Detection method for measuring mercury content in slag concentrate by atomic fluorescence spectrometry

Abstract

The invention belongs to the field of chemical analysis of spectrometry, and particularly relates to a method for detecting mercury content in copper slag concentrate by atomic fluorescence spectrometry. The method comprises the following specific steps: fully dissolving a copper slag concentrate sample to be measured by hydrochloric acid, nitric acid and ammonium bifluoride, and introducing generated mercury atom steam into an atomic fluorescence spectrometer for measurement in a (3 + 97) nitric acid medium by taking stannous chloride as a reducing agent and argon as carrier gas. The method has the characteristics of low detection lower limit, wide measurement range, high accuracy, good precision, strong practicability and the like.

Description

Technical Field

[0001] The invention belongs to the field of spectral chemical analysis, and in particular relates to a detection method for determining mercury content in copper slag concentrate by atomic fluorescence spectrometry. Technical Background

[0002] Copper slag represents the residual product from the pyrometallurgical processing of copper concentrate. Because concentrates are obtained from copper ores of varying mineral composition and processed using various smelting techniques, the slag may contain significant amounts of copper and other valuable metals. Mercury is a heavy metal that is widely present in the environment and is highly toxic and accumulative. Found in the Earth's crust and ores, it is highly volatile. Accurately measuring mercury content in materials to provide reliable data reference for production workshops is crucial. Selecting a method that accurately measures mercury content in slag concentrate is crucial.

[0003] Currently, there are no national standards for mercury in materials such as copper slag concentrates in China. Existing techniques for measuring mercury, such as those for copper concentrate, rely on traditional aqua regia sample analysis. The basic principle of this standard method is that after the sample is fully dissolved in aqua regia, potassium permanganate oxidizes the reducing ions, followed by hydroxylamine hydrochloride reduction of the excess oxidant. The absorbance is then measured by cold atomic absorption spectrometry in a sulfuric acid medium. Within a certain range, the mercury vapor concentration and absorbance conform to Beer's law.

[0004] The method described in this standard has the following deficiencies: (1) If the sample is simply dissolved with hydrochloric acid or nitric acid, the silicon-containing material may not be completely dissolved, resulting in inaccurate determination of the mercury content. (2) The determination must be made immediately after the reduction with hydroxylamine hydrochloride. When there are many samples, the absorbance of the later samples will be low, resulting in inaccurate determination results. (3) This method involves taking the test solution into the absorption bottle and then immediately adding stannous chloride for determination. Slow operation can cause mercury vapor to evaporate and overflow, resulting in inaccurate determination results. The operator must be extremely careful and meticulous in each test step, otherwise it is very easy to introduce human uncertainty. Summary of the Invention

[0005] Based on conventional fluorescence spectrometry for mercury analysis, this method, developed based on the characteristics of mercury in slag concentrate, pre-dries the sample to remove free water. The slag concentrate sample is then weighed and dissolved in hydrochloric acid, nitric acid, and hydrofluoric acid. Potassium dichromate is then added to convert all mercury in the sample into high-valent mercury. The mercury in the sample is then analyzed by atomic fluorescence spectrometry. This method boasts a low detection limit, a wide measurement range, high accuracy, good precision, and strong practicality.

[0006] In order to achieve the above object, the specific technical solution adopted by the present invention is: a method for determining the mercury content in copper slag concentrate by atomic fluorescence spectrometry, the detection method specifically comprising the following steps:

[0007] S1) Weigh a certain amount of copper slag concentrate to be tested, add ammonium bifluoride, hydrochloric acid, and nitric acid in sequence and heat and decompose to obtain a mixed solution:

[0008] S2) heating the mixed solution obtained in S1) to boil to drive out nitrogen oxides, and obtaining a solution to be tested after the test solution becomes clear and no brown gas is left in the beaker;

[0009] S3) adding an oxidant to the solution to be tested obtained in S2) and continuing to boil. If the solution fades, continue to add potassium dichromate solution dropwise until the color does not fade. Remove the solution, cool it, transfer it to a 100 mL volumetric flask, dilute it to the mark with water, and mix it;

[0010] S4) starting the atomic fluorescence spectrometer and setting the measurement parameters;

[0011] S5) preparing a mercury working curve matching the copper matrix and measuring the solution to be tested;

[0012] S6) obtaining the mass concentration of mercury from the mercury working curve, and calculating the mercury content in the copper slag concentrate.

[0013] Furthermore, the copper slag concentrate in said S1) has a silicon content greater than 20% and a sulfur content less than 8%.

[0014] Furthermore, the specific steps of S1) are:

[0015] S1.1) Dry the weighed copper slag concentrate in an oven at 100-110°C for 1.8-2.2 hours;

[0016] S1.2) Place the slag concentrate treated in S1.1) in a container, moisten with water, add ammonium bifluoride, shake well, then add hydrochloric acid and heat for 3-5 minutes at a temperature not exceeding 150°C;

[0017] S1.3) Cool to 70-80°C, add nitric acid, and continue heating until the sample is completely dissolved to obtain a mixed solution.

[0018] Furthermore, the amount of ammonium bifluoride added is 1.5-2 g; the amount of hydrochloric acid added is 15 mL, and the amount of nitric acid added is 30 mL.

[0019] Further, the specific steps of S2) are:

[0020] S2.1) First, purge the sample obtained in S1) with water to a volume of at least 50 mL. Heat to a boil on a 300°C electric hot plate for 3–5 minutes to remove nitrogen oxides.

[0021] S2.2) Once the test solution becomes clear and no brown gas remains in the beaker, the test solution is obtained.

[0022] Furthermore, the oxidant in S3) is a potassium dichromate solution with a concentration of 50 g / L, and the amount added is 2 mL.

[0023] Further, the specific steps of S4) are:

[0024] The stabilization time of the atomic fluorescence spectrometer in S4.1) is: 15 minutes.

[0025] S4.2) Use nitric acid as the carrier gas, adjust the carrier gas flow rate to 700 mL / min, use stannous chloride solution as the reducing agent, use a mercury high-intensity hollow cathode lamp as the excitation light source, the atomizer height is 10 mm, and the atomizer temperature is 200°C.

[0026] Further, the specific steps of S5) are:

[0027] S5.1) Pipette 0.0 mL, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL, and 5.00 mL of the mercury standard solution into a 100 mL volumetric flask, add 5 mL of nitric acid solution and 1 mL of potassium dichromate solution, dilute to the mark with water, and mix thoroughly;

[0028] S5.2) Under the same conditions as for measuring the test solution, measure its absorbance intensity according to the instrument operating procedures, subtract the absorbance intensity of the "zero" concentration standard solution, and draw a working curve with mercury concentration as the horizontal axis and fluorescence intensity as the vertical axis.

[0029] Furthermore, the concentration of the mercury standard solution is 0.1 μg / mL; the concentration of the potassium dichromate solution is 50 g / L.

[0030] Furthermore, in said S6), the mercury content in the slag concentrate is calculated according to the following formula:

[0031]

[0032] Where:

[0033] ρ—the mass concentration of mercury obtained from the working curve, in micrograms per milliliter (μg / mL);

[0034] V1—total volume of test solution, in milliliters (mL);

[0035] V2—volume of the test solution aliquoted, in milliliters (mL);

[0036] V3—the volume of the diluted test solution, in milliliters (mL);

[0037] m0—mass of the sample, in grams (g);

[0038] The calculated result is expressed to two decimal places. If the mass fraction is less than 0.10%, it is expressed to three decimal places.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention provides a method for detecting mercury content in slag concentrate. The method involves drying the sample to remove moisture that could affect the analysis results, and then using stannous chloride as a reducing agent for determination using an atomic fluorescence spectrometer. The copper slag concentrate sample to be tested is first fully dissolved in hydrochloric acid, nitric acid, and ammonium bifluoride. The mercury in the sample is then completely oxidized to a high-valent state using potassium dichromate. The generated mercury atomic vapor is then introduced into an atomic fluorescence spectrometer for determination in a nitric acid medium using stannous chloride as a reducing agent, argon as a carrier gas, and argon as a carrier gas.

[0041] The specific beneficial effects are as follows:

[0042] (1) This method uses ammonium bifluoride to mix thoroughly with the sample before dissolving the sample, and then adds hydrochloric acid and nitric acid to dissolve the sample and dissolve the silicon-containing material, thus avoiding the phenomenon of incomplete dissolution caused by conventional acid addition, which leads to inaccurate mercury content determination.

[0043] (2) Adding potassium dichromate as an oxidant can completely convert the low-valent mercury in the sample into a high-valent state, ensuring that the mercury in the sample is completely determined.

[0044] (3) The use of atomic fluorescence measurement avoids the requirement of immediate measurement after reduction with the unstable reducing agent hydroxylamine hydrochloride used in cold atomic absorption measurement, and the measurement results are not affected by time.

[0045] (4) This method does not involve the problem of adding stannous chloride to the test solution immediately after the test solution is dispensed into the absorption bottle, and the result shows good measurement stability.

[0046] The present invention has the characteristics of low detection limit, wide measurement range, high accuracy, good precision and strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The present invention is a flowchart of a method for determining mercury content in copper slag concentrate using atomic fluorescence spectrometry. DETAILED DESCRIPTION

[0048] The present invention will be further explained and illustrated below through specific implementation plans. It should be understood that the purpose of the following implementation plans is to make the technical solutions of the present invention clearer and easier to understand, and is not limited to the scope of protection of the claims.

[0049] like Figure 1 As shown, the present invention provides a method for detecting the amount of mercury in copper slag concentrate by atomic fluorescence spectrometry, comprising the following steps:

[0050] a. The sample was dried in an oven at 105°C for 2 hours;

[0051] b. Weigh 0.1000g of sample into a 200mL beaker, moisten with a small amount of water, add ammonium bifluoride and hydrochloric acid, and heat on a hot plate at low temperature;

[0052] c. Remove and cool slightly, add nitric acid and shake well;

[0053] d. Blow water through the test dish and the beaker wall to about 50mL, heat and boil to remove nitrogen oxides, and wait until the test solution becomes clear and there is no brown gas in the beaker;

[0054] e. Add 2 mL of potassium dichromate solution and continue boiling. If the solution fades, add potassium dichromate solution dropwise until the color does not fade. Remove the solution and cool.

[0055] f. Transfer to a 100 mL volumetric flask, dilute to the mark with water, and mix well.

[0056] g. Stabilize the instrument in advance and adjust the carrier gas flow rate to 300 mL / min.

[0057] h. Take the solution to be tested (f) and place it in the corresponding volumetric flask, dilute it to the measuring volume with water, and mix well.

[0058] i. On an atomic fluorescence spectrometer, using nitric acid as the carrier, stannous chloride solution as the reducing agent, and a mercury high-intensity hollow cathode lamp as the excitation light source, measure the fluorescence intensity of mercury in the sample solution, subtract the fluorescence intensity of the blank solution accompanying the sample, and find the corresponding mercury concentration from the working curve.

[0059] j. Plotting the mercury working curve: Pipette 0.0 mL, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL, and 5.00 mL of the mercury standard solution into a 100 mL volumetric flask. Add 5 mL of concentrated nitric acid solution and 1 mL of potassium dichromate solution, dilute to the mark with water, and mix thoroughly.

[0060] k. Under the same conditions as those for the test sample, measure its fluorescence intensity according to the instrument operating procedures, subtract the fluorescence intensity of the "zero" concentration standard solution, and draw a working curve with mercury concentration as the horizontal axis and fluorescence intensity as the vertical axis.

[0061] Step a

[0062] Slag concentrate samples contain various impurities, some of which are highly hygroscopic. Therefore, it is crucial to remove free water from the sample before analysis. Before weighing, the sample should be dried in a 105°C oven for 2 hours. After removal, place it in a desiccator and cool it to room temperature before analysis.

[0063] Step b

[0064] Weigh 0.1000 g of slag concentrate sample and place it in a 200 mL beaker. Moisten it with a small amount of water blown from a washing bottle. Use a plastic pipette to add 1 mL of saturated ammonium bifluoride solution. Increase the amount of ammonium bifluoride added when the silicon content is high. Mix it thoroughly with the sample. Use a liquid addition tube to add 15 mL of hydrochloric acid (ρ = 1.19 g / mL). Heat it on a hot plate at low temperature for 3 to 5 minutes, and the temperature shall not exceed 150 ° C.

[0065] Step c

[0066] Remove and cool slightly, add 30mL of nitric acid (ρ=1.42g / mL), shake well and continue heating at low temperature.

[0067] Step d

[0068] Blow water through the glass and the beaker to about 50mL, heat and boil to drive out nitrogen oxides, wait until the test solution becomes clear and there is no brown gas in the beaker; dissolve the soluble salts in the sample, remove and cool to room temperature;

[0069] Step e

[0070] Add 2 mL of potassium dichromate solution (50 g / L) and continue boiling. If the solution fades, continue to add potassium dichromate solution until the color does not fade. Remove the solution and cool it.

[0071] Step f

[0072] Transfer to a 100 mL volumetric flask, dilute to the mark with water, and mix well.

[0073] Step g

[0074] Turn on the atomic fluorescence spectrophotometer in advance and stabilize it for 30 minutes. Turn on the argon gas and adjust the carrier gas flow rate to 300 mL / min, the negative high voltage to 220V~280V, the lamp current to 15~30 mA, and the atomizer height to 10mm to ignite and preheat the mercury lamp.

[0075] Step h

[0076] Take the solution to be tested (f) into the corresponding volumetric flask, dilute it to the measuring volume with water, and mix well.

[0077] Step i

[0078] On an atomic fluorescence spectrometer, using nitric acid (7+93) as the carrier, stannous chloride solution (15 g / L) as the reducing agent, and a mercury high-intensity hollow cathode lamp as the excitation light source, the fluorescence intensity of mercury in the sample solution was measured, and the fluorescence intensity of the blank solution accompanying the sample was subtracted to obtain the corresponding mercury concentration from the working curve.

[0079] Step j

[0080] Plotting of mercury working curve: Pipette 0.0 mL, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL, and 5.00 mL of mercury standard solution (0.1 μg / mL) into a 100 mL volumetric flask, add 5 mL of concentrated nitric acid solution (ρ=1.42 g / mL) and 1 mL of potassium dichromate solution (50 g / L), dilute to the scale with water, and mix well.

[0081] Step k

[0082] Under the same conditions as those for the test sample, measure its fluorescence intensity according to the instrument operating procedures, subtract the fluorescence intensity of the "zero" concentration standard solution, and draw a working curve with mercury concentration as the horizontal axis and fluorescence intensity as the vertical axis.

[0083] Mercury calculation formula:

[0084]

[0085] Where:

[0086] ρ—the mass concentration of mercury obtained from the working curve, in micrograms per milliliter (μg / mL);

[0087] V1—total volume of test solution, in milliliters (mL);

[0088] V2—volume of the test solution aliquoted, in milliliters (mL);

[0089] V3—the volume of the diluted test solution, in milliliters (mL);

[0090] m0—mass of the sample, in grams (g).

[0091] The calculated result is expressed to two decimal places. If the mass fraction is less than 0.10%, it is expressed to three decimal places.

[0092] Example 1

[0093] A method for determining the mercury content in copper slag concentrate by atomic fluorescence spectrometry comprises the following steps:

[0094] a. The sample was dried in an oven at 105°C for 2 hours;

[0095] b. Weigh 0.1000 g of slag concentrate sample and place it in a 200 mL beaker. Moisten it with a small amount of water blown from a washing bottle. Use a plastic pipette to add 1 mL of saturated ammonium bifluoride solution. Increase the amount of ammonium bifluoride added when the silicon content is high. Mix it thoroughly with the sample. Use a liquid addition tube to add 15 mL of hydrochloric acid (ρ = 1.19 g / mL). Heat on a hot plate at low temperature for 3 to 5 minutes, and the temperature shall not exceed 150°C.

[0096] c. Remove and cool slightly, add 30mL of nitric acid (ρ=1.42g / mL), shake well and continue heating at low temperature.

[0097] d. Blow water through the glass and the beaker to a volume of about 50 mL. Heat to a boil to remove nitrogen oxides. Wait until the test solution becomes clear and there is no brown gas in the beaker to dissolve the soluble salts in the sample. Remove the sample and cool to room temperature.

[0098] e. Add 2 mL of potassium dichromate solution (50 g / L) and continue boiling. If the solution fades, continue to add potassium dichromate solution until the color does not fade. Remove the solution and cool it.

[0099] f. Transfer to a 100 mL volumetric flask, dilute to the mark with water, and mix well.

[0100] g. Turn on the atomic fluorescence spectrophotometer in advance and stabilize it for 30 minutes. Turn on the argon gas and adjust the carrier gas flow rate to 300mL / min, the negative high voltage to 220V~280V, the lamp current to 15~30mA, and the atomizer height to 10mm. Ignite and preheat the mercury lamp.

[0101] h. Take the solution to be tested (f) and place it in the corresponding volumetric flask, dilute it to the measuring volume with water, and mix well.

[0102] i. On an atomic fluorescence spectrometer, using nitric acid (7+93) as the carrier, stannous chloride solution (15 g / L) as the reducing agent, and a mercury high-intensity hollow cathode lamp as the excitation light source, measure the fluorescence intensity of mercury in the sample solution. Subtract the fluorescence intensity of the blank solution accompanying the sample and find the corresponding mercury concentration from the working curve.

[0103] j. Drawing of mercury working curve

[0104] Pipette 0.0 mL, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL, and 5.00 mL of mercury standard solution (0.1 μg / mL) into a 100 mL volumetric flask, add 5 mL of concentrated nitric acid solution (ρ=1.42 g / mL) and 1 mL of potassium dichromate solution (50 g / L), dilute to the scale with water, and mix well.

[0105] k. Under the same conditions as those for the test sample, measure its fluorescence intensity according to the instrument operating procedures, subtract the fluorescence intensity of the "zero" concentration standard solution, and draw a working curve with mercury concentration as the horizontal axis and fluorescence intensity as the vertical axis.

[0106] Repeat the above operation to obtain the mercury results of three slag concentrate samples as shown in Table 1:

[0107] Table 1

[0108]

[0109] From the data in the table above, we can see that the RSDs of the mercury multi-cup results are between 3.4% and 4.0%, all less than 5.0%, indicating that the sample results have good precision.

[0110] Spike recovery experiment:

[0111] Different amounts of mercury were added to the sample during weighing in step b of Example 1. The other steps were the same as in Example 1. The spiked recovery was calculated based on the analysis results to verify the accuracy of the method. The results are shown in Table 2:

[0112] Table 2

[0113]

[0114] The data in Table 2 shows that the slag concentrate samples were dried to remove moisture that could affect the analysis results, and then analyzed using an atomic fluorescence spectrometer using stannous chloride as a reducing agent. The copper slag concentrate samples were thoroughly dissolved in hydrochloric acid, nitric acid, and ammonium bifluoride. The mercury vapor generated was then introduced into an atomic fluorescence spectrometer in a nitric acid medium using stannous chloride as a reducing agent, argon as a carrier gas, and argon as a carrier gas for analysis. The spiked mercury recovery rates were measured between 98.00 and 100.10, demonstrating the high accuracy of this method.

[0115] The present invention provides a detailed description of a method for determining mercury content in copper slag concentrate using atomic fluorescence spectrometry, as provided in the examples of this application. The above examples are intended only to facilitate understanding of the method and core concepts of this application. Furthermore, those skilled in the art will appreciate variations in the specific implementation and scope of application based on the concepts of this application. Therefore, this specification should not be construed as limiting this application.

[0116] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different nouns to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" and "comprising" mentioned throughout the specification and claims are open-ended terms, so they should be interpreted as "including / including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve the technical problems within a certain error range and basically achieve the technical effects. The subsequent description in the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application, and is not used to limit the scope of the present application. The scope of protection of the present application shall be as defined in the attached claims.

[0117] It should also be noted that the terms "include," "comprises," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a product or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such product or system. In the absence of further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the product or system comprising the element.

[0118] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0119] The above description shows and describes several preferred embodiments of the present application. However, as previously mentioned, it should be understood that the present application is not limited to the form disclosed herein and should not be construed as excluding other embodiments. Instead, the present application can be used in various other combinations, modifications, and environments and can be modified within the scope of the application concept described herein through the above teachings or technology or knowledge in the relevant field. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present application should be protected by the claims appended hereto.

Claims

1. A method for determining the mercury content in copper slag concentrate by atomic fluorescence spectrometry, characterized in that: The detection method specifically comprises the following steps: S1) Weigh a certain amount of copper slag concentrate to be tested, add ammonium bifluoride, hydrochloric acid, and nitric acid in sequence and heat and decompose to obtain a mixed solution: S2) heating the mixed solution obtained in S1) to boil to drive out nitrogen oxides, and obtaining a solution to be tested after the test solution becomes clear and no brown gas is left in the beaker; S3) adding an oxidant to the solution to be tested obtained in S2) and continuing to boil. If the solution fades, continue to add potassium dichromate solution dropwise until the color does not fade. Remove the solution, cool it, transfer it to a 100 mL volumetric flask, dilute it to the mark with water, and mix it; S4) starting the atomic fluorescence spectrometer and setting the measurement parameters; S5) preparing a mercury working curve and measuring the solution to be tested; S6) Substituting the mass concentration of mercury obtained from the mercury working curve into the calculation formula to obtain the mercury content in the copper slag concentrate.

2. The detection method according to claim 1, wherein The copper slag concentrate in S1) has a silicon content greater than 20% and a sulfur content less than 8%.

3. The detection method according to claim 1, wherein The specific steps of S1) are: S1.1) Dry the weighed copper slag concentrate in an oven at 100-110°C for 1.8-2.2 hours; S1.2) Place the slag concentrate treated in S1.1) in a container, moisten with water, add ammonium bifluoride, shake well, then add hydrochloric acid and heat for 3-5 minutes at a temperature not exceeding 150°C; S1.3) Cool to 70-80°C, add nitric acid, and continue heating until the sample is completely dissolved to obtain a mixed solution.

4. The detection method according to claim 3, characterized in that The amount of ammonium bifluoride added is 1.5-2 g; the amount of hydrochloric acid added is 15 mL, and the amount of nitric acid added is 30 mL.

5. The detection method according to claim 1, wherein The specific steps of S2) are: S2.1) First, purge the sample obtained in S1) with water to a volume of at least 50 mL. Heat to a boil on a 300°C electric hot plate for 3–5 minutes to remove nitrogen oxides. S2.2) Once the test solution becomes clear and no brown gas remains in the beaker, the test solution is obtained.

6. The detection method according to claim 1, characterized in that The oxidant in S3) is a potassium dichromate solution with a concentration of 50 g / L, and the amount added is 2 mL.

7. The detection method according to claim 1, characterized in that The specific steps of S4) are: The stabilization time of the atomic fluorescence spectrometer in S4.1) is: 15 minutes; S4.2) Use nitric acid as the carrier gas, adjust the carrier gas flow rate to 700 mL / min, use stannous chloride solution as the reducing agent, use a mercury high-intensity hollow cathode lamp as the excitation light source, the atomizer height is 10 mm, and the atomizer temperature is 200°C.

8. The detection method according to claim 1, wherein The specific steps of S5) are: S5.1) Pipette 0.0 mL, 0.50 mL, 1.00 mL, 2.00 mL, 3.00 mL, 4.00 mL, and 5.00 mL of the mercury standard solution into a 100 mL volumetric flask, add 5 mL of nitric acid solution and 1 mL of potassium dichromate solution, dilute to the mark with water, and mix thoroughly; S5.2) Under the same conditions as for measuring the test solution, measure its absorbance according to the instrument operating procedures, subtract the absorbance of the "zero" concentration standard solution, and plot a working curve with mercury concentration as the horizontal axis and fluorescence intensity as the vertical axis.

9. The detection method according to claim 8, characterized in that The concentration of the mercury standard solution is 0.1 μg / mL; the concentration of the potassium dichromate solution is 50 g / L.

10. The detection method according to claim 1, characterized in that The calculation formula in the S6) is as follows: Where: ρ—the mass concentration of mercury obtained from the working curve, in micrograms per milliliter (μg / mL); V1—total volume of test solution, in milliliters (mL); V2—volume of the test solution aliquoted, in milliliters (mL); V3—the volume of the diluted test solution, in milliliters (mL); m0—mass of the sample, in grams (g); The calculated result is expressed to two decimal places. If the mass fraction is less than 0.10%, it is expressed to three decimal places.

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