CN114486979A - Method for acquiring absolute spin number of unpaired electrons of sample - Google Patents
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- UHOVQNZJYSORNB-UHFFFAOYSA-N monobenzene Natural products C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 claims description 38
- 239000010453 quartz Substances 0.000 claims description 32
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- UZFMOKQJFYMBGY-UHFFFAOYSA-N 4-hydroxy-TEMPO Chemical group CC1(C)CC(O)CC(C)(C)N1[O] UZFMOKQJFYMBGY-UHFFFAOYSA-N 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 4
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- 239000007787 solid Substances 0.000 description 3
- JLJWIVHYUCBSRC-UHFFFAOYSA-N benzene;9-[fluoren-9-ylidene(phenyl)methyl]fluorene Chemical compound C1=CC=CC=C1.C1=CC=CC=C1C([C]1C2=CC=CC=C2C2=CC=CC=C21)=C1C2=CC=CC=C2C2=CC=CC=C21 JLJWIVHYUCBSRC-UHFFFAOYSA-N 0.000 description 2
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Abstract
The invention discloses a method for acquiring the absolute spin number of unpaired electrons of a sample, which comprises the following steps: testing first electron paramagnetic resonance signals of the point-like sample at different positions in the resonant cavity to obtain a spatial distribution function of the resonant cavity; testing the intensity of a second electron paramagnetic resonance signal of the calibration sample in the resonant cavity to obtain a resonant cavity correction factor; testing a third electron paramagnetic resonance signal of the sample to be tested in the resonant cavity, and performing secondary integration on the third electron paramagnetic resonance signal to obtain a second secondary integration area; and obtaining the unpaired electron absolute spin number of the sample to be detected according to the volume of the sample to be detected, the second quadratic integral area, the electron spin quantum number, the spatial distribution function of the resonant cavity, the correction factor and the experiment setting parameters. The method can determine the absolute spin number of unpaired electrons of a sample to be detected without introducing a standard sample or a reference sample, without using an imaging device and without using a point sample with known spin number.
Description
Technical Field
The invention relates to the technical field of electron paramagnetic resonance, in particular to a method for acquiring the absolute spin number of unpaired electrons of a sample.
Background
The electron paramagnetic resonance technology is the only method which can directly detect unpaired electrons in a sample at present, and the quantitative electron paramagnetic resonance method can provide the number of electron spins in the sample, which has important significance for researching reaction kinetics, explaining reaction mechanism and commercial application. Therefore, the acquisition of the absolute spin number of unpaired electrons of a sample by electron paramagnetic resonance technology has been a hot point of research.
The current quantitative electron paramagnetic resonance method is mostly based on a relative quantitative method, and the test methods mainly comprise two methods: the first is to obtain the electron spin number of an unknown sample by comparing the electron paramagnetic resonance signals of a standard sample with a known electron spin number with that of the unknown sample under the same test conditions. However, this method is required to ensure that the cavity quality factor Q values of the standard and unknown samples remain consistent. The second method is to introduce a reference sample, put the standard sample and the unknown sample and the reference sample into a resonant cavity for testing respectively, and indirectly obtain the electron spin number of the unknown sample by comparing the difference between the electron paramagnetic resonance signal ratio of the standard sample and the electron spin number of the reference sample. In order to ensure the accuracy of the quantitative result, both methods require that the unknown sample has similar properties and similar shape and size with the standard sample and is consistent in position in the resonant cavity, but the conditions are difficult to meet in the actual testing process, especially for solid samples.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, it is an object of the present invention to propose a method for obtaining the absolute spin numbers of unpaired electrons of a sample, which method allows the absolute spin numbers of unpaired electrons of the sample to be determined without introducing a standard sample or a reference sample, without using an imaging device, and without using a punctiform sample of known spin numbers.
In order to achieve the above object, an embodiment of the first aspect of the present invention provides a method for obtaining absolute spin numbers of unpaired electrons in a sample, the method including: testing first electron paramagnetic resonance signals of a point-like sample at different positions in a resonant cavity, and obtaining a spatial distribution function of the resonant cavity according to the first electron paramagnetic resonance signals; testing a second electron paramagnetic resonance signal of the calibration sample in the resonant cavity, and performing secondary integration on the second electron paramagnetic resonance signal to obtain a first secondary integration area; obtaining a correction factor of the resonant cavity according to the spatial distribution function, the volume of the calibration sample, the first second integral area, the electron spin quantum number, the unpaired electron absolute spin number and the experiment setting parameters; testing a third electron paramagnetic resonance signal of the sample to be tested in the resonant cavity, and performing secondary integration on the third electron paramagnetic resonance signal to obtain a second secondary integration area; according to the volume of the sample to be measured
The number of unpaired electron absolute spins of the sample to be detected is obtained through the second quadratic integration area, the electron spin quantum number, the space distribution function of the resonant cavity, the correction factor and the experiment setting parameter.
The method for acquiring the absolute spin number of unpaired electrons of the sample obtains the space distribution function of the resonant cavity by testing the electron paramagnetic resonance signal of the point-shaped sample in the resonant cavity, obtains the secondary integral area of the calibration sample by testing the electron paramagnetic resonance signal of the calibration sample in the resonant cavity, calculating to obtain correction factor of the resonant cavity according to the secondary integral area, the spatial distribution function of the resonant cavity, the volume of the calibration sample, the electron spin quantum number, the unpaired electron absolute spin number and the experiment setting parameters, then testing the electron paramagnetic resonance signal of the sample to be tested in the resonant cavity to obtain the secondary integral area of the sample to be tested, and calculating the absolute spin number of unpaired electrons of the sample according to the volume of the sample to be measured, the secondary integral area, the electron spin quantum number, the spatial distribution function of the resonant cavity, the correction factor and the experiment setting parameters. The method can determine the absolute spin number of unpaired electrons of a sample to be detected without introducing a standard sample or a reference sample, without using an imaging device and without using a point sample with known spin number.
In addition, the method for obtaining the absolute spin numbers of unpaired electrons of the sample according to the above embodiment of the present invention may have the following additional technical features:
according to one embodiment of the invention, the spotted sample is a sample containing unpaired electrons.
According to one embodiment of the present invention, the spotted sample is any one of 1, 1-diphenyl-2-trinitrophenylhydrazine, a benzene radical complex, 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-1-oxyl.
According to an embodiment of the present invention, the calibration sample is a solution sample with a known shape and size, volume and concentration.
According to one embodiment of the invention, the calibration sample is a sample with a solute of 4-hydroxy-2, 2,6, 6-tetramethylpiperidin-1-oxyl and a solvent of benzene.
According to an embodiment of the present invention, the testing of the first electron paramagnetic resonance signal of the point-like sample at different positions in the resonant cavity and the obtaining of the spatial distribution function of the resonant cavity according to the first electron paramagnetic resonance signal comprise: placing the spotted sample in a first quartz capillary; placing the first quartz capillary at different positions in the resonant cavity, and recording first electron paramagnetic resonance signals of the point-like sample at different positions in the resonant cavity and quality factors of the resonant cavity tested each time; and mapping a test result by using a two-dimensional coordinate system to obtain a spatial distribution function of the resonant cavity, wherein the abscissa of the two-dimensional coordinate system is different positions of the punctiform sample in the resonant cavity, and the ordinate is a result of normalization of the quality factor by the first electron paramagnetic resonance signal.
According to an embodiment of the invention, the spatially distributed calibration coefficients are represented by:
wherein, G (B)1,Bm) Is said spatial distribution calibration coefficient, g (x) is said spatial distribution function, VsIs the volume of the spotted sample.
According to an embodiment of the invention, the second electron paramagnetic resonance signal of the test calibration sample within the resonant cavity comprises: sucking a preset volume of the calibration sample by using a second quartz capillary; and placing the second quartz capillary tube into a quartz paramagnetic tube, placing the quartz paramagnetic tube into a resonant cavity for testing, wherein the center of the calibration sample needs to be aligned to the center of the resonant cavity, and obtaining the second electron paramagnetic resonance signal.
According to one embodiment of the invention, the correction factor is obtained by:
wherein k is the correction factor, DI1Is the first quadratic integration area and is,
is the number of unpaired electron absolute spins of the calibration sample,
is the Boltzmann constant, S1Is the electron spin quantum number of the calibration sample, P is the microwave power, BmIs the modulation field amplitude, n is the number of scans, GsIs the receiver gain value, Q is the quality factor of the cavity, G (B)1,Bm) Is the spatial distribution calibration coefficient.
According to an embodiment of the present invention, the absolute spin number of unpaired electrons of the sample to be tested is obtained by the following formula:
wherein the content of the first and second substances,
is the absolute spin number, DI, of unpaired electrons of the sample to be measured2Is the second twice integrated area, k is the correction factor,
is the Boltzmann constant, S2Is the electron spin quantum number of the sample to be measured, P is the microwave power, BmIs the modulation field amplitude, n is the number of scans, GsIs a receiver increaseGain, Q is the quality factor of the resonator, G (B)1,Bm) Is the spatial distribution calibration coefficient.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a flow chart of a method of obtaining absolute spin numbers of unpaired electrons of a sample according to one embodiment of the invention;
FIG. 2 is a flow chart of obtaining a spatial distribution function of a resonant cavity according to one embodiment of the present invention;
FIG. 3 is a flow chart of a second electron paramagnetic resonance signal within a resonant cavity of a test calibration sample according to one embodiment of the present invention;
FIG. 4 is a schematic diagram of the structure of a resonant cavity in accordance with one embodiment of the present invention;
FIG. 5 is a schematic illustration of the Z-direction spatial distribution of the resonant cavity of one embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
The method for obtaining the absolute spin number of unpaired electrons in a sample according to the embodiment of the invention will be described in detail with reference to fig. 1 to 5 and specific embodiments of the specification.
FIG. 1 is a flow chart of a method of obtaining absolute spin numbers of unpaired electrons of a sample according to one embodiment of the invention.
In an embodiment of the present invention, as shown in fig. 1, a method for obtaining the absolute spin numbers of unpaired electrons of a sample includes:
s1, testing first electron paramagnetic resonance signals of the point-like sample at different positions in the resonant cavity, and obtaining a spatial distribution function of the resonant cavity according to the first electron paramagnetic resonance signals.
Specifically, the point-like sample is a solid powder sample and is small in size so as to be suitable for the spatial distribution test of the resonant cavity, and therefore the spatial distribution function of the resonant cavity is obtained through calculation.
In an embodiment of the invention, the spotted sample is a sample containing unpaired electrons.
The dot sample in the embodiment of the present invention is a sample containing unpaired electrons and having a small volume and stable properties, and any solid powder sample containing unpaired electrons and stable properties can be used as the dot sample in the present invention.
In an embodiment of the present invention, the spotted sample may be any one of 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH), a benzene radical complex (BDPA), 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-1-oxyl (TEMPOL).
In addition to 1, 1-diphenyl-2-trinitrophenylhydrazine (DPPH), a benzene radical complex (BDPA), and 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-1-oxyl (TEMPOL), the spotted sample can be regarded as a spotted sample as long as it contains unpaired electrons, is stable in properties, and has a small volume. For example, 1-diphenyl-2-trinitrophenylhydrazine (DPPH) can be selected to detect the spatial distribution of the resonant cavity.
In an embodiment of the present invention, as shown in fig. 2, the testing of the first electron paramagnetic resonance signal of the point-like sample at different positions in the resonant cavity and the obtaining of the spatial distribution function of the resonant cavity according to the first electron paramagnetic resonance signal includes:
s11, placing the spotted sample in a first quartz capillary.
Specifically, the first quartz capillary was a quartz capillary having an inner diameter of 1.0 mm, and a dotted sample was placed in the first quartz capillary.
S12, the first quartz capillary is placed at different positions in the resonant cavity, and first electron paramagnetic resonance signals of the point-like sample at different positions in the resonant cavity and quality factors of the resonant cavity tested each time are recorded.
Specifically, the position of the first quartz capillary tube in the resonant cavity should be selected as uniformly as possible to fully detect the spatial distribution condition of the resonant cavity, so as to obtain an accurate spatial distribution function of the resonant cavity. And placing the first quartz capillary tube in different positions in the resonant cavity for detection, and recording a first electron paramagnetic resonance signal corresponding to different positions in the resonant cavity for each detection and a quality factor Q value of the resonant cavity corresponding to each test, wherein the Q value is given by test software. After the detection of the first electron paramagnetic resonance signals corresponding to different positions in the resonant cavity is completed, the spatial distribution of the resonant cavity can be drawn.
And S13, drawing the test result by using a two-dimensional coordinate system to obtain a spatial distribution function of the resonant cavity.
The abscissa of the two-dimensional coordinate system is different positions of the DPPH punctiform samples in the resonant cavity, and the ordinate is a result of normalization of the quality factor Q by the first electron paramagnetic resonance signal.
In particular, to facilitate the calculation of the spatial distribution function of the resonant cavity, the resonant cavity in the present invention can be a rectangular resonant cavity, see fig. 4. And plotted in the XYZ coordinate system shown in figure 4.
As an example, as shown in fig. 5, fig. 5 is a schematic diagram of a spatial distribution curve in the Z direction of a rectangular resonant cavity. As can be seen from fig. 5, in the Z direction of the rectangular resonant cavity, the spatial distribution curve is approximately gaussian distributed, the electron paramagnetic resonance signal at the center of the resonant cavity has the largest amplitude, and the electron paramagnetic resonance signal has the strongest intensity. Alternatively, the spatial profile of the direction of the resonant cavity X, Y may be plotted. After the spatial distribution curve of the resonant cavity is obtained, the spatial distribution function of the resonant cavity can be obtained through calculation according to the spatial distribution curve of the resonant cavity.
In an embodiment of the present invention, the spatial distribution correction coefficient is represented by:
wherein, G (B)1,Bm) Is the spatial distribution calibration coefficient, g (x) is the spatial distribution function, Vs is the volume of the punctiform sample。
Based on the method for obtaining the spatial distribution function of the resonant cavity, the step that the spatial distribution function of the resonant cavity needs to be obtained through an imaging mode in the conventional electron paramagnetic resonance absolute quantitative method is avoided, and the method for obtaining the spatial distribution function of the resonant cavity does not need an imaging device.
And S2, testing a second electron paramagnetic resonance signal of the calibration sample in the resonant cavity, and performing secondary integration on the second electron paramagnetic resonance signal to obtain a first secondary integration area.
Specifically, the calibration sample is a solution sample with known shape size, volume and concentration.
In one embodiment of the invention, the calibration sample is a sample with a solute of 4-hydroxy-2, 2,6, 6-tetramethylpiperidin-1-oxyl (TEMPOL) and a solvent of benzene.
And after the solute, the solvent, the shape, the size, the volume and the concentration of the calibration solution sample are determined, a second electron paramagnetic resonance signal of the calibration sample in the resonant cavity can be detected.
In one embodiment of the present invention, as shown in fig. 3, the testing the second electron paramagnetic resonance signal of the calibration sample in the resonant cavity may include:
s21, a preset volume of the calibration sample is drawn using a second quartz capillary.
Specifically, the inner diameter of the second quartz capillary tube may be 0.1-10 mm, and optionally, the second quartz capillary tube may be a quartz capillary tube with an inner diameter of 0.6 mm, the preset volume may be 20 μ L, and the preset volume may be set according to actual needs, which is not limited herein. In the test, a TEMPOL benzene solution with a concentration of 100 μ M was prepared first, and then a quartz capillary tube with an inner diameter of 0.6 mm was used to suck a volume of 20 μ L of the TEMPOL benzene solution, and the quartz capillary tube after sucking the TEMPOL benzene solution was placed in a paramagnetic tube for the test.
S22, placing the second quartz capillary tube in the quartz paramagnetic tube, placing the quartz paramagnetic tube in the resonant cavity for testing, and aligning the center of the calibration sample to the center of the resonant cavity to obtain a second electron paramagnetic resonance signal.
Specifically, the quartz capillary (i.e., the second quartz capillary) after sucking the TEMPOL benzene solution is placed in a quartz paramagnetic tube with an outer diameter of 3 mm, and then the quartz paramagnetic tube is placed in the resonant cavity for testing, wherein care needs to be taken to align the center of the calibration sample with the center of the resonant cavity during testing. And after testing a second electron paramagnetic resonance signal of the TEMPOL benzene solution calibration sample in the resonant cavity, carrying out secondary integration on the second electron paramagnetic resonance signal to obtain a first secondary integration area.
And S3, obtaining a correction factor of the resonant cavity according to the spatial distribution function of the resonant cavity, the first second integral area of the calibration sample, the electron spin quantum number and the unpaired electron absolute spin number.
Specifically, the electron spin quantum number and the unpaired electron absolute spin number of the calibration sample are known quantities. The first secondary integral area is obtained by secondary integration of a second electron paramagnetic resonance signal of a TEMPOL benzene solution calibration sample in the resonant cavity, the spatial distribution function of the resonant cavity is obtained by calculation of a first electron paramagnetic resonance signal of a DPPH dotted sample in the resonant cavity, and then the correction factor of the resonant cavity is obtained by calculation according to the first secondary integral area of the calibration sample, the spatial distribution function of the resonant cavity, the electron spin quantum number and the unpaired electron absolute spin number of the calibration sample.
For the electron paramagnetic resonance test sample, the specific derivation formula of the second integral area is as follows:
magnetic susceptibility of sample
The following formula is satisfied:
wherein Ns is the number of unpaired electron absolute spins of the sample,
is the boltzmann constant, S is the electron spin quantum number of the sample, and Vs is the sample volume.
Fill factor of a resonant cavity
The following formula is satisfied:
wherein g (x) is the spatial distribution function of the resonator, VcIs the volume of the resonant cavity.
The second integral area of the electron paramagnetic resonance absorption spectrum line of the sample satisfies the following formula:
by
、
And DI is:
for a specific resonant cavity, it
Is a fixed value, so:
and deriving a calibration factor calculation formula of the resonant cavity based on the formula.
In an embodiment of the invention, the correction factor is obtained by:
wherein k is the correction factor, DI1Is the first quadratic integration area and is,
is the number of unpaired electron absolute spins of the calibration sample,
is the Boltzmann constant, S1Is the electron spin quantum number of the calibration sample, P is the microwave power, BmIs the modulation field amplitude, n is the number of scans, GsIs the receiver gain value, Q is the quality factor of the cavity, G (B)1,Bm) Is the spatial distribution calibration coefficient.
In particular, the microwave power P, the modulation field amplitude BmQuality factor Q of resonant cavity, scanning times n and gain value G of receiversAll given directly by the test software.
It should be noted that the magnitude of the correction factor k of the cavity is related to the type of cavity, and the correction factor of the cavity can be obtained by using a calibration sample test.
And S4, testing a third electron paramagnetic resonance signal of the sample to be tested in the resonant cavity, and performing secondary integration on the third electron paramagnetic resonance signal to obtain a second secondary integration area.
Specifically, the method for detecting the third electron paramagnetic resonance signal of the sample to be detected in the resonant cavity is similar to the method for detecting the second electron paramagnetic resonance signal of the calibration sample in the resonant cavity, and is not repeated here. It should be noted that the center of the sample to be measured may not be aligned with the center of the resonant cavity. The second secondary integration area is obtained by performing secondary integration on the third electron paramagnetic resonance signal of the sample to be detected, which is similar to the method for obtaining the first secondary integration area by performing secondary integration on the second electron paramagnetic resonance signal of the calibration sample, and the description is omitted here.
And S5, obtaining the absolute spin number of unpaired electrons of the sample to be detected according to the spatial distribution function, the correction factor, the volume of the sample to be detected, the second secondary integral area, the electron spin quantum number and the experiment setting parameters of the resonant cavity.
Specifically, the electron spin quantum number of the sample to be measured is a known quantity, the second secondary integration area is obtained by secondary integration of a third electron paramagnetic resonance signal of the sample in the resonant cavity, the spatial distribution function of the resonant cavity is obtained by calculation of a first electron paramagnetic resonance signal of a DPPH dotted sample in the resonant cavity, the correction factor of the resonant cavity is obtained by calculation of the second electron paramagnetic resonance signal secondary integration of the sample in the resonant cavity and the spatial distribution function of the resonant cavity in combination with a TEMPOL benzene solution, and then the unpaired electron absolute spin number of the sample to be measured is obtained by calculation according to the second secondary integration area, the volume of the sample to be measured, the electron spin quantum number, the spatial distribution function of the resonant cavity, the correction factor and experimental setting parameters.
In the embodiment of the present invention, the absolute spin number of unpaired electrons of the sample to be measured is obtained by the following formula:
wherein the content of the first and second substances,
is the absolute spin number, DI, of unpaired electrons of the sample to be measured2Is the second twice integrated area, k is the correction factor,
is the Boltzmann constant, S2Is the electron spin quantum number of the sample to be measured, P is the microwave power, BmIs the modulation field amplitude, n is the number of scans, GsIs the receiver gain value, Q is the quality factor of the cavity, G (B)1,Bm) Is the spatial distribution calibration coefficient.
The microwave power P and the modulation field amplitude BmQuality factor Q of resonant cavity, scanning times n and gain value G of receiversAll given directly by the test software after each test.
The method for obtaining the number of unpaired electrons absolute spins of a sample in the embodiment of the invention obtains a space distribution function of a resonant cavity by testing electron paramagnetic resonance signals of different positions of a point-shaped sample in the resonant cavity, then tests the electron paramagnetic resonance signals of a calibration sample in the resonant cavity, then carries out secondary integration to obtain a first secondary integration area, then obtains a correction factor of the resonant cavity according to the space distribution function of the resonant cavity, the volume of the calibration sample, the first secondary integration area, the electron spin quantum number, the number of unpaired electrons absolute spins and an experiment setting parameter, then tests the electron paramagnetic resonance signals of the sample to be tested in the resonant cavity, obtains a second secondary integration area after secondary integration, and obtains a second secondary integration area according to the volume of the sample to be tested, the second secondary integration area, the electron spin number, the resonant cavity space distribution function, the correction factor and the experiment setting parameter, and obtaining the absolute spin number of unpaired electrons of the sample to be detected. The method can determine the absolute spin number of unpaired electrons of a sample to be detected without introducing a standard sample or a reference sample, without using an imaging device and without using a point sample with known spin number.
It should be noted that the logic and/or steps represented in the flowcharts or otherwise described herein, such as an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.
It should be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (10)
1. A method of obtaining absolute spin numbers of unpaired electrons in a sample, the method comprising:
testing first electron paramagnetic resonance signals of a point-like sample at different positions in a resonant cavity, and obtaining a spatial distribution function of the resonant cavity according to the first electron paramagnetic resonance signals;
testing a second electron paramagnetic resonance signal of the calibration sample in the resonant cavity, and performing secondary integration on the second electron paramagnetic resonance signal to obtain a first secondary integration area;
obtaining a correction factor of the resonant cavity according to the spatial distribution function of the resonant cavity, the volume of the calibration sample, the first quadratic integral area, the electron spin quantum number, the unpaired electron absolute spin number and the experiment setting parameters;
testing a third electron paramagnetic resonance signal of the sample to be tested in the resonant cavity, and performing secondary integration on the third electron paramagnetic resonance signal to obtain a second secondary integration area;
and obtaining the absolute spin number of unpaired electrons of the sample to be detected according to the volume of the sample to be detected, the second quadratic integration area, the electron spin quantum number, the spatial distribution function of the resonant cavity, the correction factor and the experiment setting parameters.
2. The method for obtaining the absolute spin numbers of unpaired electrons in a sample according to claim 1, wherein the dotted sample is a sample containing unpaired electrons.
3. The method for obtaining the absolute spin numbers of unpaired electrons in a sample according to claim 2, wherein the dotted sample is any one of 1, 1-diphenyl-2-trinitrophenylhydrazine, a benzene radical complex, and 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-1-oxyl.
4. The method for obtaining the absolute spin numbers of unpaired electrons in a sample according to claim 3, wherein the calibration sample is a solution sample with known shape, size, volume and concentration.
5. The method for obtaining absolute spin numbers of unpaired electrons in a sample according to claim 4, wherein the calibration sample is a sample with a solute of 4-hydroxy-2, 2,6, 6-tetramethylpiperidine-1-oxyl and a solvent of benzene.
6. The method for obtaining the absolute spin numbers of unpaired electrons in a sample according to claim 1, wherein the step of testing the first electron paramagnetic resonance signal of the point-like sample at different positions in the resonant cavity and obtaining the spatial distribution function of the resonant cavity according to the first electron paramagnetic resonance signal comprises:
placing the spotted sample in a first quartz capillary;
placing the first quartz capillary at different positions in the resonant cavity, and recording first electron paramagnetic resonance signals of the point-like sample at different positions in the resonant cavity and quality factors of the resonant cavity tested each time;
and mapping a test result by using a two-dimensional coordinate system to obtain a spatial distribution function of the resonant cavity, wherein the abscissa of the two-dimensional coordinate system is different positions of the punctiform sample in the resonant cavity, and the ordinate is a result of normalization of the quality factor by the first electron paramagnetic resonance signal.
7. The method for obtaining the absolute spin numbers of unpaired electrons in the sample according to claim 4, wherein the step of testing the second electron paramagnetic resonance signal of the calibration sample in the resonant cavity comprises the steps of:
sucking a preset volume of the calibration sample by using a second quartz capillary;
and placing the second quartz capillary tube into a quartz paramagnetic tube, placing the quartz paramagnetic tube into a resonant cavity for testing, and aligning the center of the calibration sample to the center of the resonant cavity to obtain the second electron paramagnetic resonance signal.
8. The method of claim 1, wherein the correction factor is obtained by the following formula:
wherein k is the correction factor, DI1Is the first quadratic integration area and is,
is the unpaired electron absolute spin number of the calibration sample,
is the Boltzmann constant, S1Is the electron spin quantum number of the calibration sample, P is the microwave power, BmIs the modulation field amplitude, n is the number of scans, GsIs the receiver gain value, Q is the quality factor of the cavity, G (B)1,Bm) Is the spatial distribution calibration coefficient.
9. The method of claim 8, wherein the spatial distribution calibration coefficient is represented by the following equation:
wherein, G (B)1,Bm) Is said spatial distribution calibration coefficient, g (x) is said spatial distribution function, VsIs the volume of the spotted sample.
10. The method according to claim 1, wherein the absolute spin numbers of unpaired electrons in the sample to be tested are obtained by:
wherein the content of the first and second substances,
is the absolute spin number, DI, of unpaired electrons of the sample to be measured2Is the second twice integrated area, k is the correction factor,
is the Boltzmann constant, S2Is the electron spin quantum number of the sample to be measured, P is the microwave power, BmIs the modulation field amplitude, n is the number of scans, GsIs the receiver gain value, Q is the quality factor of the cavity, G (B)1,Bm) Is the spatial distribution calibration coefficient.
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