A method for measuring boron isotope abundance using carbon nanotubes as ion emitters

A technology of isotopic abundance and carbon nanotubes, applied in measurement devices, preparation of test samples, material analysis by electromagnetic means, etc., can solve the problem of low positive ion ionization efficiency, isobaric interference, and accurate measurement. It can improve the ion emission performance, the emission intensity and the stability of the ion current.

Active Publication Date: 2016-03-23
NUCLEAR POWER INSTITUTE OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Negative thermal ionization mass spectrometry is used to measure boron, which has high precision and sensitivity, but due to the detected ion BO 2 - The mass number is small (42 and 43), so the shunt effect and mass discrimination effect are serious, the measurement accuracy is not high, and in the presence of organic impurities such as residual ion exchange resin, mannitol and nitrate, it is easy to produce CNO - Ions (m / z=42), causing isobaric interference
Positive ion method, M 2 BO 2 + (M alkali metal elements: Na, K, Cs, etc.) The mass of ions is significantly increased. Although the shunt and mass discrimination effects can be reduced, the ionization efficiency of positive ions is not high. Generally, the sample amount is in the order of micrograms and nanograms. It is difficult to measure with high precision
[0003] Therefore, there is currently no method for measuring boron isotopes to that precision

Method used

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  • A method for measuring boron isotope abundance using carbon nanotubes as ion emitters
  • A method for measuring boron isotope abundance using carbon nanotubes as ion emitters
  • A method for measuring boron isotope abundance using carbon nanotubes as ion emitters

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Embodiment 1

[0036] The measurement method disclosed in the present invention is mainly composed of three major steps of sample preparation, sample coating and sample measurement, and the three steps are now described in detail.

[0037] (1) Sample preparation: including carbon nanotube suspension preparation, generator solution preparation, rhenium tape pretreatment, of which:

[0038] Preparation of carbon nanotube suspension: Weigh 0.02g of carbon nanotubes (CNTs) into a 25ml sample bottle, add 10ml of deionized water, and disperse ultrasonically for 15 minutes to form a uniform suspension for use. The tube suspension has not been used for a long time and needs to be ultrasonically dispersed before use.

[0039] The carbon nanotubes used are compound-walled carbon nanotubes with a diameter of 1 nm and a length of 5-15 μm.

[0040] After studying and comparing multiple solvents, such as ethanol, sucrose solution, acetone, etc., and considering the shedding of carbon nanotubes, the impac...

Embodiment 2

[0051] The difference between this embodiment and embodiment 1 is only:

[0052] In step (1) of this embodiment, the carbon nanotubes used are composite-walled carbon nanotubes with a diameter of 9 nm and a length of 5-15 μm; the M / B molar ratio in the preparation of the generator solution is 1.0; During pretreatment: When degassing the double-tape inserts in the burning device, raise the temperature to 2100°C, and the burning time is half an hour. After the burning is completed, cool it to room temperature in a vacuum system, take it out and place it in a desiccator stand-by;

[0053] In step (2) of this embodiment: when one of the rhenium strips of the pretreated double-band plug-in is made into a sample strip, the process is as follows: one of the rhenium strips is placed on the sample applicator, and the boron sample (boron solution ) 1μL (250ng) was dropped on the center of the belt, and most of the water was dried at 180°C (dried to no visible droplets), then the curren...

Embodiment 3

[0059] The difference between this embodiment and embodiment 1 is only:

[0060] In step (1) of this embodiment, the carbon nanotubes used are composite-walled carbon nanotubes with a diameter of 4 nm and a length of 5-15 μm; the M / B molar ratio in the preparation of the generator solution is 0.75; During pretreatment, the double-tape insert is degassed in the burning device, and the temperature is raised to 2075°C. The burning time is half an hour. After the burning is completed, it is cooled to room temperature in a vacuum system, taken out and placed in a desiccator to wait. use;

[0061] In step (2) of this embodiment: when one of the rhenium strips of the pretreated double-band plug-in is made into a sample strip, the process is as follows: one of the rhenium strips is placed on the sample applicator, and the boron sample (boron solution ) 1μL (250ng), drop accurately on the center of the belt, dry most of the water at 170°C (dry to no visible droplets), disconnect the c...

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Abstract

The invention discloses a method for measuring boron isotope abundance using carbon nanotubes as ion emitters, including: (1) sample preparation: preparation of carbon nanotube suspensions, preparation of generator solutions, and pretreatment of rhenium strips; (2) ) Sampling: Make a sample strip from one of the pretreated rhenium strips, and put it on the sample turntable together with the ionization strip to be tested; (3) Sample measurement: Send the turntable with the strip into the ion source In , the mass spectrometer is turned on, the temperature of the sample band and the ionization band is raised, and data acquisition starts when ion currents appear. The present invention adopts carbon nanotubes as ion emitters, and by optimizing the sample preparation method, sample coating technology, and measurement conditions when carbon nanotubes are used as ion emitters, the boron ion emission intensity and ionization efficiency are significantly improved, and the ion flow is stable. Performance has also been improved, while also improving the measurement accuracy, reducing the amount of sample coating and test temperature.

Description

technical field [0001] The invention relates to the field of measuring boron isotope abundance, in particular to a method for measuring boron isotope abundance using carbon nanotubes as ion emitters. Background technique [0002] Thermionic ion spectrometry is the most common method for measuring boron isotopic abundance, including positive thermal ionization mass spectrometry and negative thermal ionization mass spectrometry. Negative thermal ionization mass spectrometry is used to measure boron, which has high precision and sensitivity, but due to the detected ion BO 2 - The mass number is small (42 and 43), so the shunt effect and mass discrimination effect are serious, the measurement accuracy is not high, and in the presence of organic impurities such as residual ion exchange resin, mannitol and nitrate, it is easy to produce CNO - Ions (m / z=42), causing isobaric interference. Positive ion method, M 2 BO 2 + (M alkali metal elements: Na, K, Cs, etc.) The mass of i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N27/64G01N1/28
Inventor 李已才梁帮宏张劲松陈云明张舸杜文鹤孙鹏
Owner NUCLEAR POWER INSTITUTE OF CHINA
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