Method of determining antioxidant activity using electron paramagnetic resonance spectroscopy method

FIELD: physics, measurement.

SUBSTANCE: invention relates to physical and chemical analysis methods, particularly to analysis of solutions for quantitative determination of antioxidant activity. In the disclosed method, determination of antioxidant activity is carried out based on the difference in the number of paramagnetic particles of a stable radical, measured before and after chemical reaction of the particles of the radical with antioxidants.

EFFECT: goal of the present invention is to overcome shortcomings of existing methods and create a new method, which improves accuracy and rapidness of determination, and enables to quantitatively, in standardised units, establish antioxidant activity of a certain substance in an analysed sample and a mechanism for interaction of antioxidants with free radicals of diphenyl picryl hydrazyl.

4 dwg, 4 ex

 



 

Same patents:

FIELD: chemistry.

SUBSTANCE: method includes irradiating a hydroxyapatite sample with X-ray, gamma-radiation or electron beams, followed by recording, using an EPR technique, the resultant paramagnetic centres on a certified EPR spectrometer; calculating spectral characteristics of the observed EPR spectrum (number of observed lines and position thereof) while monitoring the measurement error and comparing the obtained spectral characteristics with spectral characteristics of nitrogen radicals; carrying out additional comparison of previously obtained spectral characteristics with spectral characteristics of nitrogen radicals in different positions substituting OH and(or) PO4 functional groups in the hydroxyapatite structure, particularly while allowing the determination of the point(s) of incorporation(substitution) of impurities of nitrogen compounds in the hydroxyapatite structure.

EFFECT: enabling determination of positions of impurities of nitrogen compounds in hydroxyapatites.

1 dwg

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to applied physics and can be used in making electron paramagnetic resonance (EPR) spectrometers. The spectrometer comprises signal 1 and heterodyne 2 microwave generators, a measuring attenuator 3, reference 4 and signal 5 channel mixers, a circulator 6 with a measuring resonator 7, reference 8 and signal 9 channel intermediate-frequency amplifiers, phase-frequency discriminators 10 and 11, frequency dividers 12 and 13, synchronous detectors 14 and 15, phase changers 16 and 17, a resonance frequency adjustment element of the measuring resonator 18, microwave power dividers 19 and 20, an operating mode three-way switch 12, a reference frequency synthesis device 22, a reference generator 23.

EFFECT: simple device, smaller dimensions thereof, low power consumption and phase noise of the microwave generator.

1 dwg

FIELD: chemistry.

SUBSTANCE: application: for identification of the purest types of the quartz raw material. Essence of the invention consists in the following: selection of a monomineral sample of quartz, crushing and quartzification of three samples are carried out. Each sample is subjected to irradiation by γ-quanta with a dose of 10±1×106 Gr. In the first sample after irradiation the content of isomorphic structural Al-O centres in quartz is determined. The third sample before irradiation is subjected to temperature processing at 590-650°C for 20-30 min and the complete content of structural Al-O centres in quartz is determined. The third sample before irradiation is activated by SHF fields with power 700-800 W for 3-5 min, and subjected to temperature processing at 590-650°C for 20-30 min and the content of mobile structures of Al-O centres in quartz is determined. After that, an index of quartz washability, C1 - content of isomorphic structural Al-O centres in quartz, C2 -complete content of structural Al-O centres in quartz, C3 - content of mobile structural Al-O centres in quartz are determined, and if a value of washability index is 0.5-1, conclusion about high quality of the quartz raw material is made.

EFFECT: increased accuracy and rapidity, as well as simplification of the process of estimation of the quartz raw material quality.

1 tbl

FIELD: chemistry.

SUBSTANCE: hydroxyapatite sample is irradiated with X-ray, gamma or electron beams, followed by recording the EPR spectrum resulting from exposure of paramagnetic centres on a certified EPR spectrometre. Spectral characteristics the observed EPR spectrum (number of observed lines and their position) are calculated while monitoring measurement error and comparing the obtained spectral characteristics with known spectral characteristics of nitrogen radicals in (poly)crystalline compounds.

EFFECT: possibility of qualitative and quantitative analysis of nitrogen compounds in substances with the structure of hydroxyapatites.

2 dwg

FIELD: physics.

SUBSTANCE: first version of the electron paramagnetic resonance (EPR) spectrometre has a fixed frequency generator (1), a variable frequency generator (11), a first power divider (2), a second power divider (12), a third power divider (13), a channel switch (14), a first mixer (6), a second mixer (15), a low frequency amplifier (16), an oscilloscope (9), a circulator (3), a resonator (4), a magnetic system (5), an output direct current amplifier (7), a recording system (8) an a computer (10). The second version of the EPR spectrometer additionally has a low frequency power amplifier (17) and a frequency multiplier (18).

EFFECT: possibility of visualising settings and easier tuning of frequency of the resonator with a sample at a fixed working frequency of the microwave generator.

2 cl, 7 dwg

FIELD: physics.

SUBSTANCE: electron paramagnetic resonance spectrometre has a microwave generator (1) in the 90-100 GHz range, a microwave bridge (20), a system for transmitting microwave power to a sample in form of series-arranged first 3 mm waveguide (2), first horn antenna (3), at least one dielectric lens (4), second horn antenna (5) whose horn faces the horn of the first horn antenna (3), and a second 3 mm waveguide (6). The spectrometre also has a resonator (7), having a piston (8) and sample holder (9), a microwave signal detector (10), a synchronous detector (11), a magnetic field modulation generator (12), modulation coils (13), a magnetic field scan unit (14), a superconducting magnet (15), a cryogenic system (16) for maintaining temperature of liquid helium, having an optical window (17) and a control unit (18). The superconducting magnet (15), modulation coils (13), second horn antenna (5), second 3 mm waveguide (6) and resonator (7) are placed in the cryogenic system (16). The second horn antenna (5) is placed opposite the optical window (17) of the cryogenic system and is connected through the second 3 mm waveguide (5) to the resonator through a coupling aperture. The first horn antenna (3) and at least one dielectric lens (4) are fitted outside the cryogenic system (16) opposite its optical window (17).

EFFECT: reduced heat losses in the cryostat and reduced amount of reflected microwave power.

3 cl, 2 dwg

FIELD: physics.

SUBSTANCE: calibration sample is put into a measuring resonator, which gives an anisotropic spectrum (EPR), made from a rutile monocrystal TiO2 which contains Fe3+ ions in amount of 0.01-0.5 wt %. The calibration sample is turned in a magnetic field until appearance of an EPR anisotropic spectrum of Fe3+ ions whose lines are recorded and the EPR spectrometre is set using the said lines to maximum signal-to-noise ratio by moving the matching piston of the resonator and moving the bottom wall of the resonator in order to adjust the frequency of the resonator.

EFFECT: simple process of tuning and calibrating an electron paramagnetic resonance spectrometre.

4 cl, 2 dwg

FIELD: nanotechnologies.

SUBSTANCE: nanodiamond is placed into installation for annealing, hydrogen is passed through and maintained at the temperature selected from the range of (900÷1100) °C, cooled down to room temperature. X-ray diffraction pattern is taken. Additionally spectrum of electronic paramagnetic resonance (EPR) is registered at room temperature. Availability of metal phases is identified.

EFFECT: invention makes it possible to increase sensitivity of magnetic admixtures content detection in nanodiamonds of detonation synthesis.

2 cl, 6 ex

FIELD: medicine.

SUBSTANCE: invention refers to pharmacy, namely identification, estimation of quality and safety of original and reproduced medical products. Described comparative estimation of physiological activity of original medical products and reproduced medical products or related preparations implies that by means of EPR spectroscopy and spin probes influence of these products on erythrocyte, lymphocyte and thrombocyte membrane structures released of the same blood sample depending on active component concentration in solution and contact time are examined by comparison of corresponding data obtained within concentration corresponding to maximum therapeutic dose.

EFFECT: method enables comparing of pharmaceutical preparations - originals and generics, or pharmaceutical substances, with various impurity compounds, both within quality assessment and from the point of safety for patients.

3 ex, 3 tbl

FIELD: inspection of degree of lacing of polyethylene.

SUBSTANCE: tested and reference samples are placed into resonator of electron paramagnetic resonance spectrometer, spectrum of absorption of electron paramagnetic resonance is recorded. Amplitude of derivative and width of absorption line of tested and standard samples is found from spectrum recorded correspondingly to subsequent determination of degree of lacing from formula K=I'ΔH2mref/I'refΔH2refm, where I' and I'ref are amplitudes of derivative of absorption line of tested and reference sample, ΔH and ΔHref is width of absorption lines of tested and reference samples, m and mref are masses of tested and reference samples.

EFFECT: improved precision of inspection; simplified method of inspection; improved efficiency of operation.

FIELD: inspection of degree of lacing of polyethylene.

SUBSTANCE: tested and reference samples are placed into resonator of electron paramagnetic resonance spectrometer, spectrum of absorption of electron paramagnetic resonance is recorded. Amplitude of derivative and width of absorption line of tested and standard samples is found from spectrum recorded correspondingly to subsequent determination of degree of lacing from formula K=I'ΔH2mref/I'refΔH2refm, where I' and I'ref are amplitudes of derivative of absorption line of tested and reference sample, ΔH and ΔHref is width of absorption lines of tested and reference samples, m and mref are masses of tested and reference samples.

EFFECT: improved precision of inspection; simplified method of inspection; improved efficiency of operation.

FIELD: medicine.

SUBSTANCE: invention refers to pharmacy, namely identification, estimation of quality and safety of original and reproduced medical products. Described comparative estimation of physiological activity of original medical products and reproduced medical products or related preparations implies that by means of EPR spectroscopy and spin probes influence of these products on erythrocyte, lymphocyte and thrombocyte membrane structures released of the same blood sample depending on active component concentration in solution and contact time are examined by comparison of corresponding data obtained within concentration corresponding to maximum therapeutic dose.

EFFECT: method enables comparing of pharmaceutical preparations - originals and generics, or pharmaceutical substances, with various impurity compounds, both within quality assessment and from the point of safety for patients.

3 ex, 3 tbl

FIELD: nanotechnologies.

SUBSTANCE: nanodiamond is placed into installation for annealing, hydrogen is passed through and maintained at the temperature selected from the range of (900÷1100) °C, cooled down to room temperature. X-ray diffraction pattern is taken. Additionally spectrum of electronic paramagnetic resonance (EPR) is registered at room temperature. Availability of metal phases is identified.

EFFECT: invention makes it possible to increase sensitivity of magnetic admixtures content detection in nanodiamonds of detonation synthesis.

2 cl, 6 ex

FIELD: physics.

SUBSTANCE: calibration sample is put into a measuring resonator, which gives an anisotropic spectrum (EPR), made from a rutile monocrystal TiO2 which contains Fe3+ ions in amount of 0.01-0.5 wt %. The calibration sample is turned in a magnetic field until appearance of an EPR anisotropic spectrum of Fe3+ ions whose lines are recorded and the EPR spectrometre is set using the said lines to maximum signal-to-noise ratio by moving the matching piston of the resonator and moving the bottom wall of the resonator in order to adjust the frequency of the resonator.

EFFECT: simple process of tuning and calibrating an electron paramagnetic resonance spectrometre.

4 cl, 2 dwg

FIELD: physics.

SUBSTANCE: electron paramagnetic resonance spectrometre has a microwave generator (1) in the 90-100 GHz range, a microwave bridge (20), a system for transmitting microwave power to a sample in form of series-arranged first 3 mm waveguide (2), first horn antenna (3), at least one dielectric lens (4), second horn antenna (5) whose horn faces the horn of the first horn antenna (3), and a second 3 mm waveguide (6). The spectrometre also has a resonator (7), having a piston (8) and sample holder (9), a microwave signal detector (10), a synchronous detector (11), a magnetic field modulation generator (12), modulation coils (13), a magnetic field scan unit (14), a superconducting magnet (15), a cryogenic system (16) for maintaining temperature of liquid helium, having an optical window (17) and a control unit (18). The superconducting magnet (15), modulation coils (13), second horn antenna (5), second 3 mm waveguide (6) and resonator (7) are placed in the cryogenic system (16). The second horn antenna (5) is placed opposite the optical window (17) of the cryogenic system and is connected through the second 3 mm waveguide (5) to the resonator through a coupling aperture. The first horn antenna (3) and at least one dielectric lens (4) are fitted outside the cryogenic system (16) opposite its optical window (17).

EFFECT: reduced heat losses in the cryostat and reduced amount of reflected microwave power.

3 cl, 2 dwg

FIELD: physics.

SUBSTANCE: first version of the electron paramagnetic resonance (EPR) spectrometre has a fixed frequency generator (1), a variable frequency generator (11), a first power divider (2), a second power divider (12), a third power divider (13), a channel switch (14), a first mixer (6), a second mixer (15), a low frequency amplifier (16), an oscilloscope (9), a circulator (3), a resonator (4), a magnetic system (5), an output direct current amplifier (7), a recording system (8) an a computer (10). The second version of the EPR spectrometer additionally has a low frequency power amplifier (17) and a frequency multiplier (18).

EFFECT: possibility of visualising settings and easier tuning of frequency of the resonator with a sample at a fixed working frequency of the microwave generator.

2 cl, 7 dwg

FIELD: chemistry.

SUBSTANCE: hydroxyapatite sample is irradiated with X-ray, gamma or electron beams, followed by recording the EPR spectrum resulting from exposure of paramagnetic centres on a certified EPR spectrometre. Spectral characteristics the observed EPR spectrum (number of observed lines and their position) are calculated while monitoring measurement error and comparing the obtained spectral characteristics with known spectral characteristics of nitrogen radicals in (poly)crystalline compounds.

EFFECT: possibility of qualitative and quantitative analysis of nitrogen compounds in substances with the structure of hydroxyapatites.

2 dwg

FIELD: chemistry.

SUBSTANCE: application: for identification of the purest types of the quartz raw material. Essence of the invention consists in the following: selection of a monomineral sample of quartz, crushing and quartzification of three samples are carried out. Each sample is subjected to irradiation by γ-quanta with a dose of 10±1×106 Gr. In the first sample after irradiation the content of isomorphic structural Al-O centres in quartz is determined. The third sample before irradiation is subjected to temperature processing at 590-650°C for 20-30 min and the complete content of structural Al-O centres in quartz is determined. The third sample before irradiation is activated by SHF fields with power 700-800 W for 3-5 min, and subjected to temperature processing at 590-650°C for 20-30 min and the content of mobile structures of Al-O centres in quartz is determined. After that, an index of quartz washability, C1 - content of isomorphic structural Al-O centres in quartz, C2 -complete content of structural Al-O centres in quartz, C3 - content of mobile structural Al-O centres in quartz are determined, and if a value of washability index is 0.5-1, conclusion about high quality of the quartz raw material is made.

EFFECT: increased accuracy and rapidity, as well as simplification of the process of estimation of the quartz raw material quality.

1 tbl

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to applied physics and can be used in making electron paramagnetic resonance (EPR) spectrometers. The spectrometer comprises signal 1 and heterodyne 2 microwave generators, a measuring attenuator 3, reference 4 and signal 5 channel mixers, a circulator 6 with a measuring resonator 7, reference 8 and signal 9 channel intermediate-frequency amplifiers, phase-frequency discriminators 10 and 11, frequency dividers 12 and 13, synchronous detectors 14 and 15, phase changers 16 and 17, a resonance frequency adjustment element of the measuring resonator 18, microwave power dividers 19 and 20, an operating mode three-way switch 12, a reference frequency synthesis device 22, a reference generator 23.

EFFECT: simple device, smaller dimensions thereof, low power consumption and phase noise of the microwave generator.

1 dwg

FIELD: chemistry.

SUBSTANCE: method includes irradiating a hydroxyapatite sample with X-ray, gamma-radiation or electron beams, followed by recording, using an EPR technique, the resultant paramagnetic centres on a certified EPR spectrometer; calculating spectral characteristics of the observed EPR spectrum (number of observed lines and position thereof) while monitoring the measurement error and comparing the obtained spectral characteristics with spectral characteristics of nitrogen radicals; carrying out additional comparison of previously obtained spectral characteristics with spectral characteristics of nitrogen radicals in different positions substituting OH and(or) PO4 functional groups in the hydroxyapatite structure, particularly while allowing the determination of the point(s) of incorporation(substitution) of impurities of nitrogen compounds in the hydroxyapatite structure.

EFFECT: enabling determination of positions of impurities of nitrogen compounds in hydroxyapatites.

1 dwg

Up!