KR101628266B1 - Sensors for detection of copper ion using luminescent silica@coordination polymer based on lanthanide metal and their synthetic method - Google Patents

Abstract

The present invention relates to a sensor to detect copper ion using luminescent silica@coordination polymer based on lanthanide (Ln) metal, and a synthetic method thereof. The sensor has a structure comprising a shell on a silica core surface. The shell is made of coordination polymer combined with lanthanide (Ln) metal ions and organic building blocks. As such, copper ions among various metal ions is able to efficiently be detected using an extinction property of fluorescence.

Description

TECHNICAL FIELD [0001] The present invention relates to a sensor for detecting copper ions and a method for preparing the same,

The present invention is a sensor for copper ion detection with coordination polymer containing the small size and the very small amount to FIG copper ion (Cu ^{2 +)} lanthanide (Ln) in the sensitivity can be increased effectively detect the copper ion to total metal and And a method for producing the same.

Effective detection of trace amounts of metal ions is important in a variety of environmental and biological systems. In particular, studies on mercury, copper, cadmium, and lead ions, which are highly toxic heavy metals, have been published by researchers around the world. Since copper ions are one of the important biological essential metals that act as coenzymes in the human body, the deficiency of copper ions in the body can cause various diseases. However, accumulation of high concentrations of copper ions in the tissues of the body causes Alzheimer's disease, Wilson's disease, and the like. Therefore, the development of a luminescent sensor capable of selectively detecting copper ions will make a great contribution to biology.

The most noteworthy interest in the detection of metal ions is the detection method using phosphors. This makes it possible to detect the analyte in solution, and it is advantageous in that it can be detected inexpensively and quickly. In particular, luminescent materials are being used as chemical sensors which are very useful in that they can easily measure signals that are selectively recognized by a particular molecule or manipulated in an applied system such as a molecular device.

Recent methods of detecting copper ions may include individual molecular uniformity sensor systems and nonuniform solid state sensors. In general, a uniform sensor based on individual molecules exhibits selectivity to the desired metal more effectively than a non-uniform solid-state sensor with low sensitivity and weak signal. However, heterogeneous solid state sensors are of great interest due to their excellent chemical stability, low fouling and good recycling. So research on efficient solid-state sensors is important and should be developed.

Coordinated polymers (CPs) or metal-organic composites (MOFs) are attractive materials for use in heterogeneous solid state sensors because their composition and properties can be easily modified by altering their constituent metal ions or organic building blocks. Metal-organic complexes (MOFs) or coordination polymers (CPs) containing the lanthanide metal have been extensively studied as fluorescent sensor materials. They are characterized by strong fluorescence due to f-f transition and long fluorescence lifetime, showing excellent ability during the sensing process.

The luminescence intensity of the metal-organic complexes (MOFs) containing the lanthanide metal generally changes depending on the interaction between the analyte and the metal or the analyte and the ligand. The metal-organic complexes (MOFs) containing the lanthanide metal have been developed as luminescent sensor materials for sensing metal ions, anions or small molecules, most of which are produced in the form of bulk macroscale.

Fluorescent signals on the outer surface of the material during the sensing process of the non-uniform solid state sensor will be more important factors in the sensitivity and selectivity of the sensing. Therefore, if the specific surface area is widened by reducing the size of the sensor material, the sensing efficiency can be increased and the sensor material can be saved. There is a demand for a non-emission uniform solid state sensor which can sensitively detect a desired metal ion and has high selectivity.

Korean Patent No. 919,136 United States Patent No. 8,409,800

It is an object of the present invention to provide a fluorescent silica (coordination polymer) containing a lanthanide (Ln) -based metal capable of effectively detecting copper with high sensitivity to copper ions (Cu ^{2 +} ) even in a small size and a very small amount of heterogeneous solid- The present invention provides a sensor for detecting copper ions.

Another object of the present invention is to provide a method for manufacturing a sensor for detecting copper ions using a fluorescent silica-coordinated polymer containing the lanthanum metal.

It is still another object of the present invention to provide a method for selectively detecting copper ions using the copper ion detection sensor.

In order to accomplish the above object, a sensor for detecting copper ions of the present invention forms a shell on the surface of a silica core, and the shell may be composed of a coordination polymer in which a lanthanide (Ln) -based metal and an organic building block are coordinated to each other.

The lanthanide metal ion may be at least one selected from the group consisting of europium (Eu) ion and terbium (Tb) ion.

The shell may be composed of a coordination polymer in which lanthanum (Ln) -based metal ion and isophthalic acid (H ₂ IPA) are coordinated to each other.

The coordination polymer comprising the silica core and the lanthanide (Ln) -based metal may be in a weight ratio of 1-8: 2-9.

The thickness of the shell may be 35 to 140 nm, and the copper ion detection sensor may have a light extinction coefficient ( K _sv ) for copper ion of 15,000 to 40,000 M ^-1 .

 The copper ion detection sensor can be reused by washing with acetonitrile.

The copper ion detecting sensor can detect copper ions in a small amount of 0.01 to 0.1 mg.

According to another aspect of the present invention, there is provided a method for producing a copper ion detecting sensor, comprising the steps of: (A) mixing silica particles surface-treated with a carboxylic acid, and a lanthanum (Ln) Preparing a reaction product by mixing the coordination polymer precursor with an organic solvent; (B) heating the reaction product to a temperature of from 130 to 150 캜; And (C) centrifuging the heated reactant to obtain core-shell microspheres.

In step (a), the lanthanide metal may be at least one selected from the group consisting of europium (Eu) and terbium (Tb).

In the step (a), the coordination polymer precursor may be a mixture of a lanthanide metal ion and isophthalic acid (H ₂ IPA).

In the step (a), the organic solvent may be used for the mixing of N, N-dimethylformamide (DMF) and tetrahydrofuran (THF).

According to another aspect of the present invention, there is provided a method for selectively detecting copper ions, the method comprising: detecting a copper ion in a sample using the copper ion detecting sensor.

Copper ions can be selectively detected by measuring fluorescence intensity reduction by the addition of the copper ions.

The wavelength of the light to be irradiated for measuring the fluorescence wavelength and fluorescence intensity may be 280 nm.

The copper ion detection sensor of the present invention is a heterogeneous solid-state sensor of a small-sized fluorescent silica-coordinated polymer substance and has excellent dispersibility and is highly sensitive to copper ions even in a stable and small amount, so that copper ions can be effectively detected .

In addition, the copper ion detecting sensor of the present invention is economical because it reduces the thickness of the shell to reduce the amount of sensor used to increase the sensitivity of copper ion sensing and can be recycled many times by simple washing.

1A is an SEM and STEM (insert) image for EuCP microspheres prepared according to Preparation Example 1; FIG. 1B is a spectrum of the EuCP microspheres measured by EDX; FIG. Figure 1c is a confocal microscope photograph of the EuCP microspheres; FIG. 1D is a graph showing an appropriate luminescence spectrum of the EuCP microsphere added to acetonitrile containing various concentrations of Cu (NO ₃ ) ₂ ; FIG. FIG. 1E is a graph showing changes in luminescence intensity after carrying the EuCP microspheres in various metal ion solutions; FIG. FIG. 1F is a photograph of the above-mentioned EuCP microsphere suspension before and after being loaded on various metal ion solutions under UV irradiation.
FIG. 2 illustrates the synthesis and sensing of EuCP microspheres and silica @EuCP core-shell microspheres prepared according to an embodiment of the present invention.
FIG. 3A is an SEM image of a silica @EuCP core-shell microspheres prepared according to an embodiment of the present invention; FIG. FIG. 3B is an image of the silica @EuCP core-shell microspheres taken by STEM; FIG. FIG. 3c is a spectrum of the silica @EuCP core-shell microspheres measured by EDX; Figure 3d is the EDX spectral profile scanning spectrum of the silica @ EuCP core-shell; FIG. 3E is an image of the silica @EuCP core-shell microspheres taken with a confocal microscope; FIG. FIG. 3f is a graph showing an appropriate luminescence spectrum of silica @EuCP core-shell microspheres added to acetonitrile containing various concentrations of Cu (NO ₃ ) ₂ ; FIG. FIG. 3g is a graph showing the change in luminescence intensity after carrying silica. EuCP core-shell microspheres on various metal ion solutions; FIG. 3h is a photograph of a silica @ EuCP microsphere suspension before and after being loaded on various metal ion solutions under UV irradiation.
FIG. 4A is an SEM image of a silica @ TbCP core-shell microsphere prepared according to another embodiment of the present invention; FIG. FIG. 4b is an image of the silica @ TbCP core-shell microspheres taken by STEM; FIG. FIG. 4C is a spectrum of the silica @ TbCP core-shell microspheres measured by EDX; FIG. 4D is an EDX spectral profile scanning graph of the silica @TbCP; Figure 4e is an image of the silica < RTI ID = 0.0 > @ TbCP < / RTI > core-shell microspheres taken with a confocal microscope; FIG. 4f is a graph showing the optimum luminescence spectrum of silica @TbCP core-shell microspheres added to acetonitrile containing various concentrations of Cu (NO ₃ ) ₂ ; FIG. FIG. 4G is a graph showing the change in luminescence intensity after the support of silica @ TbCP core-shell microspheres was carried on various metal ion solutions; Fig. 4h is a photograph of a silica < RTI ID = 0.0 > @ TBCP < / RTI > microsphere suspension before and after being loaded on various metal ion solutions under UV irradiation.
FIG. 5A is an image of a silica-thin TiCCP core-shell microsphere manufactured according to another embodiment of the present invention taken by STEM; FIG. FIG. 5b is a confocal microscope image of the thin shell silica @ TbCP core-shell microspheres; FIG. FIG. 5c is a spectrum of the silica @TbCP core-shell microsphere with a thin shell thickness measured by EDX; FIG. FIG. 5d is an EDX spectrum profile scanning graph of a thin shell of silica @ TbCP; FIG. FIG. 5E is a photograph of a thin silica @ TbCP microsphere suspension before and after being loaded on various metal ion solutions under UV lamp irradiation.
FIG. 6A is an SEM image of a thin silica @ TbCP core-shell microspheres prepared according to another embodiment of the present invention; FIG. FIG. 6B is a STEM image of the thin silica @ TbCP core-shell microspheres; FIG. FIG. 6C is a graph showing an appropriate luminescence spectrum of a thin silica @ TbCP core-shell microsphere (0.1 mg) added to acetonitrile containing various concentrations of Cu (NO ₃ ) ₂ ; FIG. FIG. 6D is a graph showing the change in the luminescence intensity after carrying the silica @TbCP core-shell microsphere (0.1 mg) having a thin shell thickness in various metal ion solutions (5 mM); FIG. 6E is a graph showing an appropriate luminescence spectrum when a small amount of silica @TbCP core-shell microsphere (0.01 mg) added to acetonitrile containing various concentrations of Cu (NO ₃ ) ₂ is present in small amounts ; FIG. 6f is a graph showing changes in luminescence intensity after a small amount of silica @TbCP core-shell microspheres (0.01 mg) having a small shell thickness is loaded on various metal ion solutions (5 mM).
7 is a graph showing the PXRD pattern of (a) the EuCP microsphere of Preparation Example 1, (b) the silica @EuCP core-shell microspheres of Example and (c) silica particles.
FIG. 8A is a photograph showing a recycling process of a thin shell of silica @TbCP core-shell microspheres manufactured according to another embodiment of the present invention; FIG. FIG. 8B is an SEM image of silica < RTI ID = 0.0 > @TbCP < / RTI > core-shell microsphere with a thin shell thickness after recycling.

The present invention is the degree of dispersion is excellent, and small size and a very small amount to FIG copper ion Fluorescent Silica @ coordination, including lanthanum (Ln) based metal capable of effectively detecting the copper ions increases the sensitivity to (Cu ^{2 +)} A sensor for detecting copper ions using a polymer, and a method for manufacturing the same.

The copper ion detection sensor of the present invention is heterogeneous solid sensors, and good dispersion and clear signals in non-uniform solid state sensors are important in defining signal detection sensitivity and selectivity.

Hereinafter, the present invention will be described in detail.

The sensor for detecting copper ions of the present invention is a sensor for detecting copper ions, which comprises a shell on the surface of a silica core, wherein the shell is composed of a coordination polymer (LnCP) in which lanthanum (Ln) based metal ions are coordinated with an organic building block.

Specifically, the sensor for detecting copper ions of the present invention is a sensor for detecting copper ions, which comprises a core-shell structure (referred to as 'silica @LnCP') by preparing a coordination polymer containing silica particles as a core and lanthanide (Ln) Sensitivity to copper ion sensing up to 550% improved by a small amount of 1/400 to 1/4000 compared to non-uniform solid state sensors.

The coordination polymer (LnCP) is a coordination polymer in which one or more lanthanum (Ln) metal ions selected from the group consisting of europium (Eu) ions and terbium (Tb) ions are coordinated with isophthalic acid (H ₂ IPA). The lanthanide metal is selected as the metal ion of the heterogeneous solid-state sensor because it has the characteristic of showing strong fluorescence by the ff transition.

The coordination polymer containing the silica particles and lanthanum (Ln) based metal ions is used in a weight ratio of 1-8: 2-9, preferably 4: 6 or 3: 1, Sensitivity to copper ion sensing is excellent.

In the sensor for detecting copper ions of the present invention, the extinction coefficient ( K _sv ) for copper ions is 15,000 to 40,000 M ^-1 , and the extinction coefficient ( K _sv ) is much higher than other metal ions.

Since the sensor for detecting copper ions of the present invention can be used many times by washing with acetonitrile after use, it is economical because it can be recycled by a simple method.

The present invention also provides a method of manufacturing a sensor for detecting copper ions.

The method for producing a copper ion detection sensor of the present invention comprises the steps of (A) mixing a silica particle surface-treated with a carboxylic acid and a coordination polymer precursor comprising a lanthanum (Ln) -based metal ion and an organic building block in an organic solvent, Lt; / RTI > (B) heating the reactant to a temperature of from 130 to 150; And (C) centrifuging the heated reactant to obtain core-shell microspheres.

First, in step (A), a coordination polymer precursor comprising silica particles surface-treated with carboxylic acid and a lanthanide (Ln) -based metal ion and an organic building block is reacted with N, N-dimethylformamide (DMF) Furan (THF) mixed solvent to prepare a reaction product.

Next, in the step (B), the reaction product is heated at a temperature of 130 to 150 ° C. for 10 to 30 minutes. In this process, the growth of the coordination polymer is formed on the silica core.

Next, in the step (C), the heated reactant is centrifuged to obtain a core-shell microsphere product, which is washed several times with DMF and acetonitrile.

The present invention also provides a method for selectively detecting copper ions among various metal ions using a sensor for detecting copper ions.

When the copper ion is added to the sensor for detecting copper ions of the present invention, a decrease in fluorescence intensity appears. At this time, the wavelength of the light to be irradiated for measuring the fluorescence wavelength and the wavelength intensity is 280 nm.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[EuCP Microsphere]

Manufacturing example  One. EuCP Microsphere  synthesis

A mixture of isophthalic acid (H ₂ IPA, 10.0 mg, 0.060 mmol) and Eu (NO ₃ ) ₃ 5H ₂ O (28.4 mg, 0.066 mmol) in 15 mL of DMF / THF mixed solvent (2: 1, v / To prepare a coordinated polymer precursor solution, which was then rapidly and conveniently synthesized through a simple solvent heating reaction by heating in an oil bath (140 ° C) for 20 minutes. After completion of the reaction, spherical particles formed were separated by centrifugation - redispersion to synthesize EuCP microspheres. Here, in EuCP, Eu means europium and CP means a coordination polymer.

IR (KBr): 1606s, 1540s, 1481m, 1446m, 1402s, 1316w, 1280w, 1165w, 1106w, 1078w, 1003w, 927w, 874w, 833w, 811w, 747m, 717m, 681w, 658w, 636w, 626w, , 534w, 472w.

Test Example 1 Measurement of morphology, optical properties and detection properties of copper ions in EuCP microspheres

1A is an SEM and STEM (insert) image for EuCP microspheres prepared according to Preparation Example 1; FIG. 1B is a spectrum of the EuCP microspheres measured by EDX; FIG. Figure 1C is a confocal microscope and optical (top insert) image for the EuCP microspheres; 1D is a graph showing an appropriate luminescence spectrum of the EuCP microsphere added to acetonitrile containing various concentrations of Cu (NO ₃ ) ₂ at an excitation wavelength of 280 nm; FIG. 1E is a graph showing changes in luminescence intensity after carrying the EuCP microspheres in various metal ion solutions (5 mM); FIG. FIG. 1F is a photograph of the above-mentioned EuCP microsphere suspension before and after being loaded on various metal ion solutions under UV irradiation.

As shown in FIG. 1A, the average particle diameter of EuCP microspheres synthesized according to Preparation Example 1 was 0.70 ± 0.06 μm (n = 100), and it was confirmed that spherical particles were formed from SEM and STEM images.

Further, as shown in FIG. 1B, the chemical composition of EuCP microspheres confirmed that carbon, oxygen and europium (Eu) atoms were detected through the EDX spectrum.

In addition, it was confirmed that the confocal microscope image (FIG. 1C) and the naked eye image of the EuCP microsphere under UV irradiation (the inset of FIG. 1D) emit light in the red region of the spectrum. The bottom inset in FIG. 1c shows EuCP microspheres well dispersed in acetonitrile.

In addition, as shown in FIG. 1d, the light emission spectrum of EuCP microspheres is Eu ³⁺ ion to show the characteristics of the transition, in particular 592 nm and the strong luminescence band at 615 nm is ⁵ of Eu ^{3 +} ion, respectively D ₀ → ⁷ F ₁ and ⁵ D ₀ → ⁷ F ₂ transitions and weak emission bands at 651 nm and 698 nm derived from ⁵ D ₀ → ⁷ F ₃ and ⁵ D ₀ → ⁷ F ₄ transitions are also observed. The inset of FIG. 1d is a photograph of a suspension of EuCP microspheres before and after being carried in a copper ion solution under UV irradiation.

The change in the CO stretching frequency of the EuCP microsphere at 1606 cm ^-1 in the IR spectrum confirms that the Eu ³⁺ ion is coordinated with the carboxylate group of IPA.

Good dispersion of heterogeneous solid state sensors in solution is important for sensitivity and reliable detection of analytes. In this regard, the EuCP microspheres exhibiting good dispersion in solution (insertions of FIG. 1c and FIG. 1d) are excellent candidates for heterogeneous solid state sensors, and are typical bulk size MOF (metal-organic composite) Which is superior to the conventional method.

As the concentration of copper ion increases, the fluorescence intensity of EuCP microspheres decreases (FIG. 1d). Compared to the typical amounts of MOF-based sensor materials (about 1 mg and 10 mg), EuCP microspheres (0.1 mg) can detect copper ions in very small amounts.

The small amount of EuCP microspheres required to detect copper ions is possible due to the small size and good dispersibility of EuCP microparticles. Due to this feature, the quenching detection of copper ions of EuCP microspheres can be easily recognized by the naked eye (Fig. 1d insertion diagram).

The initial strong red luminescence of the EuCP microsphere disappears after interaction with the copper ion, and the reduction of the emission band can be controlled from the quenching effect due to the interaction of the copper ion with the coordination polymer. Specifically, the Lewis salt interaction within the sensor material with copper ion is a well established quenching process, and the oxygen atom of the carboxyl group is known as an example of the interaction position of the copper ion.

In addition, the EuCP microsphere (12,485 M ^-1 ) copper ion The detection sensitivity was higher than that of the conventional LnMOF based sensor material (89 to 6,637 M ^-1 ). The extinction coefficient ( K _sv ) of the EuCP microspheres for copper ions is improved by over 200% over conventional LnMOF based sensor materials.

The quantified value of the quencher (quenching) the effect of the copper ion was obtained by using the Stern-Volmer equation _{(I 0 / I = 1 +} K sv [M]). I ₀ is the initial fluorescence intensity of the EuCP microsphere, and I is the fluorescence intensity of the EuCP microsphere after the metal ion deposition.

The selectivity of EuCP microspheres for copper ion detection was demonstrated by the reaction with various metals instead of copper ions.

The EuCP microspheres are various acetonitrile solution containing the other kind of metal ions such as ^{Mn 2 +, Co 2 +,} Ni 2 +, Zn 2 +, Cd 2 +, Mg 2 +, Ca 2 + and Ag ⁺ ( 5 mM). As a result, the change in luminescence intensity of the initial EuCP microspheres is very different depending on the specific type of metal ion, particularly the large change in the luminescence intensity is observed only when the EuCP microspheres are supported on the copper ion solution (Figs. 1E and 1F ).

The alkaline earth ions (Mg ^{2 +} and Ca ^{2 +),} and other transition metal ions ^{(Mn 2 +, Co 2 +} , Ni 2 +, Zn 2 +, Cd 2 +, and Ag ⁺⁾ luminescence of the initial EuCP microspheres It is significantly or almost unaffected by strength.

As shown in the following Table 1, it was confirmed that the value of the extinction coefficient ( K _sv ) for the copper ion of the EuCP microspheres was the most remarkably large among other metal ions.

Metal ion K _sv (M ^-1 ) Metal ion K _sv (M ^-1 ) Ca ²⁺ 18 Ag ⁺ One Mg ²⁺ 19 Ni ²⁺ 167 Zn ²⁺ 9 Co ²⁺ 263 Mn ²⁺ 15 Cu ²⁺ 12,485 Cd ²⁺ 4 - -

Compared to conventional macro-sized MOF-based sensor materials, the small size can sensitively detect copper ions due to the significant contribution of the emission signal of the sensor material of the EuCP microsphere to the outside of the material, rather than from the inside of the material. Therefore, the inner part of the EuCP microspheres is less important for the detection of copper ions, so that the sensor material of the core-shell structure is expected to more effectively sense.

The sensor material of the core-shell structure reduces the required amount and sensor consumption is reduced.

[Silica @ LnCP core - shell microspheres]

Example 1. Synthesis of silica @EuCP core-shell microsphere

(H ₂ IPA, 8.0 mg, 0.048 mmol) and Eu (NO ₃ ) ₃ .5H ₂ O (27.7 mg, 0.053 mmol) in 12 mL of DMF / THF mixed solvent (2: 1, v / The mixed polymer precursor solution was prepared by mixing and then mixed with carboxylic acid-treated silica (12.0 mg). The obtained reaction product was rapidly and conveniently synthesized through a simple solvent heating reaction in an oil bath (140 ° C) for 20 minutes. After completion of the reaction, spherical particles formed were collected by centrifugation and washed several times with DMF and acetonitrile to synthesize silica @EuCP core-shell microspheres (FIG. 3). Here, silica < RTI ID = 0.0 > @EuCP < / RTI > refers to a core-shell structure having silica particles as the core and EuCP as the shell.

IR (KBr): 1607s, 1543s, 1481m, 1447m, 1399s, 1316w, 1277w, 1104s, 943w, 875w, 801w, 747m, 716m, 657w, 635w, 472s.

Example 2. Synthesis of silica @ TbCP core-shell microspheres

The synthesis was carried out as Example _{1, Eu (NO 3) 3} · 5H 2 O instead of Tb (NO _{3) 3} · 5H ₂ O using silica @TbCP core-shell microspheres were synthesized.

IR (KBr): 1607s, 1543s, 1481m, 1449m, 1400s, 1315w, 1277w, 1104s, 949w, 874w, 810w, 747m, 717m, 658w, 628w, 472s.

Example 3. Synthesis of silica < RTI ID = 0.0 > @TbCP core-shell microspheres < / RTI >

(H ₂ IPA: 2.0 mg; Tb (NO ₃ ) ₃ .5H ₂ O: 5.76 mg) and the same amount of carboxylic acid-treated silica particles (12.0 g) were mixed in the same manner as in Example 1, except that a small amount of coordination polymer precursor mg) were used to synthesize silica @TbCP core-shell microspheres with a thin shell thickness.

IR (KBr): 1609s, 1543s, 1481m, 1448m, 1399s, 1106s, 948w, 875w, 803w, 748m, 716m, 661w, 624w, 473s.

Test Example  2. Silica @ EuCP  Core-shell Microsphere  Measurement of morphology, optical properties and detection properties of copper ions

FIG. 3A is an SEM image of silica @EuCP core-shell microspheres prepared according to Example 1 of the present invention; FIG. FIG. 3b is an image of a silica @EuCP core-shell microspheres prepared according to Example 1 of the present invention by STEM; FIG. FIG. 3c is a spectrum of silica @EuCP core-shell microspheres prepared according to Example 1 of the present invention measured by EDX; FIG. Figure 3d is the EDX spectral profile scanning spectrum of the silica @ EuCP core-shell; 3E is an image and optical (insert) image of a silica @EuCP core-shell microsphere prepared according to Example 1 of the present invention, taken with a confocal microscope; Figure 3f is 280 nm of the excitation wavelength, varying concentrations of Cu (NO _{3) 2} was added to the silica-containing acetonitrile the nitrile @EuCP core-graph showing the optimum emission spectrum of the shell microspheres and; FIG. 3G is a graph showing the change in luminescence intensity after carrying silica. EuCP core-shell microspheres on various metal ion solutions (5 mM); FIG. 3h is a photograph of a silica @ EuCP microsphere suspension before and after being loaded on various metal ion solutions under a UV lamp.

3A and 3B, the silica @EuCP core-shell microspheres prepared according to Example 1 of the present invention were uniformly formed, and the average particle diameter (n) after formation with silica @EuCP core- = 100) was 1.10 ± 0.03 μm, and it was clearly confirmed that the size was increased from pure silica particles (0.87 ± 0.02 μm). In particular, the STEM image clearly shows the formation of a well-formed core-shell structure, showing that the thickness of the shell (EuCP) is 115 nm.

The relative weight ratio of EuCP shell and silica core in silica @ EuCP core-shell microspheres is 6: 4 (w / w, EuCP: silica). The relative weight ratios of the EuCP shell and silica core were obtained by weighing the silica @EuCP core-shell microspheres and comparing the weight after removal of the EuCP shell from silica @EuCP core-shell microspheres using acetic acid.

3C and 3D, the chemical composition of the silica @EuCP core-shell microspheres prepared according to Example 1 of the present invention was confirmed, in particular, in FIG. 3d, the silica atoms were concentrated in the center of the particles And the europium atoms (Eu) were found to be abundantly arranged at the edges of the particles as elements of the shell.

Also shown in Figures 3e and 3h, the silica @EuCP core-shell microspheres prepared according to Example 1 of the present invention showed luminescence in the red region of the spectrum due to the luminescent EuCP shell.

In addition, a silica @EuCP core-shell microspheres having a core-shell structure was used as a luminescence sensor.

As shown in FIG. 3F, the sensitivity of the silica @EuCP core-shell microspheres prepared according to Example 1 of the present invention for copper ions was determined by varying the concentration of copper ions and the good dispersion of silica @EuCP core- The titration of the acetonitrile suspension was similar to the pure EuCP microspheres.

Also, as shown in FIGS. 3g and 3h, it was confirmed that the turn-off signal of silica @EuCP core-shell microsphere was easily confirmed by the naked eye by adding copper ion, The selectivity of the silica @EuCP core-shell microspheres as a change in intensity was almost identical to pure EuCP microspheres. For example, a large change in luminescence intensity is observed only when silica < RTI ID = 0.0 > @EuCP core-shell microspheres < / RTI >

The K _sv value (15,200 M ^-1 ) for the copper ion of the silica @EuCP core-shell microspheres prepared according to Example 1 was about 20 ( ¹ ) higher than the value of pure EuCP microsphere (Preparation Example 1) %. The amount of EuCP in silica @EuCP microspheres was reduced to about 60% compared to pure EuCP microspheres, but the sensitivity and selectivity of silica @EuCP microsphere core-shell for copper ion detection was rather increased.

As shown in Table 2 below, the value of the extinction coefficient ( K _sv ) for the copper ion of the silica @EuCP microspheres was found to be the most marked among other metal ions.

Metal ion K _sv (M ^-1 ) Metal ion K _sv (M ^-1 ) Ca ²⁺ 18 Ag ⁺ 2 Mg ²⁺ 17 Ni ²⁺ 166 Zn ²⁺ 18 Co ²⁺ 259 Mn ²⁺ 21 Cu ²⁺ 15,120 Cd ^{2 +} 0.7 - -

The EuCP microspheres (FIG. 7A) of the preparation example 1, the silica @EuCP core-shell microsphere (FIG. 7B) and the silica particles (FIG. 7C) of Example 1 were measured by PXRD. As a result, 1 microspheres were amorphous amorphous materials.

Test Example 3. Measurement of the morphology, optical properties and detection properties of copper ions in silica @TbCP core-shell microspheres

FIG. 4A is an SEM image of a silica @ TbCP core-shell microspheres prepared according to Example 2 of the present invention; FIG. FIG. 4B is an image of a silica @ TbCP core-shell microspheres prepared according to Example 2 of the present invention by STEM; FIG. FIG. 4C is a spectrum of silica @ TbCP core-shell microspheres prepared according to Example 2 of the present invention measured by EDX; FIG. 4D is an EDX spectral profile scanning graph of the silica @TbCP; 4E is an image and optical (insert) image of a silica @ TbCP core-shell microsphere prepared according to Example 2 of the present invention, taken with a confocal microscope; 4f is a graph showing an appropriate luminescence spectrum of silica @ TbCP core-shell microsphere added to MeCN containing various concentrations of Cu (NO ₃ ) ₂ at an excitation wavelength of 280 nm; FIG. 4g is a graph showing the change in luminescence intensity after carrying the silica @ TbCP core-shell microspheres on various metal ion solutions (5 mM); 4h is a photograph of a silica < RTI ID = 0.0 > @ TBCP < / RTI > microsphere suspension taken before and after being loaded onto various metal ion solutions under UV lamps.

As shown in FIGS. 4A and 4B, the silica @TbCP core-shell microspheres prepared according to Example 2 of the present invention were uniformly formed, and the average particle diameter (n) after formation of the silica @TbCP core- = 100) was 1.14 ± 0.02 μm, clearly confirming that it was increased in size from pure silica particles (0.87 ± 0.02 μm). In particular, the STEM image confirmed that the thickness of the shell (TbCP) was 135 nm.

4c and 4d, the chemical composition of the silica @ TbCP core-shell microspheres prepared according to Example 2 of the present invention was confirmed, and in particular, FIG. 4d shows that the silica atoms are concentrated in the center of the particles , And that the terbium atom (Tb) is an element of the shell, and that the terbium atom (Tb) is abundantly arranged at the edge of the particle.

In addition, as shown in Figs. 4E and 4H, the silica @ TbCP core-shell microspheres prepared according to Example 2 of the present invention showed luminescence in the green region of the spectrum due to the luminescent TbCP shell.

In addition, a silica @ TbCP core-shell microspheres having a core-shell structure was used as a luminescence sensor.

As shown in FIG. 4F, the emission spectrum of silica @ TbCP core-shell microspheres prepared according to Example 2 of the present invention shows the transfer characteristics of Tb ³⁺ ions. More specifically, ⁵ D of the strong emission band Tb ^{3 +} ions respectively at 491 nm and 546 nm ₄ → ⁷ F _6, and ⁵ D ₄ → ⁷ F ₅ and due to transition, the transition indicates a strong green emission. ⁵ D ₄ → ^The weak emission band at 585 nm and 621 nm resulting from the ⁷ F ₄ and ⁵ D ₄ → ⁷ F ₃ transitions was also observed in the emission spectrum of silica @TbCP core-shell microspheres.

The initial luminescence intensity of the silica @ TbCP core-shell microsphere was confirmed to be much stronger than that of silica @ EuCP core-shell microsphere (Example 1). The silica @ TbCP core-shell microspheres were also prepared from the silica @EuCP core-shell of Example 1 as shown in the titration of the acetonitrile suspension in which the silica @ TbCP core- It exhibits superior detection sensitivity to copper ion detection than microspheres.

4g, the sensitivity selectivity of the silica < RTI ID = 0.0 > @TbCP < / RTI > core-shell microspheres of Example 2 was measured using a silica @EuCP core-shell of Example 1 Similar to microspheres. For example, a large change in luminescence intensity is observed only when silica < RTI ID = 0.0 > @ TbCP core-shell microspheres < / RTI >

In addition, as shown in FIG. 4h, the turn-off sensitivity of the silica @TbCP core-shell microspheres of Example 2 to copper ion was readily visually confirmed by a clear reduction in the green emission after being supported on the copper ion solution .

The K _sv value for the copper ion of the silica @ TbCP core-shell microsphere of Example 2 is 30,763 M ^-1 , which is twice the silica @EuCP core-shell microspheres (15,200 M ^-1 ) of Example 1 high.

As shown in Table 3 below, the value of the extinction coefficient ( K _sv ) for the copper ion of the silica @ TbCP microspheres was found to be the most marked among other metal ions.

Metal ion K _sv (M ^-1 ) Metal ion K _sv (M ^-1 ) Ca ²⁺ 19 Ag ⁺ 2 Mg ²⁺ 18 Ni ²⁺ 183 Zn ²⁺ 13 Co ²⁺ 327 Mn ²⁺ 15 Cu ²⁺ 30,763 Cd ²⁺ 2 - -

Test Example  4. Shell  Thin thin silica @ TbCP  Core-shell Microsphere  Measurement of morphology, optical properties and detection properties of copper ions

To improve the sensor performance of the sensor material of the core-shell structure, a thin silica @TbCP core-shell microspheres were prepared. The thin silica <@@ TbCP core-shell microspheres of Example 3 were prepared by reducing the amount of coordinating polymer precursor used while maintaining the same amount of silica cores as in Example 2. [

FIG. 5A is an image obtained by STEM of a silica-thin TiCCP core-shell microspheres manufactured according to Example 3 of the present invention; FIG. FIG. 5B is an image and optical (insert) image of a thin shell of silica @TbCP core-shell microspheres prepared according to Example 3 of the present invention, taken with a confocal microscope; FIG. FIG. 5c is a spectrum of a silica thin @TbCP core-shell microspheres prepared according to Example 3 of the present invention measured by EDX; FIG. FIG. 5D is an EDX spectrum profile scanning graph of FIG. 5C; FIG. FIG. 5E is a photograph of a silica &lt; RTI ID = 0.0 &gt; @TbCP &lt; / RTI &gt; microsphere suspension having a thin shell thickness before and after being impregnated with various metal ion solutions under UV lamps.

The test of FIG. 5 was performed using 0.1 mg of silica @TbCP microspheres having a thin shell.

As shown in FIG. 5A, the silica &lt; RTI ID = 0.0 &gt; @TbCP &lt; / RTI &gt; core-shell microspheres made according to Example 3 of the present invention had a uniform thickness.

Further, as shown in the left photographs of Figs. 5B and 5E, the silica &lt; RTI ID = 0.0 &gt; @TbCP &lt; / RTI &gt; core-shell microspheres produced according to Example 3 of the present invention, It looked.

5c and 5d, the chemical composition of the thin silica @TbCP core-shell microspheres prepared according to Example 3 of the present invention was confirmed, in particular, And the terbium atom (Tb) was found to be abundantly arranged at the edge of the particle as an element of the shell.

In FIG. 5E, the turn-off sensitivity of the thin silica <@TbCP core-shell microspheres of Example 3 to copper ion was readily visually confirmed by a clear reduction in green emission after being carried in a copper ion solution.

FIG. 6A is an SEM image of a thin silica @ TbCP core-shell microspheres prepared according to Example 3 of the present invention; FIG. FIG. 6B is an image taken by a STEM of a silica-made &lt; RTI ID = 0.0 &gt; @TbCP &lt; / RTI &gt; core-shell microsphere manufactured according to Example 3 of the present invention; FIG. 6C shows the optimum luminescence spectrum of a thin silica @ TbCP core-shell microsphere (0.1 mg) added to acetonitrile containing various concentrations of Cu (NO ₃ ) ₂ at an excitation wavelength of 280 nm &Lt; / RTI &gt; FIG. 6D is a graph showing the change in luminescence intensity after carrying the silica @TbCP core-shell microspheres (0.1 mg) having a thin shell in various metal ion solutions (5 mM); FIG. 6E shows a case where a small amount of silica @TbCP core-shell microspheres (0.01 mg) thin in shell added to acetonitrile containing various concentrations of Cu (NO ₃ ) ₂ at an excitation wavelength of 280 nm &Lt; / RTI &gt; FIG. 6F is a graph showing the change in luminescence intensity after loading a small amount of silica @TbCP core-shell microspheres (0.01 mg) having a thin shell in various metal ion solutions (5 mM).

As shown in FIGS. 6A and 6B, the silica @TbCP core-shell microspheres prepared according to Example 3 of the present invention have a thin shell and are formed of a thin silica @TbCP core-shell microspheres (N = 100) was found to be an increased size from pure silica particles (0.87 ± 0.02 μm) as 0.95 ± 0.02 μm. In particular, it was confirmed that the thickness of the shell (TbCP) was 40 nm in the STEM image. At this time, the weight ratio between the TbCP shell and the silica core is 1: 3 (w / w, TbCP: silica).

In addition, as shown in FIGS. 6C and 6D, the silica @TbCP core-shell microsphere with a thin shell has a sensitivity (FIG. 6C) and selectivity (FIG. 6D) It was confirmed that it did not change even if it decreased.

The K _sv value (36,432 M ^-1 ) for the copper ion of the silica @ TbCP core-shell microspheres having a small thickness of the shell is slightly higher than that of the silica @ TbCP core-shell microspheres (30,763 M ^-1 ) of Example 2 .

In addition, the sensitivity of the thin silica <TbCP core-shell microspheres of the shell was improved by over 550% as compared with the conventional LnMOF based sensor material.

As shown in the following Table 4, it was confirmed that the value of the extinction coefficient ( K _sv ) for the copper ion of the silica @TbCP microspheres (0.1 mg) having a small shell thickness was most remarkably large among other metal ions.

Metal ion K _sv (M ^-1 ) Metal ion K _sv (M ^-1 ) Ca ²⁺ 17 Ag ⁺ 4 Mg ^{2 +} 15 Ni ²⁺ 193 Zn ²⁺ 6 Co ²⁺ 342 Mn ²⁺ 21 Cu ²⁺ 36,432 Cd ²⁺ 2 - -

Finally, as shown in FIGS. 6E and 6F, excellent sensitivity and selectivity to copper ions can be achieved when using a silica @ TbCP core-shell microspheres with a thin shell thickness of 0.01 mg instead of 0.1 mg Respectively. Specifically, the amount of TbCP present in the thin silica @ TbCP core-shell microspheres of 0.01 mg shell is 0.0026 mg, and the very small amount of TbCP is very sensitive (more than 550% improvement) Is sufficient to detect.

The small amount of TbCP (0.0026 mg) is about 1/400, 1/4000 of the amount of conventional MOF based sensor used from 1 mg to 10 mg.

As shown in the following Table 5, it was confirmed that the value of the extinction coefficient ( K _sv ) for the copper ion of the silica @ TbCP microspheres (0.01 mg) having a thin shell thickness was the most remarkably large among other metal ions.

Metal ion K _sv (M ^-1 ) Metal ion K _sv (M ^-1 ) Ca ^{2 +} 17 Ag ⁺ 2 Mg ^{2 +} 16 Ni ^{2 +} 198 Zn ^{2 +} 8 Co ^{2 +} 358 Mn ^{2 +} 24 Cu ^{2 +} 39,069 Cd ^{2 +} 12 - -

Test Example  5. Shell thin silica @ TbCP  Core-shell Microsphere  recycle

FIG. 8A is an image of a recycling process of a thin silica <@TbCP core-shell microspheres manufactured according to Example 3 of the present invention; FIG. FIG. 8B is an SEM image of the silica &lt; RTI ID = 0.0 &gt; @TbCP &lt; / RTI &gt; core-shell microspheres having a thin thickness of the recycled shell.

8A and 8B, the silica &lt; RTI ID = 0.0 &gt; @TbCP &lt; / RTI &gt; core-shell microsphere with a thin shell of Example 3 can be recycled several times by simple washing with acetonitrile after being used for sensing, It was confirmed that even after use, the uniformity, the average particle diameter, and the shell thickness were not changed as compared with before use.

- Experimental equipment

Silica particles treated with carboxylic acid on the surface were purchased from Polysciences, Inc (USA).

SEM images were obtained using a JEOL JSM-7001F Field Emission SEM, and EDX spectra were obtained using a Hitachi SU 1510 SEM equipped with a Horiba EMAX Energy E-250 EDS system.

STEM images were acquired using FEI Tecnai G2 F30 ST and performed using a dark field image in STEM mode at 300 kV; EDX spectral profile scan data were obtained with the STEM image at the Seoul Center for Basic Science in Korea.

The luminescence characteristics were measured with a Jasco FP-8500 fluorescence analyzer using a quartz cell (10 x 4 mm light path), and confocal microscopy images were obtained from a multi-photon CLSM (LSM 780 NLO, GaAsP detector, Carl-Zeiss) and a Ti: Sappuire laser (Maitai eHP deepsee, Spectra Physics).

Infrared spectra were obtained with a Jasco FT / IR-4200 spectrometer and the X-ray diffraction (PXRS) pattern was measured using a Rigaku Ultima IV with a graphite-monochromated Cu _k radiation source (40 kV, 40 mA) .

- Measurement of luminescence characteristics

The luminescence characteristics of the samples were measured by using acetonitrile suspension at room temperature. The optimum luminescence spectra were obtained by adding EuCP microspheres (1.0 mL) to MeCN solution (1.0 mL) containing various concentrations of Cu (NO ₃ ) ₂ (Preparation Example 1) or silica @LnCP microparticles (0.1 mg or 0.01 mg).

With respect to the detection selectivity experiment, EuCP microspheres or is of 5 mM M @LnCP silica microparticles (0.1 mg or _{0.01 mg) (NO 3) 2} (M = Mg 2 +, Ca 2 +, Mn 2 +, Co 2 + , Ni ^{2 +,} is measured in the ^{Cu 2+, Zn 2 +, Cd} 2 +) or MeCN solution (1.0 mL) with a containing AgNO _3.

Claims (15)

A sensor for detecting copper ions comprising a coordinated polymer shell on the surface of a silica core,
Wherein the shell is made of a coordination polymer in which terbium (Tb) metal ions and an organic building block are coordinated to each other. delete The sensor for detecting copper ions according to claim 1, wherein the shell comprises a coordination polymer in which terbium (Tb) metal ions and isophthalic acid (H ₂ IPA) are coordinated to each other. The sensor for detecting copper ions according to claim 1, wherein the silica core and the coordinated polymer shell are used in a weight ratio of 1-8: 2-9. The sensor for detecting copper ions according to claim 1, wherein the thickness of the shell is 35 to 140 nm. The sensor for detecting copper ions according to claim 1, wherein the sensor for detecting copper ions has an extinction coefficient ( K _sv ) of 15,000 to 40,000 M ^-1 for copper ions. The sensor for detecting copper ions according to claim 1, wherein the sensor for detecting copper ions is washed again with acetonitrile and reused. The sensor for detecting copper ions according to claim 1, wherein the sensor for detecting copper ions is 0.01 to 0.1 mg. (A) preparing a reactant by mixing silica particles surface-treated with carboxylic acid, a coordination polymer precursor comprising terbium (Tb) metal ions and an organic building block in an organic solvent;
(B) heating the reaction product to a temperature of from 130 to 150 캜; And
(C) centrifuging the heated reactant to obtain core-shell microspheres,
Wherein the silica particles are used as a core and the coordination polymer is used as a shell. delete 10. The method of claim 9, wherein the coordination polymer precursor in step (a) is a mixture of terbium (Tb) metal ion and isophthalic acid (H ₂ IPA). 10. The method according to claim 9, wherein the organic solvent in step (a) is a mixed solvent of N, N-dimethylformamide (DMF) and tetrahydrofuran (THF).  A method for selectively detecting copper ions in a sample using the copper ion detecting sensor of claim 1. 14. The method of claim 13, wherein the decrease in fluorescence intensity due to the addition of copper ions is measured. 14. The method of claim 13, wherein the wavelength of light irradiated for the change in fluorescence intensity is 280 nm.

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