Paper-based detection method for detecting carbon disulfide

Abstract

The invention discloses a paper-based detection method for detecting carbon disulfide, which comprises the following specific steps: firstly, dissolving silver nitrate in water, dissolving cetyltrimethylammonium bromide in xylene, mixing and stirring the silver nitrate and the cetyltrimethylammonium bromide, and transferring silver ions into an organic phase; and adding dodecanethiol as a modifier into the extracted organic phase, uniformly stirring, dropwise adding NaBH4 into the mixed organic solution, and reducing to prepare the silver nanoparticles. The prepared nano-silver solution is diluted into five concentrations, and a paper-based colorimetric sensor array with silver nanoparticle sensing element points in a 1 * 5 mode is constructed on a hydrophobic PVDF paper base. And finally, applying the paper-based sensor to qualitative and quantitative analysis of carbon disulfide gas. The silver nanoparticle paper-based colorimetric sensor array provided by the invention has the advantages of portability, high sensitivity and strong selectivity, and can effectively and rapidly detect trace carbon disulfide gas leakage in an industrial environment.

Description

Technical Field

[0001] The present application relates to a paper-based detection method for detecting carbon disulfide, belonging to the technical field of chemical analysis. Background Art

[0002] Carbon disulfide is a common sulfide pollutant in the air. Pure carbon disulfide has a sweet aroma similar to chloroform, but impure industrial products are usually mixed with other sulfides (such as carbonyl sulfide) and become slightly yellowish, and have an unpleasant smell of rotten carrots. Carbon disulfide is highly volatile, flammable and explosive. In addition, it is a broad enzyme inhibitor with cytotoxic effects. It can destroy the normal metabolism of cells and interfere with lipoprotein metabolism to cause vascular lesions, neuropathy and damage to major organs throughout the body. Long-term exposure to low concentrations can cause multiple neuritis, accompanied by symptoms such as headaches, insomnia, and memory loss. The United States and Japan stipulate that the maximum allowable concentration in the atmosphere is 10ppm (30mg / m 3 ). At present, carbon disulfide plays an important role in the manufacturing fields of rayon, pesticides, accelerators, etc. In industry, natural gas method has been widely used to produce carbon disulfide. The leakage of trace carbon disulfide poses a serious threat to environmental air pollution and workers' health.

[0003] There are many methods for detecting carbon disulfide, the most common ones are electrochemical method, mass spectrometry, gas chromatography, etc. These instrumental analysis methods are costly, complex to operate, time-consuming to detect, low in sensitivity, and complex sample pre-treatment. Sampling must be carried out in the laboratory for analysis, so real-time on-site monitoring is not possible.

[0004] In contrast, paper-based colorimetric chemical sensors have the outstanding advantages of low cost, portability, strong selectivity, high sensitivity, and good stability. Its sensing mechanism is that a chemical reaction occurs between the sensitive material of the sensor and the analyte being measured, causing the sensor color to change. Different analytes have different color changes, thereby achieving the identification and detection of the analyte.

[0005] At present, there are more and more studies on chemical sensors using gold and silver nanoparticles as sensitive materials in the field of gas. Silver nanoparticles have a larger extinction coefficient and a narrower surface plasmon resonance band, so they have better colorimetric performance, higher sensitivity, and higher reactivity. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention is based on the fact that silver nanoparticles are easy to be surface functionalized, monodispersed silver nanoparticles react chemically with the analysis agent, and the surface modifier falls off, so that the nanoparticles agglomerate and produce an obvious colorimetric response. A paper-based colorimetric sensor based on silver nanoparticles is provided for visual detection of carbon disulfide and a preparation method thereof.

[0007] The invention adopts a water-oil two-phase chemical reduction method, uses silver nitrate as a silver source, dodecanethiol as a modifier, and CTAB as a phase transfer agent to prepare hydrophobic silver nanoparticles. Using a PVDF hydrophobic paper base as a carrier, a silver nanoparticle paper-based colorimetric sensor for visual detection of carbon disulfide and a preparation method thereof are provided.

[0008] According to one aspect of the present application, a paper-based detection method for detecting carbon disulfide is provided, and the paper-based detection method comprises the following steps:

[0009] (1) Mix the silver nitrate solution with the phase transfer solution, stir I, separate the organic phase, add the modifier to the organic phase and stir II, then add NaBH 4 solution, reducing to obtain hydrophobic silver nanoparticles modified with a modifier;

[0010] (2) diluting the hydrophobic silver nanoparticles modified with the same modifier with different volumes of xylene to obtain hydrophobic silver nanoparticles modified with the modifier with different concentrations;

[0011] (3) taking the same volume of hydrophobic silver nanoparticles modified with modifiers of different concentrations and immobilizing them on a paper substrate, and printing them to obtain a silver nanoparticle paper-based colorimetric sensor with multiple sensing origins;

[0012] (4) exposing the silver nanoparticle paper-based colorimetric sensor with multiple sensing origins to carbon disulfide gas of different concentrations, observing the color response, and obtaining a carbon disulfide gas standard colorimetric card;

[0013] (5) Carbon disulfide gas of unknown concentration is placed in a silver nanoparticle paper-based colorimetric sensor with multiple sensing origins, and the color response is observed and compared with the carbon disulfide gas standard colorimetric card to determine the concentration of the carbon disulfide gas.

[0014] Optionally, in step (1), the phase transfer agent in the phase transfer solution is selected from at least one of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and tetradecyltrimethylammonium bromide.

[0015] Optionally, the modifier is selected from at least one of dodecanethiol, octadecylthiol and n-octylthiol.

[0016] Optionally, in step (1), the concentration of the silver nitrate solution is 0.12-0.13M.

[0017] Optionally, in step (1), the concentration of the silver nitrate solution is selected from any value among 0.12M, 0.122M, 0.125M, 0.128M, 0.13M or a range between any two of the above.

[0018] Optionally, the concentration of the phase transfer solution is 0.35-0.45M.

[0019] Optionally, the concentration of the phase transfer solution is selected from any value among 0.35M, 0.38M, 0.40M, 0.42M, 0.45M or a range between any two of the above.

[0020] Optionally, the concentration of the modifier is 0.12-0.14M.

[0021] Optionally, the concentration of the modifier is selected from any value among 0.12M, 0.125M, 0.13M, 0.135M, 0.14M or a range between any two of the above values.

[0022] Optionally, the NaBH 4 The concentration of the solution is 0.12~0.13M.

[0023] Optionally, the NaBH 4 The concentration of the solution is selected from any value among 0.12M, 0.122M, 0.125M, 0.128M, 0.13M or a range between any two of the above values.

[0024] Optionally, in step (1), the time of stirring I and stirring II is independently selected from 15 min to 40 min.

[0025] Optionally, in step (2), the amount of hydrophobic silver nanoparticles modified with the same modifier is 1 to 1.2 mL.

[0026] Optionally, the silver nanoparticle paper-based colorimetric sensor with multiple sensing origins has a detection limit of 47.34 to 48.00 ppb for carbon disulfide.

[0027] Optionally, in step (3), the diameter of the sensing origin in the silver nanoparticle paper-based colorimetric sensor having multiple sensing origins is 3.0 to 3.5 mm.

[0028] Optionally, in step (3), the silver nanoparticle paper-based colorimetric sensor with multiple sensing origins has an anti-interference range of 10% to 90% to humidity.

[0029] Optionally, in step (3), the paper base is selected from at least one of PVDF, whatman No. 1 filter paper, and whatman No. 4 filter paper.

[0030] Optionally, in step (4), the carbon disulfide gas standard colorimetric card is stored in an inactive atmosphere.

[0031] Optionally, the inert atmosphere is selected from at least one of nitrogen, helium and argon.

[0032] As a specific implementation scheme, the present application is implemented through the following technical solutions:

[0033] A preparation method for visually detecting carbon disulfide based on a silver nanoparticle paper-based colorimetric sensor comprises the following steps:

[0034] Step 1, preparation of hydrophobic silver nanoparticles:

[0035] First, silver nitrate was dissolved in 40 ml ultrapure water, and the phase transfer agent hexadecyltrimethylammonium bromide (CTAB) was dissolved in 25 ml xylene. The two were mixed and stirred for 30 minutes, and the phases were allowed to stand for 12 hours. The silver ions were transferred to the organic phase, and the organic phase was separated and collected. Dodecanethiol was added to the extracted organic phase as a modifier, and mixed and stirred for 15 minutes. Finally, 20 ml of fresh NaBH was added dropwise to the mixed organic phase. 4 The solution was rapidly stirred for reduction for 2 hours, and the phases were separated for 3 hours, and the silver nanoparticles were transferred to the organic phase. The extracted organic phase was centrifuged and the supernatant was collected to obtain the dodecanethiol-modified hydrophobic silver nanoparticles.

[0036] Step 2: Construction of paper-based colorimetric sensor array device

[0037] The hydrophobic silver nanoparticles prepared in step 1 were diluted to 5 concentrations with different volumes of xylene, and then the nanosilver solution was dripped onto the PVDF paper substrate by a pipette to print a silver nanoparticle paper-based colorimetric sensor array with 5 sensing elements. The sensor was placed in a screw-mouth glass bottle and N 2 Store in an oxygen-free environment at room temperature for later use.

[0038] Step 3: Prepare the carbon disulfide standard colorimetric card and quantitative detection model M

[0039] The silver nanoparticle paper-based colorimetric array sensor was exposed to carbon disulfide gas of different concentrations and tested for 10 minutes. The sensor's response to carbon disulfide formed different color response fingerprints for different gas concentrations. Different color response fingerprints were matched with different concentrations of carbon disulfide gas and arranged in order from small to large carbon disulfide gas concentrations to establish a standard colorimetric test paper card for detecting carbon disulfide gas. The ΔRGB values ​​of the images before and after the response were extracted to establish a model M for quantitative detection of carbon disulfide.

[0040] Step 4: Specific recognition and detection of carbon disulfide gas by paper-based colorimetric sensor array

[0041] The specific identification and detection of carbon disulfide gas by paper-based sensors includes: the influence of common potential interfering gases on carbon disulfide gas detection; the influence of environmental humidity on the sensor.

[0042] Optionally, in step 1, the organic solvent is selected from at least one of benzene, toluene, xylene and n-hexane; and the centrifugation parameters are: rotation speed 5000-6000 r / min, and centrifugation time 5 min.

[0043] Optionally, in step 2, the same equal portion of the nanosilver stock solution is 1 ml, and different volumes of xylene are 0, 2, 4, 6, and 8 ml respectively; the volume of the pipette is 1 to 1.5 ul, the diameter of the sensing element is 3.0 to 3.5 mm, and the paper-based sensor is passed through N 2 1h, and place at room temperature for 12h.

[0044] Optionally, in step 3, the concentrations of carbon disulfide gas are 0.1 ppm, 0.5 ppm, 1.0 ppm, 1.5 ppm, 2.0 ppm, 2.5 ppm, 3.0 ppm, 3.5 ppm, and 4.0 ppm, respectively.

[0045] Optionally, in step 4, the interfering gases are: ethylenediamine, ammonia, acetic acid, methyl mercaptan, methyl sulfide, formaldehyde, ethanol, styrene; and the ambient humidity is 10% to 90%.

[0046] In this application, silver nitrate is first dissolved in ultrapure water, and the phase transfer agent hexadecyltrimethylammonium bromide (CTAB) is dissolved in xylene. The two are mixed and stirred, and silver ions are transferred to the organic phase. Dodecanethiol is added to the extracted organic phase as a modifier, and after stirring evenly, NaBH is added dropwise to the mixed organic solution. 4 Reduction is performed to prepare silver nanoparticles. The prepared nanosilver solution is diluted to 5 concentrations, and a paper-based colorimetric sensor array with 1x 5 patterns of silver nanoparticle sensing elements is constructed on a hydrophobic PVDF paper substrate. Finally, the paper-based sensor is used for qualitative and quantitative analysis of carbon disulfide gas, and the minimum detection limit of carbon disulfide is 47.34ppb. The paper-based sensor has excellent specific recognition ability for carbon disulfide gas, high sensitivity, and fast response speed. The silver nanoparticle paper-based colorimetric sensor array provided by the present invention has the advantages of portability, high sensitivity, and strong selectivity, and can effectively detect trace carbon disulfide gas leakage in industrial environments.

[0047] The beneficial effects of this application include:

[0048] 1) The silver nanoparticle paper-based colorimetric sensor array provided in the present application has an obvious specific recognition response to the detection of carbon disulfide gas, and can be used for the preventive detection of trace carbon disulfide gas leakage in industrial environments.

[0049] 2) The hydrophobic paper substrate provided in this application reduces the influence of environmental humidity on the sensor. At the same time, the colorimetric array method is used to improve the detection sensitivity of the sensor to carbon disulfide. The preparation method of the silver nanoparticle paper-based colorimetric sensor for visual detection of carbon disulfide disclosed in this application is simple to operate, portable, highly sensitive, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a TEM image of the morphology of the silver nanoparticles modified with dodecanethiol prepared in Example 1 of the present application, with a scale of 20 nm.

[0051] Figure 2 This is the silver nanoparticle paper-based colorimetric sensor array prepared in Example 1 of the present application.

[0052] Figure 3 This is the standard colorimetric test paper card for detecting carbon disulfide prepared in Example 1 of the present application.

[0053] Figure 4 This is a diagram of the model M-linear fitting equation for quantitative detection of carbon disulfide by the paper-based sensor prepared in Example 1 of the present application.

[0054] Figure 5 This is the effect of interfering gas on carbon disulfide gas detection in Example 2 of the present application.

[0055] Figure 6 This is the effect of ambient humidity on the paper-based sensor in Example 3 of the present application. DETAILED DESCRIPTION

[0056] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0057] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0058] Example 1

[0059] A preparation method for visually detecting carbon disulfide based on a silver nanoparticle paper-based colorimetric sensor. The method comprises the following steps:

[0060] (1) Preparation of hydrophobic silver nanoparticles

[0061] First, 0.12M silver nitrate was dissolved in 40ml ultrapure water, and the phase transfer agent 0.4M hexadecyltrimethylammonium bromide (CTAB) was dissolved in 25ml xylene. The two were mixed and stirred for 30min, and the phases were allowed to stand for 12h. The silver ions were transferred to the organic phase, and the organic phase was separated and collected. 0.12M dodecanethiol was added to the extracted organic phase as a modifier, and mixed and stirred for 15min. Finally, 20ml of fresh NaBH2O was added dropwise to the mixed organic phase. 4 The solution was rapidly stirred for reduction for 2 hours, and then allowed to stand for 3 hours to separate the phases. The silver nanoparticles were transferred to the organic phase. The extracted organic phase was centrifuged at 5000-6000 r / min for 5 minutes, and the supernatant was collected to obtain hydrophobic silver nanoparticles modified with dodecanethiol. Figure 1 TEM showed that the prepared dodecanethiol-modified hydrophobic silver nanoparticles were spherical and had good monodispersity.

[0062] (2) Construction of Paper-Based Colorimetric Sensor Array Device

[0063] The dodecanethiol-modified hydrophobic silver nanoparticles prepared in step (1) were diluted to five concentrations using 0, 2, 4, 6, and 8 ml of xylene, respectively. Then, 1 ul of the nanosilver solution was dripped onto a PVDF paper substrate using a pipette to print a dodecanethiol-modified silver nanoparticle paper-based colorimetric sensor array having five sensing elements (e.g., Figure 2 The diameter of the sensor element is 3.0-3.5 mm. The sensor is placed in a screw-mouth glass bottle and N 2 1h, and place at room temperature for 12h.

[0064] (3) Preparation of carbon disulfide standard colorimetric card and quantitative detection model M

[0065] The silver nanoparticle paper-based colorimetric array sensor modified with dodecanethiol was exposed to carbon disulfide gas with concentrations of 0.1ppm, 0.5ppm, 1.0ppm, 1.5ppm, 2.0ppm, 2.5ppm, 3.0ppm, 3.5ppm, and 4.0ppm, respectively, and detected for 10 minutes. The sensor's response to carbon disulfide formed different color response fingerprints for different gas concentrations. Different color response fingerprints were matched to different concentrations of carbon disulfide gas, and arranged in order from small to large carbon disulfide gas concentrations to establish a standard colorimetric test paper card for detecting carbon disulfide gas (such as Figure 3 A flatbed scanner was used to extract the spectra before and after the sensor response, and Photoshop was used to extract the ΔRGB value of the image. The formula ΔR is the difference in red color values ​​before and after the response, ΔG is the difference in green color values ​​before and after the response, and ΔB is the difference in blue color values ​​before and after the response.

[0066] The ED value is plotted as the ordinate and the carbon disulfide concentration is plotted as the abscissa, and a model M for quantitative detection of carbon disulfide is established—a linear fitting equation y=25.35x+29.91 (e.g. Figure 4 As shown), where x is the concentration of carbon disulfide. The LOD of the gas is calculated by the formula LOD = 3δ / K. Where K is the slope of the fitting curve, and δ = 0.4 is the relative standard deviation of the blank group. Figure 4 It can be seen that the minimum detection limit of carbon disulfide is 47.34 ppb.

[0067] Example 2

[0068] The influence of interfering gases on carbon disulfide gas detection

[0069] The sensor detects gas in an 18L closed gas box. A micro-injector is used to drop carbon disulfide stock solution onto the heating plate in the gas box, and the carbon disulfide concentration in the gas box is adjusted to 1.0ppm. After standing for 10 minutes, the paper-based sensor is exposed to the gas box and detected for 10 minutes. The same steps are used to detect 5ppm of ethylenediamine, ammonia, acetic acid, methyl mercaptan, dimethyl sulfide, formaldehyde, ethanol, and styrene using paper-based sensors for 10 minutes. Finally, a flatbed scanner is used to collect spectra of the sensor before and after its response to the above 9 gases, and the colorimetric response fingerprint is extracted using the ChemEye older software. By Figure 5 It can be seen that the paper-based sensor has an obvious colorimetric response to carbon disulfide, but has no response to other interfering gases, even when the concentration is more than 5 times (5 ppm).

[0070] Example 3

[0071] Effect of environmental humidity on paper-based sensors

[0072] The humidity of the air test box was adjusted by a humidifier to 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%. The paper-based colorimetric sensor array was placed in the above different humidity levels and left to stand for 10 minutes. A flatbed scanner was used to collect the sensor spectra before and after standing at the above 9 humidity levels, and the colorimetric response fingerprint was extracted using the ChemEye older software. Figure 6 It can be seen that the environmental humidity has little effect on the sensor itself, which shows that the paper-based sensor has excellent moisture resistance.

[0073] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A paper-based detection method for detecting carbon disulfide, characterized in that: The paper-based detection method comprises the following steps: (1) mixing a silver nitrate solution with a phase transfer solution, stirring I, separating an organic phase, adding a modifier to the organic phase and stirring II, then adding a NaBH4 solution, reducing, and obtaining hydrophobic silver nanoparticles modified with the modifier; (2) diluting the hydrophobic silver nanoparticles modified with the same modifier with different volumes of xylene to obtain hydrophobic silver nanoparticles modified with the modifier with different concentrations; (3) taking the same volume of hydrophobic silver nanoparticles modified with modifiers of different concentrations and immobilizing them on a paper substrate, and printing them to obtain a silver nanoparticle paper-based colorimetric sensor with multiple sensing origins; (4) exposing the silver nanoparticle paper-based colorimetric sensor with multiple sensing origins to carbon disulfide gas of different concentrations, observing the color response, and obtaining a carbon disulfide gas standard colorimetric card; (5) Carbon disulfide gas of unknown concentration is placed in a silver nanoparticle paper-based colorimetric sensor with multiple sensing origins, and the color response is observed and compared with the carbon disulfide gas standard colorimetric card to determine the concentration of the carbon disulfide gas.

2. The paper-based detection method according to claim 1, characterized in that: In the step (1), the phase transfer agent in the phase transfer solution is selected from at least one of hexadecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and tetradecyltrimethylammonium bromide; Preferably, the modifier is selected from at least one of dodecanethiol, octadecylthiol and n-octylthiol.

3. The paper-based detection method according to claim 1, characterized in that: In the step (1), the concentration of the silver nitrate solution is 0.12-0.13 M; Preferably, the concentration of the phase transfer solution is 0.35 to 0.45 M; Preferably, the concentration of the modifier is 0.12 to 0.14 M; Preferably, the concentration of the NaBH4 solution is 0.12-0.13M.

4. The paper-based detection method according to claim 1, characterized in that: In the step (1), the time of stirring I and stirring II is independently selected from 15 min to 40 min.

5. The paper-based detection method according to claim 1, characterized in that: In the step (2), the amount of the hydrophobic silver nanoparticles modified with the same modifier is 1 to 1.2 mL.

6. The paper-based detection method according to claim 1, characterized in that: The silver nanoparticle paper-based colorimetric sensor with multiple sensing origins has a detection limit of 47.34-48.00 ppb for carbon disulfide.

7. The paper-based detection method according to claim 1, characterized in that: In the step (3), the diameter of the sensing origin in the silver nanoparticle paper-based colorimetric sensor having multiple sensing origins is 3.0 to 3.5 mm.

8. The paper-based detection method according to claim 1, characterized in that: In the step (3), the silver nanoparticle paper-based colorimetric sensor with multiple sensing origins has an anti-interference range of 10% to 90% to humidity.

9. The paper-based detection method according to claim 1, characterized in that: In the step (3), the paper base is selected from at least one of PVDF, whatman No. 1 filter paper, and whatman No. 4 filter paper.

10. The paper-based detection method according to claim 1, characterized in that: In the step (4), the carbon disulfide gas standard colorimetric card is stored in an inert atmosphere; Preferably, the inert atmosphere is selected from at least one of nitrogen, helium and argon.

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