CN104267092A - Method for testing hafnium isotope by using mass spectrometer - Google Patents
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Abstract
The invention provides a method for testing a hafnium isotope by using a mass spectrometer. According to the method, when the hafnium isotope is analyzed by using a multi-collector inductively-coupled plasma mass spectrometer, a sample to be tested is pre-scanned, and if signal fluctuation exists, hydrofluoric acid with the volume fraction of 50% is added by several times until a signal is steady. By adopting the method, the sample with a smooth signal can be obtained without re-separation, the cleaning time is greatly shortened, the effective support is provided for the accurate test of the hafnium isotope, and for some low-hafnium content samples, re-evaporation and extraction are not required, so that secondary pollution as well as the reduction of the recycling rate caused by secondary separation are reduced.
Description
Technical field
The present invention relates to mass spectrometer and measure hafnium isotope, be specifically related to the chemical method optimizing mass spectrometer test hafnium isotope signal smoothness.
Background technology
Hafnium is a kind of chemical element, and its symbol of element is Hf.The atomic number of hafnium is 72, and atomic weight is 178.49, belongs to IVB race element.Simple substance hafnium is the glossiness silver gray transition metal of a kind of band.Its fusing point is 2233 DEG C, and boiling point is 4602 DEG C, and density is 13.31g/cm
3.Fine and close metal hafnium character torpescence, surface easily forms oxide cap, very stable at normal temperatures.Hafnium not with watery hydrochloric acid, dilute sulfuric acid and strong base solution effect, but dissolve in hydrofluorite and chloroazotic acid.The oxidation state of hafnium is+2 ,+3 ,+4 valencys, and wherein the compound of+4 valencys is the most stable.Lutetium-hafnium isotope system is widely used in field of earth sciences, and wherein the separation of hafnium isotope and analysis test method have also been obtained further investigation.Form purer hafnium solution to be measured after the steps such as geological sample is cleared up through acid mixture High Temperature High Pressure, ion exchange resin is separated, extraction hafnium, finally utilize many receiving inductances couple plasma mass spectrometer (MC-ICPMS) to carry out isotope test.
Existing extraction hafnium operation steps is:
1. the purer hafnium solution through ion exchange resin separator well is positioned over the complete evaporate to dryness of electric hot plate;
2. in the sample of evaporate to dryness, add 50 μ L high-pure hydrofluoric acids;
3. the sample adding high-pure hydrofluoric acid to be positioned on electric hot plate and to steam to a droplet (about 3 minutes) at 140 DEG C, adding 20 μ L high pure nitric acids, and 1mL high purity water, cover bottle cap and obtain solution to be measured;
But, in test process, often occur that in part solution to be measured, hafnium constituent content is extremely low, or in test process, hafnium elemental signals fluctuates great phenomenon.Hafnium content is too low in testing, and be commonly considered as when extracting hafnium element, the excessive evaporate to dryness of hydrofluorite, the hafnium element in sample cannot stripping in nitric acid, causes can't detect.And hafnium signal fluctuation is excessive, may be because in detachment process, the existence of some matrix causes, thus needs again to be separated.If hafnium content is too low in test, the many employings of forefathers, by heavy for solution evaporate to dryness to be measured molten, are extracted with hydrofluorite again, must repeat 2,3 steps; If test signal fluctuation is excessive, even need to adopt the method be again separated to process, but this method length consuming time, easily introduce pollution, especially for the sample of some rare samples and low hafnium content, the method process cannot be adopted.
In addition, hafnium can well be dissolved in hydrofluorite, and solute effect is not good in nitric acid.Therefore, in hafnium isotope test process, in solution to be measured, more or less all hydrofluorite can be contained.And hydrofluorite has very strong corrosivity to quartz, the atomizer of MC-ICPMS and torch pipe are all quartzy materials, therefore, when utilizing MC-ICPMS to carry out hafnium isotope analysis, PFA corrosion-resistant miniflow atomizer and film need be adopted to remove molten equipment (removing the solvent in solution to be measured), to reduce the corrosion of hydrofluorite to atomizer and torch pipe.But hafnium is easily adsorbed in film goes molten internal duct, when utilizing MC-ICPMS to test hafnium isotope, sample collection (the namely testing) time is about 10 ~ 12min, and scavenging period is about 5 ~ 6min.But often occur that sample background value is higher, in the short time, cannot baseline values be cleaned to, significantly need extend scavenging period.Even use 2% nitric acid+0.5% hydrofluorite washing lotion and 2% nitric acid washing lotion alternately to clean and also need more than 15min, make troubles to sample analysis.
Summary of the invention
The object of the present invention is to provide a kind of method utilizing mass spectrometer to test hafnium isotope.
For achieving the above object, present invention employs following technical scheme:
1) when utilizing many receiving inductances couple plasma mass spectrometer to carry out hafnium isotope analysis, according to prescan result by the process of one of following three kinds of situations:
Situation one, after prescan is carried out to sample to be analyzed, if the hafnium isotope signal that obtains of prescan steadily and
176hf signal numerical value is greater than 10 times of detection limits, then directly enter step 2);
Situation two, after prescan is carried out to sample to be analyzed, if there is fluctuation in the hafnium isotope signal that prescan obtains, then add hydrofluorite to gradation in sample to be analyzed, again prescan is carried out after often adding a hydrofluorite, until the hafnium isotope signal that prescan obtains is steady, then enter step 2);
Situation three, after carrying out prescan to sample to be analyzed, if although the hafnium isotope signal that obtains of prescan is steady
176hf signal numerical value is less than or equal to 10 times of detection limits, then add hydrofluorite to gradation in sample to be analyzed, ultrasonic process 1 ~ 5 minute after often adding a hydrofluorite, and again carry out prescan after ultrasound exposure, until prescan obtains
176hf signal numerical value is greater than 10 times of detection limits, then enters step 2);
2) through step 1) after, the concentration according to analyzing hafnium standard model solution used carries out adjustment coupling to the concentration of hafnium in sample to be analyzed.
Described adjustment coupling specifically comprises the following steps:
Through step 1) after, if the concentration of hafnium is greater than 300ppb in sample to be analyzed, then with concentration dilution to the 100 ~ 300ppb of mixed acid solution by hafnium in sample to be analyzed, in described mixed acid solution, the volume fraction of nitric acid is 2%, and the volume fraction of hydrofluorite is 0.1%.
Described mixed acid solution adopt high purity water, through the pure hydrofluorite of top grade of sub-boiling distillation purifying and the pure nitric acid of top grade formulated.
In situation two and situation three, the single addition of hydrofluorite is 5 μ L, and the volume fraction of hydrofluorite is 50%, the hydrofluorite of volume fraction 50% adopt high purity water and the pure hydrofluorite of top grade through sub-boiling distillation purifying formulated.
Through step 2) after, in sample to be analyzed, the volume fraction of hydrofluorite controls be less than or equal to 2%.
Beneficial effect of the present invention is embodied in:
After adopting the inventive method, the stable sample of signal can be obtained without the need to being again separated, hafnium isotope accurately being tested to providing effective support, for part low hafnium content sample, due to without the need to evaporate to dryness and extraction again, decrease secondary pollution and the loss of the secondary separation recovery.
Further, by suitably adding hydrofluorite, utilizing the ability of hydrofluorite stripping hafnium, solving hafnium and the problem that film goes molten internal duct to be combined, before making to detect fresh sample, the scavenging period of equipment is significantly shortened.
Accompanying drawing explanation
Fig. 1 is the hafnium isotope test of sample BHVO-2
180hf signal intensity figure.
Embodiment
Below in conjunction with drawings and Examples, the present invention is elaborated.
A certain amount of hydrofluorite high-purity solutions adds in solution to be measured by the present invention, obtain stably, higher test signal, and guarantee that sample signal can be reduced to baseline values in the scavenging period of 6min, strong support is provided to the hafnium isotope high precision measurement based on many receiving inductances couple plasma mass spectrometer (MC-ICPMS).
The mixed solution of hydrofluorite and nitric acid, has highly acid, strong oxidizing property and the strong coordination ability to the valent element of height, transitional element and non-metal simple-substance before solubilized.Wherein, hydrofluorite (HF) and silicon dioxide (SiO
2) easily react at normal temperatures, its reactional equation is:
SiO
2(s)+4?HF(aq)→SiF
4(g)+2H
2O(l)
Consider that hydrofluorite is to instrument and equipment (the mainly torch tube portion of plasma mass spectrograph, quartzy material, SiO
2content >99%) severe corrosive, hafnium isotope be separated after avoid as far as possible a large amount of hydrofluorite remain.In conventional Chemical Decomposition product, fluohydric acid content is generally 0.05% ~ 0.1%.Because sample composition and hafnium constituent content are not quite similar, the hafnium content after isolated and matrix composition also difference to some extent, in test process, there is the situation that signal fluctuation is large in sample segment.Suspect in nitric acid medium, generating portion complex compound, be easy to be attached to sample introduction pipeline in sample introduction process or degree of ionization weak, cause hafnium signal to fluctuate widely.
Add a small amount of hydrofluorite in the sample of separator well after, signal fluctuation obviously improves.And the sample containing hydrofluorite is easy to cleaning, effectively reduces background interference, reduces and be separated or extract the secondary pollution introduced.
Experiment shows, fluohydric acid content removes molten (DSN) sample introduction 24 hours lower than the aqueous solution PFA corrosion-resistant miniflow atomizer (100 μ L/min) of 4% (volume fraction) and film, does not produce corrosive attack to torch pipe.
Experimental example 1
The operation steps of this experimental example is:
1. after the steps such as geological sample (BHVO-2) clears up (Yuan Honglin etc., rock journal, 2007) through acid mixture High Temperature High Pressure, ion exchange resin is separated, extraction hafnium, form purer hafnium solution to be measured;
2. utilize high purity water, high-pure hydrofluoric acid and high pure nitric acid to prepare the mixed acid solution (being designated as reagent A) containing 2% (volume fraction) nitric acid+0.1% (volume fraction) hydrofluorite; Utilize the hydrofluorite of high purity water and high-pure hydrofluoric acid dose volume mark 50% (being designated as reagent B);
3. by solution prescan to be measured, if signal steadily and
176hf signal numerical value is greater than 10 times of detection limits, then dilute concentration to the 100 ~ 300ppb (if solution hafnium concentration to be measured is less than or equal to 300ppb, does not then do and dilute or other process) of hafnium in solution to be measured by reagent A;
4. through prescan, if there is the solution to be measured that hafnium signal fluctuation is large, reagent B is repeatedly added on a small quantity in this solution to be measured, each addition is 5 μ L, until pre-scan signal steadily (absolute value of the difference of the signal strength values that described steady finger point any two sweep times is corresponding is less than 100mV), then concentration to the 100 ~ 300ppb (if solution hafnium concentration to be measured is less than or equal to 300ppb, does not then do and dilute or other process) of hafnium in solution to be measured is diluted by reagent A.
General hydrofluorite add within concentration can be controlled in 1% (volume fraction), indivedual particular sample is slightly high, but hydrofluoric acid concentration is no more than 2% (volume fraction).After above-mentioned steps 3 or 4, the formal hafnium isotope analysis based on many receiving inductances couple plasma mass spectrometer (MC-ICPMS) can be carried out.
See Fig. 1, certain pre-scan signal is fluctuated large hafnium solution to be measured, when curve A representative does not add reagent B
180hf signal intensity, after curve B represents and adds second time (for the last time) reagent B
180hf change in signal strength trend.Can be known by Fig. 1 and see, add sample signal fluctuation before reagent B greatly, cannot Measurement accuracy hafnium isotope ratio; And after adding the reagent B of a certain amount of (10 μ L), sample signal tends to be steady, isotopic ratio test can be carried out.
To fluctuate large solution to be measured for pre-scan signal, most total amount needing the reagent B added is 5 ~ 20 μ L, needs individually the total amount of the reagent B added slightly high.
Experimental example 2
The operation steps of this experimental example is:
1. after the steps such as geological sample (AGV-1) is cleared up through acid mixture High Temperature High Pressure, ion exchange resin is separated, extraction hafnium, form purer hafnium solution to be measured;
2. utilize high-pure hydrofluoric acid and high pure nitric acid preparation to contain the mixed acid solution (being designated as reagent A) of 2% (volume fraction) nitric acid+0.1% (volume fraction) hydrofluorite; Utilize the hydrofluorite of high-pure hydrofluoric acid dose volume mark 50% (being designated as reagent B);
3. by solution prescan to be measured, if signal steadily and
176hf signal numerical value is greater than 10 times of detection limits, then dilute concentration to the 100 ~ 300ppb (if solution hafnium concentration to be measured is less than or equal to 300ppb, does not then do and dilute or other process) of hafnium in solution to be measured by reagent A;
4. through prescan, right
176hf signal intensity is less than or equal to the solution to be measured of 10 times of detection limits, can carry out with reference to the step 4 of experimental example 1, but in order to promote the stripping of hafnium, need after adding reagent B, carry out ultrasonic process (time is 3 minutes at every turn, power is 100%), and then carry out prescan, until prescan obtains
176hf signal numerical value is greater than 10 times of detection limits; Then concentration to the 100 ~ 300ppb (if solution hafnium concentration to be measured is less than or equal to 300ppb, does not then do and dilute or other process) of hafnium in solution to be measured is diluted by reagent A.
General hydrofluorite add within concentration can be controlled in 1% (volume fraction), indivedual particular sample is slightly high, but hydrofluoric acid concentration is no more than 2% (volume fraction).After above-mentioned steps 3 or 4, the formal hafnium isotope analysis based on many receiving inductances couple plasma mass spectrometer (MC-ICPMS) can be carried out.
For experimental example 1, be usually separated the hafnium solution to be measured that obtains
176hf signal numerical value can much larger than 10 times of detection limits, therefore, by a small amount of gradation add signal that hydrofluorite makes solution to be measured steadily after, can ensure
176hf signal numerical value is greater than 10 times of detection limits.For experimental example 2, a small amount of gradation adds hydrofluorite and pre-scan signal can not be caused to fluctuate.In experimental example 1 ~ 2, the object using reagent A to carry out diluting makes hafnium concentration of element in solution to be measured close with standard model solution concentration (being generally 100 ~ 300ppb), reduces the systematic error of test.
In this experimental example 1 ~ 2, high-pure hydrofluoric acid used (about 23mol/L) adopts the pure hydrofluorite of top grade to obtain after three sub-boiling distillation purifying, and its hafnium background is less than 200pg; Described high pure nitric acid (about 14mol/L) adopts the pure nitric acid of top grade to obtain after twice sub-boiling distillation purifying; Milli-Q high purity water (high purity water), resistivity reaches 18.2M Ω cm
-1(25 DEG C).
Claims (5)
1. utilize mass spectrometer to test a method for hafnium isotope, it is characterized in that: comprise the following steps:
1) when utilizing many receiving inductances couple plasma mass spectrometer to carry out hafnium isotope analysis, according to prescan result by the process of one of following three kinds of situations:
Situation one, after prescan is carried out to sample to be analyzed, if the hafnium isotope signal that obtains of prescan steadily and
176hf signal numerical value is greater than 10 times of detection limits, then directly enter step 2);
Situation two, after prescan is carried out to sample to be analyzed, if there is fluctuation in the hafnium isotope signal that prescan obtains, then add hydrofluorite to gradation in sample to be analyzed, again prescan is carried out after often adding a hydrofluorite, until the hafnium isotope signal that prescan obtains is steady, then enter step 2);
Situation three, after carrying out prescan to sample to be analyzed, if although the hafnium isotope signal that obtains of prescan is steady
176hf signal numerical value is less than or equal to 10 times of detection limits, then add hydrofluorite to gradation in sample to be analyzed, ultrasonic process 1 ~ 5 minute after often adding a hydrofluorite, and again carry out prescan after ultrasound exposure, until prescan obtains
176hf signal numerical value is greater than 10 times of detection limits, then enters step 2);
2) through step 1) after, the concentration according to analyzing hafnium standard model solution used carries out adjustment coupling to the concentration of hafnium in sample to be analyzed.
2. the method for hafnium isotope tested by a kind of mass spectrometer that utilizes according to claim 1, it is characterized in that: described adjustment is mated and specifically comprised the following steps:
Through step 1) after, if the concentration of hafnium is greater than 300ppb in sample to be analyzed, then with concentration dilution to the 100 ~ 300ppb of mixed acid solution by hafnium in sample to be analyzed, in described mixed acid solution, the volume fraction of nitric acid is 2%, and the volume fraction of hydrofluorite is 0.1%.
3. the method for hafnium isotope tested by a kind of mass spectrometer that utilizes according to claim 2, it is characterized in that: described mixed acid solution adopt high purity water, through the hydrofluorite of sub-boiling distillation purifying and nitric acid formulated.
4. the method for hafnium isotope tested by a kind of mass spectrometer that utilizes according to claim 1, it is characterized in that: in situation two and situation three, the single addition of hydrofluorite is 5 μ L, the volume fraction of hydrofluorite is 50%, the hydrofluorite of volume fraction 50% adopt high purity water and the hydrofluorite through sub-boiling distillation purifying formulated.
5. the method for hafnium isotope tested by a kind of mass spectrometer that utilizes according to claim 1, it is characterized in that: through step 2) after, in sample to be analyzed, the volume fraction of hydrofluorite controls be less than or equal to 2%.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108459071A (en) * | 2018-03-02 | 2018-08-28 | 中国科学院地质与地球物理研究所 | A kind of method of lutetium-hafnium isotope mass spectrometric measurement |
| CN109580761A (en) * | 2018-11-27 | 2019-04-05 | 中国科学院广州地球化学研究所 | One kind being suitable for the device and method of the absolute micro-zone in situ analysis of hafnium (oxygen) isotope and uranium lead age |
| CN110596231A (en) * | 2019-11-04 | 2019-12-20 | 中国核动力研究设计院 | Method for measuring hafnium isotope abundance by thermal ionization mass spectrometer |
| CN113219110A (en) * | 2021-03-31 | 2021-08-06 | 国核锆铪理化检测有限公司 | Method for determining content of boron and uranium elements in hafnium-based material |
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| US5110546A (en) * | 1991-05-07 | 1992-05-05 | The United States Of America As Represented By The Secretary Of The Interior | Method for locating metallic nitride inclusions in metallic alloy ingots |
| CN101936836B (en) * | 2010-09-07 | 2012-12-12 | 沈阳地质矿产研究所 | Mixed standard solution for plasma mass spectrometer and preparation method |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108459071A (en) * | 2018-03-02 | 2018-08-28 | 中国科学院地质与地球物理研究所 | A kind of method of lutetium-hafnium isotope mass spectrometric measurement |
| CN108459071B (en) * | 2018-03-02 | 2019-05-24 | 中国科学院地质与地球物理研究所 | A kind of method of lutetium-hafnium isotope mass spectrometric measurement |
| CN109580761A (en) * | 2018-11-27 | 2019-04-05 | 中国科学院广州地球化学研究所 | One kind being suitable for the device and method of the absolute micro-zone in situ analysis of hafnium (oxygen) isotope and uranium lead age |
| CN109580761B (en) * | 2018-11-27 | 2020-05-05 | 中国科学院广州地球化学研究所 | Device and method suitable for absolute micro-area in-situ analysis of hafnium isotope and uranium-lead age |
| CN110596231A (en) * | 2019-11-04 | 2019-12-20 | 中国核动力研究设计院 | Method for measuring hafnium isotope abundance by thermal ionization mass spectrometer |
| CN110596231B (en) * | 2019-11-04 | 2022-03-11 | 中国核动力研究设计院 | Method for measuring hafnium isotope abundance by thermal ionization mass spectrometer |
| CN113219110A (en) * | 2021-03-31 | 2021-08-06 | 国核锆铪理化检测有限公司 | Method for determining content of boron and uranium elements in hafnium-based material |
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