阅读说明：本技术 一种大气颗粒物标准样品的制备方法 (Preparation method of standard sample of atmospheric particulates ) 是由 程依光 于 2020-11-09 设计创作，主要内容包括：本发明公开了一种大气颗粒物标准样品制备方法,用于大气颗粒物重金属元素分析的X射线荧光光谱标定。其制备步骤包括根据目标浓度称取一定量的标准土壤样品,经盐酸初步消解后,通过硝酸、氢氟酸、高氯酸混合液加热消解,然后沉积在特氟龙滤膜上并烘干。采用本发明方法可以制备浓度为1～100ug/cm～2的样品,具有一定的浓度梯度,并保持良好的均匀性和稳定性。(The invention discloses a preparation method of a standard sample of atmospheric particulates, which is used for X-ray fluorescence spectrum calibration of analysis of heavy metal elements in the atmospheric particulates. The preparation method comprises the steps of weighing a certain amount of standard soil samples according to target concentration, preliminarily digesting by hydrochloric acid, heating and digesting by mixed liquor of nitric acid, hydrofluoric acid and perchloric acid, depositing on a Teflon filter membrane and drying. The method can prepare the product with the concentration of 1-100 ug/cm 2 The sample has a certain concentration gradient, and good uniformity and stability are maintained.)

1. A preparation method of a standard sample of atmospheric particulates is characterized by comprising the following steps:

weighing required standard soil according to the concentration of atmospheric particulates to obtain a sample;

putting the weighed sample into a container, and adding deionized water to enable the sample to reach a wet state;

adding hydrochloric acid into the container, shaking up and heating;

after heating, adding nitric acid, hydrofluoric acid and perchloric acid into the container, and heating;

when the sample in the container is sticky, taking down the container, and adding deionized water into the container until the sample is completely dissolved to obtain a sample solution;

transferring the dissolved sample solution into a beaker, heating, and then flatly placing a filter membrane into the beaker to cover the sample solution with the filter membrane;

heating the beaker again until the liquid in the beaker evaporates;

putting the beaker into an oven for baking, taking out the beaker after drying, and taking out the filter membrane from the beaker to obtain a standard sample attached to the filter membrane;

the filters with attached standard samples were tested.

2. The method for preparing the atmospheric particulate standard sample according to claim 1, wherein when the standard soil is weighed, the weight of the weighed standard soil is 0.0500g, and the weighing precision is 0.0001 g.

3. The method of claim 1, wherein the container is a teflon crucible.

4. The method for preparing a standard sample of atmospheric particulates according to claim 1, wherein the amount of hydrochloric acid added is 5ml when the hydrochloric acid is added to the container.

5. The method for preparing a standard sample of atmospheric particulates according to claim 1, wherein when the nitric acid, the hydrofluoric acid and the perchloric acid are added to the container, the amounts of the nitric acid, the hydrofluoric acid and the perchloric acid are 5ml, 4ml and 2ml, respectively;

after adding nitric acid, hydrofluoric acid and perchloric acid, the heating time is 2-3 hours, and the heating temperature is 180-210 ℃.

6. The method for preparing the standard sample of the atmospheric particulates according to claim 1, wherein the content of the sample is 0.8-1 ml when the sample is in a viscous state.

7. The method for preparing the atmospheric particulate standard sample according to claim 1, wherein after the sample solution is transferred to the beaker, the beaker is heated at a temperature of 130 to 160 ℃ for 1.5 to 2.5 hours;

the baking temperature of the oven is 86-92 ℃, and the baking time is 2.5-3.2 hours.

8. The method for preparing the standard sample of the atmospheric particulates according to claim 1, characterized in that the hydrochloric acid is concentrated hydrochloric acid with a mass fraction of 36-38%; the nitric acid is concentrated nitric acid, and the mass fraction of the nitric acid is 66-68%; the mass fraction of the hydrofluoric acid is 36-40%; the mass fraction of the perchloric acid is 65-70%.

9. The method for preparing a standard sample of atmospheric particulates according to claim 1, wherein the standard soil is any one of soil component analysis standard substances GBW07401 to GBW07408, GBW07423 to GBW07430, and GBW07446 to GBW 07457.

10. The method for preparing the standard sample of atmospheric particulates according to claim 1, wherein the filter membrane is a Teflon filter membrane, and the pore size of the filter membrane is 0.20-0.23 μm.

Technical Field

The invention relates to an atmospheric particulate detection technology, in particular to a preparation method of an atmospheric particulate standard sample.

Background

A large amount of dust can be generated in production and life of cities, heavy metal pollutants are enriched on atmospheric particulates and harm human health through various ways, and an X-ray fluorescence analysis method is used for an atmospheric heavy metal online analyzer and has the characteristics of simple structure, convenience in use, quickness and accuracy in detection and large monitoring range. However, the filter membranes used for calibration by the method are imported from abroad and are expensive, so that the popularization and the application of the on-line analysis of the atmospheric particulate heavy metal are greatly influenced.

Disclosure of Invention

In order to solve the defects in the prior art, the invention aims to provide a method for preparing a standard sample of atmospheric particulates, which can reduce the cost of the standard sample and can prepare the standard sample with better uniformity and stability.

The technical scheme adopted by the invention for solving the technical problems is as follows: a preparation method of a standard sample of atmospheric particulates comprises the following steps:

weighing required standard soil according to the concentration of atmospheric particulates to obtain a sample;

putting the weighed sample into a container, and adding deionized water to enable the sample to reach a wet state;

adding hydrochloric acid into the container, shaking up and heating;

after heating, adding nitric acid, hydrofluoric acid and perchloric acid into the container, and heating;

when the sample in the container is sticky, taking down the container, and adding deionized water into the container until the sample is completely dissolved to obtain a sample solution;

transferring the dissolved sample solution into a beaker, heating, and then flatly placing a filter membrane into the beaker to cover the sample solution with the filter membrane;

heating the beaker again until the liquid in the beaker evaporates;

putting the beaker into an oven for baking, taking out the beaker after drying, and taking out the filter membrane from the beaker to obtain a standard sample attached to the filter membrane;

the filters with attached standard samples were tested.

Optionally, when the standard soil is weighed, the weight of the weighed standard soil is 0.0500g, and the weighing precision is 0.0001 g.

Optionally, the container is a teflon crucible.

Alternatively, when hydrochloric acid is added to the container, the amount of hydrochloric acid added is 5 ml.

Optionally, when adding nitric acid, hydrofluoric acid and perchloric acid into the container, the adding amount of the nitric acid, the hydrofluoric acid and the perchloric acid is 5ml, 4ml and 2ml respectively;

after adding nitric acid, hydrofluoric acid and perchloric acid, the heating time is 2-3 hours, and the heating temperature is 180-210 ℃.

Optionally, when the sample is viscous, the content of the sample is 0.8-1 ml.

Optionally, after the sample solution is transferred to the beaker, the temperature of heating the beaker is 130-160 ℃, and the heating time is 1.5-2.5 hours;

the baking temperature of the oven is 86-92 ℃, and the baking time is 2.5-3.2 hours.

Optionally, the hydrochloric acid is concentrated hydrochloric acid with the mass fraction of 36-38%; the nitric acid is concentrated nitric acid, and the mass fraction of the nitric acid is 66-68%; the mass fraction of the hydrofluoric acid is 36-40%; the mass fraction of the perchloric acid is 65-70%.

Optionally, the standard soil is any one of soil component analysis standard substances GBW 07401-GBW 07408, GBW 07423-GBW 07430 and GBW 07446-GBW 07457.

Optionally, the filter membrane is a teflon filter membrane, and the aperture of the filter membrane is 0.20-0.23 μm.

By adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:

1. according to the invention, soil is transferred to the filter membrane, so that an atmospheric particulate sample is simulated, the preparation of the sample is more economic, and the cost is lower;

2. the preparation method of the invention can realize that different elements are mixed in the filter membrane;

3. the preparation method can adjust the solution adaptation according to the required standard sample elements and concentration, and is very flexible;

4. by adopting the preparation method, the prepared standard sample has good uniformity and stability;

5. the method can prepare the product with the concentration of 1-100 ug/cm²Has a certain concentration gradient.

Drawings

FIG. 1 is a flow chart of the preparation of the present invention;

FIG. 2 is a schematic diagram of the sampling distribution of the present invention when examining a standard sample.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

Fig. 1 is a flow chart of a method for preparing a standard sample according to the present invention, which specifically includes the following steps:

and S1, weighing the required standard soil according to the concentration of the atmospheric particulates to obtain a sample.

Wherein the standard soil is any one selected from among soil component analysis standard substances GBW07401 to GBW07408, GBW07423 to GBW07430 and GBW07446 to GBW 07457. The invention simulates the components in the atmospheric particulates by analyzing the standard substances through the soil components.

The concentration of the standard sample prepared by the invention is known, so that when the standard soil is weighed, the amount of the standard soil to be weighed, such as 0.0500g, is obtained according to the concentration value of the standard sample, and it is noted that when the standard soil is weighed, the precision of the weighing amount needs to reach 0.0001g so as to improve the concentration precision of the prepared standard sample.

And S2, putting the weighed sample into a container, and adding deionized water to enable the sample to be in a wet state.

In one embodiment of the present invention, the container is a teflon crucible with a capacity of 50ml, and because the standard soil has water absorption, the sample is only wetted when adding the deionized water, so as to avoid the deionized water remaining in the teflon crucible, that is, the amount of the added deionized water should be completely absorbed by the sample.

S3, adding hydrochloric acid into the container, shaking up and heating.

In this step, 5ml of hydrochloric acid was added to a polytetrafluoroethylene crucible, and after the sample was submerged in the amount of hydrochloric acid, the sample was shaken and heated to dissolve the sample.

In the step, the added hydrochloric acid is concentrated hydrochloric acid, the mass fraction of the hydrochloric acid is 36-38%, and the grade of the hydrochloric acid is guaranteed to be superior grade pure.

And S4, after the heating is finished, adding nitric acid, hydrofluoric acid and perchloric acid into the container, and then heating.

In the step, the adding amount of the nitric acid, the hydrofluoric acid and the perchloric acid is respectively 5ml, 4ml and 2ml, wherein the nitric acid is concentrated nitric acid and the mass fraction is 66-68%; the mass fraction of hydrofluoric acid is 36-40%; the mass fraction of perchloric acid is 65-70%, and the three grades are high grade purity.

In addition, in the step, the heating time is 2-3 hours, and the heating temperature is 180-210 ℃.

And (3) observing the polytetrafluoroethylene crucible while heating, when the sample in the polytetrafluoroethylene crucible is viscous, taking down the polytetrafluoroethylene crucible when the volume of the sample in the polytetrafluoroethylene crucible is 0.8-1 ml, and then adding 20ml of deionized water into the polytetrafluoroethylene crucible until the sample is completely dissolved to obtain a sample solution.

S5, taking a beaker, transferring the dissolved sample solution into the beaker, heating for 1.5-2.5 hours at the temperature of 130-160 ℃, and flatly placing the filter membrane into the beaker when the volume of the sample in the beaker is 3ml, so that the filter membrane covers the sample solution.

Wherein the filter membrane is a Teflon filter membrane which is a hydrophilic polytetrafluoroethylene filter membrane, and the aperture of the filter membrane is 0.20-0.23 μm.

And S6, heating the beaker again until no obvious liquid is found in the beaker.

And S7, putting the beaker into an oven for baking, taking out the beaker after drying, and taking out the filter membrane from the beaker to obtain the standard sample attached to the filter membrane.

In the step, the baking temperature of the oven is 86-92 ℃, and the baking time is 2.5-3.2 hours.

S8, testing the filter membrane attached with the standard sample.

When the standard sample is tested, the homogeneity of the standard sample is tested by an analysis of variance method.

According to the method for preparing standard samples of the present invention, ten sets of standard samples were prepared according to the above method. When the standard samples are tested, three test points are taken on each standard sample and are respectively positioned at the center point of the filter membrane, the radius 1/2 of the filter membrane and the radius of the filter membrane, the distribution of the sampling points is shown in figure 2, after sampling, the content of Mn is detected, F values between the standard samples and in the standard samples are calculated according to the analysis result of variance so as to carry out uniformity detection, and the result shows that the statistic F is less than F (0.05, 9 and 20), so that the standard samples represent that the difference between all the test points in the standard samples and between the standard samples is not obvious, namely the standard samples are uniform.

The preparation process conditions for the ten sets of standard samples are shown in table 1 below.

TABLE 1

The results of the measurements on ten groups of standard samples are shown in Table 2, and the unit of measurement is ug/cm²。

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Other technical features than those described in the specification are known to those skilled in the art, and are not described herein in detail in order to highlight the innovative features of the present invention.