Rapid detection method for mercury content

Abstract

The invention discloses a rapid detection method for mercury content. The rapid detection method comprises the following steps: preparing a titanium carbide / gold nanoparticle composite material; the titanium carbide / gold nanoparticle composite material is mixed with a to-be-detected sample treatment solution, a TMB solution and an H2O2 solution are added, and Hg < 2 + > in the to-be-detected sample treatment solution is utilized to carry out peroxidase activity enhanced titanium carbide / gold nanoparticle composite material catalysis TMB and H2O2 chromogenic reaction; measuring the RGB value after the color development reaction; and calculating the mercury content in the to-be-detected sample according to the RGB value. According to the rapid detection method for the mercury content, a titanium carbide / gold nanoparticle composite material with high enzyme mimetic activity is prepared, TMB is used as a chromogenic substrate, a TMB and H2O2 chromogenic reaction platform based on h-Ti3C2 / AuNPs peroxidase activity is built, the mercury content in a to-be-detected sample is calculated according to an RGB value obtained after chromogenic reaction, and rapid and high-sensitivity detection of mercury in the sample is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of food analysis, and more specifically, to a rapid detection method for mercury content. Background Art

[0002] Mercury is one of the highly toxic heavy metal elements in the environment. It is persistent, highly toxic and bioaccumulative. Mercury is enriched and accumulated in the human body through bioaccumulation and biomagnification, posing potential health risks to the human body.

[0003] At present, the analytical detection methods and technologies for mercury in agricultural products are relatively mature, mainly inductively coupled plasma mass spectrometry (ICP-MS) and atomic fluorescence spectrometry (AFS). Although these analytical methods have advantages such as high sensitivity and detection limit, the instrument cost is relatively high, and the operation process is cumbersome and time-consuming, which is not conducive to on-site use.

[0004] Therefore, a rapid detection method for mercury content is urgently needed. Summary of the invention

[0005] The purpose of the present invention is to provide a method for rapid detection of mercury content to solve the above-mentioned problems in the prior art, which can be applicable to on-site and real-time detection of mercury ions, and the detection process is fast, low-cost, simple and reliable.

[0006] The present invention provides a method for rapid detection of mercury content, which comprises:

[0007] Preparation of titanium carbide / gold nanoparticle composites;

[0008] After the titanium carbide / gold nanoparticle composite material was mixed with the sample treatment solution, TMB solution and H 2 O 2 Solution, in order to utilize the Hg in the solution treated with the sample to be tested 2+ Titanium carbide / gold nanoparticle composites with enhanced peroxidase activity catalyze TMB and H 2 O 2 The color reaction;

[0009] Determine the RGB value after the color reaction;

[0010] The mercury content in the sample to be tested is calculated based on the RGB value.

[0011] The rapid detection method for mercury content as described above, wherein preferably, the preparation of the titanium carbide / gold nanoparticle composite material specifically comprises:

[0012] Preparation of hydroxylated two-dimensional transition titanium carbide;

[0013] Titanium carbide / gold nanoparticle composites with peroxidase activity were prepared using hydroxylated two-dimensional transitional titanium carbide as a reducing agent and template.

[0014] In the above-mentioned rapid detection method for mercury content, preferably, the preparation of hydroxylated two-dimensional transition titanium carbide specifically comprises:

[0015] 1 g Ti 3 AlC 2 Place in a polytetrafluoroethylene beaker, add 25 mL of hydrofluoric acid to the beaker, and then stir and react at 40°C for 10 h;

[0016] After the reaction is completed, the solid product is collected and washed to obtain a two-dimensional transition metal carbide Ti 3 C 2 ;

[0017] Add 0.25 g Ti into the PTFE beaker. 3 C 2 and 20 mL of 5% NaOH solution;

[0018] After stirring for 2 h at room temperature under a magnetic stirrer, the mixture was centrifuged and washed with water. After discarding the supernatant, 20 mL of dimethyl sulfoxide was added.

[0019] After centrifugation, the solid was redispersed in 75 mL of oxygen-free water, ultrasonicated for 5 h in an ultrasonic cleaner, and then centrifuged at 8000 r / min for 1 h to obtain a single / few layers of hydroxylated titanium carbide h-Ti 3 C 2 The solution was gray-green, and the supernatant was collected and used later.

[0020] The rapid detection method for mercury content as described above, wherein preferably, the titanium carbide / gold nanoparticle composite material with peroxidase activity is prepared by using hydroxylated two-dimensional transition titanium carbide as a reducing agent and template, specifically comprising:

[0021] Accurately measure 5 mL of single / few-layer hydroxylated titanium carbide h-Ti 3 C 2 The solution was placed in a 10 mL glass bottle, and 0.10 g of polyvinyl pyrrolidone was added to the solution, which was then mixed with a 5 μL-30 μL chloroauric acid solution with a concentration of 0.1 g / mL. After ultrasonication for 2 h, the solution was allowed to stand for 4 h to obtain a titanium carbide / gold nanoparticle composite material with peroxidase activity.

[0022] In the above-mentioned rapid detection method for mercury content, preferably, after the titanium carbide / gold nanoparticle composite material is mixed with the sample treatment solution to be tested, TMB solution and H 2 O2 Solution, in order to utilize the Hg in the solution treated with the sample to be tested 2+ Titanium carbide / gold nanoparticle composites with enhanced peroxidase activity catalyze TMB and H 2 O 2 The color reaction includes:

[0023] Treating the sample to be tested to obtain a treated solution of the sample to be tested;

[0024] Take 20 μL of titanium carbide / gold nanoparticle composite material solution and mix it with 100 μL of the test solution, then add 50 μL of 0.01 M TMB solution and 100 μL of 30% H 2 O 2 The solution was diluted to 1.0 mL with 0.2 mol / L NaAc-HAc buffer at pH 4.0 and shaken at 37°C for 30 min.

[0025] In the above-mentioned rapid detection method for mercury content, preferably, the processing of the sample to be tested to obtain the sample processing liquid specifically includes:

[0026] Take 5.0 g of the sample to be tested, place it in the inner tank of the microwave digestion furnace, add 8 mL of HNO 3 and 2 mL H 2 O 2 ;

[0027] Perform microwave digestion heating according to the preset heating program;

[0028] After microwave digestion and heating, the sample was transferred to a 250 mL volumetric flask and made up to volume with pure water.

[0029] In the above-mentioned rapid detection method for mercury content, preferably, the microwave digestion and heating according to a preset heating program specifically includes:

[0030] In the preheating stage, the temperature is raised from room temperature to 160°C within 5 minutes and maintained for 5 minutes;

[0031] In the insulation stage, the temperature was raised from 160°C to 200°C within 5 min and maintained for 15 min;

[0032] In the cooling stage, the temperature was lowered from 200°C to 50°C within 5 minutes and maintained for 20 minutes.

[0033] In the above-mentioned rapid detection method for mercury content, preferably, the determination of the RGB value after the color development reaction specifically includes:

[0034] The titanium carbide / gold nanoparticle composite material, the sample treatment solution, TMB solution and H 2 O 2 The mixed solution composed of the solutions is placed in a cuvette;

[0035] The RGB value of the mixed solution was obtained through the smartphone camera.

[0036] In the above-mentioned rapid detection method for mercury content, preferably, the mercury content in the sample to be tested is calculated according to the RGB value, specifically comprising:

[0037] Get Hg 2+ A standard working curve for content determination, wherein the standard working curve is used to characterize the corresponding relationship between mercury content and RGB value;

[0038] The measured RGB value is substituted into the standard working curve to obtain the mercury content of the sample to be tested.

[0039] The rapid detection method for mercury content as described above, wherein preferably, the acquisition of Hg 2+ The standard working curve for content determination specifically includes:

[0040] Configure a series of Hg with different concentrations 2+ Standard solution;

[0041] Collect a series of Hg at different concentrations 2+ The intensity ratio B / R in the RGB value corresponding to the standard solution is used to establish a standard working curve.

[0042] The present invention provides a method for rapid detection of mercury content by preparing a titanium carbide / gold nanoparticle composite material (h-Ti 3 C 2 / AuNPs), using 3,3',5,5'-tetramethylbenzidine (TMB) as the chromogenic substrate, and constructing a h-Ti 3 C 2 TMB and H / AuNPs peroxidase activity 2 O 2 A color reaction platform is used to determine the RGB value after the color reaction; the mercury content in the sample to be tested is calculated according to the RGB value, thereby realizing rapid and highly sensitive detection of mercury (II) in the sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0044] Figure 1 A flow chart of an embodiment of a method for rapid detection of mercury content provided by the present invention;

[0045] Figure 2 Hg 2+ Schematic diagram of the determination principle;

[0046] Figure 3 h-Ti 3 C 2 Transmission electron microscope photographs of

[0047] Figure 4 h-Ti 3 C 2 Transmission electron microscopy images of / AuNPs composite nanomaterials;

[0048] Figure 5 h-Ti 3 C 2 / AuNPs, TMB and H 2 O 2 Detection reagents in different Hg 2+ UV-Vis absorption spectra and photographs under concentration conditions;

[0049] Figure 6 The interference test results of different cations are shown;

[0050] Figure 7 The interference experiment results of different anions are shown in Figure 2.

[0051] Figure 8 Hg 2+ Standard working curve for content determination. DETAILED DESCRIPTION

[0052] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present disclosure thorough and complete and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the components and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary and not as limiting.

[0053] The words "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprises" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0054] In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be an intermediate component between the specific component and the first component or the second component. When a specific component is described as being connected to other components, the specific component may be directly connected to the other components without an intermediate component, or may not be directly connected to the other components but have an intermediate component.

[0055] All terms (including technical terms or scientific terms) used in the present disclosure have the same meanings as those understood by ordinary technicians in the field to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0056] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0057] In recent years, colorimetric analysis based on nanomaterials has attracted wide attention in the field of heavy metal detection due to its excellent selectivity, ultra-high sensitivity and simple operation procedures. 3 C 2 ) as a reducing agent and template to prepare titanium carbide / gold nanoparticle composites with peroxidase activity (h-Ti 3 C 2 / AuNPs), and based on its enzyme-catalyzed signal amplification principle, 3,3',5,5'-tetramethylbenzidine (TMB) is used as a chromogenic substrate to achieve rapid and highly sensitive detection of mercury in food.

[0058] The following are some of the reagents and instruments used in the examples:

[0059] Main reagents: titanium aluminum carbide (Ti 3 AlC 2 ) (Jilin Yiyi Technology Co., Ltd.); sodium hydroxide (NaOH), hydrogen peroxide (H 2 O 2 )、dimethyl sulfoxide (DMSO), 3,3',5,5'-tetramethylbenzidine (TMB), sodium acetate trihydrate (CH 3 COONa·3H 2 O), glacial acetic acid (CH3COOH), chloroauric acid (HAuCl 4 ·3H 2O), polyvinyl pyrrolidone (PVP-K90) (analytical grade, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.), mercuric nitrate (Hg(NO 3 ) 2 ), hydrofluoric acid (HF) (analytical grade, purchased from Sinopharm Chemical Reagent Co., Ltd.).

[0060] Main instruments and equipment: BNCH 78-1 constant temperature magnetic stirrer (Wenzhou Biaonuo Instrument Co., Ltd.), CT14RDⅡ desktop high-speed centrifuge (Tianmei Technology Co., Ltd.), UV-2600 ultraviolet-visible spectrophotometer (Shimadzu, Japan), SB-5200DT ultrasonic cleaning machine (Ningbo Xinzhi Biotechnology Co., Ltd.), LGJ-10 vacuum freeze dryer (Beijing Sihuan Scientific Instrument Factory Co., Ltd.).

[0061] like Figure 1 As shown, the rapid detection method for mercury (II) content provided in this embodiment includes the following steps in actual implementation:

[0062] Step S1, preparing a titanium carbide / gold nanoparticle composite material.

[0063] In one embodiment of the rapid detection method for mercury content of the present invention, step S1 may specifically include:

[0064] Step S11, preparing hydroxylated two-dimensional transition titanium carbide.

[0065] In one embodiment of the method for rapid detection of mercury content of the present invention, step S11 may specifically include:

[0066] Step S111: 1 g Ti 3 AlC 2 Place it in a polytetrafluoroethylene beaker, add 25 mL of hydrofluoric acid into the beaker, and then stir and react at a constant temperature of 40°C for 10 h.

[0067] Step S112: After the reaction is completed, the solid product is collected and washed to obtain a two-dimensional transition metal carbide (MXene) Ti 3 C 2 .

[0068] Step S113, add 0.25 g Ti into the polytetrafluoroethylene beaker 3 C 2 and 20 mL of 5% NaOH solution.

[0069] Step S114, stirring at room temperature for 2 h under a magnetic stirrer, centrifuging and washing with water, discarding the supernatant and adding 20 mL of dimethyl sulfoxide.

[0070] Step S115: After centrifugation, the solid is redispersed in 75 mL of oxygen-free water, ultrasonicated for 5 h in an ultrasonic cleaner, and then centrifuged at 8000 r / min for 1 h to obtain a supernatant liquid of a single / few layers of hydroxylated titanium carbide h-Ti 3 C 2 The solution was gray-green, and the supernatant was collected and used later.

[0071] Step S12: using hydroxylated two-dimensional transition titanium carbide as a reducing agent and template to prepare a titanium carbide / gold nanoparticle composite material with peroxidase activity (h-Ti 3 C 2 / AuNPs).

[0072] The present invention uses hydroxylated titanium carbide (h-Ti 3 C 2 ) materials are used as reducing agents and templates to in situ grow gold nanoparticles AuNPs, and no external reducing agent is required during the preparation process. Specifically, accurately measure 5 mL of single / few-layer hydroxylated titanium carbide h-Ti 3 C 2 The solution was placed in a 10 mL glass bottle, and 0.10 g of polyvinyl pyrrolidone was added to the solution. Then, it was mixed with a 5 μL-30 μL chloroauric acid solution with a concentration of 0.1 g / mL. After ultrasonic treatment for 2 h, it was allowed to stand for 4 h. The solution in the bottle was observed to be clear, transparent, uniformly dispersed, and free of precipitation. The color of the solution was generally purple-red, indicating that h-Ti 3 C 2 / AuNPs were prepared and titanium carbide / gold nanoparticle composite materials with peroxidase activity were obtained.

[0073] Figure 3 and Figure 4 h-Ti 3 C 2 and h-Ti 3 C 2 Transmission electron microscopy images of h-Ti / AuNPs composite nanomaterials 3 C 2 and titanium carbide / gold nanoparticle composite structures, Figure 3 It shows that h-Ti 3 C 2 The morphology is nanosheets; Figure 4 It shows that AuNPs are based on h-Ti 3 C 2 As a template for growth, evenly distributed in h-Ti 3 C 2 Nanosheet surface.

[0074] Step S2: After mixing the titanium carbide / gold nanoparticle composite material with the sample treatment solution to be tested, TMB (3,3',5,5'-tetramethylbenzidine) solution and H 2 O 2 Solution, in order to utilize the Hg in the solution treated with the sample to be tested 2+ Titanium carbide / gold nanoparticle composites with enhanced peroxidase activity catalyze TMB and H 2 O 2 The color reaction.

[0075] The present invention uses the titanium carbide / gold nanoparticle composite material (h-Ti 3 C 2 / AuNPs) is the peroxidase in the signal amplification reaction. 3 C 2 Determination of Hg by catalytic colorimetric analysis of AuNPs 2+ The principle is as follows Figure 2 As shown, Hg 2+ Under the action of h-Ti 3 C 2 The peroxidase activity of / AuNPs was enhanced, which could catalyze the oxidation of TMB solution and H 2 O 2 In one embodiment of the method for rapid detection of mercury content of the present invention, step S2 may specifically include:

[0076] Step S21, processing the sample to be tested to obtain a sample processing solution to be tested.

[0077] In one embodiment of the rapid detection method for mercury content of the present invention, step S21 may specifically include:

[0078] Step S211, take 5.0 g of the sample to be tested, place it in the inner tank of the microwave digestion furnace, add 8 mL of HNO 3 and 2 mL H 2 O 2 .

[0079] In some embodiments of the present invention, the samples to be tested are fresh fish and shrimp samples (samples 1-3).

[0080] Step S212: performing microwave digestion heating according to a preset heating program.

[0081] Exemplarily, as shown in Table 1, the preset heating program is:

[0082] In the preheating stage, the temperature is raised from room temperature to 160°C within 5 minutes and maintained for 5 minutes;

[0083] In the insulation stage, the temperature was raised from 160°C to 200°C within 5 min and maintained for 15 min;

[0084] In the cooling stage, the temperature was lowered from 200°C to 50°C within 5 minutes and maintained for 20 minutes.

[0085] Table 1 Microwave digestion procedure

[0086]

[0087] Step S213: After the microwave digestion and heating is completed, the sample is transferred to a 250 mL volumetric flask and fixed to volume with pure water.

[0088] In some embodiments of the present invention, a sample blank is prepared according to the method of steps S211 to S213.

[0089] Step S22, take 20 μL of titanium carbide / gold nanoparticle composite material (h-Ti 3 C 2 / AuNPs) solution was mixed with 100 μL of the test solution, followed by the addition of 50 μL of 0.01 M TMB solution and 100 μL of 30% H 2 O 2 The solution was diluted to 1.0 mL with 0.2 mol / L NaAc-HAc buffer at pH 4.0 and shaken at 37°C for 30 min.

[0090] Figure 5 h-Ti 3 C 2 / AuNPs, TMB and H 2 O 2 Detection reagents in different Hg 2+ The UV-visible absorption spectra and photos under the concentration conditions show that h-Ti 3 C 2 / AuNPs have peroxidase activity, which catalyzes the oxidation of TMB and H 2 O 2 Color reaction to achieve Hg 2+ Colorimetric sensing analysis.

[0091] Figure 6 and Figure 7 The interference experimental results of different cations and different anions are shown respectively, indicating that the established analytical method is effective for Hg 2+ It has good selectivity and anti-interference ability.

[0092] Step S3, measuring the RGB value after the color development reaction.

[0093] In one embodiment of the rapid detection method for mercury content of the present invention, step S3 may specifically include:

[0094] Step S31, the titanium carbide / gold nanoparticle composite material, the sample treatment solution, the TMB solution and the H 2 O 2 The mixed solution composed of the solutions (ie, the mixed solution obtained in step S2) is placed in a cuvette.

[0095] Step S32: Acquire the RGB value of the mixed solution through the smartphone camera.

[0096] Step S4: Calculate the mercury content in the sample to be tested according to the RGB value.

[0097] In one embodiment of the rapid detection method for mercury content of the present invention, step S4 may specifically include:

[0098] Step S41: Obtain Hg 2+ A standard working curve for content determination, wherein the standard working curve is used to characterize the corresponding relationship between mercury content and RGB value.

[0099] In one embodiment of the method for rapid detection of mercury content of the present invention, step S41 may specifically include:

[0100] Step S411: Prepare a series of Hg with different concentrations 2+ Standard solution.

[0101] In some embodiments of the present invention, Hg can be configured 2+ The concentrations of the standard solutions were 0.1 μg / L, 0.5 μg / L, 1.0 μg / L, 2.0 μg / L and 5.0 μg / L respectively.

[0102] Step S412: Collect a series of Hg with different concentrations 2+ The intensity ratio B / R in the RGB value corresponding to the standard solution is used to establish a standard working curve.

[0103] like Figure 8 As shown in the figure, the linear fitting equation of the standard working curve is y = 1.035x + 1.3028 (R² = 0.9986), where y represents the intensity ratio B / R in the RGB value and x represents Hg 2+ The linear range of the standard working curve was (0.1~5.0) μg / L, the detection limit (3σ, n=11) was 0.036 μg / L, and the relative standard deviation (RSD) was 0.19%, with high precision and good reproducibility.

[0104] Step S42: Substitute the measured RGB value into the standard working curve to obtain the mercury content of the sample to be tested.

[0105] Specifically, the intensity ratio B / R in the measured RGB value is substituted into the linear fitting equation of the standard working curve y = 1.035x + 1.3028 to obtain the mercury content of the sample to be tested. The Hg content test results of samples 1-3 are shown in Table 2.

[0106] Table 2 Hg content in samples 1-3

[0107] Sample No. 1 2 3 Hg content (μg / kg) 22.5 36.0 19.7

[0108] The present invention uses hydroxylated titanium carbide (h-Ti 3 C 2 ) materials are used as reducing agents and templates to in-situ grow gold nanoparticles AuNPs, and no external reducing agent is required during the preparation process. 3 C 2 / AuNPs have peroxidase activity and can catalyze the oxidation of TMB and H 2 O 2 The color reaction was developed, and a highly selective and sensitive Hg 2+ Colorimetric analysis method.

[0109] The method for rapid detection of mercury content provided by the embodiment of the present invention is to prepare a titanium carbide / gold nanoparticle composite material (h-Ti 3 C 2 / AuNPs), using 3,3',5,5'-tetramethylbenzidine (TMB) as the chromogenic substrate, and constructing a h-Ti 3 C 2 TMB and H / AuNPs peroxidase activity 2 O 2 A color reaction platform is used to determine the RGB value after the color reaction; the mercury content in the sample to be tested is calculated according to the RGB value, thereby realizing rapid and highly sensitive detection of mercury (II) in the sample.

[0110] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0111] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A method for rapid detection of mercury content, characterized in that: include: Preparation of titanium carbide / gold nanoparticle composites; After the titanium carbide / gold nanoparticle composite material is mixed with the sample treatment solution to be tested, TMB solution and H2O2 solution are added to utilize the Hg in the sample treatment solution to be tested. 2+ The color reaction of TMB and H2O2 catalyzed by titanium carbide / gold nanoparticle composites with enhanced peroxidase activity was carried out; Determine the RGB value after the color reaction; The mercury content in the sample to be tested is calculated based on the RGB value.

2. The rapid detection method for mercury content according to claim 1, characterized in that: The preparation of the titanium carbide / gold nanoparticle composite material specifically comprises: Preparation of hydroxylated two-dimensional transition titanium carbide; Titanium carbide / gold nanoparticle composites with peroxidase activity were prepared using hydroxylated two-dimensional transitional titanium carbide as a reducing agent and template.

3. The rapid detection method for mercury content according to claim 2, characterized in that: The preparation of hydroxylated two-dimensional transition titanium carbide specifically comprises: Place 1 g of Ti3AlC2 in a polytetrafluoroethylene beaker, add 25 mL of hydrofluoric acid to the beaker, and then stir and react at 40°C for 10 h. After the reaction is completed, the solid product is collected and washed to obtain two-dimensional transition metal carbide Ti3C2; Add 0.25 g Ti3C2 and 20 mL 5% NaOH solution to a polytetrafluoroethylene beaker; After stirring for 2 h at room temperature under a magnetic stirrer, the mixture was centrifuged and washed with water. After discarding the supernatant, 20 mL of dimethyl sulfoxide was added. After centrifugation, the solid was redispersed in 75 mL of oxygen-free water, ultrasonicated for 5 h in an ultrasonic cleaner, and then centrifuged at 8000 r / min for 1 h to obtain a supernatant liquid which was a single / few-layer hydroxylated titanium carbide h-Ti3C2 solution with a gray-green color. The supernatant liquid was collected and used later.

4. The rapid detection method for mercury content according to claim 2, characterized in that: The method of using hydroxylated two-dimensional transition titanium carbide as a reducing agent and a template to prepare a titanium carbide / gold nanoparticle composite material with peroxidase activity specifically includes: Accurately measure 5 mL of single / few-layer hydroxylated titanium carbide h-Ti3C2 solution and place it in a 10 mL glass bottle, add 0.10 g of polyvinyl pyrrolidone to the solution, and then mix it with 5 μL-30 μL of chloroauric acid solution with a concentration of 0.1 g / mL. After ultrasonication for 2 h, let it stand for 4 h to obtain a titanium carbide / gold nanoparticle composite material with peroxidase activity.

5. The rapid detection method for mercury content according to claim 1, characterized in that: After the titanium carbide / gold nanoparticle composite material is mixed with the sample treatment solution to be tested, TMB solution and H2O2 solution are added to utilize the Hg in the sample treatment solution to be tested. 2+ The titanium carbide / gold nanoparticle composite material with enhanced peroxidase activity catalyzes a color reaction of TMB and H2O2, specifically comprising: Treating the sample to be tested to obtain a treated solution of the sample to be tested; Take 20 μL of titanium carbide / gold nanoparticle composite material solution and mix it with 100 μL of the test solution, then add 50 μL of 0.01 M TMB solution and 100 μL of 30% H2O2 solution in sequence, make the volume to 1.0 mL with 0.2 mol / L, pH 4.0 NaAc-HAc buffer, and oscillate at 37°C for 30 min.

6. The rapid detection method for mercury content according to claim 5, characterized in that: The processing of the sample to be tested to obtain a sample processing solution specifically includes: Take 5.0 g of the sample to be tested, place it in the inner tank of a microwave digestion furnace, and add 8 mL of HNO3 and 2 mL of H2O2; Perform microwave digestion heating according to the preset heating program; After microwave digestion and heating, the sample was transferred to a 250 mL volumetric flask and made up to volume with pure water.

7. The rapid detection method for mercury content according to claim 6, characterized in that: The microwave digestion and heating according to the preset heating program specifically includes: In the preheating stage, the temperature is raised from room temperature to 160°C within 5 minutes and maintained for 5 minutes; In the insulation stage, the temperature was raised from 160°C to 200°C within 5 min and maintained for 15 min; In the cooling stage, the temperature was lowered from 200°C to 50°C within 5 minutes and maintained for 20 minutes.

8. The method for rapid detection of mercury content according to claim 1, characterized in that: Determining the RGB value after the color development reaction specifically includes: A mixed solution consisting of a titanium carbide / gold nanoparticle composite material, a sample treatment solution, a TMB solution, and a H2O2 solution is placed in a cuvette; The RGB value of the mixed solution was obtained through the smartphone camera.

9. The method for rapid detection of mercury content according to claim 1, characterized in that: The step of calculating the mercury content in the sample to be tested according to the RGB value specifically includes: Get Hg 2+ A standard working curve for content determination, wherein the standard working curve is used to characterize the corresponding relationship between mercury content and RGB value; The measured RGB value is substituted into the standard working curve to obtain the mercury content of the sample to be tested.

10. The method for rapid detection of mercury content according to claim 9, characterized in that: The acquisition of Hg 2+ The standard working curve for content determination specifically includes: Configure a series of Hg with different concentrations 2+ Standard solution; Collect a series of Hg at different concentrations 2+ The intensity ratio B / R in the RGB value corresponding to the standard solution is used to establish a standard working curve.

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