KR102233903B1 - Colorimetric sensor for detecting calcium ion, barium ion or cadmium ion comprising silver nanoparticles and anionic surfactant, a method for producing the same and calcium ion, barium ion or cadmium ion detection method using the same - Google Patents

Abstract

In the present specification, a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions including silver nanoparticles and anionic surfactants, a method of manufacturing the same, and a method of detecting calcium ions, barium ions, or cadmium ions using the same are disclosed.

Description

Colorimetric sensor for detecting calcium ions, barium ions or cadmium ions containing silver nanoparticles and anionic surfactants, manufacturing method thereof, and calcium ions, barium ions or cadmium ions detection method using the same {COLORIMETRIC SENSOR FOR DETECTING CALCIUM ION, BARIUM ION OR CADMIUM ION COMPRISING SILVER NANOPARTICLES AND ANIONIC SURFACTANT, A METHOD FOR PRODUCING THE SAME AND CALCIUM ION, BARIUM ION OR CADMIUM ION DETECTION METHOD USING THE SAME}

The present specification relates to a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions including silver nanoparticles and anionic surfactants, a method of manufacturing the same, and a method of detecting calcium ions, barium ions, or cadmium ions using the same.

More specifically, by coating the silver nanoparticles with an anionic surfactant, the stability of the silver nanoparticles is improved in the sensor, and the silver nanoparticles condense with calcium, barium, and cadmium ions in the colorimetric sensor, thereby selective color change. It relates to a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions derived from, a method of manufacturing the same, and a method of detecting calcium ions, barium ions, or cadmium ions using the same.

Calcium is the most important and abundant metal element in the human body, and is an important component of human bones and teeth. Calcium ions also play an important function in cell adhesion, and calcium ions are also involved in maintaining cell membrane function. Transmembrane transport and intervention of biological information, cellular responses to external stimuli, and low calcium intake can lead to many diseases such as growth retardation, osteoporosis and hypertension.

Water-soluble barium compounds are toxic substances. At low doses, barium ions act as a muscle stimulant, but at high doses it can cause nervous system effects, cardiac arrhythmias, tremors, weakness, anxiety, shortness of breath and paralysis.

Cadmium ions are representative environmental pollutants and are the cause of Itai-itai disease in Japan. It leads to impaired kidney function, impaired calcium metabolism and the development of certain forms of cancer. The maximum permissible cadmium ion (Cd ^{2 +} ) concentration in drinking water is based on 3 μg/L by the World Health Organization (WHO).

Calcium, barium, and cadmium ions have been detected by Atomic Absorption Spectrometry (AAS), Atomic Emission Spectrometry (AES), Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), In addition, X-ray Diffraction Spectrometry (XRD) and Voltametric cycle were mainly analyzed.

Cadmium ion (Cd ^{2 +} ) is developing a method to detect by colorimetric method by adding functionality to silver nanoparticles [Res. Chem. Intrmed. 44(2018) 2305-2317], [Analyst. 136(2011) 3725-3730] or a label-free detection method was developed [Anal. Chem., 86(2014) 8530-8534].

Environment and biological systems Ca ^{2 +} ions mainly monitoring, the past few decades, the fluorescence sensor is a practical tool for detecting Ca ^{2 +.} Metal ions and anion analysis in biochemical and imaging is utilized in a living cell research to detect the change of Ca ^{2 +} in the sensor cell, such as Fluo-3, Fluo-4, Calcium Green-1, Indo-1 and Indo-5F It was widely used. However, for most Ca ^{2 +} sensors, the selectivity is not satisfactory due to the interference ^{of Mg 2 +.}

In addition, ^{the detection of Ba 2 +} ions is limited in detection due to the interference of many alkaline metal ions.

Therefore, ^{developing a simple and reliable method for detecting Ca 2 +} , Ba ^{2 +} or Cd ^{2 +} ions is very important in environmental monitoring and biological analysis.

KR 10-2017-0007042 A KR 10-2012-0047635 A KR 10-2010-0089443 A KR 10-2012-0114808 A

Res. Chem. Intrmed. 44(2018) 2305-2317], [Analyst. 136(2011) 3725-3730 Anal. Chem., 86(2014) 8530-8534

In embodiments of the present invention, it is intended to provide a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions including silver nanoparticles and anionic surfactants, a method for manufacturing the same, and a method for detecting calcium ions, barium ions, or cadmium ions using the same. .

In one embodiment of the present invention, a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions including silver nanoparticles and anionic surfactant is provided.

In another embodiment of the present invention, a method of manufacturing a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions described above, comprising: adding silver nitrate to a solution containing an anionic surfactant; And preparing silver nanoparticles by adding trisodium citrate and sodium borohydride (NaBH _{4) to the solution.} It provides a method for manufacturing a colorimetric sensor for detecting calcium ions, barium ions or cadmium ions comprising a.

In another embodiment of the present invention, a method for detecting calcium ions, barium ions, or cadmium ions, comprising: an input step of introducing a sample to be detected into a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions; And a sensing step of detecting calcium ions, barium ions, or cadmium ions in the sample to be detected by color change of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions; containing, detecting calcium ions, barium ions, or cadmium ions Provides a way.

The colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions according to an embodiment of the present invention includes silver nanoparticles and anionic surfactants, improving the stability of silver nanoparticles in a colorimetric sensor, and improving the stability of silver nanoparticles in a colorimetric sensor. By condensing the silver nanoparticles with calcium, barium, and cadmium ions, the selectivity and sensitivity to calcium, barium, or cadmium ions are high, so that they can be very suitable for colorimetric detection.

In one embodiment of the present invention, calcium, barium, cadmium ions are detected in industrial sites such as soil, groundwater and fine dust, industrial wastewater, livestock waste, medical waste, etc. by using a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions according to one embodiment of the present invention. It has high stability, can be detected and analyzed quickly, and can be measured and continuously managed in real time, and can be manufactured on a small scale with a simple manufacturing method.

1A and 1B are TEM photographs (1a) and size distribution (1b) of silver nanoparticles according to Preparation Example 1 of the present specification.
Figures 2a and 2b is a colorimetric sensor probe according to Preparation Example 2 of the present specification and Ca ^{2 +} and Ba ²⁺ , Cd ^{2 +} UV-Vis spectrum and color comparison (2a) after ion reaction, and images and particles showing the particle change thereof It is a size distribution diagram (2b).
3A-3F are UV-Vis absorption spectra after reaction between ^{Ca 2 +} , Ba ^{2 +} and Cd ^{2 +} ions and colorimetric sensor solution according to a change in concentration of a phosphate buffer solution in Example 1 of the present specification. Shows the color change, when no phosphate buffer solution is added (3a), 10 μM is added (3b), 20 μM is added (3c), 25 ~ 50 μM is added (3d), 60 μM is added (3e), 70 Corresponds to the addition of μM or more (3f).
_{4A-4C show the absorption ratio (A 550} /A ₃₉₀ ) (4a), Ba ² according to the reaction between the ^{colorimetric sensor probe and Ca 2 +} ions according to the concentration of the phosphate buffer solution in Example 1 of the present specification. ^It is a graph showing the change of the absorption ratio (A ₆₀₀ /A ₃₉₀ ) (4b) ^{according to the reaction with +} ions and the absorption ratio (A ₅₀₀ /A ₃₉₀ ^{) (4c) according to the reaction with Cd 2 + ions.}
5A-5E show pH 6.0 (5a), pH 7.0 (5b), pH 8.0 (5c), pH 8.5 (5d), and pH 9.0 (5e) of the colorimetric sensor buffer solution according to pH change in Example 2 of the present specification. This is a graph showing the UV-Vis absorption spectrum and color change after reaction with various cations in
6a-6c show the absorption ratio (A ₅₅₀ /A ₃₉₀ ) and color change (6a) over ^{time after addition of Ca 2 +} ion concentration in Example 3 of the present specification, ^{and time after addition of Ba 2 +} ion concentration The absorption ratio (A ₆₀₀ /A ₃₉₀ ) and color change (6b), _{the absorption ratio (A 500} /A ₃₉₀ ) and color change (6c) according to time after addition of each ^{Cd 2 + ion concentration were shown.}
_{Figures 7a-7d show the color change (7a) and its absorption ratio (A 550} / A ₃₉₀ ) in the phosphate buffer 20-50 μM and pH 8.5 of the colorimetric sensor solution when various metal cations are added in Example 4 of the present specification ( 7b), absorption ratio (A ₆₀₀ /A ₃₉₀ ) (7c), absorption ratio (A ₅₀₀ /A ₃₉₀ ) (7d).
^{Figures 8a-8c are Ca 2 +} absorption ratio by ion concentration (A ₅₅₀ / A ₃₉₀ ) (8a), Ba ^{2 +} absorption ratio by ion concentration (A ₆₀₀ / A ₃₉₀ ) (8b) in Example 5 of the present specification, It is a quantitative curve using ^{Cd 2 +} absorption ratio by ion concentration (A ₅₀₀ /A _{390 )(8c).}
9 is a graph analyzed by using a quantitative curve ^{of Ca 2 +} ions of FIG. 8A on an actual sample according to Example 6 of the present specification.

In the present specification, when a certain part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Embodiments of the present invention have been described with reference to the accompanying drawings, but this is described for purposes of illustration, by which the technical idea of the present invention and its configuration and application are not limited.

Calcium ion , Barium ion or For cadmium ion detection Colorimetric sensor

In exemplary embodiments of the present invention, a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions including silver nanoparticles and an anionic surfactant is provided.

The colorimetric sensor according to an embodiment of the present invention is a colorimetric sensor of the concept of using a single sensor to detect multiple target substances, and includes calcium ions (Ca ^{2 +} ) and barium ions (Ba ^{2 +).} ) And cadmium ions (Cd ^{2 +} ) have excellent selectivity and sensitivity for each ion.

Specifically, by including the anionic surfactant together with the silver nanoparticles, the stability of the silver nanoparticles in the colorimetric sensor solution can be improved, and the silver nanoparticles in the colorimetric sensor include calcium, barium, cadmium ions and specific conditions. As a result of the selective reaction at, a surface plasmon resonance phenomenon occurs due to the change in particle size, resulting in a color change, resulting in high selectivity and sensitivity to calcium ions, barium ions, or cadmium ions, making it suitable for colorimetric detection methods. It can be used very suitably.

In addition, the present invention makes it very easy to develop a sensor because no organic material for imparting functionality to the particles is added, and in particular, it is possible to detect not only cadmium ions but also calcium ions and barium ions simultaneously by adjusting the amount of surfactant and pH control, and selecting the absorbance ratio. can do.

On the other hand, anionic surfactants are relatively insoluble in water, but are used as a stabilizer, and they exhibit hydrophobic and hydrophilic properties due to good chemical modification in micelles to improve mass transfer, and increase the stability of particles by increasing ionic repulsion. Low toxicity and low cost.

In an exemplary embodiment, the anionic surfactant may be dioctylsulfosuccinate.

In an exemplary embodiment, the size of the silver nanoparticles may be 5 to 20 nm. Plasmonic phenomena occur in the range of 1 to 100 nm in particle size, and most particularly occur at 5 to 20 nm.

In an exemplary embodiment, the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions may further include a phosphate buffer solution. The phosphate solution has a pH of 7.4, and the optimum pH of the colorimetric sensor according to an embodiment of the present invention is about pH 8.5, so that it is convenient to adjust the pH and has an advantage as an eco-friendly solvent.

In an exemplary embodiment, the concentration of the phosphate buffer solution may be 0.02 to 0.2 mM. When the concentration is less than 0.02 mM, a characteristic color change, that is, aggregation of the silver nanoparticles and the target ions may not occur, and when the concentration is more than 0.2 mM, the color change of calcium and barium ions may be the same.

In an exemplary embodiment, the maximum absorbance of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions may be 350 to 450 nm.

In an exemplary embodiment, when the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions reacts with calcium ions, the maximum absorbance is 500 to 600 nm, and the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions is barium ions When overreacting, the maximum absorbance is 550 to 650 nm, and when the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions reacts with cadmium ions, the maximum absorbance may be 450 to 550 nm. By indicating the wavelength, selective detection is possible.

In an exemplary embodiment, the absorption ratio of the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions is expressed as a value of _{A 550} /A _{390 when reacted with calcium ions, and a value of A 600} /A _{390 when reacted with barium ions} And when reacted with cadmium ions, it can be expressed as a value of _{A 500} /A _390.

The absorption ratio value may be 0.01 to 1, specifically, for calcium ions and cadmium ions, it may be 0.01 to 0.6, and for barium ions, it may be 0.01 to 0.9.

In an exemplary embodiment, the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions may detect calcium ions, barium ions, or cadmium ions at pH 8 to 9, preferably calcium ions and barium at pH 8.5. Ions or cadmium ions can be detected.

In acidic and neutral solutions having a pH of 7 or less, it may not react with the target ions. At pH 9 or more, calcium ions and barium ions may not be distinguished by color, and magnesium ions also start to react, so it is not suitable.

In an exemplary embodiment, the detection time of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions may be within 20 minutes when detecting calcium ions, within 30 minutes when detecting barium ions, and within 25 minutes when detecting cadmium ions. have. Therefore, since ions can be detected within a relatively short time, the utility value is high.

In an exemplary embodiment, the detection limit of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions may be 24.8 ppb when detecting calcium ions, 4.59 ppb when detecting barium ions, and 19.5 ppb when detecting cadmium ions. Therefore, trace amounts of calcium ions, barium ions, or cadmium ions can be detected.

As described above, in the case of the colorimetric sensor according to an embodiment of the present invention, the presence or absence of calcium ions, barium ions, or cadmium ions can be highly sensitive and selectively determined using this, and thus can be widely used in various fields.

Calcium ion , Barium ion or For cadmium ion detection Manufacturing method of colorimetric sensor

In another embodiment of the present invention, a method of manufacturing a colorimetric sensor for detecting calcium ions, barium ions or cadmium ions described above, comprising: adding silver nitrate to a solution containing an anionic surfactant; And preparing silver nanoparticles by adding trisodium citrate and sodium borohydride (NaBH _{4) to the solution.} It provides a method for manufacturing a colorimetric sensor for detecting calcium ions, barium ions or cadmium ions comprising a.

Specifically, when a surfactant and silver nitrate are dissolved in distilled water, when trisodium citrate and sodium borohydride (NaBH ₄ ) are added, silver nanoparticles are generated due to a reduction reaction, and then anionic surfactant By surrounding the silver nanoparticles, a more stable colorimetric sensor can be manufactured.

Therefore, the method of manufacturing a colorimetric sensor according to an embodiment of the present invention does not require a complicated synthesis process or a ligand compound, and silver nanoparticles can be obtained by adding silver nitrate to a solution containing an anionic surfactant and reducing it. The colorimetric sensor can be manufactured by the method.

In an exemplary embodiment, the step of adding a phosphate buffer solution to the solution containing the silver nanoparticles; may further include.

Calcium ion , Barium ion or Cadmium ion detection Way

In another embodiment of the present invention, a method for detecting calcium ions, barium ions, or cadmium ions, comprising: an input step of introducing a sample to be detected into a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions; And a sensing step of detecting calcium ions, barium ions, or cadmium ions in the sample to be detected by color change of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions; containing, detecting calcium ions, barium ions, or cadmium ions Provides a way.

As described above, when a sample to be detected is introduced into the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions according to an embodiment of the present invention, the color of the sensor can be detected by the naked eye due to plasma resonance. This changes, and furthermore, it is possible to measure the concentration of calcium ions, barium ions, or cadmium ions.

In an exemplary embodiment, after the inputting step, adjusting the pH of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions; It may further include.

In an exemplary embodiment, after the sensing step, the color change of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions in the sensing step is measured with a UV-vis spectrophotometer or a colorimeter, and calcium ions in the sample to be detected , The concentration measurement step of calibrating the concentration of barium ions or cadmium ions; may further include.

That is, the concentration measurement step is performed by a change in color with a UV-vis spectrophotometer or a colorimeter, that is, what wavelength of light emitted by the aggregated silver nanoparticles by the surface plasmon resonance phenomenon, or by the surface plasmon resonance phenomenon. By measuring where the indicated color is clearly on the color coordinate, and comparing it with the light emitted by the silver nanoparticles before aggregation or the color displayed, to determine the degree of change quantitatively, the concentration of calcium ions, barium ions, or cadmium ions. It can be measured if it is included.

In this way, by using a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions, detection of calcium ions, barium ions, or cadmium ions can be performed through a very simple method, and selectivity and sensitivity to calcium ions, barium ions, or cadmium ions Is very high, and calcium ions, barium ions, or cadmium ions can be easily detected with the naked eye and/or with a UV-vis spectrophotometer/colorimeter alone.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments so that those of ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms, and is not limited to the embodiments described herein.

Manufacturing example 1: Preparation of silver nanoparticles

To prepare silver nanoparticles, 47.5 ml of distilled water was added to a two-neck round bottom flask having a capacity of 250 mL, and 30 mg of dioctylsulfosuccinate, an anionic surfactant, was added and sufficiently dissolved. 2 ml of 10 mM silver nitrate was added to this solution. In order to maintain a low temperature and control the reaction rate, the reaction vessel was stirred at a speed of 600 rpm while proceeding in an ice-bath. Add 2 ml of 30 mM trisodium citrate (C ₆ H ₅ Na ₃ O ₇ ·2H ₂ O) to the silver nitrate solution above, and add 2 ml of a 50 mM sodium borohydride (NaBH ₄ ) solution. It was reacted by dropping it drop by drop. The reaction was carried out for 2 hours while continuously stirring in an ice reactor to prepare yellow silver nanoparticles, and the resulting solution was stored in a refrigerator. 1a-1b shows a TEM photograph and a size distribution diagram of the silver nanoparticles.

In the silver nanoparticles prepared according to Preparation Example 1, as shown in FIGS. 1A-1B, the silver nanoparticle distribution has a size of 5-20 nm, and it can be seen that the TEM photograph and the particle distribution are identical.

Manufacturing example 2: Preparation of colorimetric sensor using silver nanoparticles

In order to prepare a colorimetric sensor solution for detecting target ions, a 0.1 M phosphate buffer solution was added to 20 ml of the nanoparticle solution obtained according to Preparation Example 1 according to Example 1 and mixed with 0 to 0.193 mM, and then 1N NaOH and 1N The proper pH was adjusted to 6.0-9.0 using HCl.

Example 1: of silver nanoparticles according to the change in phosphate buffer concentration Ca ^{2 +} , Ba ^{2 +} And Cd ²⁺ Ion reactivity

In order to optimize the reactivity and selectivity between the silver nanoparticles and metal ions obtained in Preparation Example 1, a 0.1 M phosphate buffer solution was added to 5 ml of silver nanoparticles by adding 0, 10, 20, 25 to 50, 60, and 90 μl, respectively. The final concentration was made to be 0 ~ 0.193 mM. Ca ^{2 +,} Ba ²⁺ and Cd ²⁺ are reactivity of the phosphate buffer concentration of phosphate buffer concentration through the absorption ratio graph of Figure 4a-4c of ions increase as Ca ^2+, Ba ²⁺ and Cd ²⁺ ions of the reactive You can see that this is getting better.

4A-4C, in the case of calcium ions, the absorption ratio A ₅₅₀ /A ₃₉₀ is the most appropriate range in 30 to 60 μl of a 0.1 M phosphate buffer solution, and in the case of barium ions, 20 to ₆₀ μl in A 600 /A _{390 and cadmium ions} It was _{confirmed that the A 500} /A ₃₉₀ corresponds to an appropriate range for reactivity confirmation in 20 to 60 μl.

And the corresponding color change is shown in Figs. 3a-3f. Specifically, in Example 1, the UV-Vis absorption spectrum and color change after the reaction of ^{Ca 2 +} , Ba ^{2 +} and Cd ²⁺ ions with the colorimetric sensor solution according to the change in the concentration of the phosphate buffer solution were shown. When no phosphate buffer solution is added (3a), 10 μM is added (3b), 20 μM is added (3c), 25 ~ 50 μM is added (3d), 60 μM is added (3e), 70 μM or more (3f) is added. Indicated when added.

As a result of observation, in the case of Fig. 3a there is no color change or in the case of Fig. 3b, a characteristic color change does not occur, and when 20 μl of a phosphate buffer solution is added (c), 25 to 50 μl (d) and 60 μl are added, the color change is distinct, and the spectrum It can be seen that the change of is also very characteristic. However, when 70μl or more is added, the color of calcium and barium ions may become the same.

Therefore, when comparing the color change and UV-Vis absorption spectrum, for ^{the selectivity of detecting Ca 2 +} , Ba ^{2 +} and Cd ^{2 +} ions, the concentration of the phosphate buffer should be 20 to 60 μl of 0.1 M phosphate buffer solution per 5 ml of silver nanoparticles. It is suitable, which corresponds to the concentration of 0.029 to 0.118 mM phosphate buffer. In particular, it is preferable that the concentration of 0.059 mM phosphate buffer is added to 30 μl of a 0.1 M phosphate buffer solution per 5 ml of silver nanoparticles.

Example 2: According to the pH of the silver nanoparticles Ca ^{2 +} , Ba ^{2 +} And CD ^{2 +} Ion reactivity

In order to test the ion selectivity according to the pH of the colorimetric sensor probe solution prepared using the appropriate concentration of the silver nanoparticles obtained in Preparation Examples 1 and 2 and the phosphate buffer obtained in Example 1, the pH was 6.0, 7.0, 8.0, 8.5 and 9.0, respectively. A phosphorus sample was prepared. At this time, the pH was adjusted using 1N NaOH and 1N HCl.

In FIG. 5A, 10 ppm of a working solution of various metal cations was added to a colorimetric sensor probe solution having a pH of 6.0, and a photograph of a color change and a UV-Vis absorption spectrum after the reaction at a final ion concentration of 1 ppm were shown. In the same manner, FIG. 5B shows a photograph of the color change and UV-Vis absorption spectrum after the reaction at pH 7.0, FIG. 5C shows pH 8.0, FIG. 5D shows pH 8.5, and FIG. 5E shows the UV-Vis absorption spectrum after the reaction at pH 9.0.

Referring to FIGS. 5A and 5B, the color change did not occur at pH 7.0 or lower, and through this, it can be seen that the silver nanoparticle colorimetric sensor does not react with target ions in acidic and neutral solutions of pH 7.0 or lower. ^{Ba 2 +} and Cd ^{2 +} ions reacted from pH 8.0, and in ^{the case of Ca 2 +} ions, the reaction started from pH 8.5 or higher. In Figure 5e, it was confirmed that at pH 9.0 or higher, ^{the color discrimination of Ca 2 +} and Ba ^{2 +} ions began to disappear, and Mg ^{2 +} ions also started to react, so that it was not appropriate. Therefore, future experiments were carried out at pH 8.5.

The silver nanoparticle colorimetric sensor optimized in Preparation Examples 1 and 2 of the present invention shows an absorption spectrum as shown in FIG. 2A under the conditions of 0.059 mM phosphate buffer concentration and pH 8.5, and changes in absorbance when calcium, barium, and cadmium ions are added. Can be seen that occurs. It can be seen that the absorbance of silver nanoparticles peaks at 370 to 420 nm, and peaks are generated at 500 to 600 nm when calcium ions are added, 550 to 650 nm when barium ions are added, and 450 to 550 nm when cadmium is added. In addition, as shown in FIG. 2B, when calcium, barium, and cadmium ions are added to the silver nanoparticle colorimetric sensor, it can be seen that the size increases due to aggregation of the nanoparticles.

Example 3: Ca ^{2 +} , Ba ^{2 +} And CD ^{2 +} Reactivity of colorimetric sensor over time by ion concentration

Using the colorimetric sensor solution obtained in Preparation Example 2, UV-Vis absorption spectrum was obtained according to the time of each concentration of target ions at room temperature, and a graph according to the absorption ratio was drawn.

In detail, in Fig. 6a, the Ca ^{2 +} ion concentration is finally 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 ppm, and the reaction is measured to obtain a UV-Vis absorption spectrum to obtain an absorption ratio (A ₅₅₀ / A ₃₉₀ ). Is plotted over time. In FIG. 6B, ^{the final concentrations of Ba 2 +} ions were 0.2, 0.4, 0.5, 0.8, and 1.0 ppm, respectively, and the reaction proceeded to _{graph the absorption ratio (A 600} /A ₃₉₀ ) over time. In FIG. 6C, ^{the reaction was proceeded with the Cd 2 +} ion concentration finally being 0.5, 0.8, 1.0, and 1.5 ppm, and the absorption ratio (A ₅₀₀ /A ₃₉₀ ) was plotted as a graph over time.

6A-6C, the reaction time was set to 20 minutes for ^{Ca 2 +} ions, 30 minutes for ^{Ba 2 + ions, and 25 minutes for Cd 2 +} ions, and the experiment was conducted.

Example 4: Selectivity and interference effect of colorimetric sensor solution

In the colorimetric sensor solution obtained in Preparation Example 2, 18 kinds of cations (Li ⁺ , Na ⁺ , K ⁺ , Mg ^{2 +} , Ca ²⁺ , Ba ^{2 +} , Add Cr ^{6 +} , Fe ^{3 +} , As ^{3 +} , Co ^{2 +} , Ni ^{2 +} , Cu ^{2 +} , Zn ^{2 +} , Cd ^{2 +} , Hg ^{2 +} , Al ^{3 +} , Si ^{4 +} , Pb ^{2 +} ) Thus, the reaction time was 20 minutes ^{for Ca 2 +} ions, 30 minutes for ^{Ba 2 + ions, and 25 minutes for Cd 2 +} ions, and the color change was observed. 7A is an illustration of each sample after the reaction.

In Figure 6a, the colorimetric sensor solution after the reaction starts to change to light brown after the reaction with ^{calcium ions (Ca 2 + ), barium ions (Ba 2 +} ) turn dark green (Fig. 6b) and cadmium ions (Cd ^{2 +} ) Turns orange (Fig. 6c).

Solutions to which other metal ions were added show absorption spectra very similar to the colorimetric sensor solution, the maximum absorption peak at 390 nm, and the colorimetric sensor solution to which cadmium ions (Cd ^{2 +} ) were added showed the maximum absorbance at 500 nm. It can be done (Fig. 5D).

For calcium ions (Ca ^{2 +} ) and barium ions (Ba ^{2 +} ), respectively, 550 nm and 600 nm were selected as the maximum wavelengths to minimize interference between the two ions, and in FIG. 7B, the absorption ratio of 18 metal ions (A in Figure 7c showed a ₅₅₀ / a _390), the extinction ratio (a ₆₀₀ / a _390), the extinction ratio (a ₅₀₀ / a ₃₉₀₎ in Figure 7d shows, for each of the metal ions.

7b-7d, FIG. 7b shows high selectivity in calcium and barium ions compared to other metal ions, and in FIG. 7c shows high selectivity in barium ions and high selectivity in calcium, barium, and cadmium ions in FIG. 7d Can be seen. Through this, it is possible to secure selectivity for detecting each substance to be measured by selecting the absorption ratio.

Example 5: Sensitivity of the colorimetric sensor to the target ions and Calibration curve

^{After adding Ca 2 +} ion concentration to 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8 ppm to the colorimetric sensor solution obtained in Preparation Example 2, the reaction time was 20 minutes in case ^{of Ca 2 + ion at room temperature, Ba} for ^{2 +} ions, 30 minutes, Cd ^{2 +} 25 min the reaction was measured for.

_{Figure 8a is a graph of the absorption ratio (A 550} / A ₃₉₀ ) for detection of calcium ions was prepared as a quantitative curve graph, with a quantitative line y = 0.87264x-0.16959 and an extinction coefficient (r ² ) = 0.99075. The detection limit of Ca ^{2 +} ions was found to be very good at 24.8 ppb.

In addition, FIG. 8B shows that ^{the final concentrations of Ba 2 +} ions were added to the colorimetric sensor solution to be 0.2, 0.4, 0.5, 0.8, and 1.0 ppm, respectively, and the reaction was performed at room temperature for 30 minutes.

The absorption ratio (A ₆₀₀ /A ₃₉₀ ) for detection of barium ions was drawn up as a quantitative curve graph, and the quantitative line y = 0.929884x-0.12236, and the extinction coefficient (r ² ) = 0.99307 gave very good results, and this colorimetric sensor The detection limit of Ba ^{2 +} ions was found to be 4.59 ppb.

^{In addition, Cd 2 +} ions were added to the colorimetric sensor solution so that the final concentrations were 0.5, 0.8, 1.0, and 1.5 ppm, respectively, and the reaction was performed at room temperature for 25 minutes.

Figure 8c is the absorption ratio (A ₅₀₀ / A ₃₉₀ ) was prepared as a quantitative curve graph, the quantitative line y = 0.63107x-0.20193, extinction coefficient (r ² ) = 0.96294, excellent results were obtained, Cd ^{2 +} detection of ions The limit was found to be 19.5 ppb.

Example 6: Evaluation and detection of the effectiveness of colorimetric sensor solutions through actual samples

For the ^{experiment of detecting Ca 2 +} ions in fine dust, 0.1 g of a fine dust sample was taken, eluted with nitric acid, and the final volume was 25 ml. In the case of the blank sample, all pretreatment procedures were performed in the same manner without adding a sample, and a 0.2 μm syringe filter was used after filtering for the colorimetric sensor experiment.

After adding the prepared sample to the colorimetric sensor probe solution according to Preparation Example 2, reacting at room temperature for 20 minutes, measuring the absorbance with a UV-Vis spectrophotometer, and diluting the sample using the calibration curve of FIG. 8A prepared in Example 5 above. The drainage, the detected amount, and the recovery rate (recovery, %) were measured, and the result values were compared with the values measured using ICP-OES, and are shown in Table 1 below. 9 is a graph showing the position of calcium ions among fine dust in the calibration curve obtained in FIG. 8A with an asterisk.

Metal ions in fine dust Detection concentration (wt%) RSD (n=3, %) Recovery rate (%) ICP-OES (wt%) Ca ^{2 +} 4.62 1.78 95.65 4.83

As shown in Table 1, the RSD of calcium ion detection was very good within 1.78%, and the recovery rate was also 95.65% or more.

The embodiments of the present invention described above should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those of ordinary skill in the technical field of the present invention can improve and change the technical idea of the present invention in various forms. Therefore, such improvements and changes will fall within the scope of the present invention as long as it is apparent to those of ordinary skill in the art.

Claims (16)

Containing silver nanoparticles and anionic surfactants,
The anionic surfactant is dioctylsulfosuccinate,
The size of the silver nanoparticles is 5 to 20 nm,
Further comprising a phosphate buffer solution, the concentration of the phosphate buffer solution is 0.02 to 0.2 mM,
Colorimetric sensor for detecting calcium ions, barium ions or cadmium ions, which detects calcium ions, barium ions or cadmium ions at pH 8.5. delete delete delete delete The method of claim 1,
The maximum absorbance of the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions is 350 to 450 nm, a colorimetric sensor for detecting calcium ions, barium ions or cadmium ions. The method of claim 1,
When the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions reacts with calcium ions, the maximum absorbance is 500 to 600 nm,
When the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions reacts with barium ions, the maximum absorbance is 550 to 650 nm,
When the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions reacts with cadmium ions, the maximum absorbance is 450 to 550 nm, a colorimetric sensor for detecting calcium ions, barium ions or cadmium ions. The method of claim 1,
The absorption ratio of the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions is expressed as a value of _{A 550} /A _{390 when reacted with calcium ions, and expressed as a value of A 600} /A ₃₉₀ when reacted with barium ions, and A colorimetric sensor for detecting calcium ions, barium ions or cadmium ions, which is represented by a value of _{A 500} /A ₃₉₀ during the reaction. delete The method of claim 1,
The detection time of the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions is within 20 minutes when detecting calcium ions, within 30 minutes when detecting barium ions, and within 25 minutes when detecting cadmium ions, calcium ions, barium ions, or Colorimetric sensor for detecting cadmium ions. The method of claim 1,
The detection limit of the colorimetric sensor for detecting calcium ions, barium ions or cadmium ions is 24.8 ppb when detecting calcium ions, 4.59 ppb when detecting barium ions, and 19.5 ppb when detecting cadmium ions, calcium ions, barium ions, or cadmium ions. Colorimetric sensor. A method of manufacturing a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions according to any one of claims 1, 6 to 8, 10 and 11, comprising:
Adding silver nitrate to a solution containing an anionic surfactant; And
Preparing silver nanoparticles by adding trisodium citrate and sodium borohydride (NaBH _{4) to the solution;} Including,
The method of manufacturing a colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions further comprising; adding a phosphate buffer solution to the solution containing the silver nanoparticles. delete As a method for detecting calcium ions, barium ions or cadmium ions,
Injecting a detection target sample into the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions according to any one of claims 1, 6 to 8, 10 and 11; And
A sensing step of detecting calcium ions, barium ions, or cadmium ions in the sample to be detected by color change of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions; and
After the injecting step, adjusting the pH of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions; A method for detecting calcium ions, barium ions, or cadmium ions further comprising a. delete The method of claim 14,
After the sensing step, the color change of the colorimetric sensor for detecting calcium ions, barium ions, or cadmium ions in the sensing step is measured with a UV-vis spectrophotometer or colorimeter, and calcium ions, barium ions, or cadmium ions in the sample to be detected The method of detecting a calcium ion, barium ion or cadmium ion further comprising a concentration measuring step of calibrating the concentration of.

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