CN115639265A - Plasma mass spectrometry method for measuring arsenic content in cobalt - Google Patents

Abstract

The invention belongs to the technical field of chemical detection, and particularly relates to a plasma mass spectrometry method for determining arsenic content in cobalt, which comprises the steps of sample treatment, sample dissolving acid selection, solution acidity selection, precipitant dosage selection, precipitation time selection and determination; the method successfully establishes the method for detecting the content of the arsenic impurity element in the cobalt, can accurately determine the content of the arsenic element in the cobalt by using the experimental conditions listed in the invention content to be 0.5-20 mu g/g, solves the determination work of the content of the arsenic impurity element in the cobalt required in the production, and meets the requirement of detecting the content of the arsenic element in the cobalt material. By adopting the method, the linear correlation coefficient of the element to be detected is more than or equal to 0.999, the recovery rate of the added standard is between 94 and 106 percent, and the precision is better than 5 percent. The method is simple, convenient, rapid and accurate to operate and is suitable for analyzing and detecting the cobalt material.

Description

Plasma mass spectrometry method for measuring arsenic content in cobalt

Technical Field

The invention belongs to the technical field of chemical detection, and particularly relates to a plasma mass spectrometry method for determining arsenic content in cobalt.

Background

The common arsenic content measuring method is mainly an atomic fluorescence spectroscopy technology, which is a measuring method with strong specificity and high maturity and is applied to the detection of arsenic content in various industries. However, the detection technology is rarely adopted at present abroad, and inductively coupled plasma atomic emission spectrometry (ICP-AES) is adopted. The inductively coupled plasma atomic emission technology has been widely used in various industries due to its characteristics of high sensitivity, high accuracy, simultaneous measurement of multiple elements, etc., and has been rapidly developed in the field of elemental analysis, and has slowly replaced the traditional elemental analysis technologies such as Atomic Absorption Spectroscopy (AAS), atomic Fluorescence Spectroscopy (AFS), ultraviolet spectroscopy (UV), etc., as the main detection technology.

As a high-technology industrial project, the cobalt-60 radioactive source project has large domestic demand, the arsenic content in the cobalt adjusting rod component for the cobalt source is high and low, the performance of the component can be directly influenced, the arsenic content is detected by adopting a plasma mass spectrometry, a cobalt matrix seriously interferes the determination of the arsenic content, and a detection method of the arsenic content in the relevant cobalt is not consulted at home at present.

Disclosure of Invention

Aiming at the defects, the invention aims to provide a plasma mass spectrometry method for measuring the arsenic content in cobalt, which adopts acid dissolution and then adds a precipitator to separate arsenic from a cobalt matrix, thereby ensuring the accuracy and stability of a detection result, and having simple and convenient steps, easy operation and high precision.

The technical scheme of the invention is as follows:

a plasma mass spectrometry method for determining arsenic content in cobalt comprises a first step of sample treatment, a second step of sample dissolving acid selection, a third step of solution acidity selection, a fourth step of precipitant dosage selection, a fifth step of precipitation time selection, and a sixth step of determination;

selecting sample dissolving acid, namely dissolving a sample by adopting phosphoric acid;

step four, selecting the dosage of the precipitator;

the dosage of the sodium sulfide solution is 1.0-1.5 mL;

step six, measuring; and diluting the arsenic national standard solution with 1000 mu g/mL according to the detection range of the sample to obtain a working standard solution. Diluting 1000 mu g/mL of rhodium national standard solution into internal standard solution, sequentially measuring working standard solution, blank solution and sample solution on an inductively coupled plasma mass spectrometer, continuously introducing the internal standard solution during measurement, and measuring the content of the element to be measured by a standard curve method, wherein the unit is nanogram per milliliter ng/mL.

Step one, sample treatment;

detecting a cobalt sample with the arsenic content ranging from 0.5 to 20 mu g/g;

taking a turning-shaped chip sample, accurately measuring the sample to 0.1mg, placing the sample in a quartz beaker, adding 15-18 mL of phosphoric acid solution, and placing the sample on an electric heating plate to be heated at low temperature until the sample is completely dissolved.

After the sample is completely dissolved, taking down the sample for cooling, adding 1.0mL of sodium sulfide solution while shaking to completely precipitate arsenic ions, and standing for 3min.

Processing a sample, standing, filtering on a funnel by using quantitative filter paper, washing a beaker by using deionized water for 3 times, filtering washing liquid together, and washing a precipitate for 3-4 times until pink color disappears;

discarding the filtrate, replacing a 100mL volumetric flask, adding a proper amount of nitric acid to dissolve and precipitate, receiving the liquid in the volumetric flask, continuously washing the filter paper for 3 times by using water, collecting the filtrates together, then fixing the volume to a scribed line by using water, and shaking up to be tested;

and carrying out a blank experiment along with the sample, and using the blank experiment as a blank solution to be tested.

And step two, selecting sample dissolving acid, wherein the using amount of phosphoric acid is 15-18 mL.

Selecting acidity of the solution; the concentration of the phosphoric acid solution was 3mol/L.

Selecting the dosage of the precipitator;

the dosage of the sodium sulfide solution is 1.0-1.5 mL.

Step four, selecting the dosage of the precipitator; the amount of sodium sulfide used was 1.0mL.

Selecting the precipitation time;

after the sodium sulfide is added into the sample solution, standing is needed for several minutes to ensure that arsenic ions in the solution are completely precipitated, and when the solution is kept standing for 2.0-4.0 min, the measurement result tends to be stable.

Selecting the precipitation time; the precipitation time is 3min.

The invention has the beneficial effects that:

the method for detecting the content of the arsenic impurity element in the cobalt is successfully established, the content of the arsenic element in the cobalt can be accurately determined to be 0.5-20 mu g/g by using the experimental conditions listed in the invention, the work of determining the content of the arsenic impurity element in the cobalt required in production is solved, and the requirement of detecting the content of the arsenic element in the cobalt material is met.

By adopting the method, the linear correlation coefficient of the element to be detected is more than or equal to 0.999, the standard addition recovery rate is between 94 and 106 percent, and the precision is better than 5 percent. The method is simple, convenient, rapid and accurate to operate and is suitable for analyzing and detecting the cobalt material.

Drawings

FIG. 1 is a flow chart of a plasma mass spectrometry method for determining arsenic content in cobalt according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

A plasma mass spectrometry method for determining arsenic content in cobalt comprises a first step of sample treatment, a second step of sample dissolving acid selection, a third step of solution acidity selection, a fourth step of precipitant dosage selection, a fifth step of precipitation time selection and a sixth step of determination.

Step one, sample treatment;

detecting the cobalt sample with arsenic content in the range of (0.5-20) mu g/g.

Taking a turning-shaped chip sample, accurately measuring the sample to 0.1mg, placing the sample in a quartz beaker, adding 15-18 mL of phosphoric acid solution, and placing the sample on an electric heating plate to be heated at low temperature until the sample is completely dissolved.

After the mixture is taken down and cooled slightly, 1.0mL of sodium sulfide solution is added under shaking to ensure that arsenic ions are completely precipitated without adsorbing a cobalt matrix, so that the effect of separating cobalt from arsenic is achieved, and the mixture is kept stand for 3min.

Then filtering on a funnel by using quantitative filter paper, washing the beaker by using deionized water for 3 times, filtering the washing liquid together, and washing the precipitate for 3-4 times until pink disappears.

Discarding the filtrate, replacing the flask with a 100mL volumetric flask, adding a proper amount of nitric acid to dissolve and precipitate, receiving the liquid in the volumetric flask, continuously washing the filter paper for 3 times with water, collecting the filtrates together, then diluting to a constant volume with water to be scribed, and shaking up to be tested.

And carrying out a blank experiment along with the sample, and using the blank experiment as a blank solution to be tested.

Step two, selecting sample dissolving acid;

common acids for sample dissolution comprise nitric acid, hydrochloric acid, sulfuric acid and phosphoric acid, and the four acids are respectively investigated in experiments, so that the arsenic sulfide precipitate is only dissolved in the nitric acid, the nitric acid cannot be used for dissolving the sample, and the nitric acid can be used for dissolving the precipitate; when hydrochloric acid is used, because the carrier gas used for ICP-MS measurement is high-purity argon, ar can be caused by adopting hydrochloric acid to dissolve a sample ⁺ And Cl ^- Binding causes severe interference with arsenic determination; for sulfuric acid, the precipitate generated by sample pretreatment needs to be filtered by filter paper, and the sulfuric acid has strong oxidizing property and water absorption property and can burn through the filter paper; when phosphoric acid is adopted, the three conditions do not occur, and the sample can be completely dissolved, so the method adopts phosphoric acid to dissolve the sample, and examines the amount of the phosphoric acid.

When the dosage of the phosphoric acid is less than 15mL, the sample is not completely dissolved, and the dosage of the phosphoric acid is 15-18 mL.

Step three, selecting the acidity of the solution;

the concentration of the phosphoric acid solution was 3mol/L.

Step four, selecting the dosage of the precipitator;

the dosage of the sodium sulfide solution is (1.0-1.5) mL, and the dosage of the sodium sulfide selected by the method is 1.0mL, so that the determination requirement can be met.

Step five, selecting precipitation time;

after the sodium sulfide is added into the sample solution, the solution needs to be stood for several minutes to ensure that arsenic ions in the solution are completely precipitated, when the solution is stood for 2.0-4.0 minutes, the measurement result tends to be stable, the fact that the arsenic ions are completely precipitated when the solution is stood for 2.0 minutes proves that the arsenic ions are completely precipitated, and the optimal precipitation time is 3 minutes.

Step six, measuring;

and diluting the arsenic national standard solution with 1000 mu g/mL according to the detection range of the sample to obtain a working standard solution. And diluting the rhodium national standard solution into an internal standard solution by 1000 mu g/mL. And sequentially measuring the working standard solution, the blank solution and the sample solution on an inductively coupled plasma mass spectrometer, continuously introducing the internal standard solution during measurement, and measuring the content of the element to be measured by using a standard curve method, wherein the unit is nanogram per milliliter ng/mL.

It should be noted that, in the description of the present invention, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Further, in the description of the present invention, the meaning of "a plurality" means at least two unless otherwise specified.

In the description of the specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means 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.

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.

In the attached drawings of the disclosed embodiment of the invention, only methods related to the disclosed embodiment are related, other methods can refer to common design, and the same embodiment and different embodiments of the invention can be combined mutually under the condition of no conflict;

the above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that are within the spirit and principle of the present invention are intended to be included in the scope of the present invention.

Claims (10)

1. A plasma mass spectrometry method for determining arsenic content in cobalt comprises a first step of sample treatment, a second step of sample dissolving acid selection, a third step of solution acidity selection, a fourth step of precipitant dosage selection, a fifth step of precipitation time selection and a sixth step of determination;

the method is characterized in that:

selecting sample dissolving acid, namely dissolving a sample by adopting phosphoric acid;

step four, selecting the dosage of the precipitator;

the dosage of the sodium sulfide solution is 1.0-1.5 mL;

step six, determination; and diluting the arsenic national standard solution with 1000 mu g/mL according to the detection range of the sample to obtain a working standard solution. Diluting 1000 mu g/mL of rhodium national standard solution into internal standard solution, sequentially measuring working standard solution, blank solution and sample solution on an inductively coupled plasma mass spectrometer, continuously introducing the internal standard solution during measurement, and measuring the content of the element to be measured by a standard curve method, wherein the unit is nanogram per milliliter ng/mL.

2. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 1, wherein: step one, sample treatment;

detecting a cobalt sample with arsenic content ranging from 0.5 to 20 mu g/g;

taking a turning-shaped chip sample, accurately measuring the sample to 0.1mg, placing the sample in a quartz beaker, adding 15-18 mL of phosphoric acid solution, and placing the sample on an electric heating plate to be heated at low temperature until the sample is completely dissolved.

3. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 2, wherein: after the arsenic ions are completely dissolved, taking down the sample for slight cooling, adding 1.0mL of sodium sulfide solution while shaking to completely precipitate the arsenic ions, and standing for 3min.

4. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 3, wherein: step one, sample treatment, after standing, filtering on a funnel by using quantitative filter paper, washing a beaker for 3 times by using deionized water, filtering a washing liquid together, and washing a precipitate for 3-4 times until pink disappears;

discarding the filtrate, replacing the volumetric flask with a 100mL volumetric flask, adding a proper amount of nitric acid to dissolve and precipitate, receiving the liquid in the volumetric flask, continuously washing the filter paper for 3 times with water, collecting the filtrates together, then adding water to fix the volume to the scribed line, and shaking up to be tested;

and carrying out a blank experiment along with the sample, and using the blank experiment as a blank solution to be tested.

5. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 1, wherein: and step two, selecting sample dissolving acid, wherein the using amount of phosphoric acid is 15-18 mL.

6. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 1, wherein: selecting acidity of the solution; the concentration of the phosphoric acid solution is 3mol/L.

7. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 1, wherein: selecting the dosage of the precipitator;

the dosage of the sodium sulfide solution is 1.0-1.5 mL.

8. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 7, wherein: selecting the dosage of the precipitator; the amount of sodium sulfide used was 1.0mL.

9. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 1, wherein: selecting the precipitation time;

after the sodium sulfide is added into the sample solution, standing is needed for several minutes to ensure that arsenic ions in the solution are completely precipitated, and when the solution is kept standing for 2.0-4.0 min, the measurement result tends to be stable.

10. The method for plasma mass spectrometry of arsenic content in cobalt as claimed in claim 1, wherein: selecting the precipitation time; the precipitation time is 3min.

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