Qualitative and quantitative analysis method for metal cyanide in water body

Abstract

The invention belongs to the field of water pollutant analysis and detection, and relates to a qualitative and quantitative analysis method for metal cyanide in a water body. The method comprises the following steps: loading star-shaped gold nanoparticles on a silicon dioxide substrate to obtain a slide glass, reacting the slide glass with metal cyanide standard solutions with different types of gradient concentrations to obtain a spectrogram of the reacted slide glass under a specific wavelength, and drawing a standard curve according to the corresponding absorbance; reacting the slide with a to-be-detected water sample to obtain a spectrogram of the to-be-detected water sample and absorbance under a specific wavelength, determining the type of the metal cyanide in the to-be-detected water sample according to the fitting degree of the spectrogram, and substituting the absorbance under the specific wavelength into the standard curve to calculate the concentration of the metal cyanide in the to-be-detected water sample. Qualitative and quantitative analysis of the metal cyanide in the water body is completed. The method provided by the invention is simple, convenient and rapid, qualitative and quantitative analysis of the metal cyanide in the water body can be completed by using small spectrum equipment under the condition of only providing the slide glass, and on-site rapid detection is realized.

Description

Technical Field

[0001] The invention belongs to the field of water pollutant analysis and detection, and specifically relates to a qualitative and quantitative analysis method of metal cyanide in water. Background Art

[0002] Metal cyanides are often formed by combining one or more cyanide ions with a single transition metal cation to form a complex. These complexes have a unified structural formula [M(CN) b ] x- , where M represents a transition metal cation such as Au + 、Ag + , Cu 2+ 、Ni 2+ , Fe 2+ 、Co 3+ etc., b is the number of cyanide ions bound to the complex, and x represents the anionic valence of the complex. Metal cyanide is relatively stable under normal conditions, which may cause continuous pollution to water bodies. In some cases, metal cyanide may release cyanide through degradation and splitting, thereby causing continuous pollution to water bodies. Therefore, it has become a compound of general concern to environmental workers. For example, in environmental water samples with a pH of less than 9.3, cyanide ions will be converted into highly toxic HCN. Therefore, in addition to the field of environmental protection and ecology, metal cyanide has also been widely concerned in the mining industry, precious metal recycling industry, and metal surface finishing industry.

[0003] Although metal cyanides have important applications in industries such as metallurgy and electroplating, their severe toxicity and difficulty in natural degradation make them extremely harmful to the environment. Therefore, metal cyanides are strictly monitored in the current water environment standards.

[0004] The current analysis methods for metal cyanide in water bodies are mainly spectrophotometry and electrochemical methods. The spectrophotometry method requires the water sample to be pre-treated by acidification, oxidation, etc., and then an iron-containing reagent is added to form a complex with Prussian blue, and the absorption of the 600-650nm band is detected by spectrophotometry. The electrochemical method mainly monitors the characteristic current or electrode potential generated during the reduction of metal cyanide for detection. The main principle is to apply a specific potential to the electrode so that the cyanide undergoes a redox reaction on the electrode. At the same time, the reaction on the electrode will produce a specific electrical signal. By identifying this specific electrical signal, the detection of metal cyanide can be achieved.

[0005] However, spectrophotometry and electrochemical methods still have some defects in the process of practical application, such as spectrophotometry to determine cyanide content requires pre-treatment, can not achieve real-time, rapid results, difficult to achieve on-site detection. And complex water environment (such as the color of other substances in the water, turbidity, etc.) may also affect the accuracy of spectrophotometry. In order to ensure the stability of the color development reaction, it is convenient to identify the color development reaction, so spectrophotometry is very dependent on the laboratory environment, can not achieve on-site detection and analysis. The most critical thing is that spectrophotometry cannot distinguish between metal cyanide and cyanide, can only measure the content of total cyanide, and thus the use of spectrophotometry to detect the content of metal cyanide in water may lead to a high test result.

[0006] The electrochemical method also faces some problems. Like the spectrophotometric method, the electrochemical method requires real-time monitoring of the characteristic current generated by the reduction of metal cyanide, so the detection process is complicated and on-site detection and analysis cannot be performed. In addition, the electrochemical method will be interfered by other electroactive substances, and the related equipment used also needs to be maintained regularly, otherwise it will be affected by electrode aging and damage, which further increases the detection cost of the electrochemical method. In addition, complex water environments may also cause electrode contamination, resulting in inaccurate results.

[0007] It can be seen that the existing qualitative and quantitative analysis methods of metal cyanide in water bodies have some problems, which make the detection process of metal cyanide in water bodies too complicated and the detection results biased.

[0008] Based on this, the art urgently needs an analytical method for metal cyanide in water that is simple to operate, highly accurate, and capable of rapid on-site detection. Summary of the invention

[0009] In view of the above-mentioned deficiencies in the prior art, the present invention provides a qualitative and quantitative analysis method for metal cyanide in water, which can not only solve the problems of complicated detection process, poor analysis efficiency and deviation in analysis results of traditional spectrophotometry, but also solve the problems that electrochemical method is easily affected by electroactive substances and the maintenance cost of electrochemical equipment is high, and has broader application prospects.

[0010] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0011] The present invention provides a method for qualitative and quantitative analysis of metal cyanide in water, comprising the following steps:

[0012] S1. Prepare a solution of star-shaped gold nanoparticles;

[0013] S2. loading the gold nanoparticles in the prepared star-shaped gold nanoparticle solution onto the surface of the modified silica substrate to obtain a slide;

[0014] S3. Prepare different types of metal cyanide gradient concentration standard solutions;

[0015] S4. Immerse the slides in different types of metal cyanide gradient concentration standard solutions, and obtain the standard solution slide after the reaction between the slide and the standard solution is completed, obtain the standard solution spectrum of the standard solution slide, and draw a standard curve according to the corresponding absorbance, the standard curve passes through the origin;

[0016] S5. Clean the standard solution slide to obtain a clean slide, immerse the clean slide in the water sample to be tested, obtain a water sample slide after the reaction between the clean slide and the water sample to be tested is completed, obtain a water sample spectrum of the water sample slide, compare the water sample spectrum with the standard solution spectrum, and determine the type of metal cyanide contained in the water sample according to the degree of matching between the two;

[0017] S6. Substitute the absorbance of the water sample slide into the standard curve to obtain the content of metal cyanide in the water sample to be tested, and complete the qualitative and quantitative analysis of metal cyanide in the water body.

[0018] Optionally, the method for preparing the star-shaped nanogold particle solution comprises the following steps:

[0019] S1.1. Mixing sodium citrate solution and chloroauric acid solution to react, and obtaining spherical nanogold particle solution after the reaction is completed;

[0020] S1.2. Mix the spherical nanogold particle solution with chloroauric acid solution, hydrochloric acid, silver nitrate solution and ascorbic acid solution under stirring, and obtain the star-shaped nanogold particle solution after the reaction is completed.

[0021] Optionally, in step S1.1:

[0022] The concentration of chloroauric acid solution is 2.0-3.0 mM, and the volume is 50-150 mL;

[0023] The concentration of the sodium citrate solution is 3-4% (w / v), and the volume is 0.5-1.5 mL.

[0024] Optionally, in step S1.2:

[0025] The concentration of chloroauric acid solution is 0.05mM to 0.15mM, and the volume is 5 to 15mL;

[0026] The concentration of hydrochloric acid is 0.5-1.5M, and the volume is 0.5-1.5μL;

[0027] The concentration of silver nitrate solution is 1-3 mM and the volume is 100-200 μL;

[0028] The concentration of the ascorbic acid solution is 50-150 mM, and the volume is 25-75 μL.

[0029] Optionally, the method for preparing the slide comprises the following steps:

[0030] S2.1. Pretreating the silica substrate to expose hydroxyl groups on the surface of the silica substrate;

[0031] S2.2. The pretreated silica substrate was cleaned and immersed in an ethanol solution of 3-aminopropyltrimethoxysilane or an ethanol solution of 3-thiolpropyltrimethoxysilane for modification;

[0032] S2.3. Clean and modify the silica substrate, immerse it in a solution of star-shaped gold nanoparticles, load the star-shaped gold nanoparticles, and obtain a slide.

[0033] Optionally, in step S2.2:

[0034] The concentration of 3-aminopropyltrimethoxysilane in the ethanol solution of 3-aminopropyltrimethoxysilane is 2.5 to 7.5% (w / w);

[0035] The concentration of 3-thiolpropyltrimethoxysilane in the ethanol solution of 3-thiolpropyltrimethoxysilane is 2.5 to 7.5% (w / w).

[0036] Optionally, the metal ion in the metal cyanide is Au[(CN)2] - 、Ag[(CN)2] - 、Cu[(CN)4] 2- 、Ni[(CN)6] 3- 、Co[(CN)6] 3- Any one of .

[0037] Optionally, the gradient concentration of the metal cyanide gradient concentration standard solution is 1 to 500 ppm.

[0038] Optionally, the reaction time of immersing the slide in the standard solution is 3 to 5 minutes.

[0039] Optionally, the reaction time of immersing the clean slide in the water sample to be tested is 3 to 5 minutes.

[0040] Optionally, three identical water samples to be tested are collected for analysis and testing, and the content of metal cyanide in the water samples to be tested is taken as the average value of the three tests.

[0041] Beneficial effects of the present invention:

[0042] (1) The method provided by the present invention is simple and quick. It can complete the qualitative and quantitative analysis of water samples by using a small spectral device, only by providing a slide, and can realize rapid on-site detection, which is more convenient to use.

[0043] (2) The method provided by the present invention can not only avoid the defects of spectrophotometry that it depends on the laboratory environment and can only analyze the overall content of cyanide in the sample, but also avoid the problems of the electrochemical method that the detection process is complicated and the use of precise equipment requires high maintenance costs, and has good practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the color change reaction principle of the slide provided by the present invention.

[0045] Figure 2 The test flow chart of the detection method of the present invention.

[0046] Figure 3 This is the TEM image of the star-shaped gold nanoparticles prepared in Example 1.

[0047] Figure 4 This is the SEM image of the slide prepared in Example 1.

[0048] Figure 5 The slide prepared in Example 1 and Ag(CN)2 - SEM images after action.

[0049] Figure 6 This is a standard curve diagram of the three metal cyanide complex ions in Example 1.

[0050] Figure 7 This is a comparison chart of the spectra of water sample I and water sample II tested in Example 1.

[0051] Figure 8 This is the standard curve diagram of the three metal cyanide complex ions in Example 2.

[0052] Fig. 9 This is a comparison chart of the spectra of water sample I and water sample II tested in Example 2.

[0053] Fig.10 This is a standard curve diagram of three metal cyanide complex ions in Example 3.

[0054] Fig.11 This is a comparison chart of the spectra of water sample I and water sample II tested in Example 3.

[0055] Fig.12 The following is a comparison chart of the spectra of the slide obtained in Verification Example 1 before reaction, after reaction with natural water sample, and after reaction with natural water sample + oxidant.

[0056] Fig.13 The unreacted, ultrapure water-reacted and Ag[(CN)2] - Comparison of slide photos after reaction.

[0057] Fig.14 The carrier obtained in Example 1 and Ag(CN)2 - Comparison of spectra before and after the reaction.

[0058] Fig.15 The carrier obtained in Example 1 and Ag(CN)2 - Thermodynamic image of gold element in the corresponding area before reaction.

[0059] Fig.16 The carrier obtained in Example 1 and Ag(CN)2 - Thermodynamic image of silver element in the corresponding area after reaction.

[0060] Fig.17 The unreacted comparative slide and its Ag[(CN)2] - 、Au[(CN)2] - 、Cu[(CN)4] 2- Comparison of the spectra of these three metal cyanides after reaction.

[0061] Fig.18 This is a SEM image of an unreacted comparative slide.

[0062] Fig.19 For the comparative example, the slide and Ag[(CN)2] - SEM images after reaction.

[0063] Fig. 20 For the comparative example, the slide and Au[(CN)2] - SEM images after reaction.

[0064] Fig.21 For the comparative example, the slide and Cu[(CN)4] 2- SEM images after reaction. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0066] As used herein, the terms "comprises," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0067] "Optional" or "any one" means that the subsequently described matter or event can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0068] The indefinite articles "a" and "an" before the elements or components of the present invention have no limitation on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the quantity obviously refers to the singular form only.

[0069] The terms "one embodiment", "some embodiments", "exemplarily", "specific examples" or "some examples" described in the present invention mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this document, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0070] The numerical range described in the present invention not only includes the point values ​​listed in the embodiments, but also includes any point values ​​not listed between the numerical ranges described in the present invention. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0071] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the field.

[0072] The present invention provides a method for qualitative and quantitative analysis of metal cyanide in water, comprising the following steps:

[0073] S1. Prepare a solution of star-shaped gold nanoparticles;

[0074] S2. loading the gold nanoparticles in the prepared star-shaped gold nanoparticle solution onto the surface of the modified silica substrate to obtain a slide;

[0075] S3. Prepare different types of metal cyanide gradient concentration standard solutions;

[0076] S4. Immerse the slides in different types of metal cyanide gradient concentration standard solutions, and obtain the standard solution slide after the reaction between the slide and the standard solution is completed, obtain the standard solution spectrum of the standard solution slide, and draw a standard curve according to the corresponding absorbance, the standard curve passes through the origin;

[0077] S5. Clean the standard solution slide to obtain a clean slide, immerse the clean slide in the water sample to be tested, obtain a water sample slide after the reaction between the clean slide and the water sample to be tested is completed, obtain a water sample spectrum of the water sample slide, compare the water sample spectrum with the standard solution spectrum, and determine the type of metal cyanide contained in the water sample according to the degree of matching between the two;

[0078] S6. Substitute the absorbance of the water sample slide into the standard curve to obtain the content of metal cyanide in the water sample to be tested, and complete the qualitative and quantitative analysis of metal cyanide in the water body.

[0079] Now combined Figure 1 and Figure 2 The present invention introduces the process of detecting metal cyanide in water, wherein Figure 1 This is the principle of the slide color development reaction provided by the present invention. Figure 2 It is a schematic diagram of the detection process of the present invention. Generally speaking, the surface plasmon of nanomaterials can generate hot electrons, and the life cycle of such hot electrons is in the picosecond to femtosecond level, which is much lower than the time dimension of chemical reactions and cannot effectively carry out chemical reactions. In this embodiment, star-shaped nano-gold particles are loaded on the surface of the carrier. Such star-shaped nano-gold particles can improve the efficiency of generating hot electrons, and in the process of synthesizing the star-shaped nano-gold particles, the citrate ions on the surface will be oxidized by the hot electrons, releasing carbon dioxide, and increasing the reduction potential of the nano-gold particles. This process is an irreversible reaction, and the reaction causes the nano-gold particles to accumulate reduction potential.

[0080] like Figure 1 As shown, the star-shaped gold nanoparticles used in the present invention are free of surfactants and have an exposed surface, which can effectively contact the cyanide ligand of the metal cyanide and transfer electrons, thereby performing a specific reaction. The above characteristics of the star-shaped gold nanoparticles can solve the problem of mismatch between the time dimension of hot electrons and chemical reactions. The reduced metal cyanide will form nanometer or micrometer-sized particles of the corresponding metal on the surface of the slide, showing the color of the corresponding metal nanoparticles, each with an independent absorption wavelength, so that it can be observed by a spectral device.

[0081] The detection principle of the present invention is as follows:

[0082] The present invention utilizes the chemical reaction activity of surface plasmons of star-shaped nanogold particles to allow the star-shaped nanogold particles to undergo a specific reaction with metal cyanide and then reduce the metal cyanide. After the metal cyanide is reduced, the color of the nanogold particles on the slide will change, and the changed color is related to the type and concentration of the metal contained in the metal cyanide, thereby achieving qualitative and quantitative analysis of the type and concentration of metal cyanide in the target water body.

[0083] On this basis, the invention obtains spectra of standard solution slides with gradient concentrations of different types of metal cyanides, draws a standard curve, and then obtains the spectrum of the water sample slide, and then compares it with the spectra of different metal cyanides to select the most consistent metal cyanide, thereby determining the type of metal cyanide in the water sample. Finally, the absorbance corresponding to the spectrum of the water sample slide is substituted into the drawn standard curve to obtain the specific concentration of the target cyanide in the water sample, which can solve the problem of complicated detection process of the existing metal cyanide detection method in water.

[0084] In particular, in some specific embodiments, the slide used in the present invention has a square structure and a size of (3-10) mm*(3-10) mm, such as 3mm*3mm, 4mm*4mm, 5mm*5mm, 6mm*6mm, 7mm*8mm, 10mm*9mm, 10mm*10mm. As long as the side length of the slide is within this range, the slide used in the present invention can be used in conjunction with a simple portable spectroscopic device to conduct on-site rapid detection of water bodies outside the laboratory environment, which is faster.

[0085] In some specific embodiments, the method for preparing the star-shaped nanogold particle solution comprises the following steps:

[0086] S1.1. Mixing sodium citrate solution and chloroauric acid solution to react, and obtaining spherical nano-gold particle solution after the reaction is completed;

[0087] S1.2. Mix the spherical nanogold particle solution with chloroauric acid solution, hydrochloric acid, silver nitrate solution and ascorbic acid solution under stirring, and obtain the star-shaped nanogold particle solution after the reaction is completed.

[0088] In step S1.1:

[0089] The concentration of the chloroauric acid solution is 2.0-3.0 mM. As an example, the concentration of the chloroauric acid solution can be 2.0 mM, 2.1 mM, 2.2 mM, 2.3 mM, 2.4 mM, 2.5 mM, 2.6 mM, 2.7 mM, 2.8 mM, 2.9 mM, or 3.0 mM, as long as the concentration of the chloroauric acid solution is within the range.

[0090] The volume of the chloroauric acid solution is 50 to 150 mL. As an example, the volume of the chloroauric acid solution can be 50 mL, 60 mL, 70 mL, 80 mL, 90 mL, 100 mL, 110 mL, 120 mL, 130 mL, 140 mL, or 150 mL, as long as the volume of the chloroauric acid solution is within the range.

[0091] The concentration of the sodium citrate solution is 3.0-4.0% (w / v). As an example, the concentration of sodium citrate can be 3.0% (w / v), 3.1% (w / v), 3.2% (w / v), 3.3% (w / v), 3.4% (w / v), 3.5% (w / v), 3.6% (w / v), 3.7% (w / v), 3.8% (w / v), 3.9% (w / v), or 4.0% (w / v), as long as the concentration of the sodium citrate solution is within the range.

[0092] The volume of the sodium citrate solution is 0.5 to 1.5 mL. As an example, the volume of the sodium citrate solution can be 0.5 mL, 0.6 mL, 0.7 mL, 0.8 mL, 0.9 mL, 1.0 mL, 1.1 mL, 1.2 mL, 1.3 mL, 1.4 mL, or 1.5 mL, as long as the volume of the sodium citrate solution is within the range.

[0093] In some specific embodiments, the chloroauric acid solution is mixed with the sodium citrate solution under boiling conditions, and the boiling sodium citrate solution is conducive to the generation of spherical gold nanoparticles of uniform size.

[0094] In some specific embodiments, the mixing reaction of the chloroauric acid solution and the sodium citrate solution is carried out under stirring, which also helps to form nano-gold particles of uniform size.

[0095] In some specific embodiments, the stirring speed during the reaction of chloroauric acid solution and citric acid solution is 500-1500 rpm. As an example, the stirring speed during the reaction of chloroauric acid solution and citric acid solution can be 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, as long as the speed is within the range.

[0096] In step S1.2:

[0097] The concentration of the chloroauric acid solution is 0.05mM to 0.15mM. As an example, the concentration of the chloroauric acid solution can be 0.05mM, 0.06mM, 0.07mM, 0.08mM, 0.09mM, 0.10mM, 0.11mM, 0.12mM, 0.13mM, 0.14mM, or 0.15mM, as long as the concentration of the chloroauric acid solution is within the range.

[0098] The volume of the chloroauric acid solution is 5 to 15 mL. As an example, the volume of the chloroauric acid solution can be 5 mL, 6 mL, 7 mL, 8 mL, 9 mL, 10 mL, 11 mL, 12 mL, 13 mL, 14 mL, 15 mL, as long as the volume of the chloroauric acid solution is within the range.

[0099] The concentration of hydrochloric acid is 0.5 to 1.5 M. As an example, the concentration of hydrochloric acid can be 0.5 M, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1.0 M, 1.1 M, 1.2 M, 1.3 M, 1.4 M, or 1.5 M, as long as the concentration of hydrochloric acid is within the range.

[0100] The volume of hydrochloric acid is 0.5 to 1.5 μL. As an example, the volume of hydrochloric acid can be 0.5 μL, 0.6 μL, 0.7 μL, 0.8 μL, 0.9 μL, 1.0 μL, 1.1 μL, 1.2 μL, 1.3 μL, 1.4 μL, or 1.5 μL, as long as the volume of hydrochloric acid is within the range.

[0101] The concentration of the silver nitrate solution is 1.0 to 3.0 mM. As an example, the concentration of the silver nitrate solution can be 1.0 mM, 1.2 mM, 1.4 mM, 1.6 mM, 1.8 mM, 2.0 mM, 2.2 mM, 2.4 mM, 2.6 mM, 2.8 mM, or 3.0 mM, as long as the concentration of the silver nitrate solution is within the range.

[0102] The volume of the silver nitrate solution is 100-200 μL. As an example, the volume of the silver nitrate solution can be 100 μL, 110 μL, 120 μL, 130 μL, 140 μL, 150 μL, 160 μL, 170 μL, 180 μL, 190 μL, or 200 μL, as long as the volume of the silver nitrate solution is within the range.

[0103] The concentration of the ascorbic acid solution is 50-150 mM. As an example, the concentration of the ascorbic acid solution can be 50 mM, 60 mM, 70 mM, 80 mM, 90 mM, 100 mM, 110 mM, 120 mM, 130 mM, 140 mM, or 150 mM, as long as the concentration of the ascorbic acid solution is within the range.

[0104] The volume of the ascorbic acid solution is 25 to 75 μL. As an example, the volume of the ascorbic acid solution can be 25 μL, 30 μL, 35 μL, 40 μL, 45 μL, 50 μL, 55 μL, 60 μL, 65 μL, 70 μL, or 75 μL, as long as the volume of the ascorbic acid solution is within the range.

[0105] In some specific embodiments, the spherical nanogold particle solution is mixed with the chloroauric acid solution, hydrochloric acid, silver nitrate solution, and ascorbic acid solution under more intense stirring, and the stirring speed is 2000-30000 rpm. As an example, the stirring speed can be 2000 rpm, 2100 rpm, 2200 rpm, 2300 rpm, 2400 rpm, 2500 rpm, 2600 rpm, 2700 rpm, 2800 rpm, 2900 rpm, and 30000 rpm, as long as the stirring speed is within the range.

[0106] In particular, the reaction of the spherical nanogold particle solution with the chloroauric acid solution, hydrochloric acid, silver nitrate solution, and ascorbic acid solution can be carried out under vortex conditions. This embodiment does not further limit the specific parameters of the vortex, as long as the reaction requirements are met and star-shaped nanogold particles can be generated.

[0107] In some specific embodiments, the method for preparing the slide comprises the following steps:

[0108] S2.1. Pretreating the silica substrate to expose hydroxyl groups on the surface of the silica substrate;

[0109] S2.2. The pretreated silica substrate was cleaned and immersed in an ethanol solution of 3-aminopropyltrimethoxysilane or an ethanol solution of 3-thiolpropyltrimethoxysilane for modification;

[0110] S2.3. Clean and modify the silica substrate, immerse it in a solution of stellate nanogold particles, load the stellate nanogold particles, and obtain a slide.

[0111] In step S2.1, in order to expose the hydroxyl groups on the surface of the silica substrate, it is necessary to create defects on the surface of the silica substrate. The defects can be created by immersing the silica substrate in piranha etching solution (a mixed solution of concentrated sulfuric acid and hydrogen peroxide), or by using an alkaline solution (such as a sodium hydroxide solution or a potassium hydroxide solution), or by using ozone to treat the surface of the silica substrate, or by other methods that can cause defects on the surface of the silica substrate.

[0112] In step S2.2:

[0113] The concentration of 3-aminopropyltrimethoxysilane in the ethanol solution of 3-aminopropyltrimethoxysilane is 2.5-7.5% (w / w). As an example, the concentration of 3-aminopropyltrimethoxysilane in the ethanol solution of 3-aminopropyltrimethoxysilane can be 2.5% (w / w), 3.0% (w / w), 3.5% (w / w), 4.0% (w / w), 4.5% (w / w), 5.0% (w / w), 5.5% (w / w), 6.0% (w / w), 6.5% (w / w), 7.0% (w / w), and 7.5% (w / w), as long as the concentration of 3-aminopropyltrimethoxysilane in the ethanol solution of 3-aminopropyltrimethoxysilane is within this range.

[0114] Similarly, when an ethanol solution of 3-thiolpropyltrimethoxysilane is selected, the concentration of 3-thiolpropyltrimethoxysilane in the ethanol solution of 3-thiolpropyltrimethoxysilane is 2.5-7.5% (w / w). As an example, the concentration of 3-thiolpropyltrimethoxysilane in the ethanol solution of 3-thiolpropyltrimethoxysilane can be 2.5% (w / w), 3.0% (w / w), 3.5% (w / w), 4.0% (w / w), 4.5% (w / w), 5.0% (w / w), 5.5% (w / w), 6.0% (w / w), 6.5% (w / w), 7.0% (w / w), 7.5% (w / w), as long as the concentration of 3-thiolpropyltrimethoxysilane in the ethanol solution of 3-thiolpropyltrimethoxysilane is within this range.

[0115] In some specific embodiments, the pretreated substrate needs to be immersed in an ethanol solution of 3-aminopropyltrimethoxysilane or an ethanol solution of 3-thiolpropyltrimethoxysilane at a temperature above 45° C. overnight to complete the modification.

[0116] In some specific embodiments, the metal ion in the metal cyanide is Au[(CN)2] - 、Ag[(CN)2] - 、Cu[(CN)4] 2- 、Ni[(CN)6] 3- 、Co[(CN)6] 3- Any one of .

[0117] In some specific embodiments, the gradient concentration of the metal cyanide gradient concentration standard solution is 1 to 500 ppm. As an example, the gradient concentration of the metal cyanide gradient concentration standard solution can be 1 ppm, 5 ppm, 25 ppm, 50 ppm, 100 ppm, 200 ppm, 300 ppm, 400 ppm, and 500 ppm. Of course, the gradient concentration of the metal cyanide standard solution can also be adaptively adjusted according to the actual detection scenarios.

[0118] In some specific embodiments, the reaction time of the slide being immersed in the standard solution is 3 to 5 minutes. For example, the reaction time of the slide being immersed in the standard solution is 3 minutes, 4 minutes, and 5 minutes. Within this time range, the slide can fully react with the metal cyanide in the standard solution, and a significant change in the color of the slide can be observed with the naked eye.

[0119] In some specific embodiments, the reaction time of the clean slide being immersed in the water sample to be tested is 3 to 5 minutes. For example, the reaction time of the clean slide being immersed in the water sample to be tested is 3 minutes, 4 minutes, and 5 minutes. Similarly, if the water sample to be tested contains metal hydride, the color of the clean slide can also be observed to change significantly with the naked eye within this time range.

[0120] The present invention will be further described below by means of specific embodiments:

[0121] Example 1

[0122] S1.1 100 mL of 2.5 mM chlorauric acid solution was heated to boiling, and then 1 mL of 3.3% (w / v) sodium citrate solution was added. The whole process was stirred at a speed of 1000 rpm, and the solution turned red after 5 minutes. Heating was stopped after the solution color stopped changing, and a spherical nano-gold particle solution was obtained, and the particle size of the spherical nano-gold particles was about 15 nm.

[0123] S1.2 Add 200 μL of spherical gold nanoparticles to 10 mL of 0.1 mM aureochloric acid solution, and add 0.1 μL of 1 M hydrochloric acid. Stir at 2500 rpm, and add 150 μL of 2 mM silver nitrate solution and 50 μL of 100 mM ascorbic acid solution. The solution turns blue-green. Stir for 30 seconds to obtain a star-shaped gold nanoparticle solution, the TEM morphology of which is as follows: Figure 3 As shown, combined with the aforementioned inventive principle part of the present invention and Figure 3 It can be seen that the star-shaped nano-gold particles referred to in the present invention are nano-gold particles with spherical nano-gold particles as the core, and a number of spike-like protrusion structures are grown on the surface of the spherical nano-gold particles through reaction.

[0124] S2.1 Pre-treat the glass slide with freshly prepared piranha etching solution, then rinse thoroughly with deionized water and dry. Immerse the glass slide in an ethanol solution containing 5% (w / w) (3-aminopropyl) trimethoxysilane, maintain the solution temperature at 45°C, and let it stand overnight. Take out the glass slide, rinse it with ethanol, blow it dry, and then put it into the nanogold particle solution prepared in S1.2. Let it stand overnight to obtain a blue-green slide with star-shaped nanogold particles on the surface. The SEM morphology of the slide is as follows: Figure 4 shown.

[0125] S3. Preparation of Ag[(CN)2] - 、Au[(CN)2] - 、Cu[(CN)4] 2- The concentrations of the three standard solutions of metal cyanide complex ions are 5ppm, 25ppm, 50ppm, 100ppm, 200ppm and 300ppm respectively.

[0126] S4. Immerse the slides in different types of metal cyanide gradient concentration standard solutions, wait for the slides to react with the standard solutions for 5 minutes to obtain standard solution slides, place the standard solution slides in a handheld spectrometer, obtain a spectrum, and record the absorbance of the slides near 450nm, 530nm, and 610nm. Figure 5 The slide prepared in Example 1 and Ag(CN)2 - SEM morphology after complex ion reaction.

[0127] S5. Use absorbance as the horizontal axis and the concentration of the standard solution as the vertical axis to draw a standard curve. The standard curve is as follows: Figure 6 As shown, the standard curve passes through the origin.

[0128] S6. Prepare water sample I and water sample II to be tested. Water sample I is a clean natural water sample, and water sample II is a water sample with about 200 ppm of Ag(CN)2 artificially added. - The standard liquid slide is cleaned to obtain a clean slide, and the clean slide is immersed in the water sample I to be tested. The clean slide and the water sample I to be tested react for 5 minutes to obtain the water sample I slide. The water sample I slide is placed in a handheld spectrometer to obtain the spectral data of the water sample I to be tested. The water sample I slide is cleaned and immersed in the water sample II to be tested to react for 5 minutes to obtain the water sample II slide to be tested. The spectral data of the water sample II to be tested is obtained. The spectral data of the water sample I to be tested and the spectral data of the water sample II to be tested are arranged into a spectral comparison diagram, which is Figure 7 .from Figure 7It can be found that the absorbance of the slide of water sample I at 450nm does not change, and the absorbance of the slide of water sample II at 450nm is 0.55Abs. By comparing the spectrum of water sample II with the spectrum of the standard solution, it can be known that the metal cyanide contained in water sample II is Ag[(CN)2] - , and then substituted into the standard curve to calculate the Ag[(CN)2] in the water sample II to be tested - The concentration was 209 ppm, while the concentration of metal cyanide in the water sample I to be tested was not detected.

[0129] Example 2

[0130] S1.1 100 mL of 2.5 mM chlorauric acid solution was heated to boiling, and then 1 mL of 3.3% (w / v) sodium citrate solution was added. The whole process was stirred at a speed of 1000 rpm, and the solution turned red after 4 minutes. Heating was stopped after the solution color stopped changing, and a spherical nano-gold particle solution was obtained, and the particle size of the spherical nano-gold particles was about 15 nm.

[0131] S1.2 Add 200 μL of spherical gold nanoparticles to 10 mL of 0.1 mM gold chloride solution, and add 0.1 μL of 1 M hydrochloric acid. While vortexing, add 150 μL of 2 mM silver nitrate solution and 50 μL of 100 mM ascorbic acid solution, and the solution turns blue-green. Keep stirring for 30 seconds to obtain a solution of star-shaped gold nanoparticles.

[0132] S2.1 Pre-treat the glass slide using an ultraviolet ozone generator, then thoroughly wash and dry with deionized water. Immerse the glass slide in an ethanol solution containing 5% (w / w) (3-thiolpropyl)trimethoxysilane, keep the solution temperature at 45°C, and let it stand overnight. Take out the glass slide, wash it with ethanol, blow it dry, and then put it into the nanogold particle solution prepared in S1.2, let it stand overnight, and you can get a blue-green carrier with star-shaped nanogold particles loaded on the surface.

[0133] S3. Preparation of Ag[(CN)2] - 、Au[(CN)2] - 、Cu[(CN)4] 2- The concentrations of the three standard solutions of metal cyanide complex ions are 5ppm, 25ppm, 50ppm, 100ppm, 200ppm and 300ppm respectively.

[0134] S4. Immerse the slides in different types of metal cyanide gradient concentration standard solutions respectively. After the slides react with the standard solutions for 5 minutes, place the slides in the standard solutions. Place the slides in the handheld spectrometer, obtain the spectrum, and record the absorbance of the slides near 450nm, 530nm, and 610nm.

[0135] S5. Use absorbance as the horizontal axis and the concentration of the standard solution as the vertical axis to draw a standard curve. The standard curve is as follows: Figure 8 As shown, the standard curve passes through the origin.

[0136] S6. Prepare water sample I and water sample II to be tested. Water sample I is a clean natural water sample, and water sample II is a water sample with about 100 ppm of Au(CN)2 artificially added. - Natural water sample. Clean the standard liquid slide to obtain a clean slide, immerse the clean slide into the water sample I to be tested, react the clean slide with the water sample I to be tested for 4 minutes to obtain the water sample I slide, place the water sample I slide in a handheld spectrometer to obtain the spectral data of the water sample I to be tested. Clean the water sample I slide and immerse it into the water sample II to be tested and react for 4 minutes to obtain the water sample II slide, obtain the spectral data of the water sample II to be tested, and record that the absorbance of the water sample I slide near 530nm does not change, and the absorbance of the water sample II slide near 530nm is 0.27Abs. The spectral data of water sample I to be tested and the spectral data of water sample II to be tested are arranged into a spectral comparison chart, which is Fig. 9 By comparing the spectrum of the water sample II to be tested with the spectrum of the standard solution, it can be seen that the metal cyanide contained in the water sample II to be tested is Ag[(CN)2] - , and then substituted into the standard curve to calculate the Ag[(CN)2] in the water sample II to be tested - The concentration was 97 ppm, while the concentration of metal cyanide in the water sample I to be tested was not detected.

[0137] Example 3

[0138] S1.1 100 mL of 2.5 mM gold chloride solution was heated to boiling, and then 1 mL of 3.3% (w / v) sodium citrate solution was added. The whole process was stirred at a speed of 2000 rpm, and the solution turned red after 3 minutes. Heating was stopped after the solution color stopped changing, and a spherical nano-gold particle solution was obtained, and the particle size of the spherical nano-gold particles was about 15 nm.

[0139] S1.2 Add 200 μL of spherical gold nanoparticles to 10 mL of 0.1 mM gold chloride solution, and add 0.1 μL of 1 M hydrochloric acid. Stir at 3000 rpm, and add 150 μL of 2 mM silver nitrate solution and 50 μL of 100 mM ascorbic acid solution. The solution turns blue-green. Keep stirring for 30 seconds to obtain a solution of star-shaped gold nanoparticles.

[0140] S2.1 Pre-treat the glass slide with freshly prepared piranha etching solution, then rinse thoroughly with deionized water and dry. Immerse the glass slide in an ethanol solution containing 5% (w / w) (3-aminopropyl) trimethoxysilane, keep the solution temperature at 45°C, and let it stand overnight. Take out the glass slide, rinse it with ethanol, blow it dry, and then put it into the nanogold particle solution prepared in S1.2, let it stand overnight, and you can get a blue-green slide with star-shaped nanogold particles loaded on the surface.

[0141] S3. Preparation of Ag[(CN)2] - 、Au[(CN)2] - 、Cu[(CN)4] 2- The concentrations of the three standard solutions of metal cyanide complex ions are 5ppm, 25ppm, 50ppm, 100ppm, 200ppm and 300ppm respectively.

[0142] S4. Immerse the slides in different types of metal cyanide gradient concentration standard solutions respectively. After the slides react with the standard solutions for 5 minutes, place the slides in the standard solutions and place them in a handheld spectrometer to obtain a spectrum and record the absorbance of the slides near 610 nm.

[0143] S5. Use absorbance as the horizontal axis and the concentration of the standard solution as the vertical axis to draw a standard curve. The standard curve is as follows: Fig.10 As shown, the standard curve passes through the origin.

[0144] S6. Prepare water samples I and II to be tested. Water sample I is a clean natural water sample, and water sample II is a water sample with about 50 ppm of Cu(CN)4 artificially added. 2- Natural water sample. Clean the standard solution slide to obtain a clean slide, immerse the clean slide into the water sample I to be tested, react the clean slide with the water sample I to be tested for 3 minutes to obtain the water sample I slide, place the water sample I slide in a handheld spectrometer to obtain the spectral data of the water sample I to be tested. Clean the water sample I slide and immerse it into the water sample II to be tested and react for 3 minutes to obtain the water sample II slide, obtain the spectral data of the water sample II to be tested, and record that the absorbance of the water sample I slide near 530nm does not change, and the absorbance of the water sample II slide near 530nm is 0.12Abs. The spectral data of water sample I to be tested and the spectral data of water sample II to be tested are arranged into a spectral comparison chart, which is Fig.11 .from Fig.11It can be found that the absorbance of the slide of water sample I at 610nm does not change, and the absorbance of the slide of water sample II at 510nm is 0.12Abs. After comparing the spectrum of water sample II with the spectrum of the standard solution, it can be known that the metal cyanide contained in water sample II is Cu(CN)4 2- , and then substituted into the standard curve to calculate the content of water sample II to be tested Cu(CN)4 2- The concentration was 48 ppm, while the concentration of metal cyanide in the water sample I to be tested was not detected.

[0145] Verification Example 1

[0146] To further demonstrate the stability of the method provided by the present invention, this verification example conducted the following tests:

[0147] After cleaning the slide obtained in Example 1, place it under a handheld spectrometer for analysis to obtain the spectrum before treatment; then place the slide in a natural water sample (ultrapure water) and soak it for 5 minutes, take it out, wipe it dry and place it under a handheld spectrometer to obtain the spectrum of the natural water sample; finally, place the slide in a 5% hydrogen peroxide aqueous solution prepared with ultrapure water, soak it for 5 minutes, take it out, clean it and place it under a handheld spectrometer to obtain the spectrum of the natural water sample + oxidant group under oxidant interference. The comparison chart of the spectra under the three states is as follows: Fig.12 .

[0148] pass Fig.12 It can be seen that the spectral differences between the untreated slide, the slide soaked in natural water samples, and the slide with oxidant added as the interference group are not obvious. In the presence of oxidant as the interfering component, the normal detection requirements can still be met. Therefore, it can be considered that the detection method provided by the present invention has strong stability.

[0149] Verification Example 2

[0150] This verification example describes some parts of the test and analysis process of Example 1 in more detail by combining the accompanying drawings, as follows:

[0151] (1) Fig.13 The topmost slide is the slide without any additional treatment, the middle slide is the slide soaked in ultrapure water, and the bottom slide is the slide soaked in ultrapure water. - It can be found that the slide after being soaked in pure water has no color change compared with the untreated slide, but compared with Ag(CN)2 - The color of the slide after the reaction changes visibly, which proves that it is feasible to conduct qualitative and quantitative analysis of metal cyanide in water by comparing the color change of the slide after the reaction with metal cyanide.

[0152] (2) Fig.14 The carrier obtained in Example 1 and Ag(CN)2 - Comparison of spectra before and after the reaction, where the blue line is the spectrum before the slide reaction, and the orange line is the comparison after the slide reaction. It can be seen that the star-shaped gold nanoparticles on the slide are - The shift in the spectrum after the reaction proves that new substances are generated.

[0153] (3) Fig.15 The carrier obtained in Example 1 and Ag(CN)2 - Thermodynamic image of gold element in the corresponding area before reaction. Fig.16 The carrier obtained in Example 1 and Ag(CN)2 - The thermodynamic image of silver element in the corresponding area after the reaction can prove that the star-shaped gold nanoparticles and Ag(CN)2 - After the reaction, silver element is generated. The specific morphology of silver element is as follows: Figure 5 As shown, the main shape is rod-like.

[0154] Comparative Example

[0155] In order to further prove the accuracy and reliability of the method provided by the present invention, a comparative test is now conducted. This comparative example is to verify the specificity of the star-shaped nanogold particle carrier and metal cyanide in the detection method provided by the present invention. The spherical nanogold particles obtained in step S1.1 are loaded onto a silica substrate to form a comparative example carrier. The specific steps are different from those in Example 1 only in that step S1.2 (the process of converting spherical nanogold particles into star-shaped nanogold particles) is missing, as follows:

[0156] S1.1 100 mL of 2.5 mM chlorauric acid solution was heated to boiling, and then 1 mL of 3.3% (w / v) sodium citrate solution was added. The whole process was stirred at a speed of 1000 rpm, and the solution turned red after 5 minutes. Heating was stopped after the solution color stopped changing, and a spherical nano-gold particle solution was obtained, and the particle size of the spherical nano-gold particles was about 15 nm.

[0157] S2.1 Pre-treat the glass slide with freshly prepared piranha etching solution, then rinse thoroughly with deionized water and dry. Immerse the glass slide in an ethanol solution containing 5% (w / w) (3-aminopropyl) trimethoxysilane, keep the solution temperature at 45°C, and let it stand overnight. Take out the glass slide, rinse it with ethanol, blow it dry, and then put it into the spherical nanogold particle solution prepared in 1.1, let it stand overnight, and you can get a comparative slide with spherical nanogold particles loaded on the surface.

[0158] S3. Preparation of Ag[(CN)2]- 、Au[(CN)2] - 、Cu[(CN)4] 2- The concentrations of the three standard solutions of metal cyanide complex ions are 5ppm, 25ppm, 50ppm, 100ppm, 200ppm and 300ppm respectively.

[0159] S4. Immerse the comparative sample slides in the gradient concentration standard solutions of gold, silver, and copper metal cyanide, respectively, and wait for the comparative sample slides to react with the standard solutions for 5 minutes to obtain the corresponding comparative sample standard solution slides. Place the comparative sample standard solution slides in a handheld spectrometer to obtain spectral data. The unreacted comparative sample slides and the sample slides reacted with Ag[(CN)2] - 、Au[(CN)2] - 、Cu[(CN)4] 2- The comparison of the spectra of these three metal cyanides after reaction is shown in the figure below. Fig.17 The absorbance of the slide was recorded at 450nm, 530nm, and 610nm, and no significant changes were found. - The comparative example slide after the reaction, and Au[(CN)2] - The comparative example slide after the reaction, and the Cu[(CN)4] 2- The comparative slides after the reaction were subjected to SEM analysis, and the corresponding images were Fig.18 , Fig.19 , Fig. 20 Fig.21 It can be found that there is no obvious difference in the SEM imaging of the comparative slides under the above four conditions, which means that the slides carrying spherical gold nanoparticles have no reaction with metal cyanide.

[0160] Through comparative analysis, it can be seen that although both Example 1 and the comparative example can prepare nanogold particle carriers, the spherical nanogold particle carrier obtained in the comparative example cannot produce a specific reaction with metal cyanide like Example 1 to cause the carrier to change color, which proves the importance of the structure of the stellate nanogold particles for their specific reaction with metal cyanide.

[0161] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, they can make improvements or changes based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A qualitative and quantitative analysis method for metal cyanide in water, characterized in that: The following steps are involved: S1. Prepare a solution of star-shaped gold nanoparticles; S2. loading the gold nanoparticles in the prepared star-shaped gold nanoparticle solution onto the surface of the modified silica substrate to obtain a slide; S3. Prepare different types of metal cyanide gradient concentration standard solutions; S4. Immerse the slides in different types of metal cyanide gradient concentration standard solutions, and obtain the standard solution slide after the reaction between the slide and the standard solution is completed, obtain the standard solution spectrum of the standard solution slide, and draw a standard curve according to the corresponding absorbance, the standard curve passes through the origin; S5. Clean the standard solution slide to obtain a clean slide, immerse the clean slide in the water sample to be tested, obtain a water sample slide after the reaction between the clean slide and the water sample to be tested is completed, obtain a water sample spectrum of the water sample slide, compare the water sample spectrum with the standard solution spectrum, and determine the type of metal cyanide contained in the water sample according to the degree of matching between the two; S6. Substitute the absorbance of the water sample slide into the standard curve to obtain the content of metal cyanide in the water sample to be tested, and complete the qualitative and quantitative analysis of metal cyanide in the water body.

2. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 1, characterized in that: The preparation method of the star-shaped nano-gold particle solution comprises the following steps: S1.

1. Mixing sodium citrate solution and chloroauric acid solution to react, and obtaining spherical nano-gold particle solution after the reaction is completed; S1.

2. Mix the spherical nanogold particle solution with chloroauric acid solution, hydrochloric acid, silver nitrate solution and ascorbic acid solution under stirring, and obtain the star-shaped nanogold particle solution after the reaction is completed.

3. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 2, characterized in that: In step S1.1: The concentration of chloroauric acid solution is 2.0-3.0 mM, and the volume is 50-150 mL; The concentration of the sodium citrate solution is 3.0-4.0% (w / v), and the volume is 0.5-1.5 mL.

4. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 2, characterized in that: In step S1.2: The concentration of chloroauric acid solution is 0.05mM to 0.15mM, and the volume is 5 to 15mL; The concentration of hydrochloric acid is 0.5-1.5M, and the volume is 0.5-1.5μL; The concentration of the silver nitrate solution is 1.0 to 3.0 mM and the volume is 100 to 200 μL; The concentration of the ascorbic acid solution is 50-150 mM, and the volume is 25-75 μL.

5. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 1, characterized in that: The method for preparing the slide comprises the following steps: S2.

1. Pretreating the silica substrate to expose hydroxyl groups on the surface of the silica substrate; S2.

2. The pretreated silica substrate was cleaned and immersed in an ethanol solution of 3-aminopropyltrimethoxysilane or an ethanol solution of 3-thiolpropyltrimethoxysilane for modification; S2.

3. Clean and modify the silica substrate, immerse it in a solution of stellate nanogold particles, load the stellate nanogold particles, and obtain a slide.

6. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 5, characterized in that: In step S2.2: The concentration of 3-aminopropyltrimethoxysilane in the ethanol solution of 3-aminopropyltrimethoxysilane is 2.5 to 7.5% (w / w); The concentration of 3-thiolpropyltrimethoxysilane in the ethanol solution of 3-thiolpropyltrimethoxysilane is 2.5 to 7.5% (w / w).

7. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 1, characterized in that: The metal ion in the metal cyanide is Au[(CN)2] - 、Ag[(CN)2] - 、Cu[(CN)4] 2- 、Ni[(CN)6] 3- 、Co[(CN)6] 3- Any one of .

8. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 1, characterized in that: The gradient concentration of the metal cyanide gradient concentration standard solution is 1 to 500 ppm.

9. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 1, characterized in that: The reaction time of the slide being immersed in the standard solution is 3 to 5 minutes; The reaction time of the clean slide being immersed in the water sample to be tested is 3 to 5 minutes.

10. The method for qualitative and quantitative analysis of metal cyanide in water according to claim 1, characterized in that: Three identical water samples were collected for analysis and testing, and the content of metal cyanide in the water samples was taken as the average value of the three tests.

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