CN107290337B

CN107290337B - Method for detecting hydrogen sulfide based on ruthenium nanoparticle colorimetric method

Info

Publication number: CN107290337B
Application number: CN201710446518.1A
Authority: CN
Inventors: 赵媛; 罗耀东; 崔林艳; 杨璇
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2017-06-14
Filing date: 2017-06-14
Publication date: 2020-03-27
Anticipated expiration: 2037-06-14
Also published as: CN107290337A

Abstract

The invention provides a method for detecting hydrogen sulfide based on a ruthenium nanoparticle colorimetric method, which specifically comprises the following steps: ruthenium nanoparticles can discolor azo dyes in the presence of hydrazine hydrate. And the hydrogen sulfide can be combined with the ruthenium nano particles to form ruthenium-sulfur bonds (Ru-S), so that the activity of the ruthenium nano particles for degrading the dye is passivated. The higher the hydrogen sulfide concentration, the more deeply the ruthenium nanoparticles are passivated, indicating that the azo dye is less susceptible to discoloration. A novel colorimetric method for detecting hydrogen sulfide is developed by utilizing ruthenium nano particle inactivation induced by hydrogen sulfide. By optimizing experimental parameters, the method can detect hydrogen sulfide in the concentration ranges of 5.0-100nM and 100-800nM under the optimal conditions, and shows two good linear relations, with the detection limit of 0.6 nM. Compared with a colorimetric method reported in the literature, the method can realize rapid analysis, has extremely high sensitivity and excellent selectivity, and can be used for detecting hydrogen sulfide in actual samples, particularly in the atmosphere.

Description

Method for detecting hydrogen sulfide based on ruthenium nanoparticle colorimetric method

Technical Field

The present invention relates to the detection of hydrogen sulfide. In particular to a method for detecting hydrogen sulfide based on a ruthenium nanoparticle colorimetric method, which belongs to the fields of analytical chemistry and nanotechnology.

Background

Hydrogen sulfide is a rotten egg odor and has high toxicity. A large amount of hydrogen sulfide is generated in the industries of sewage, coal mines, petroleum and natural gas and the like. On the other hand, hydrogen sulfide is considered as an important gas signal molecule, and is involved in various physiological processes, and the content thereof is related to various diseases, such as alzheimer disease, diabetes, liver cirrhosis, and the like. In summary, the content of hydrogen sulfide is not only an important environmental index but also an important biomedical index, so that the quantitative detection of hydrogen sulfide is of great significance to the environment.

Currently, the most common techniques for detecting hydrogen sulfide are electrochemical, gas chromatography, and fluorescence methods, among others. However, these methods typically require cumbersome sample and reagent preparation or complex instrumentation, and are not suitable for routine laboratory and field analysis. Recently, colorimetric methods, which are classical techniques, have been widely used for detecting dissolved hydrogen sulfide because colorimetric methods have significant advantages, such as low cost, simplicity, practicality, visibility to the naked eye, and the like, compared to other methods.

The most common nanomaterial used in colorimetric detection of hydrogen sulfide is gold nanoparticles. The principle is that the combination of the sulfur ions and the gold nanoparticles can lead the gold nanoparticles to be aggregated, so that the wave band of the surface plasma moves to a longer wavelength to cause obvious color change, thereby achieving the purpose of detection. Although these methods are very simple, the detection sensitivity for hydrogen sulfide is far from sufficient. Recently, several colorimetric methods based on target-induced nanocatalyst deactivation have been established for the detection of hydrogen sulfide. For example, gold nanoparticles have outstanding peroxidase activity and can catalyze the oxidation of colorless 3,30,5, 50-Tetramethylbenzidine (TMB) in the presence of hydrogen peroxide to produce colored products. The existence of the sulfur ions can inactivate the activity of the gold nanoparticle catalyst, and establish the relationship between the concentration of the sulfur ions and the inactivation degree, thereby providing a way for the concentration of the sulfide. Therefore, this method has an advantage of being able to amplify the reaction to improve sensitivity. However, the current method for detecting hydrogen sulfide based on a colorimetric method has low sensitivity and is not suitable for detecting trace hydrogen sulfide.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a colorimetric method for detecting hydrogen sulfide based on azo dyes catalytically degraded by ruthenium nanoparticles, which has the advantages of high sensitivity, short detection time, high selectivity and the like and is very suitable for detecting trace hydrogen sulfide in actual samples.

The technical scheme of the invention is as follows: firstly, in the presence of hydrazine hydrate, ruthenium nano-particles as a catalyst can transfer electrons in a reducing agent to an azo bond (-N ═ N-) so that the azo bond is hydrogenated to form an amino group (-NH)₂). Because azo bond is a chromophoric group of dye, the dye color is changed into colorless along with colored fading after the azo bond is broken.

Secondly. The ruthenium nanometer particles are combined with ruthenium nanometer particles to form ruthenium sulfur bond (Ru-S) under the existence of hydrogen sulfide, so that the activity of the ruthenium nanometer particles for degrading dyes is passivated. Therefore, the catalytic activity of the ruthenium nanoparticles depends on the concentration of the added hydrogen sulfide, and the addition of different concentrations of hydrogen sulfide to the degradation dye system is directly reflected by different fading time of the dye and different reaction rates of the degradation of the dye. Thereby achieving the purpose of detecting the hydrogen sulfide.

Finally, it should be noted that the determination of hydrogen sulfide in the present invention is performed with respect to sodium sulfide, since sodium sulfide is a donor of hydrogen sulfide, which is generated in aqueous solution during vulcanization.

The specific process steps are as follows:

1) synthesizing the ruthenium nanometer particles. The precursor is ruthenium trichloride hydrate, the complexing agent is polyvinylpyrrolidone (PVP), and the molar ratio of the monomers of the precursor to the polyvinylpyrrolidone is 1: 10. Both were dissolved under ultrasound in a volume of ethylene glycol, which served as both solvent and reducing agent. The precursor of ruthenium can be reduced from high valence to zero valence simple substance at a certain temperature.

2) First, the azo dye is added to the reducing agent, where the azo dye does not degrade due to the absence of the catalyst. Then preparing a sodium sulfide standard solution with a certain concentration gradient, fully mixing sulfide ions with the prepared ruthenium nano particle catalyst aqueous solution, and finally adding the mixed solution of the sulfide ions and the ruthenium nano particle aqueous solution into a reducing agent, wherein the solution begins to fade. The fade kinetics of the azo dye was monitored with an ultraviolet spectrophotometer.

3) The kinetic curves are plotted as the reaction time on the abscissa, ln (A)_t/A₀) The velocity curve is plotted on the ordinate. And establishing a standard curve of the relation between the hydrogen sulfide concentration and the reaction rate constant.

4) The selectivity of the detection method was evaluated by adding different interferents.

5) And (3) detecting hydrogen sulfide in an actual sample, wherein a filter membrane is used for filtering to remove large-particle impurities before detection.

The azo dye is degraded by the catalytic hydrogenation property of the nanoparticles to detect the hydrogen sulfide, and the specific surface area of the nanoparticles is large, so that the recognition objects can be in full contact with the detected objects, and the detection sensitivity is improved. The invention constructs a method for rapidly detecting hydrogen sulfide with high sensitivity and high accuracy.

Drawings

FIG. 1 is a transmission electron microscope photograph of synthesized ruthenium nanoparticles

FIG. 2 shows the difference of Na₂Kinetic Curve of dye degradation at S concentration

FIG. 3Na₂S detection standard curve

Detailed Description

Example 1:

according to Ru³⁺: the PVP monomer molar ratio is 1:10, 0.0123g of RuCl is weighed out separately₃·nH₂And O and 0.0555g PVP are fully dissolved in 10mL of ethylene glycol under ultrasound to form a high-molecular protected ruthenium complex, the mixed solution is poured into a 50mL round-bottom flask, a stirrer is added, then the solution is heated to 170 ℃ and kept at the temperature for 6 hours, and the solution is changed from brown red to brown black finally, namely the reaction is finished. Mixing the stock solution with a precipitant acetone 1:3, centrifuging at 8000 rpm for 5min, and washing the precipitate with water. Repeatedly washing with acetone and deionized water for 3-5 times to obtain precipitate, and dissolving in water to obtain ruthenium nanoparticle water (Ru NPs) solution with Ru NPs concentration of 26 μ M. The result of the obtained ruthenium nanoparticles after TEM characterization is shown in FIG. 1, the uniform particle size of the ruthenium nanoparticles is 1.7nm, and the dispersibility is good.

Example 2:

the treated Ru NPs aqueous solution was diluted 32-fold before testing to a concentration of 0.81. mu.M. And the maximum absorbance of orange I under alkaline conditions was previously measured with an ultraviolet spectrophotometer at a wavelength position of 512 nm.

First, 4. mu.L of 10^-2M orange I dye was added to a 2mL 0.8M hydrazine hydrate cuvette, at which time the final concentration of orange I was 0.02mM and the solution was basic, and the orange I color changed to deep red. Then, 20. mu.L of Na with different concentrations (0.5-80. mu.M) are prepared₂S is added into 10 mu L of 0.81 mu M Ru NPs solution, and after the two are mixed evenly, the Ru NPs-Na is added₂The S mixed solution was immediately added to the cuvette. Finally, purpleThe degradation kinetics of orange I at the maximum wavelength (512nm) in alkaline solution was measured with an external visible spectrophotometer. All tests were carried out at ambient temperature (21-26 ℃).

As shown in FIG. 2, the absorbance at 512nm gradually decreased with Ru NPs catalysis, accompanied by a change in the color of the solution from red to colorless. When the amount of sodium sulfide is increased, the inactivation degree of the Ru NPs is gradually increased, the catalytic activity is gradually weakened, and the kinetic curve shows more gradually. The color of the solution at a certain time was different due to the amount of hydrogen sulfide added. Thus, the amount of hydrogen sulfide can be roughly quantified by a spectrophotometer and the naked eye.

Example 3:

for accurate detection of hydrogen sulfide, FIG. 3 was obtained by calculating the relationship between the concentration of hydrogen sulfide and the reaction rate constant of each curve. The quantification curve shows a good linear relationship in the concentration range of 5.0-100nM and 100-800 nM. The correlation coefficients of the curves are r-0.9923 and n-8 respectively; r is 0.9981 and n is 4. The method has a limit of detection of about 0.6nM for hydrogen sulfide based on signal-to-noise ratio (S/N) ═ 3.

Example 4:

in order to evaluate the method for detecting the selectivity of hydrogen sulfide, some interference substances (such as CO) are added₃ ^2-，HCO₃ ^-，NO₂ ^-，NO₃ ^-， NH₄ ⁺，SO₄ ^2-，S₂O₈ ^2-，SO₃ ^2-). The final concentrations of the interferents were 2. mu.M, and the final concentrations of the sulfide ions were 0.2. mu.M. The final concentration of the fixed hydrazine hydrate is 0.8M, the final concentration of orange I is 0.02mM, the concentration of Ru NPs added is 0.81 mu M, and the absorbance of each experimental group at 512nm is measured.

The experimental group only added with sulfide ions has obvious absorbance at 512nm, the solution is light red at the moment, the absorbance of each interferent almost disappears, and the reaction system is colorless. This shows that only sulfide ions have a passivation effect on Ru NPs, which indicates that the detection method has high selectivity on the detection of hydrogen sulfide, and other ions do not obviously interfere the qualitative and quantitative detection of hydrogen sulfide by the probe.

Example 5:

in order to evaluate the application of the method in actual samples, the method is used for detecting the concentration of the sulfur ions in the tap water samples, and because the detection system contains hydrazine hydrate solution which is alkaline, metal ions in the tap water can be precipitated, so that the detection cannot be interfered. Therefore, another advantage of the detection method over other detection methods is that no EDTA is required to eliminate interference of metal ions.

It was found experimentally that in tap water without doping with sulphur ions, the sulphur ion content is below the detection limit of the method. Thus making an addition of S^2-The addition recovery experiment of the standard substance proves that the recovery rate of the sample is in the range of 97.5-102.3%, and the RSD is from 0.5% to 1.9%, thus the detection method can detect the content of the hydrogen sulfide in the actual sample.

Claims

1. A method for detecting hydrogen sulfide based on a ruthenium nanoparticle colorimetry is characterized by comprising the following steps: according to the molar ratio of the ruthenium precursor to PVP of 1: weighing 10, fully dissolving the two in ethylene glycol under ultrasound, rapidly stirring for 6 hours in a water bath at 170 ℃ until the reaction is finished, adding excessive acetone into the stock solution after the reaction is finished, mixing, performing centrifugal separation, washing with water, repeatedly precipitating and washing for 3-5 times, dissolving in water to obtain an aqueous solution of ruthenium nanoparticles, and reserving for later use, wherein the specific method for detecting the hydrogen sulfide based on the ruthenium nanoparticle colorimetry comprises the following steps: first, 4. mu.L of 10^-2Adding M azo dye into a cuvette filled with a reducing agent, and then, preparing 20 mu L of Na with different concentrations₂Adding S into 10 μ L of 0.81 μ M ruthenium nanoparticle solution, mixing the two solutions uniformly, and mixing the solution to obtain a final volume of 30 μ L, adding RuNPs-Na₂Immediately adding the S mixed solution into a cuvette, finally measuring a kinetic curve of dye degradation by using an ultraviolet-visible spectrophotometer, and taking the kinetic curve as ln (A) with the reaction time as a horizontal coordinate_t/A₀) The hydrogen sulfide concentration is calculated to obtain a relation graph of the hydrogen sulfide concentration and the reaction rate constant of each curve, which is a rate curve of an ordinate, and the relation graph is used as a standard curve for detecting the hydrogen sulfide, so that the hydrogen sulfide can be measured by the same methodAnd obtaining the content of the hydrogen sulfide in the actual sample.

2. The process according to claim 1, wherein the azo dye added is orange I.

3. The method of claim 2, wherein the orange I is added in a volume and concentration of 4 μ L10^-2M。

4. The method according to claim 1, characterized in that the reducing agent is hydrazine hydrate.

5. The method of claim 4, wherein the hydrazine hydrate is added in a volume and concentration of 2mL to 0.8M.