KR102035709B1 - Colorimetric detection sensor and method for nitrite ion using gold nanocube - Google Patents

Abstract

There is provided a colorimetric detection sensor and a colorimetric detection method using the same, wherein the gold nanocubes in the form of a cube changes into a sphere by etching of nitrite ions to detect nitrite ions. By adjusting the reaction conditions such as salt concentration, pH, temperature, reaction time, and the like of the colorimetric detection sensor including a hexahedral gold nanocube, it is possible to optimize the sensitivity and reaction rate of the nitrite ion. The colorimetric detection sensor and colorimetric detection method using the same can be used to determine the concentration of nitrite ions contained in biological samples, drinking water, environmental samples, etc. by changing the color to be conveniently used to measure the concentration of nitrite ions in the field in real time. Can be.

Description

Colorimetric detection sensor and colorimetric detection method of nitrite ion using gold nanocube {COLORIMETRIC DETECTION SENSOR AND METHOD FOR NITRITE ION USING GOLD NANOCUBE}

Hazardous in colorimetric detection sensor and relates to a colorimetric detection method and, more particularly, to melt or containing such a biological sample, or potable water, environmental samples of ^- the invention is gold nano-cube (gold nanocube) for using nitrite ions (NO ₂₎ The present invention relates to a colorimetric detection sensor and a colorimetric detection method of nitrite ion (NO ₂ ⁻ ) using a gold nanocube for detecting and quantifying nitrite as a substance.

Nitrite ions, especially nitrites, can cause systemic inflammation, oxidative stress, and vascular endothelial damage after prolonged exposure. Inhalation of nitrite vapors can cause strong irritation to the airways, eyes, and throat, cyanosis, shortness of breath, and severe death of lung edema.

The U.S. Environmental Protection Agency (EPA) sets a maximum permissible concentration of 1 ppm (1 mg / L) in drinking water [EPA 2002; EPA 2012], which applies to all commonly used water.

Current nitrite nitrite measurements include X-ray Diffraction Spectroscopy (XRD), Fourier Transform Infrared Spectrometer (FT-IR), and X-ray Photoelectron Spectroscopy. Spectroscopy, Liquid Chromatography (LC), and Molecular Absorption Spectrometry of the molecules are used for detection.

However, these techniques are time consuming, costly, relying on expert skill in the analysis and complicated sample preparation, which leads to multiple procedures.

Surface Plasmon Resonance occurs in gold nanoparticles, etc., and emits a specific wavelength, and has various colors depending on the size and shape of the particle. Through this, it can be applied to various sensors such as measuring and monitoring environmental pollutants.

As a method for the detection of nitrites using metal nanoparticles known to date, Professor Weston of Northwestern University of the United States of America has identified sulfanilamide and naphtylethylenediamine with nitrite. We have developed a sensor that can be combined to form a color code.

Sulfanilamide and naphtylethylenediamine bind selectively to nitrite ions to transparently change the red color of the spherical gold nanoparticles, and absorb light due to the aggregation effect when reacting with nitrite Strength decreases. Using this, nitrous acid content can be calculated | required (nonpatent literature 1).

In addition, the Chinese Nankai University professor of yarn mate (Nankai university) is polyethylene glycol to spherical gold particles (polyethylene glycol) and 4-amino-benzenethiol to nitrite ion modified with _{(4-aminobenzenethiol) (NO 2} -) and upon engagement Negative ions were detected using reduced absorbance. At this time, it was possible to detect nitrite ions having high selectivity using various solvents and NaCl concentration (Non-Patent Document 2).

Vinode's team at Sastra University, India, linked phenol derivatives to silver nanoparticles and reacted with nitrite ions. N, N'-bis (2-hydroxybenzyl) -1,2-diaminobenzene was used as a phenol derivative to develop a color sensor that can detect and react selectively with nitrite ions among various anions. The color change is due to aggregation due to adsorption of functional groups and nitrite ions bonded to the surface of the nanoparticles (Non-Patent Document 3).

In India, Nagapanpylai's team synthesized aza-BODIPY compounds and developed a chemical sensor optimized for the detection of nitrite ions. As the nitrite ion and the aza-body were combined, the color of the aqueous solution was changed from red to green, and due to the hydrogen ion protonation effect, it was possible to detect the difference in absorbance region (Non Patent Literature 4).

Professor Zhen of China detected nitrite ions using the etch phenomenon of nanorod particles and used the color change according to the shape of the particles from rod shape to spherical shape (Non Patent Literature 5).

[Non-Patent Document 1] J. Am. Chem. Soc. 2009, 131, 6362-6363 Non-Patent Document 2: Nanoscale 2017, 9, 1811-1815 Non-Patent Document 3: Anal. Chim. Acta 2014, 842, 57-62 Non-Patent Document 4: Anal. Chem. 2013, 85, 10008-10012 Non-Patent Document 5: Analyst, 2012, 137, 5197-5200

An object of embodiments of the present invention is, in one aspect, colorimetric detection, which is capable of detecting nitrite ions (nitrite, NO ₂ ^— ) using gold nanocubes and having high selectivity and measurement sensitivity and in a short time. A colorimetric detection sensor and a colorimetric detection method are provided.

An object of embodiments of the present invention, in another aspect, by adjusting the reaction conditions, such as salt concentration, pH, temperature, reaction time in a colorimetric detection sensor comprising a hexahedral gold nanocube, nitrite ion measurement sensitivity and reaction rate To provide a colorimetric detection sensor and colorimetric detection method that can be optimized.

In exemplary embodiments of the present invention, as a colorimetric detection sensor for nitrite ion detection, the colorimetric detection sensor includes a hexahedral gold nanocube, and the hexahedral nanocube is etched from the nitrite ion Provided is a colorimetric detection sensor that changes to a sphere by) to detect nitrite ions.

In exemplary embodiments of the present invention, there is also provided a colorimetric detection method for detecting nitrite ions using the colorimetric detection sensor.

In exemplary embodiments of the present invention, there is also provided a method for manufacturing the colorimetric detection sensor, comprising: preparing a seed solution comprising gold nanoparticle precursor; Preparing a growth solution for growing the gold nanoparticles into a nanocube; It provides a method for producing a colorimetric detection sensor comprising a; mixing the growth solution and the seed solution to prepare gold nanoparticles in the form of a cube of gold nanocube.

According to embodiments of the present invention, nitrite ions (nitrite, NO ₂ ⁻ ) may be detected using a gold nanocubes by colorimetric detection with high selectivity and measurement sensitivity and within a short time. In addition, by adjusting the reaction conditions such as salt concentration, pH, temperature, reaction time, etc. of the colorimetric detection sensor including a hexahedral gold nanocube, it is possible to optimize the sensitivity and reaction rate of nitrite ion. The color change of the colorimetric detection sensor for nitrite ion detection can be checked with the naked eye or equipment, and the change in color can be quantitatively detected up to the detection limit of 0.01 μg / mL according to the change of the nitrite ion concentration.

Colorimetric detection sensor and colorimetric detection method of embodiments of the present invention can determine the concentration of nitrite ions contained in biological samples, drinking water, environmental samples, etc. by changing the color to easily measure the concentration of nitrite ions in the field in real time It can be used to

1 illustrates, in one embodiment of the present invention, using gold chloride (HAuCl ₄ ) to form gold nanoparticles into functionalized gold nanocubes (AuNCs), and then react with nitrite ions (NO ₂ ⁻ ) This is a schematic diagram showing the color change and phenomenon that the cube shape is etched into spherical nanoparticles.
Figure 2a is a cube cube-shaped gold nano cubes (AuNCs) in the embodiment of the present invention, UV-vis spectrum graph and color (left) of the nanocube solution before the reaction, gold nanocube and nitrite ions after addition of nitrite ions reaction of the (NO ₂ ^- -AuNCs) solution color and UV-vis spectrum is indicative of a change in a graph (right).
Figure 2b is a TEM image and a size distribution graph showing the average size of the nanocube before reaction with nitrite ions in one embodiment of the present invention.
Figure 2c is a size distribution graph and TEM image showing the average size of the nano-cube after the reaction reaction with nitrite ions in one embodiment of the present invention.
3 is a graph showing a change in color (Fig. 3a) and UV-vis spectra of the gold nanocube according to pH according to an embodiment of the present invention (Fig. 3b).
4 is a color change picture (FIG. 4A), a spectral change graph (FIG. 4B), and an absorbance ratio (A) according to a change in reaction temperature according to the addition of 10 ppm of nitrite ions to the prepared gold nanocube in an embodiment of the present invention. ₅₅₀ / A ₆₅₀ ) graph (Figure 4c).
FIG. 5 is a graph illustrating a spectral change graph (FIG. 5A) and an absorbance ratio (A ₅₅₀ / A ₆₅₀ ) graph according to NaCl concentration change before and after 10 ppm of nitrite ion is added to the prepared gold nanocube in an embodiment of the present invention. )to be.
FIG. 6 is a graph illustrating changes in absorbance ratio (A ₅₅₀ / A ₆₅₀ ) according to the addition of 10 ppm of nitrite ions to the prepared gold nanocube and the reaction time at a reaction temperature of 90 ° C. and 20 mM NaCl. to be.
FIG. 7 is a graph illustrating a color change (FIG. 7A) and an absorbance ratio (A ₅₅₀ / A ₆₅₀ ) of a reaction solution according to nitrite ion (NO ₂ ⁻ ) concentration in a manufactured gold nanocube (FIG. 7B). )to be.
FIG. 8 is a diagram illustrating color change (FIG. 8A) and absorbance spectrum graph (FIG. 8B), and selectivity of a reaction solution according to addition of nitrite ions (NO ₂ ⁻ ) and anions to a manufactured gold nanocube. Absorbance ratio (A ₅₅₀ / A ₆₅₀ ) graph shown (FIG. 8C).

Term Definition

As used herein, the seed solution refers to a solution including a seed for making a nanocube. For example, seed nanoparticles having a size of 10 to 20 nm are present in the seed solution, and a nanocube can be grown from the nanoparticle seed by mixing a growth solution with a seed solution containing the nanoparticles.

As used herein, the growth solution refers to a solution for growing nanoparticles, which are seeds of a seed solution, in a nanocube form, and may be mixed with the seed solution to obtain nanocubes having a desired size and / or shape from the seed.

Functionalization in the present specification means to give the nanoparticles the ability to improve the selectivity and / or interference effects on the detection target material.

In the present specification, the spherical shape does not refer only to the shape of a perfect sphere, but is meant to include a substantially spherical shape.

Description of Example Embodiments

Hereinafter, exemplary embodiments of the present invention will be described in detail.

In exemplary embodiments of the present invention, as a colorimetric detection sensor for nitrite ion detection, the colorimetric detection sensor includes a hexahedral gold nanocube, and the hexahedral nanocube is etched from the nitrite ion Provided is a colorimetric detection sensor that changes to a sphere by) to detect nitrite ions.

A hexahedral gold nanocubes are nanocubes with a particle size of 100 nm or less and uniform particle size, which reacts with nitrite ions, resulting in etching and thus the structure and shape of the nanocube. And the absorption frequency due to surface plasmon resonance is changed.

Surface plasmon resonance is a phenomenon that causes free electron vibrations on the surface of nanoparticles by light waves absorbed by nano-sized particles. In this case, resonance occurs and emits a specific wavelength. Depending on the size, shape, and type of a variety of colors can be used to use it as a colorimetric sensor.

The colorimetric detection sensor of the exemplary embodiments of the present invention is particularly suitable for the colorimetric detection method due to the high selectivity and sensitivity of the sensor according to the nitrite ion concentration because it uses a shape change in which the nitrite ion is etched in the nanocube form. . Carving metal nanoparticles during oxidative etching with nitrite ions, it is easier to control the size and shape of the nano-cube structure than the nanorods. Accordingly, the nanocube has very high selectivity and sensitivity compared to the nanorods. For example, unlike nanorods when oxidized to nitrite ions, the detection limit (LOD) is significantly reduced when using nanocubes.

In an exemplary embodiment, the gold nanocube may have an absorbance ratio (A550 / A650) of 0 to 10 at 600 nm to 700 nm of absorbance before nitrite and 500 nm to 600 nm of absorbance after reaction with nitrite ions. The concentration of nitrite ions can be most clearly distinguished in the range of the absorbance ratio of 0 to 10, and when the concentration is outside the range, the division of concentrations of nitrite ions may not be clear.

In an exemplary embodiment, the colorimetric detection sensor may be an aqueous solution including gold nanocubes.

In an exemplary embodiment, the colorimetric detection sensor may further include a salt that is a stabilizer. In a non-limiting example, the salt can be NaCl.

In a non-limiting example, the concentration of salt such as NaCl is preferably greater than 0 and 50 mM or less for the colorimetric detection sensor solution, and beyond this range the nanoparticles may no longer maintain nanocube form.

In an exemplary embodiment, the colorimetric detection sensor detects nitrite ions in the range of pH 3-12, preferably in particular pH 3.

In one exemplary embodiment, the colorimetric detection sensor detects nitrite ions at a reaction temperature from room temperature to 90 ° C., preferably in particular from 60 to 90 ° C.

In an exemplary embodiment, the colorimetric detection sensor may exhibit a color change from the initial blue color to red color (red or bright red color) upon detection of nitrite ion.

In an exemplary embodiment, the colorimetric detection sensor may have a nitrite ion detectable concentration of 0.01 ppm or less, or 0.01 ppm to 1 ppm.

In an exemplary embodiment, the colorimetric detection sensor, wherein the nanocube has a diameter of 100 nm or less.

In an exemplary embodiment, the color change of the colorimetric detection sensor may be measured visually or quantitatively with a spectrophotometer, a fluorometer, or a colorimeter.

In exemplary embodiments of the present invention, there is also provided a colorimetric detection method for detecting nitrite ions using the colorimetric detection sensor.

In an exemplary embodiment, the colorimetric detection method may include: injecting a sample to be detected into a colorimetric detection sensor; And detecting nitrite ions in the sample to be detected by the color change of the colorimetric detection sensor.

In an exemplary embodiment, the colorimetric detection method may further include a concentration measurement step of quantifying the concentration of nitrite ions in the sample to be detected by measuring the color change of the colorimetric detection sensor with a spectrophotometer, a fluorescence photometer, or a colorimeter. have.

Meanwhile, in exemplary embodiments of the present invention, there is also provided a method of manufacturing the colorimetric detection sensor, comprising: preparing a seed solution containing gold nanoparticle precursor; Preparing a growth solution for growing the gold nanoparticles into a nanocube; It provides a method for producing a colorimetric detection sensor comprising a; mixing the growth solution and the seed solution to prepare gold nanoparticles in the form of a cube of gold nanocube.

After mixing the seed solution, which is the first solution, and the growth solution, which is the second solution, the shape is changed while growing the gold nanoparticle seed of the seed solution, thereby preparing a cube-shaped nanocube.

In an exemplary embodiment, such a seed solution comprises a gold nanoparticle precursor, a surface active agent which allows the gold nanoparticle precursor to be stably present in a solution, in particular an aqueous solution state, and a reducing agent of the gold nanoparticle precursor.

In a non-limiting example, the seed solution may include a gold nanoparticle precursor gold chloride hydrate, cetyltrimetyl ammonium bromide (CTAB), reducing agent sodium tetraborate (NaBH ₄ ). That is, the seed gold nanoparticles are prepared by reducing the gold chloride hydrate, which is a precursor of the gold nanoparticles, with sodium borohydride as a reducing agent under CTAB, which is a surface active agent.

In a non-limiting example, the growth solution may also include gold nanoparticle precursor gold chloride, surface active agent CTAB, reducing agent sodium tetraborate, and may further include silver nitrate and ascorbic acid.

In the growth solution, CTAC is a material that acts as a surface activator to help the nanoparticles to be stably present in the aqueous solution as in the seed solution, and silver nitrate and gold chloride hydrate become materials to grow from the nanoparticles to the nanocube shape. . Ascorbic acid acts as a reducing agent. For reference, ascorbic acid has the advantage of excellent water solubility, little toxicity and excellent biodegradability.

In an exemplary embodiment, the molar ratio of the nanocube to the reducing agent when the growth solution and the seed solution are mixed may be 0.46 to 2.14. The shape of the nanocube is best manufactured in the molar ratio range of the nanocube, and if it is out of the range, the nanocube may not be formed or may be made too large to precipitate. In this regard, the size of the nanoparticles varies with the amount of reducing agent. Therefore, it is useful to obtain the ratio of the nanocube based on the reducing agent which is the basic material.

In an exemplary embodiment, the seed solution may include cetyltrimethylammonium chloride (CTAC), gold chloride (HAuCl ₄ ) and sodium borohydride (NaBH ₄ ).

In an exemplary embodiment, the growth solution is cetyltrimethylammonium chloride (CTAC), gold hydride (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO ₃ ) And ascorbic acid.

Hereinafter, specific embodiments according to exemplary embodiments of the present invention will be described in more detail. However, the present invention is not limited to the following examples, and various forms of embodiments can be implemented within the scope of the appended claims, and the following examples are only common in the art while making the disclosure of the present invention complete. It is to be understood that the invention is intended to facilitate the practice of the invention.

Example: Gold Chloride Hydrate (HAuCl ₄ Of hexagonal crystal-shaped nanoparticles

To prepare the seed solution (seed solution) of gold nanoparticles chloride, cetyltrimethylammonium (cetyltrimethylammonium chloride, CTAC) 100 gold chloride hydrate in mM aqueous solution (HAuCl ₄₎ 10 mM aqueous solution and four hydrogen boron sodium (sodium borohydried, NaBH ₄ ) And reacted with a 10 mM aqueous solution.

As a growth solution, in a 100 mM aqueous solution of cetyltrimethylammonium chloride (CTAC), a 10 mM aqueous solution of HAuCl ₄ , a 10 mM aqueous solution of silver nitrate (AgNO ₃ ) and ascorbic acid ) Was prepared by mixing 100 mM aqueous solution.

After the mixture solution of the growth solution and the seed solution was reacted for 24 hours, a cube-shaped gold nanocubes were prepared.

1 is, in one embodiment of the present invention, formed from functionalized gold nanocube (AuNCs) from a seed containing gold chloride (HAuCl ₄ ), and then reacted with nitrite ions (NO ₂ ⁻ ), nanocube form Schematic diagram showing the phenomenon of color change and the etching of spherical nanoparticles.

As shown in FIG. 1, the functionalized gold nanocubes (AuNCs) made using gold chloride (HAuCl ₄ ) are reacted with nitrite ions (NO ₂ ⁻ ) between pH 3 and 5, thereby making the cube form spherical nanoparticles. Etched into particles and changing color.

As such, the nitrite ion continuously etches the cubic-shaped nanoparticle surface, transforming it into spherical nanoparticles, and the color changes due to the surface resonance phenomenon. This phenomenon occurs only in the nitrite ion and the nitrite ion It can be used as a nano-cubic sensor that can detect.

In the example related to Figure 2 below, the prepared gold nanocube was reacted with nitrite ions at pH 3, temperature 90 ℃, 20 mM NaCl.

FIG. 2A illustrates a UV-vis spectrum graph and color (left) of a nanocube solution before addition of hexahedral cube-shaped gold nanocubes (AuNCs) to react with nitrite ions, and the addition of nitrite ions. and the nitrite ion and a reaction product of ^- indicates the change in the (NO ₂ -AuNCs) solution color and UV-vis spectrum graph (right).

Figure 2b is a size distribution graph and TEM image showing the average size of the nanoparticles before the reaction with nitrite ions in one embodiment of the present invention.

Figure 2c is a TEM image and a size distribution graph showing the average size of the nanoparticles after reaction with nitrite ions in one embodiment of the present invention.

As can be seen in Figures 2b and 2c, the average size of the nanoparticles before and after the reaction with the nitrite ion is maintained at about 50 nm, before the reaction is a hexagonal cube shape, it can be seen that after the reaction was changed to a spherical shape. .

Stability Test with pH Change of Gold Nanocubes

3 is a graph showing the change in color (Fig. 3a) and the UV-vis spectra of the hexagonal gold nanocube according to pH according to an embodiment of the present invention (Fig. 3b).

Figure 3a was observed by changing the pH to 2 to 13 for the stability test of the gold nanocube, of which the gold nanocube showed a blue color at pH 3-12.

Figure 3b shows the UV-vis spectrum according to the pH change, except that the pH (pH 2 and pH 13) corresponding to the strong acid, strong base, gold nanocube (AuNCs) was found to be stable at all pH.

In the present embodiment, since the gold nanocube in the form of hexagonal surface was prepared immediately after the pH 3, the experiment was conducted by selecting the pH, and stability was confirmed from maintaining a constant gold nanocube state without color change.

Reactivity and Stability Test of Gold Nanocubes with Reaction Temperature

The addition of 10 ppm and then the reaction by each different reaction temperature at 20 ~ 90 ℃ 30 minute and then the color change at each temperature and the UV-vis spectrum ^{change-nitrite} ions (NO ₂₎ in the prepared gold nanoparticles cube Observed.

4 is a color change picture (FIG. 4A), a spectral change graph (FIG. 4B), and an absorbance ratio graph (FIG. 4A) according to a change in reaction temperature according to the addition of 10 ppm of nitrite ions to the prepared gold nanocube. A ₅₅₀ / A ₆₅₀ ) (FIG. 4C).

As can be seen in Figure 4a, the reaction of the nanocube did not change significantly up to 50 ℃, but the color was changed to red up to 60 ~ 90 ℃. This shows the same result in the UV-vis spectrum of Figure 4b. FIG. 4C shows the absorbance ratio A ₅₅₀ / A ₆₅₀ and shows the highest absorbance ratio at 90 ° C.

Reactivity and Stability Tests of NaCl Concentrations in Gold Nanocubes

Before and after adding 10 ppm of nitrite ions (NO ₂ ⁻ ) to the prepared nanocube, the reaction was carried out at various reaction temperatures of sodium chloride (1 to 400 mM) at a reaction temperature of 90 ° C. and the change of nitrite ion and nanocube was observed after 30 minutes. .

5 is a spectrum change graph (Fig. 5a) and absorbance ratio graph (A ₅₅₀ / A ₆₅₀ ) according to the NaCl concentration change before and after the addition of 10 ppm nitrite ion to the prepared gold nanocube in an embodiment of the present invention (Fig. 5b).

Before the addition of nitrite ions, the gold nanocube became unstable and changed blue color at sodium chloride concentration of 100 mM or higher. 5a shows the same result in the change of the spectrum according to the change in sodium chloride concentration. 5B shows the absorbance ratio (A ₅₅₀ / A ₆₅₀ ) of FIG. 5, and it can be seen that an optimal salt concentration for nitrite ion detection is 20 mM.

Reaction rate as a function of pH, temperature and NaCl concentration of gold nanocubes

10 ppm of nitrite ions (NO ₂ ⁻ ) were added to the prepared nanocube, and the absorbance ratio (A ₅₅₀ / A ₆₅₀ ) was continuously measured.

6 is a reaction showing the change in absorbance ratio (A ₅₅₀ / A ₆₅₀ ) according to the reaction time at the reaction temperature of 90 ° C. and NaCl 20 mM in addition of 10 ppm of nitrite ion to the prepared gold nanocube Speed graph.

As can be seen in Figure 6, the absorbance ratio shows that the reaction rate increases steeply up to 30 minutes, and almost no further etching reaction occurs after 30 minutes. Therefore, the reaction between the nanocube and the nitrite ion was selected to be completed in about 30 minutes.

Sensitivity and Selectivity Testing of Anionic Compounds of Gold Nanocube

A hexahedral gold nanocube prepared according to the example was subjected to a sensitivity test for nitrite ions and a selectivity test due to reaction with other anions.

First, nitrite ions were added to the colorimetric sensor including the gold nanocube in concentrations (0.1 to 10 ppm) to measure the absorbance ratio (A ₅₅₀ / A ₆₅₀ ). FIG. 7 is a graph illustrating a color change (FIG. 7A) and an absorbance ratio (A ₅₅₀ / A ₆₅₀ ) of a reaction solution according to nitrite ion (NO ₂ ⁻ ) concentration in a manufactured gold nanocube (FIG. 7B). )to be.

As shown in FIG. 7A, the red color increases as the concentration of the added nitrite ion increases. FIG. 7B maintains the linearity (r ² = 0.9663) according to the absorbance ratio, and the linear y = 0.7879x. -0.1333 is shown.

With respect to the embodiment of the nano ^{_{cube, 1) NO 2 -, 2}} ) NO 3 -, 3) Cl -, 4) Br -, 5) SO 4 2-, 6) PO 4 2-, 7) CN -, 8) ^{I -, 9) F -,} 10) C 6 H 4 (COO -) 2, 11) CH 3 COO -, 12) C 3 H 5 O (COO) 3 3 - was tested and the selectivity of.

FIG. 8 is a diagram illustrating color change (FIG. 8A), absorbance spectrum graph (FIG. 8B), and selectivity of a reaction solution according to the addition of nitrite ions (NO ₂ ⁻ ) and other anions to the prepared gold nanocube. It is an absorbance ratio (A ₅₅₀ / A ₆₅₀ ) graph (FIG. 8C) shown.

In FIG. 8A, nitrite ions have a red color differently from other anions, and only the color change can clearly confirm the reactivity of nitrite ions with other ions. FIG. 8B is a result of the spectrum of FIG. 8A and it can be seen that nitrite ions exhibit different absorbances A ₅₅₀ and A ₆₅₀ than other ions. FIG. 8C shows the absorbance ratio of FIG. 8B, which shows that nitrite ions have excellent selectivity for etching hexahedral nanocubes unlike other anions.

In other words, the detection system according to the embodiments of the present invention has high sensitivity to nitrite ions compared to other anions, so that the naked eye can be distinguished from the naked eye. Can be.

Evaluation of the effectiveness of detection systems containing gold nanocubes

Anion detection experiments were performed in natural mineral water, which is a real sample. The natural mineral water on the market was purchased, and it was confirmed whether the target substance was contained in the product, and after confirming that the target substance did not exist, the sample was used as a conjugated sample (blank).

First, a conjugated sample containing 1 ppm and 0.3 ppm of nitrite ions to be detected was prepared, and the detected amount, coefficient of variation (CV), and recovery (%) were measured using the calibration curve prepared in Example 5. .

Concentration
(ug / ml) Amount of nitrite ion added to conjugated sample (μg / ml) Detection concentration
(ug / ml) CV (Coefficient of Variation) Recovery rate
(%) Detection limit
(ppb) 0.30 0.29 ± 0.01 3.45 98.5 ± 5.21 9.56 1.00 1.03 ± 0.06 5.82 103.1 ± 6.07

As shown in Table 1, the limit of detection (LOD) of nitrite ions using a colorimetric sensor is expressed as 0.01 ppm or less. The detected amounts of 0.3 ppm and 1 ppm were 0.29 ± 0.01 and 1.03 ± 0.06, respectively, and the coefficients of variation were excellent, including 3.45 and 5.82, and the recoveries were also 98.5 ± 5.21 and 103.1 ± 6.07.

Drinking water and beverages are products made of various compositions, but there may be many obstacles in detecting nitrite ions. However, the present invention is used as a colorimetric sensor by etching nitrite ions. It can be seen that the performance is very good and the selectivity is high.

Although the non-limiting and exemplary embodiments of the present invention have been described above, the technical idea of the present invention is not limited to the accompanying drawings and the above description. It will be apparent to those skilled in the art that various forms of modifications can be made without departing from the spirit of the present invention, and furthermore, such modifications will be within the scope of the claims of the present invention.

Claims (18)

A colorimetric detection sensor for detecting nitrite ions (nitrite),
The colorimetric detection sensor includes a hexahedral gold nanocube,
A hexahedral gold nanocube changes to a sphere by etching of nitrite ions to detect nitrite ions.
The hexahedral gold nanocube is grown from a gold nanoparticle seed colorimetric detection sensor.
The method of claim 1,
The colorimetric detection sensor is a colorimetric detection sensor, characterized in that the aqueous solution containing a gold nanocube.
The method of claim 1,
The colorimetric detection sensor further comprises a salt that is a stabilizer (stabilizer).
The method of claim 3, wherein
The salt is a colorimetric detection sensor, characterized in that NaCl.
The method of claim 3, wherein
The concentration of the salt is a colorimetric detection sensor, characterized in that more than 0 and 50mM or less in the colorimetric detection sensor solution.
The method of claim 1,
The colorimetric detection sensor is a colorimetric detection sensor, characterized in that for detecting nitrite ions in the range of pH 3 to 12.
The method of claim 1,
The colorimetric detection sensor is a colorimetric detection sensor, characterized in that for detecting the nitrite ion by reacting at a reaction temperature in the range of room temperature to 90 ℃.
The method of claim 1,
The colorimetric detection sensor is a colorimetric detection sensor, characterized in that the nitrite ion detectable concentration is 0.01 ppm or less.
The method of claim 1,
The gold nanocube colorimetric detection sensor, characterized in that the absorbance ratio (A550 / A650) at the absorbance of 600 nm to 700 nm before the nitrite ion reaction and the absorbance 500 nm to 600 nm after the reaction with the nitrite ion is 0 to 10.
The method of claim 1,
The colorimetric detection sensor is a colorimetric detection sensor, characterized in that the color change from blue to red color when detecting nitrite ion.
The method of claim 1,
The color change of the colorimetric detection sensor is measured by the naked eye, or colorimetric detection sensor characterized in that it is measured quantitatively by a spectrophotometer, a fluorometer or a colorimeter.
The colorimetric detection method which detects a nitrite ion using the colorimetric detection sensor in any one of Claims 1-11.
The method of claim 12,
The colorimetric detection method may include: injecting a sample to be detected into a colorimetric detection sensor; And detecting nitrite ions (nitrite) in the sample to be detected by color change of the colorimetric detection sensor.
The method of claim 12,
The colorimetric detection method further comprises a concentration measurement step of quantifying the concentration of the nitrite ion in the sample to be detected by measuring the color change of the colorimetric detection sensor with a spectrophotometer, a fluorescence photometer or a colorimeter.
As a manufacturing method of the colorimetric detection sensor of any one of Claims 1-11,
Preparing a seed solution comprising a gold nanoparticle precursor;
Preparing a growth solution for growing the gold nanoparticles into a nanocube; And
A method of manufacturing a colorimetric detection sensor comprising a; mixing a growth solution and a seed solution to produce gold nanoparticles into a hexahedral gold nanocube.
The method of claim 15,
The molar ratio of the gold nanocube to the reducing agent (molar ratio) when the growth solution and the seed solution is mixed, characterized in that 0.46 ~ 2.14.
The method of claim 15,
The seed solution is cetyltrimethylammonium chloride (CTAC), gold chloride (HAuCl ₄ ) and sodium borohydride (sodium borohydride, NaBH ₄ ) manufacturing method characterized in that it comprises a color detection sensor.
The method of claim 15,
The growth solution is cetyltrimethylammonium chloride (CTAC), gold chloride (HAuCl ₄ ), sodium borohydride (NaBH ₄ ), silver nitrate (AgNO ₃ ) and ascorbic acid (ascorbic acid) Colorimetric detection sensor manufacturing method comprising a.

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