass bead standard sample combination obtained by adopting different grading technology methods and the sensitivity of the laser diffraction method particle size analyzer measured by adopting the specific combination have the advantages that compared with a single standard sample sold in the market and a conventional sensitivity measurement method, the sensitivity of the laser diffraction method particle size analyzer measured by adopting the specific combination is greatly improved; according to the standard sample combination and the measurement method, a to-be-measured actual sample can be simulated more truly, and the sensitivity value range of an instrument under the condition that the particle size distribution of the standard sample is similar to that of the actual sample can be measured.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical analysis, and particularly relates to a glass microbead standard sample combination applied to laser diffraction particle size analysis, and a method for measuring the sensitivity of a laser diffraction particle size analyzer using the standard sample combination. Background Art

[0002] Laser diffraction is a method for determining the particle size distribution by measuring the intensity of scattered light at different angles when a laser beam passes through a dispersed particle sample. Since its inception, this method has undergone decades of development and application and has become more mature. It has become the irreplaceable mainstream of particle size analysis in the 21st century and is widely used in the fields of pharmaceuticals, chemicals, food, materials, and the environment.

[0003] Currently, commercial laser diffraction particle size analyzers can measure particles with diameters ranging from tens of nanometers to several millimeters, covering particle size ranges of multiple orders of magnitude, including nanometers, submicrons, and microns. The measurement speed is fast, and the test time is independent of the sample particle size distribution. A typical test process is generally less than one minute. Each measurement can sample a large number of particles and scan the sample multiple times, and the test results are highly repeatable. There are many types of sampling methods, which can be applied to various types of samples.

[0004] Laser diffraction method The principle of particle size analysis by laser diffraction method is based on the diffraction and scattering of light. The particle size distribution is estimated by measuring the intensity distribution of scattered light at different angles generated when the laser passes through the dispersed particle sample.

[0005] However, due to the limitations of the measurement principle, laser diffraction particle size analysis is not a high-resolution, high-sensitivity measurement method (Literature: Accuracy of laser diffraction particle size analysis and its comparison with image analysis results, Xu Xiqing et al., Instrumentation and Analysis Monitoring. 2020(04)P.26-32).

[0006] Definition of resolution (also known as resolving power) for particle size analysis using laser diffraction: The resolution of a particle size distribution describes the ability of a measuring device to distinguish between adjacent particle sizes. Therefore, higher resolution makes it easier to distinguish particles of different sizes and obtain the correct particle size distribution width. (GB / T 19077-2024 Particle Size Analysis - Laser Diffraction Method, 5.6.1 General Principles). The resolution of the maximum particle size is limited by the limited optical detector with small scattering angles, while the resolution of the minimum particle size is limited by the ability to receive the weak scattered signals from these particles. (GB / T 19077-2024 Particle Size Analysis - Laser Diffraction Method, 5.6.2 Resolution)

[0007] Definition of sensitivity in laser diffraction particle size analysis: The sensitivity of a particle size distribution describes the ability of a measuring device to distinguish small changes in the number of particles within a given size fraction. Therefore, higher sensitivity yields a better representation of the size distribution of mixed particles and the ability to identify small numbers of extremely large and small particles within the distribution. (GB / T.19077-2024 Particle Size Analysis, Laser Diffraction Method, 5.6.1 General Principles). Due to the scattering characteristics of particles of different sizes, limitations on the number and angular range of some detectors, and limitations in data inversion, sensitivity is not uniform across the covered particle size range. (GB / T19077-2024 Particle Size Analysis, Laser Diffraction Method, 5.6.3 Sensitivity and Result Variability)

[0008] However, the above-mentioned resolution and sensitivity are strongly dependent on the following factors: the number, position, geometry and area of ​​the detector units; the number, width and generation method of the particle size fractions in the particle size distribution; the application of appropriate optical models; the fine structure in the measured scattering pattern, especially the particle size analysis of narrow distributions; the actual particle size range and distribution width of the particulate material; the smoothing and regularization processing methods used in the light intensity signal and / or deconvolution program; the signal-to-noise ratio, etc. All of these factors have a significant impact on the resolution and sensitivity, so there is no simple procedure or measure to obtain the resolution and sensitivity of the measuring device. If the above-mentioned items of the instrument are comparable to some extent, if there is a need for quality control, the actual values ​​of the resolution and sensitivity can be determined using a mixture of known components. (GB / T19077-2024 Particle Size Analysis Laser Diffraction Method 5.6.1 General)

[0009] Therefore, there is an urgent need in the art to provide a method that can measure the resolution and sensitivity of the existing laser diffraction particle size analysis method, which can be used for quality control of particle size analysis or reliability evaluation of measurement results. Summary of the Invention

[0010] In order to solve the above problems, the first aspect of the present invention provides a standard sample combination for particle size analysis using a laser diffraction method, wherein the standard sample combination comprises a first standard sample, a second standard sample, and a third standard sample;

[0011] The first, second and third standard samples are obtained by screening from the same batch of granular raw materials;

[0012] The particle raw material is glass microspheres, and the particle size distribution range is 1 μm to 200 μm, and each individual particle satisfies the characteristics of sphericity greater than 99%, smooth particle surface, refractive index of 1.500 to 2.200, and optical uniformity inside the particle;

[0013] The particle size of the first standard sample is in the range of 1 μm to 22 μm, and the volume median diameter D of the first standard sample is50 Falling within the range of 10.35 to 12.65 μm;

[0014] The particle size of the second standard sample is in the range of 25 μm to 50 μm, and the volume median diameter D of the second standard sample is 50 Falling within the range of 33.75 to 41.25 μm;

[0015] The particle size of the third standard sample is in the range of 80 μm to 200 μm, and the volume median diameter D of the third standard sample is 50 Falling into the range of 126 to 154 μm;

[0016] The particle size distributions of the first, second and third standard samples all meet the following conditions: a) unimodal dispersion characteristics; b) volume median diameter D 50 and volume average particle size D MEAN , volume peak diameter D MODE The deviation value is ±5% of the volume median diameter D 50 c) the ratio of the volume characteristic particle diameter D90 to D10 falls within the range of 1.4 to 3.

[0017] Preferably, the refractive index of the particle raw material is 1.900 to 2.200.

[0018] Preferably, the optical uniformity inside the particles satisfies the characteristic that the devitrification rate is below 1%.

[0019] In one or more embodiments of the present application, the standard sample combination is obtained by the following steps:

[0020] Step I) obtaining a granular raw material having a refractive index of 1.900 to 2.200, a devitrification rate of less than 1%, and a particle size distribution range of 1 μm to 200 μm; and then screening the granular raw material with a sphericity greater than 99% through centrifugal sorting technology;

[0021] Step II) For the same batch of granular raw materials obtained in step I), sample particles with particle sizes falling within the ranges of 80 μm to 200 μm, 25 μm to 50 μm, and 1 μm to 22 μm are screened out by screening and classification technology and airflow classification technology, respectively;

[0022] Step III) further classifies the sample particles obtained in step II) by sedimentation classification fine separation technology to obtain the first, second and third standard samples.

[0023] A second aspect of the present invention provides a method for measuring the sensitivity of a laser diffraction particle size analyzer, wherein the method uses the above-mentioned standard sample combination.

[0024] In one or more embodiments of the present application, the first standard sample and the second standard sample are mixed in different weight ratios using a 1 / 10,000 balance, and the total weight of the mixture is 0.0001 to 50 g. After dispersion in an aqueous medium, the particle size distribution is measured using the laser diffraction particle size analyzer.

[0025] Step 1) The two are first mixed in a weight ratio of 1:1, and the resolution is qualitatively determined by measuring whether the obtained frequency distribution curve shows two independent and non-overlapping peaks;

[0026] If the result of step 2a) is "yes", the weight percentage of the second standard sample is gradually reduced until the volume frequency of the peak of the second standard sample in the measured frequency distribution curve reaches the noise level. The weight percentage of the second standard sample corresponding to the last mixed sample is the first detection limit; and

[0027] Step 2b) If the result is "yes," gradually reduce the weight percentage of the first standard sample until the volume frequency of the peak of the first standard sample in the measured frequency distribution curve reaches the noise level. The weight percentage of the first standard sample corresponding to the final mixed sample is the second detection limit;

[0028] The laser diffraction particle size analyzer has a sensitivity range for measuring particle sizes of 1 μm to 50 μm between the first detection limit and the second detection limit.

[0029] In one or more embodiments of the present application, the volume median diameter D50 values ​​of the first standard sample and the second standard sample are measured respectively; the volume peak diameters D50 obtained in step 2a) and step 2b) are converted to MODE The corresponding volume median diameter D 50 The values ​​are compared to obtain the relative error range.

[0030] In one or more embodiments of the present application, the first, second, and third standard samples are mixed in different weight ratios using a 1 / 10,000 balance, and the total weight of the mixture is 0.0001 to 50 g. After dispersion in an aqueous medium, the particle size distribution is measured using the laser diffraction particle size analyzer.

[0031] Step 1') The three components are first mixed in a weight ratio of 1:1:1, and the resolution is qualitatively determined by measuring whether the obtained frequency distribution curve exhibits three independent and non-overlapping peaks;

[0032] If the result of step 2a') is "yes", the weight percentages of the first standard sample and the third standard sample are gradually and synchronously reduced until the volume frequency of the peak of the first standard sample or the third standard sample in the measured frequency distribution curve approaches the noise level; the weight percentage of the first standard sample or the third standard sample corresponding to the last mixed sample is the third detection limit; and

[0033] If the result of step 2b') is "yes", the weight percentage of the second standard sample is gradually reduced until the volume frequency of the peak of the second standard sample in the measured frequency distribution curve approaches the noise level. The weight percentage of the second standard sample corresponding to the last mixed sample is the fourth detection limit;

[0034] The sensitivity range of the laser diffraction particle size analyzer for measuring particle sizes of 1 μm to 200 μm is between the third detection limit and the fourth detection limit.

[0035] In one or more embodiments of the present application, the volume median diameter D of the first standard sample, the second standard sample, and the third standard sample are measured respectively. 50 value;

[0036] The volume peak diameters D obtained in step 2a') and step 2b') are MODE The corresponding volume median diameter D 50 The values ​​are compared to obtain the relative error range.

[0037] In one or more embodiments of the present application, the aqueous medium is ultrapure water.

[0038] Preferably, the light obscuration measured by the laser diffraction particle size analyzer falls within the range of 10% to 20%.

[0039] Preferably, in the operation of the laser diffraction particle size analyzer, the background measurement duration is 0 seconds to 30 seconds, and the sample measurement duration is 0 seconds to 30 seconds.

[0040] The present invention provides a glass microbead standard sample combination for use in laser diffraction particle size analysis, and a method for measuring the sensitivity of a laser diffraction particle size analyzer using the standard sample combination. The inventors have made numerous attempts and employed different classification techniques to obtain the specific glass microbead standard sample combination of the present invention, as well as the sensitivity of a laser diffraction particle size analyzer using the specific combination. Compared with single standard samples and conventional sensitivity measurement methods available on the market, the standard sample combination and the measurement method of the present invention can more realistically simulate actual samples to be measured, and can measure the sensitivity value range of the instrument under conditions close to the particle size distribution of the actual samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1-Figure 3 These are the volume frequency distribution curves of the first, second and third standard samples obtained in Example 1 of the present application, measured by a laser diffraction particle size analyzer;

[0042] Figure 4 This is a volume frequency distribution curve obtained by measuring step 1) of Example 2 of the present application;

[0043] Figure 5 This is a volume frequency distribution curve obtained by measuring in step 2a) of Example 2 of the present application;

[0044] Figure 6 This is a volume frequency distribution curve obtained by measuring in step 2b) of Example 2 of the present application;

[0045] Figure 7 This is a volume frequency distribution curve obtained by measuring in step 1′) of Example 3 of the present application;

[0046] Figure 8 This is a volume frequency distribution curve obtained by measuring in step 2a') of Example 3 of the present application;

[0047] Figure 9 This is a volume frequency distribution curve obtained by measuring in step 2b') of Example 3 of the present application;

[0048] Figure 10-14 They are the volume frequency distribution curves obtained by measuring the five gradient samples in Comparative Example 1;

[0049] Figure 15 This is a volume frequency distribution curve obtained by measuring the sample of Comparative Example 2. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and examples, but the present invention is not limited to the scope of the examples. The process parameters not specified in the examples of this application can be carried out according to conventional methods, and the raw materials used can be obtained through commercial channels.

[0051] Example 1

[0052] The standard sample combination used for laser diffraction particle size analysis in Example 1 was obtained by the following steps.

[0053] Step I)

[0054] Source of particle raw materials: high refractive index glass microsphere products (product model nD = 1.93) purchased from Jiangxi Shengfulai Optical Technology Co., Ltd., with a refractive index of 1.93, a devitrification rate of less than 1% (satisfying the optical uniformity characteristics of the particles inside), and a particle size distribution range of 1 μm to 200 μm, which meets the characteristics of smooth particle surface.

[0055] For the purchased granular raw materials, firstly, the granular raw materials with a sphericity greater than 99% are screened through centrifugal sorting technology.

[0056] Step II)

[0057] The following operations are then performed based on the same batch of granular raw materials obtained in step 1):

[0058] First, the screening and classification technology is used to screen out sample particles with particle sizes falling into the ranges of 80μm to 200μm, 25μm to 50μm, and 1μm to 22μm from the same batch of granular raw materials.

[0059] The sample particles screened out above are further classified by airflow classification technology, and sample particles with particle sizes falling into the ranges of 80 μm to 200 μm, 25 μm to 50 μm, and 1 μm to 22 μm are screened out.

[0060] Step III)

[0061] Finally, the sample particles obtained in step II) are further classified by sedimentation classification fine separation technology to obtain the first, second and third standard samples.

[0062] In a specific embodiment of the present invention, the particle size of the first standard sample obtained is in the range of 1 μm to 22 μm, and the volume median diameter D of the first standard sample is 50 falls within the range of 10.35 to 12.65 μm; the particle size range of the second standard sample is 25 μm to 50 μm, and the volume median diameter D of the second standard sample is 50 falls within the range of 33.75 to 41.25 μm; the particle size range of the third standard sample is 80 μm to 200 μm, and the volume median diameter D of the third standard sample is 50 Falling into the range of 126~154μm;.

[0063] In a specific embodiment of the present invention, the particle size distributions of the first, second and third standard samples obtained all meet the following conditions: a) the characteristics of unimodal dispersion; b) the volume median diameter D 50 and volume average particle size D MEAN , volume peak diameter D MODE The deviation value is ±5% of the median diameter D 50c) the ratio of the volume characteristic particle diameter D90 to D10 falls within the range of 1.4 to 3.

[0064] Specifically, in this embodiment, the laser diffraction particle size analysis results of the first, second and third standard samples obtained (using a laser diffraction particle size analyzer model MS3000 purchased from MALVERN, which is used hereinafter) are shown in FIG. Figure 1-Figure 3 .

[0065] from Figure 1-3 It can be seen that the first, second and third standard samples obtained in Example 1 of the present application all meet the characteristics of unimodal dispersion; Figure 1-3 The particle size data shown in Table 1 below were obtained.

[0066] Table 1

[0067]

[0068] Example 2

[0069] The standard sample combination obtained in Example 1 was used to measure the sensitivity of a laser diffraction particle size analyzer (using a laser diffraction particle size analyzer model MS3000 purchased from MALVERN).

[0070] In some specific embodiments of the present application, a 1 / 10,000 balance is used for weighing, and the obtained first standard sample and the second standard sample are mixed in different weight ratios, and the total weight after mixing is 0.0001 to 50 g. After being dispersed in an aqueous medium, the particle size distribution is measured using the above-mentioned laser diffraction particle size analyzer.

[0071] Specifically in this embodiment 2, ultrapure water is used as the aqueous medium for dispersion.

[0072] In some specific embodiments of the present application, regarding the detection parameters of the laser diffraction particle size analyzer, the measured shading falls within the range of 10% to 20%, the background measurement duration is 0 seconds to 30 seconds, and the sample measurement duration is 0 seconds to 30 seconds.

[0073] Specifically, in this embodiment 2, regarding the detection parameters of the laser diffraction particle size analyzer, the measured light shielding degree is about 10-20%, the background measurement duration is 10 seconds, and the sample measurement duration is 10 seconds.

[0074] The process for measuring sensitivity uses the following steps:

[0075] In some specific embodiments of the present application, step 1) firstly mixes the two in a weight ratio of 1:1, and measures whether the obtained frequency distribution curve shows two independent and non-overlapping peaks to qualitatively determine the resolution;

[0076] Specifically in this embodiment 2, the weight ratio of the first standard sample to the second standard sample is 1:1, and the total weight after the two are mixed is 0.2g. The measurement results (frequency distribution curve) are as follows: Figure 4 As shown in the figure, two independent and non-overlapping peaks are clearly shown. Therefore, it can be qualitatively judged that the laser diffraction particle size analyzer used in this embodiment has better resolution and is capable of distinguishing small particle sizes (1μm to 22μm) and medium particle sizes (25μm to 50μm).

[0077] If two independent and non-overlapping peaks are present in the frequency distribution curve, ie, the above result is "yes", the following step of measuring sensitivity is performed.

[0078] In some specific embodiments of the present application, if the result of step 2a) is "yes", the weight percentage of the second standard sample is gradually reduced until the volume frequency of the peak of the second standard sample in the measured frequency distribution curve reaches the noise level. The weight percentage of the second standard sample corresponding to the last mixed sample is the first detection limit.

[0079] Specifically in this embodiment, the shading rate is controlled at 10%-20%, and the weight percentage of the second standard sample is gradually reduced; specifically, the weight ratio of the first standard sample (abbreviated as: first) to the second standard sample (abbreviated as: second) changes in a gradient of 1:1, 4:1, 9:1, 19:1, 29:1, 49:1, 99:1...

[0080] The test results are shown in Table 2 below.

[0081] Table 2

[0082]

[0083] The "peak diameter relative error 1" in Table 2 refers to the volume peak diameter D corresponding to the peak area 1. MODE The volume median diameter D of the first standard sample 50 The relative error of the value (10.4μm).

[0084] The "peak diameter relative error 2" in Table 2 refers to the volume peak diameter D corresponding to the peak area 2. MODE The volume median diameter D of the second standard sample 50 The relative error of the value (37.5μm) is

[0085] In this embodiment, when the weight ratio of the two is 49:1, the frequency distribution curve obtained by measurement is as follows: Figure 5 shown; see Figure 5As can be seen from the data in Table 2, the volume frequency of the peak of the second standard sample in this experiment essentially reached the noise level (peak area 2 was 2.63%). When the applicant continued with the next gradient, controlling the weight ratio of the first standard sample to the second standard sample at 99:1, the measured frequency distribution curve showed other significant interfering noise signals, and therefore the results of this gradient were not considered.

[0086] Therefore, when the weight ratio of the two is 49:1, the weight percentage of the second standard sample in the mixed sample (2.0%) is the first detection limit.

[0087] In some specific embodiments of the present application, if the result of step 2b) is "yes", the weight percentage of the first standard sample is gradually reduced until the volume frequency of the peak of the first standard sample in the measured frequency distribution curve reaches the noise level. The weight percentage of the first standard sample corresponding to the last mixed sample is the second detection limit.

[0088] Specifically in this embodiment, the shading rate is controlled at 10%-20%, and the weight percentage of the first standard sample is gradually reduced; specifically, the weight ratio of the first standard sample to the second standard sample changes in a gradient of 1:1, 1:4, 1:29:1:49...

[0089] The test results are shown in Table 3 below.

[0090] Table 3

[0091]

[0092] The "peak diameter relative error 1" in Table 3 refers to the volume peak diameter D corresponding to the peak area 1. MODE The volume median diameter D of the first standard sample 50 The relative error of the value (10.4μm).

[0093] The "peak diameter relative error 2" in Table 3 refers to the volume peak diameter D corresponding to the peak area 2. MODE The volume median diameter D of the second standard sample 50 The relative error of the value (37.5μm) is

[0094] When the weight ratio of the two is 1:29, the frequency distribution curve obtained by measurement is as follows Figure 6 shown; see Figure 6 From the data in Table 3, it can be seen that the volume frequency of the peak of the first standard sample has basically reached the noise level (peak area 1 is 3.16%).

[0095] When continuing with the next gradient, when the applicant controlled the weight ratio of the first standard sample to the second standard sample at 1:49, other obvious interference noise signals appeared in the frequency distribution curve obtained by measurement, so the gradient result was not considered.

[0096] Therefore, when the weight ratio of the two is 1:29, the weight percentage of the first standard sample in the mixed sample (3.33%) is the second detection limit.

[0097] The laser diffraction particle size analyzer has a sensitivity range for measuring particle sizes of 1 μm to 50 μm between the first detection limit and the second detection limit.

[0098] Specifically in this embodiment, through the above measurements, it can be concluded that the sensitivity range of the laser diffraction particle size analyzer used in this embodiment for measuring particle sizes of 1 μm to 50 μm is between 2.0% and 3.33%.

[0099] Example 3

[0100] The standard sample combination obtained in Example 1 was used to measure the sensitivity of a laser diffraction particle size analyzer (using a laser diffraction particle size analyzer model MS3000 purchased from MALVERN).

[0101] In some specific embodiments of the present application, the first, second, and third standard samples are mixed in different weight ratios using a 1 / 10,000 balance, and the total weight of the mixture is 0.0001 to 50 g. After dispersion in an aqueous medium, the particle size distribution is measured using the laser diffraction particle size analyzer.

[0102] Specifically, in this embodiment 3, ultrapure water is used as the aqueous medium for dispersion.

[0103] Specifically, in this embodiment 3, regarding the detection parameters of the laser diffraction particle size analyzer, the measured light shielding degree is about 10-20%, the background measurement duration is 10 seconds, and the sample measurement duration is 10 seconds.

[0104] The process for measuring sensitivity uses the following steps:

[0105] In some specific embodiments of the present application, in step 1'), the three are first mixed in a weight ratio of 1:1:1 to measure whether the obtained frequency distribution curve shows three independent and non-overlapping peaks to qualitatively determine the resolution.

[0106] Specifically in this embodiment 3, the weight ratio of the first, second and third standard samples is 1:1:1, and the measurement results (frequency distribution curve) are as follows: Figure 7As shown in the figure, three independent and non-overlapping peaks are clearly shown. Therefore, it can be qualitatively judged that the laser diffraction particle size analyzer used in this embodiment has better resolution and is capable of distinguishing smaller particle sizes (1μm to 22μm), medium particle sizes (25μm to 50μm) and larger particle sizes (80μm to 200μm).

[0107] If three independent and non-overlapping peaks are present in the frequency distribution curve, ie, the above result is "yes", the following step of measuring sensitivity is performed.

[0108] In some specific embodiments of the present application, if the result of step 2a') is "yes", the weight percentages of the first standard sample and the third standard sample are gradually and synchronously reduced until the volume frequency of the peak of the first standard sample or the third standard sample in the measured frequency distribution curve is close to the noise level; then the weight percentage of the first standard sample or the third standard sample corresponding to the last mixed sample is the third detection limit.

[0109] Specifically in this embodiment, the shading rate is controlled at 10%-20%, and the weight percentages of the first standard sample and the third standard sample are gradually and synchronously reduced; specifically, the weight ratios of the first standard sample: the second standard sample: the third standard sample, the gradient changes are 1:1:1, 1:3:1, 1:8:1, 1:18:1, 1:48:1, 1:98:1...

[0110] The test results are shown in Table 4 below.

[0111] Table 4

[0112]

[0113] The "peak diameter relative error 1" in Table 4 refers to the volume peak diameter D corresponding to the peak area 1. MODE The volume median diameter D of the first standard sample 50 The relative error of the value (10.4μm).

[0114] The "peak diameter relative error 2" in Table 4 refers to the volume peak diameter D corresponding to the peak area 2. MODE The volume median diameter D of the second standard sample 50 The relative error of the value (37.5μm) is

[0115] The "peak diameter relative error 3" in Table 4 refers to the volume peak diameter D corresponding to the peak area 3. MODE The volume median diameter D of the third standard sample 50 The relative error of the value (134μm).

[0116] In this embodiment, when the weight ratio of the three is 1:48:1, the peaks of the first and third standard samples can no longer be detected.

[0117] When the weight ratio of the three is 1:18:1, the frequency distribution curve obtained by measurement is as follows Figure 8 shown; see Figure 8 As can be seen from the data in Table 4, the volume frequencies of the peaks for the first and third standard samples approach the noise level (peak area 1 and peak area 3 are 3.21% and 3.15%, respectively). Therefore, the weight percentage of the first standard sample (or third standard sample) in the mixed sample (5%) is the third detection limit.

[0118] In some specific embodiments of the present application, if the result of step 2b') is "yes", the weight percentages of the first standard sample and the third standard sample are gradually and synchronously increased until the volume frequency of the peak of the second standard sample in the measured frequency distribution curve is close to the noise level. The weight percentage of the second standard sample corresponding to the last mixed sample is the fourth detection limit;

[0119] Specifically in this embodiment, the shading rate is controlled at 10%-20%, and then the weight percentages of the first standard sample and the third standard sample are gradually and synchronously increased; specifically, the weight ratios of the first standard sample: the second standard sample: the third standard sample, the gradient changes are 1:1:1, 3:1:3, 9.5:1:9.5, 19.5:1:19.5, 49.5:1:49.5, 99.5:1:99.5, 199.5:1:199.5, 299.5:1:299.5.....

[0120] The test results are shown in Table 5 below.

[0121] Table 5

[0122]

[0123] The "peak diameter relative error 1" in Table 5 refers to the volume peak diameter D corresponding to the peak area 1. MODE The volume median diameter D of the first standard sample 50 The relative error of the value (10.4μm).

[0124] The "peak diameter relative error 2" in Table 5 refers to the volume peak diameter D corresponding to the peak area 2. MODE The volume median diameter D of the second standard sample 50 The relative error of the value (37.5μm) is

[0125] The "peak diameter relative error 3" in Table 5 refers to the volume peak diameter D corresponding to the peak area 3. MODEThe volume median diameter D of the third standard sample 50 The relative error of the value (134μm).

[0126] In this embodiment, when the weight ratio of the three is 299.5:1:299.5, the peak of the second standard sample can no longer be detected.

[0127] When the weight ratio of the three is 199.5:1:199.5, the frequency distribution curve obtained by measurement is as follows Figure 9 shown; see Figure 9 From the data in Table 5, it can be seen that the volume frequency of the peak of the second standard sample is close to the noise level (peak area 2 is 0.74%). Figure 9 A weak noise peak also appears near 1μm, which can be ignored.

[0128] When the weight ratio of the three is 199.5:1:199.5, the weight percentage of the second standard sample in the mixed sample (0.25%) is the fourth detection limit.

[0129] The sensitivity range of the laser diffraction particle size analyzer for measuring particle sizes of 1 μm to 200 μm is between the third detection limit and the fourth detection limit.

[0130] Specifically in this embodiment, through the above measurements, it can be concluded that the sensitivity range of the laser diffraction particle size analyzer used in this embodiment for measuring particle sizes of 1 μm to 200 μm is between 0.25% and 5%.

[0131] Comparative Example 1

[0132] The comparative example adopts the traditional method to measure the sensitivity range of the laser diffraction particle size analyzer.

[0133] Specifically, the commercially available SB040102 glass microsphere particle size standard sample was selected, and its volume median diameter D 50 It is 10.6±0.6μm.

[0134] The sampling mass was gradually reduced, and the sampling volume was gradually reduced from 0.1g to 0.0005g, in the order of 0.1g, 0.01g, 0.005g, 0.001g, and 0.0005g. The water volume of the sample pool was 100ml each time.

[0135] The minimum amount that can accurately measure the particle size distribution is the sensitivity of the laser diffraction particle size analyzer.

[0136] This comparative example uses MS3000 laser diffraction particle size analyzer to test the above samples in turn. The test results are shown in Figure 10-14 .

[0137] from Figure 10-14It can be seen that when the sample concentration is 0.001 / 100ml (equivalent to a mass ratio of 0.001g / 100g), the instrument can still identify the scattered light signal generated by the particles. However, because the scattered light signal is too low, the sample signal peak and the instrument noise signal peak appear simultaneously in the measurement results.

[0138] Using traditional methods, even if the measurement concentration is reduced to the instrument noise, it is still impossible to obtain an effective particle size analysis sensitivity value.

[0139] Comparative Example 2

[0140] Two commercially available glass microbead particle size standard samples, SB040102 (2-40 μm) and SB040105 (10-100 μm), were selected. The volume median diameter D 50 The frequency distribution curves of the two particles were obtained by mixing them in a weight ratio of 1:1. Figure 15 , two independent and non-overlapping peaks cannot appear, so it is impossible to qualitatively judge the resolution of the instrument, let alone measure the sensitivity of the instrument.

[0141] The present invention is not limited to the above-described embodiments. Any changes in shape or structure fall within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims. Those skilled in the art may make various changes, modifications, substitutions, combinations, and simplifications to these embodiments without departing from the principles and essence of the present invention. All such changes shall be considered equivalent replacements and fall within the scope of protection of the present invention.

Claims

1. A standard sample combination for particle size analysis using a laser diffraction method, characterized in that: The standard sample combination comprises a first standard sample, a second standard sample and a third standard sample; The first, second and third standard samples are obtained by screening from the same batch of granular raw materials; The particle raw material is glass microspheres, and the particle size distribution range is 1 μm to 200 μm, and each individual particle satisfies the characteristics of sphericity greater than 99%, smooth particle surface, refractive index of 1.500 to 2.200, and optical uniformity inside the particle; The particle size of the first standard sample is in the range of 1 μm to 22 μm, and the volume median diameter D of the first standard sample is 50 Falling within the range of 10.35 to 12.65 μm; The particle size of the second standard sample is in the range of 25 μm to 50 μm, and the volume median diameter D of the second standard sample is 50 Falling within the range of 33.75 to 41.25 μm; The particle size of the third standard sample is in the range of 80 μm to 200 μm, and the volume median diameter D of the third standard sample is 50 Falling into the range of 126 to 154 μm; The particle size distributions of the first, second and third standard samples all satisfy the following conditions: a) unimodal dispersion characteristics; b) Volume median diameter D 50 and volume average particle size D MEAN , volume peak diameter D MODE The deviation value is ±5% of the volume median diameter D 50 c) the ratio of the volume characteristic particle diameter D90 to D10 falls within the range of 1.4 to 3.

2. The standard sample combination according to claim 1, wherein: The refractive index of the particle raw material is 1.900 to 2.

200.

3. The standard sample combination according to claim 2, wherein: The optical uniformity inside the particles satisfies the requirement that the devitrification rate is below 1%.

4. The standard sample combination according to claim 3, wherein: The standard sample combination is obtained by the following steps: Step I) obtaining a granular raw material having a refractive index of 1.900 to 2.200, a devitrification rate of less than 1%, and a particle size distribution range of 1 μm to 200 μm; and then screening the granular raw material with a sphericity greater than 99% through centrifugal sorting technology; Step II) For the same batch of granular raw materials obtained in step I), sample particles with particle sizes falling within the ranges of 80 μm to 200 μm, 25 μm to 50 μm, and 1 μm to 22 μm are screened out by screening and classification technology and airflow classification technology, respectively; Step III) further classifies the sample particles obtained in step II) by sedimentation classification fine separation technology to obtain the first, second and third standard samples.

5. A method for measuring the sensitivity of a laser diffraction particle size analyzer, characterized in that: The method adopts the standard sample combination described in any one of claims 1 to 4.

6. The measuring method according to claim 5, wherein: Weighing with a 1 / 10,000 balance, the first standard sample and the second standard sample are mixed in different weight ratios, with the total weight of the mixture being 0.0001 to 50 g, dispersed in an aqueous medium, and then measuring the particle size distribution using the laser diffraction particle size analyzer; Step 1) The two are first mixed in a weight ratio of 1:1, and the resolution is qualitatively determined by measuring whether the obtained frequency distribution curve shows two independent and non-overlapping peaks; If the result of step 2a) is "yes", the weight percentage of the second standard sample is gradually reduced until the volume frequency of the peak of the second standard sample in the measured frequency distribution curve reaches the noise level. The weight percentage of the second standard sample corresponding to the last mixed sample is the first detection limit; as well as If the result of step 2b) is "yes", the weight percentage of the first standard sample is gradually reduced until the volume frequency of the peak of the first standard sample in the measured frequency distribution curve reaches the noise level. The weight percentage of the first standard sample corresponding to the final mixed sample is the second detection limit; The laser diffraction particle size analyzer has a sensitivity range for measuring particle sizes of 1 μm to 50 μm between the first detection limit and the second detection limit.

7. The measuring method according to claim 6, wherein: Measuring the volume median diameter D50 values ​​of the first standard sample and the second standard sample respectively; The volume peak diameters D obtained in step 2a) and step 2b) are MODE The corresponding volume median diameter D 50 The values ​​are compared to obtain the relative error range.

8. The measuring method according to claim 5, wherein: Weighing the first, second, and third standard samples in different weight ratios using a 1 / 10,000 balance, with the total weight of the mixture being 0.0001 to 50 g, dispersing the mixture in an aqueous medium, and measuring the particle size distribution using the laser diffraction particle size analyzer; Step 1') The three components are first mixed in a weight ratio of 1:1:1, and the resolution is qualitatively determined by measuring whether the obtained frequency distribution curve exhibits three independent and non-overlapping peaks; If the result of step 2a') is "yes", the weight percentages of the first standard sample and the third standard sample are gradually and synchronously reduced until the volume frequency of the peak of the first standard sample or the third standard sample in the measured frequency distribution curve approaches the noise level; the weight percentage of the first standard sample or the third standard sample corresponding to the final mixed sample is the third detection limit; and If the result of step 2b') is "yes", the weight percentage of the second standard sample is gradually reduced until the volume frequency of the peak of the second standard sample in the measured frequency distribution curve approaches the noise level. The weight percentage of the second standard sample corresponding to the final mixed sample is the fourth detection limit; The sensitivity range of the laser diffraction particle size analyzer for measuring particle sizes of 1 μm to 200 μm is between the third detection limit and the fourth detection limit.

9. The measuring method according to claim 8, wherein: Measure the volume median diameter D of the first standard sample, the second standard sample, and the third standard sample respectively 50 value; The volume peak diameters D obtained in step 2a') and step 2b') are MODE The corresponding volume median diameter D 50 The values ​​are compared to obtain the relative error range.

10. The measuring method according to any one of claims 6 to 9, characterized in that The aqueous medium is ultrapure water; Preferably, the light obscuration measured by the laser diffraction particle size analyzer falls within the range of 10% to 20%. Preferably, in the operation of the laser diffraction particle size analyzer, the background measurement duration is 0 seconds to 30 seconds, and the sample measurement duration is 0 seconds to 30 seconds.

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