Method for analyzing iron ions in acidic water

Abstract

The invention belongs to the technical field of chemical analysis, and particularly relates to a method for analyzing iron ions in acidic water. The method includes: preparing a standard solution; debugging an inductively coupled plasma emission spectrometer, and preparing a sample solution; putting the standard solution into an inductively coupled plasma emission spectrometer, and drawing a standard curve by taking the emission intensity of iron atoms as an X axis and the iron element content as a Y axis; adding 1: 1 hydrochloric acid or hydrogen peroxide into the sample solution to acidize until the pH value is less than 1, putting the sample solution into the inductively coupled plasma emission spectrometer, and measuring the emission intensity of iron atoms in the sample solution; calling the standard curve, and determining the iron element content in the sample solution according to the emission intensity of the iron atoms in the sample solution. The interference of the color of the water sample on analysis is eliminated. The method has the advantages of small dosage of chemical reagents, good detection repeatability, high accuracy, and reduction of the analysis time and the labor intensity.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical analysis, and particularly relates to a method for analyzing iron ions in acidic water. Background Art

[0002] During the experiment, it is usually necessary to determine the iron ions in coal mine acidic water or sewage.

[0003] However, the laboratory generally uses the "o-phenanthroline spectrophotometry", which has a high accuracy for colorless, transparent or translucent water samples, but has a large error when analyzing acidic water, because most acidic water is turbid and opaque, and some are black or brown. The background color of the water sample seriously affects the accuracy of the iron ion analysis data. Therefore, it is necessary to design a method for iron ion analysis in acidic water to solve the above problems. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for analyzing iron ions in acidic water to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for analyzing iron ions in acidic water, comprising the following steps:

[0006] Step S1, preparing a standard solution;

[0007] Step S2, debugging the inductively coupled plasma emission spectrometer and preparing the sample solution;

[0008] Step S3, placing the standard solution into an inductively coupled plasma emission spectrometer, and drawing a standard curve with the emission intensity of iron atoms as the X-axis and the iron content as the Y-axis;

[0009] Step S4, adding 1:1 hydrochloric acid or hydrogen peroxide to the sample solution to acidify it to a pH less than 1, placing the sample solution into the inductively coupled plasma emission spectrometer, and measuring the emission intensity of iron atoms in the sample solution;

[0010] Step S5, calling the standard curve, and determining the iron content in the sample solution according to the emission intensity of the iron atoms in the sample solution.

[0011] Furthermore, the step S1 includes:

[0012] Each element was labeled with 1000ug / ml to prepare a 50ug / ml mixed standard. 2.5ml of the 1000ppm mixed standard solution was taken and the volume was fixed to 50ml to prepare a 50ug / ml mixed standard solution.

[0013] Furthermore, the step S2 comprises:

[0014] Step S21, debugging the test mode of the inductively coupled plasma emission spectrometer, adjusting the exposure time to 10s for UV and 10s for visible, adjusting the RF power to 1150W for UV and 1150W for visible, the nebulizer gas flow rate to 0.50L / min for UV and 0.50L / min for visible, adjusting the capture full spectrum to UV-no and visible-no, adjusting the cooling gas flow rate to 12L / min, and adjusting the auxiliary gas flow rate to 0.5L / min;

[0015] Step S22, adjusting the acquisition parameters of the inductively coupled plasma emission spectrometer, adjusting the pump speed to 50RPM, and adjusting the flushing pump speed to 50RPM.

[0016] Furthermore, the step S2 further includes:

[0017] Step S23, preparing the sample solution, the gas source, the exhaust, the voltage stabilizer, the host, the atomization chamber, the sample injection tube and the computer software.

[0018] Furthermore, the inductively coupled plasma emission spectrometer includes a plasma light source, an RF generator, a liquid injector, a nebulizer, a torch and a detector, wherein the liquid injector, the nebulizer and the torch are connected in sequence, the plasma light source and the RF generator are arranged in the torch, and the detector is provided with a photomultiplier tube and a grating.

[0019] Further, the step S4 includes:

[0020] Step S41, using a liquid injector to introduce the sample solution into a nebulizer to atomize the sample solution;

[0021] Step S42, introducing argon carrier gas into the atomizer, generating a plasma torch using the plasma light source in the torch tube, and using the argon carrier gas to bring the atomized sample solution into the plasma torch;

[0022] Step S43, using the plasma torch and the RF generator to ionize the atomized sample solution to achieve atomization, ionization and excitation, and using the detector to detect the characteristic spectrum emitted by the iron atoms at the time of excitation or ionization to obtain the emission intensity of the iron atoms in the sample solution.

[0023] Technical effects and advantages of the present invention:

[0024] 1. For sample pretreatment, only acidification is required. No reagents or test papers such as sodium acetate, hydroxylamine hydrochloride, o-phenanthroline, or Congo red test paper are required.

[0025] 2. Eliminates the interference of water sample color on analysis.

[0026] 3. This method requires less chemical reagents, has good detection repeatability and high accuracy, and can reduce analysis time and labor intensity.

[0027] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A flow chart of a method for analyzing iron ions in acidic water according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] like Figure 1 As shown, a method for analyzing iron ions in acidic water according to an embodiment of the present invention comprises the following steps:

[0032] Step S1, preparing a standard solution;

[0033] Step S2, debugging the inductively coupled plasma emission spectrometer and preparing the sample solution;

[0034] Step S3, placing the standard solution into an inductively coupled plasma emission spectrometer, and drawing a standard curve with the emission intensity of iron atoms as the X-axis and the iron content as the Y-axis;

[0035] Step S4, adding 1:1 hydrochloric acid or hydrogen peroxide to the sample solution to acidify it to a pH less than 1, placing the sample solution into the inductively coupled plasma emission spectrometer, and measuring the emission intensity of iron atoms in the sample solution;

[0036] Step S5, calling the standard curve, and determining the iron content in the sample solution according to the emission intensity of the iron atoms in the sample solution.

[0037] In this embodiment, before using the inductively coupled plasma emission spectrometer to test the sample solution, the instrument status is checked first: after the instrument displays "spectrometer optimization" and "success", click "log browsing" in the lower left corner of the instrument to observe the values ​​of X and Y. X and Y are within ±3 for the best, and it is recommended to adjust within ±3 <XY <±10. If the X and Y values ​​are not within the normal range, the knobs on the back of the instrument can be adjusted to the normal range. After the dashboard interface shows success, the sample can be tested.

[0038] When using an inductively coupled plasma emission spectrometer to test a sample solution, specifically include: 1. Method selection: Double-click "File Manager" on the homepage interface, double-click "Methods and Data", click "Methods", copy the sample template to be used, click "Analysis Data", paste the copied template, rename the copied sample template with the sample name and date, double-click to open this file, and load it into the workspace. 2. Sample information input: In the sample list interface, click "+ Add" to add the required number of rows. Enter the sample name under the list "Label"; enter the number of measurements under "Repeat", generally each sample is measured 3 times; select unknown under "Sample Type" for cleaning and samples to be tested; select STD under STD1...STD5, select "BLK" under blank. If the sample is diluted, enter the dilution multiple of the sample under "Dilution Factor", and the sample will automatically display 1 if it is not diluted. Measure the sample under the same conditions as the calibration curve. 3. Sample operation: Click Save in the upper left corner of the interface, confirm, and then click Run. Then click the lower left corner of the instrument and perform the analysis operation according to the prompts. The emission intensity of iron atoms in the test sample is used to check the iron content on the calibration curve. Before and after the analysis of inorganic samples, flush the system with 5% HNO3 for 5 minutes, flush the system with deionized water for 5 minutes, and use high-purity water for blank test.

[0039] In the pretreatment of water samples, most acidic water with black or brown color contains high hydrogen sulfide, and the water is black and smelly. The sample solution needs to be processed in a fume hood with good ventilation. If there is precipitation in the acidic water, it is necessary to add 1:1 hydrochloric acid or hydrogen peroxide to acidify it to a pH less than 1, mix it well, and dissolve the acid-soluble substances in the sample. Most of these precipitates are rust. After acidification, the insoluble iron in the water sample is released and processed to ensure the accuracy of the analysis data. Therefore, for sample pretreatment, only acid acidification is needed, and no reagents and test papers such as sodium acetate, hydroxylamine hydrochloride, o-phenanthroline, and Congo red test paper are needed. Secondly, the interference of water sample color on analysis is eliminated. The method uses less chemical reagents, has good detection repeatability, high accuracy, and can reduce analysis time and labor intensity.

[0040] Optionally, the step S1 includes:

[0041] Each element was labeled with 1000ug / ml to prepare a 50ug / ml mixed standard. 2.5ml of the 1000ppm mixed standard solution was taken and the volume was fixed to 50ml to prepare a 50ug / ml mixed standard solution.

[0042] In this embodiment, the inorganic solution is prepared as shown in the following table:

[0043]

[0044] Optionally, step S2 includes:

[0045] Step S21, debugging the test mode of the inductively coupled plasma emission spectrometer, adjusting the exposure time to 10s for UV and 10s for visible, adjusting the RF power to 1150W for UV and 1150W for visible, the nebulizer gas flow rate to 0.50L / min for UV and 0.50L / min for visible, adjusting the capture full spectrum to UV-no and visible-no, adjusting the cooling gas flow rate to 12L / min, and adjusting the auxiliary gas flow rate to 0.5L / min;

[0046] Step S22, adjusting the acquisition parameters of the inductively coupled plasma emission spectrometer, adjusting the pump speed to 50RPM, and adjusting the flushing pump speed to 50RPM.

[0047] Optionally, the step S2 further includes:

[0048] Step S23, preparing the sample solution, the gas source, the exhaust, the voltage stabilizer, the host, the atomization chamber, the sample injection tube and the computer software.

[0049] In this embodiment, sample preparation refers to processing and volume fixing of samples in advance according to the methods of raw oil ashing and naphtha extraction, and preparing them for standby use. Gas source preparation refers to opening liquid argon (purity greater than 99.996%) in the gas cylinder room, opening the liquid argon switch of the functional column in the analysis room, and checking that the argon partial pressure is between 6-6.5 bar. Exhaust preparation refers to first turning on the ICP exhaust fan switch in the distribution box of the instrument analysis room (first turn on the blue switch, then turn on the black switch), and then turning on the manual switch above the ICP instrument, and the wind speed is required to reach 10m / s. Stabilizer preparation refers to turning on the stabilizer power switch (behind the host), then pressing the green button on the right side of the switch, hearing the sound of the stabilizer turning on, and checking that the stabilizer fan is normal. Host preparation: Turn on the instrument power switch (the black knife switch at the bottom left rear side of the instrument), check that the LED lights on the right rear side of the instrument are all on, wait for about 1 minute, and confirm the "network" connection of the computer. Preparation of the spray chamber means that the atomizer for analyzing organic solutions needs to be replaced with an inorganic solution atomizer chamber, the center tube needs to be replaced with a φ2mm quartz center tube, and the atomizer needs to be installed. Preparation of the sample injection tube means that the sample inlet and outlet tubes for analyzing inorganic substances are white, the sample injection tube is φ0.64mm, and the discharge tube is φ1.02mm. Preparation of computer software means turning on the computer, double-clicking the desktop icon, and entering the software operation interface. In addition, it also includes online preparation, by clicking "Dashboard", double-clicking "Dashboard-iCAP 7000", selecting "i CAP 7000", and clicking OK.

[0050] Optionally, the inductively coupled plasma emission spectrometer includes a plasma light source, an RF generator, a liquid injector, a nebulizer, a torch and a detector, wherein the liquid injector, the nebulizer and the torch are connected in sequence, the plasma light source and the RF generator are arranged in the torch, and a photomultiplier tube and a grating are arranged in the detector.

[0051] In this embodiment, the liquid injector is configured as a peristaltic pump.

[0052] Optionally, step S4 includes:

[0053] Step S41, using a liquid injector to introduce the sample solution into a nebulizer to atomize the sample solution;

[0054] Step S42, introducing argon carrier gas into the atomizer, generating a plasma torch using the plasma light source in the torch tube, and using the argon carrier gas to bring the atomized sample solution into the plasma torch;

[0055] Step S43, using the plasma torch and the RF generator to ionize the atomized sample solution to achieve atomization, ionization and excitation, and using the detector to detect the characteristic spectrum emitted by the iron atoms at the time of excitation or ionization to obtain the emission intensity of the iron atoms in the sample solution.

[0056] In this embodiment, the iron atoms in acidic water emit a characteristic spectrum when excited or ionized. The strength of the characteristic spectrum is related to the atomic concentration in the sample solution. By comparing it with the standard solution, the content of iron in the sample solution can be quantitatively determined. The characteristic spectrum line of iron atoms is: 259.94

[0057] 238.204. Next, argon carrier gas was introduced into the nebulizer using the nebulizer gas inlet.

[0058] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for analyzing iron ions in acidic water, characterized in that: The following steps are involved: Step S1, preparing a standard solution; Step S2, debugging the inductively coupled plasma emission spectrometer and preparing the sample solution; Step S3, placing the standard solution into an inductively coupled plasma emission spectrometer, and drawing a standard curve with the emission intensity of iron atoms as the X-axis and the iron content as the Y-axis; Step S4, adding 1:1 hydrochloric acid or hydrogen peroxide to the sample solution to acidify it to a pH less than 1, placing the sample solution into the inductively coupled plasma emission spectrometer, and measuring the emission intensity of iron atoms in the sample solution; Step S5, calling the standard curve, and determining the iron content in the sample solution according to the emission intensity of the iron atoms in the sample solution.

2. The method for analyzing iron ions in acidic water according to claim 1, characterized in that: The step S1 comprises: Each element was labeled with 1000ug / ml to prepare a 50ug / ml mixed standard. 2.5ml of the 1000ppm mixed standard solution was taken and the volume was fixed to 50ml to prepare a 50ug / ml mixed standard solution.

3. The method for analyzing iron ions in acidic water according to claim 2, characterized in that: The step S2 comprises: Step S21, debugging the test mode of the inductively coupled plasma emission spectrometer, adjusting the exposure time to 10s for UV and 10s for visible, adjusting the RF power to 1150W for UV and 1150W for visible, the nebulizer gas flow rate to 0.50L / min for UV and 0.50L / min for visible, adjusting the capture full spectrum to UV-no and visible-no, adjusting the cooling gas flow rate to 12L / min, and adjusting the auxiliary gas flow rate to 0.5L / min; Step S22, adjusting the acquisition parameters of the inductively coupled plasma emission spectrometer, adjusting the pump speed to 50RPM, and adjusting the flushing pump speed to 50RPM.

4. The method for analyzing iron ions in acidic water according to claim 3, characterized in that: The step S2 further comprises: Step S23, preparing the sample solution, the gas source, the exhaust, the voltage stabilizer, the host, the atomization chamber, the sample injection tube and the computer software.

5. The method for analyzing iron ions in acidic water according to claim 3, characterized in that: The inductively coupled plasma emission spectrometer comprises a plasma light source, an RF generator, a liquid injector, an atomizer, a torch and a detector. The liquid injector, the atomizer and the torch are connected in sequence. The torch is provided with the plasma light source and the RF generator, and the detector is provided with a photomultiplier tube and a grating.

6. The method for analyzing iron ions according to claim 5, characterized in that: The step S4 comprises: Step S41, using a liquid injector to introduce the sample solution into a nebulizer to atomize the sample solution; Step S42, introducing argon carrier gas into the atomizer, generating a plasma torch using the plasma light source in the torch tube, and using the argon carrier gas to bring the atomized sample solution into the plasma torch; Step S43, using the plasma torch and the RF generator to ionize the atomized sample solution to achieve atomization, ionization and excitation, and using the detector to detect the characteristic spectrum emitted by the iron atoms at the time of excitation or ionization to obtain the emission intensity of the iron atoms in the sample solution.

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