KR101633692B1 - Organic silica-based sorbents for removal of metal cations and optical sensor using the same - Google Patents

Abstract

The present invention relates to an adsorbent for removing metal cations based on organosilica and an optical sensor using the same. More specifically, the present invention is characterized in that a fluorescent bromine compound selectively bonding with at least two metal cations is formed by covalent bonding with an organic silica support An adsorbent for removing metal cations based on an organic silica, and an optical sensor which exhibits at least two emboli by adsorption of metal cations.
The adsorbent for removing metal cations according to the present invention exhibits high adsorption power and double embolization, so that at least two metal cations can be detected at the same time. Especially, mercury ion and iron ion exhibit double embolization which can be visually confirmed and can be applied to an optical sensor and exhibit excellent effects.

Description

TECHNICAL FIELD The present invention relates to an adsorbent for removing metal cations based on organic silica and an optical sensor using the same.

The present invention relates to an adsorbent for removing metal cation based on organic silica and an optical sensor using the same, wherein a chromogenic receptor compound having a selective binding force to at least two metal cations is formed by bonding to a silica support surface.

Fluorescence sensors are technologies that selectively recognize an analyte through a chemical reaction between an analyte and a sensitive substance, and can observe or image a specific substance in real time through the chemical reaction. Research on high-performance new fluorescent sensors capable of detecting heavy metals and toxic metal ions in the surrounding environment and living organisms has received considerable attention. If the natural environment and aquatic ecosystems are contaminated with heavy metals or toxic metals, this will have a detrimental effect on human and animal health. Therefore, there is a need for the development of chemical sensors to detect metal ions that are toxic to water and living cells or tissues.

Most of the fluorescence / colorimetric probes based on the currently reported organic molecules are difficult to reuse due to their homogeneity and thus are not effective in terms of cost in practice. This is the biggest drawback of colorimetric molecular probes.

To date there have been few reports of mesoporous silica-based fluorescence sensors for the detection of metal ions. Most of these reports also have limitations that can detect only one metal ion. Therefore, a novel multi-detection optical sensor capable of exhibiting significant color change and change in luminescence characteristics with high adsorption characteristics for specific cations in order to remove many ions from water and to detect metal ions which are toxic to living cells The development of Korea is needed more.

Disclosure of the Invention The present invention has been made in view of the above problems, and it is an object of the present invention to provide an adsorbent for removing metal cation based on organic silica which selectively binds at least two metal cations.

Another object of the present invention is to provide a method for producing the adsorbent for removing metal cation.

Another object of the present invention is to provide a metal cation multi-detection optical sensor using the adsorbent for removing metal cation.

It is another object of the present invention to provide a metal cation multi-detection apparatus including the optical sensor.

According to an aspect of the present invention, there is provided an adsorbent for removing metal cation based on organosilica, which is formed by covalently bonding a fluorescent bromine compound selectively binding to at least two metal cations to an organic silica support, to provide.

In another aspect, the present invention provides a method for producing a fluorescent compound, comprising: a first step of dissolving a fluorescent bromine compound in an organic solvent to prepare a solution; A second step of preparing an alkoxysilane precursor having a fluorescent bromine compound bonded thereto by reacting the solution with alkoxysilane; And a third step of mixing the precursor and the TEOS solution and reacting them to prepare an organic silica having a fluorescent bromine compound covalently bonded thereto. The present invention also provides a method for preparing an adsorbent for removing metal cation based on an organic silica.

According to another aspect of the present invention, there is provided a metal cation multi-detection optical sensor, comprising the adsorbent, wherein the adsorbent exhibits at least two emboli by adsorption of metal cations.

According to another aspect of the present invention, there is provided a metal cation multi-detector apparatus including the optical sensor.

The adsorbent for removing metal cation according to the present invention is characterized in that a color acceptor compound having a selective binding force to at least two metal cations is covalently bonded to the surface of a silica support having a high surface area to exhibit a high adsorptivity and double embolism, It is possible to simultaneously detect positive ions. Particularly, it exhibits high adsorption power for mercury ion and iron ion, and it has a clear color change before and after adsorption, so that it can be used as a portable color measuring instrument and a luminescence measuring instrument for detecting metal ions which are toxic to water and living cells or tissue And can exhibit excellent effects.

FIG. 1 is a schematic view showing a process for producing an EB-PMO adsorbent according to an embodiment of the present invention, a fluorescence extinction process for mercury ions and iron ions, and a fluorescence intensity according to the wavelength before and after adsorption.
2 is a graph showing an XRD pattern of an EB-PMO chemical sensor synthesized according to the present invention. (A) before the surfactant extraction, (b) after the surfactant extraction,
3 is a graph showing the results of FT-IR spectroscopy analysis of EB_PMO synthesized according to the present invention.
FIG. 4 is a graph showing the nitrogen isotherm adsorption / desorption curve of the EB-PMO chemical sensor synthesized according to the present invention and the distribution of pore sizes calculated therefrom.
FIG. 5 is a graph showing the results of fluorescence extinction and embolization according to kinds of metal ions for an EB-PMO chemical sensor synthesized according to the present invention. (A) fluorescence quenching under ultraviolet light, (B) embolization under natural light, (C) relative fluorescence ( I / I ₀ ) at a wavelength of 550 nm,
FIG. 6 is a graph showing the results of fluorescence extinction and embolization according to addition of NO ₃ ^- , SO ₄ ^2- , and PO ₄ ^3- to an EB-PMO chemical sensor synthesized according to the present invention. ((A) fluorescence quenching under ultraviolet light, (B) embolization under natural light)
FIG. 7 is a graph showing changes in fluorescence intensity according to a change in pH value for an EB-PMO chemical sensor according to the present invention. (A): (a) in the absence of mercury ions, (b) in the presence of mercury ions / (B): in the absence of iron ions,
FIG. 8 is a graph showing the result of observing MCF-7 cells cultured together with the EB-PMO chemical sensor according to the present invention by a confocal microscope. ((A) in the absence of mercury ions, (B) in the presence of mercury ions, (C) in the absence of iron ions, and (D)
9 is a graph showing the results of a biocompatibility test for an EB-PMO chemical sensor according to the present invention. (When cells were treated with EB-PMO, EB-PMO-Hg ⁺ , (B) with EB-PMO or EB-PMO-Fe ³⁺ )

Hereinafter, the present invention will be described in detail.

In one aspect, the present invention provides an adsorbent for removing metal cations based on an organic silica, wherein a fluorescent bromine compound that selectively binds to at least two metal cations is formed by covalent bonding with an organic silica support.

In the present invention, the fluorescent bromine compound may be characterized by using any one of ethodium bromide and rhodium bromide, and more preferably, ethidium bromide may be used. (EB) is covalently bonded to the periodic mesoporous organic silica (PMO) to form EB-PMO, and in the EB-PMO, the etchant bromide is subjected to mineral oil electronic transfer between the phenyl group and the nitrogen atom Photoinduced electron transfer (PET), or proton transfer in the molecule.

In the present invention, the organic silica support is not particularly limited as long as it is commonly used in the art, but silica mesoporous, silica particles, silica nanotubes and silica nanorods and periodic mesoporous silica mesoporous organosilicones (PMOs), and more preferably, periodic mesoporous organosilica (PMOs). The cyclic mesoporous organosilica is a new type of material having an organic / inorganic hybrid structure formed by synthesizing an organosilane precursor, and is characterized in that it can be made into a stable structure including various functional groups. The organic silica support containing such periodic mesoporous organic silica has a wide specific surface area and an aligned mesopore structure, so that the functional group content can be increased as compared with the case where functional groups such as chromophore exist only on the surface of the support.

In the present invention, the metal cations selectively bonded to the fluorescent bromine compound may include mercury ions and iron ions. The adsorbent for removing metal cations based on organosilica according to the present invention may contain mercury ions And ferrite ions.

In another aspect, the present invention provides a method for producing a fluorescent compound, comprising: a first step of dissolving a fluorescent bromine compound in an organic solvent to prepare a solution; A second step of preparing an alkoxysilane precursor having a fluorescent bromine compound bonded thereto by reacting the solution with alkoxysilane; And a third step of mixing the precursor and the TEOS solution and reacting them to prepare an organic silica having a fluorescent bromine compound covalently bonded thereto. The present invention also provides a method for preparing an adsorbent for removing metal cation based on an organic silica.

In the present invention, the organic solvent is not particularly limited as long as it is commonly used in the art, and preferably ethyl caprylate, 1-octanol, 1-decanol, 1-dodecanol, Isopropyl myristate, polydimethylsiloxane, and chloroform anhydrous, and more preferably anhydrous chloroform may be added in an atmosphere of nitrogen.

Further, in the present invention, the fluorescent bromine compound is characterized in that any one of the ethidium bromide and the magnesium bromide is used.

Preferably, in the present invention, the alkoxysilane is at least one selected from the group consisting of methyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, propyltriethoxysilane, methyltriethoxysilane, hexadecyltriethoxysilane and octadecyl Triethoxysilane, and triethoxysilane can be used. More preferably, 3-chloropropyltriethoxysilane can be used.

In addition, the third step of the present invention may include the steps of (1) mixing and stirring an aqueous surfactant solution and an aqueous ammonia solution to prepare a surfactant mixture; (2) adding and stirring the precursor and the TEOS solution to the surfactant mixture; And (3) purifying and washing the suspension, and adding an acidified alcohol to the reaction mixture, thereby extracting the surfactant in the suspension to prepare an organic silica having a fluorescent bromine compound covalently bonded thereto .

In the present invention, the surfactant is selected from hexadecyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (DTAB), or benzalkonium chloride, more preferably cetyltrimethylammonium bromide (CTAB) or benzal And most preferably cetyltrimethylammonium bromide (CTAB) can be used.

According to another aspect of the present invention, there is provided a metal cation multi-detection optical sensor, comprising: the organic silica-based adsorbent for removing metal cation, wherein the adsorbent adsorbs at least two metal cations to exhibit at least two emboli to provide.

In the present invention, the metal cation adsorbed by the adsorbent may include mercury ions and iron ions. When the adsorbent adsorbs mercury ions, it exhibits an embolus from pink to light green, and iron In the case of adsorbing ions, they exhibit embolization from pink to reddish, so that they can be used as optical sensors for detecting mercury ions and iron ions in an aqueous solution.

In the present invention, the sensor may be a biosensor.

According to another aspect of the present invention, there is provided a metal cation multi-detector apparatus including the optical sensor.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the following examples. However, the present invention is not limited to these examples.

Example

Example 1: Preparation of an alkoxysilane precursor (EB-precursor) having a fluorescent bromine group

0.5 g of ethidium bromide was added to 60 mL of anhydrous chloroform and stirred. 0.65 g of 3-chloropropyltriethoxysilane was added dropwise to the solution under agitation at 25 占 폚 in a nitrogen atmosphere. After addition of the basic catalyst sodium hydride, the reaction mixture was further stirred for 2 hours. The progress of the reaction of the solution during stirring was confirmed by thin film chromatography. After completion of the reaction, the reaction product was purified by column chromatography to obtain an alkoxysilane precursor (hereinafter referred to as "EB-precursor") having a fluorescent bromine group.

Example 2: Preparation of periodic mesoporous organic silica (EB-PMOs)

1.0 g of cetyl trimethylammonium bromide was dissolved in 35 mL of distilled water. 13 mL of ammonia water (28%) was then added to the aqueous solution of cetyltrimethylammonium bromide and stirred for 30 minutes until a clear solution was obtained. Cetyltrimethylammonium bromide solution was added to the prepared EB-precursor and TEOS (Tetraethyl orthosilicate) solution while stirring. The resulting suspension was stirred at 35 < 0 > C for 24 hours. Thereafter, it was aged at 95 DEG C overnight without stirring for one night. The resulting product was then collected by filtration and washed several times with distilled water and ethanol. The invisible surfactant in the product was extracted in 50 ml of ethanol which had been acidified with 6 g of hydrogen chloride and then the product was dried at 60 ° C to produce cyclic mesoporous organic silica (hereinafter referred to as EB-PMOs) . The process of making the EB-PMOs is illustrated in FIG.

Test example: colorimetric detection of metal ion

(Cu ²⁺ , Ni ²⁺ , Hg ²⁺ , Co ²⁺ , Zn ²⁺ , Cr ³⁺ , Cd ²⁺ , Fe ³⁺ , Pb ²⁺ , and Mn ^{2 +} ) Nitrate was prepared at a concentration of 1.25 x 10 <" ³ > M. A 0.1 g L- ¹ concentration of EB-PMO suspension was prepared with Tris-HCl buffer at various pHs adjusted with 1 M hydrogen chloride and sodium hydroxide. 2 mL of EB-PMO suspension was placed in a 1 cm quartz cell and the stock solution was added in small portions using a micropipette. The total volume of the stock solution to be added was made to be 100 μL or less. All heavy metal ions were evaluated qualitatively as color change and fluorescence emission. Referring to FIG. 5, the photograph of (b) shows the embolization of EB-POM when mercury ions and iron ions are added. The addition of mercury ions changes from pink to greenish color, An embolism has occurred. The selectivity based on the color was easily observed with the naked eye. Relative fluorescence of EB-PMO suspension at 0.1 g L ^-1 concentration in the presence of various ions of 6.25 x 10 ^-6 M was analyzed at 550 nm wavelength. As a result, Cu, In the case of various metal ions such as ions, lead ions and manganese ions, no significant extinction was observed, but on the basis of excellent fluorescence extinction and coloring for mercury and iron ions,

Hereinafter, the results of the above embodiments will be described in detail with reference to the drawings.

FIG. 1 is a schematic view of a process of producing an EB-PMO chemical sensor according to the present invention and a process of the EB-PMO chemical sensor showing fluorescence extinction characteristics by binding with metal cations. Referring to FIG. 1, It is associated with mercury ion, indicating pink to greenish color, and it is associated with iron ion, resulting in embolization from pink to reddish pink.

FIG. 2 is a graph showing the XRD pattern of the EB-PMO chemical sensor synthesized according to the present invention before and after the surfactant extraction. Referring to FIG. 2, when the d-spacing is 3.6 nm and the 2θ is 2.54 nm, . It can be seen that EB-PMO has a well-aligned hexagonal mesoporous silica structure. The peak intensities at (100) and (110) increased further after removal of the surfactant.

3 is due to the nitro hydronium ion (-N ⁺⁾ at the C = N, 782 cm ^-1 in EB_PMO of FT-IR spectroscopy to analyze the graph, referring them from ^{1639 cm -1 C = N, 1476} cm -1 peak . The peak at 1388 cm ^-1 is due to the aromatic group of the EB moiety. The vibration peaks at 2863 cm ^-1 and 2917 cm ^-1 are due to the stretching vibration of CH in the EB group substituted with a silyl group. This confirms that the EB precursor is well covalently bound to the PMO structure. Peaks at 1081 cm ^-1 and 960 cm ^-1 are due to Si-O-Si bonds and Si-OH bonds, respectively.

FIG. 4 is a graph showing the nitrogen isotherm adsorption / desorption curve and pore size distribution of the EB-PMO chemical sensor. Referring to FIG. 4, this material exhibits H1 hysteresis and follows the type IV adsorption isotherm. This means that this material has well-aligned mesopores with a uniform mesopore size distribution.

FIG. 5 is a graph showing the results of fluorescence extinction and embolization according to the type of metal ion for an EB-PMO chemical sensor synthesized according to the present invention. FIG. 5A is a diagram showing fluorescence extinction under ultraviolet light, ( I / I ₀ ) at a wavelength of 550 nm. Referring to FIG. 3, EB-PMO is a graph showing the embolization and coloration of mercury and iron ions Channel detection selectivity. In the photographs, no significant extinguishment was observed for various metal ions such as 50 μM of copper ion, nickel ion, cobalt ion, zinc ion, chromium ion, cadmium ion, lead ion and manganese ion. On the other hand, fluorescence quenching occurred only for mercury and iron ions. In addition, the addition of mercury ions from pink to lime green, and the addition of iron ions from embryonic to pink. The relative fluorescence of the EB-PMO suspension of 0.1 g L ^{-1 in the} presence of various ions of 6.25 × 10 ^-6 M was analyzed at a wavelength of 550 nm. As a result, , But no significant quenching was observed in various metal ions such as nickel ion, cobalt ion, zinc ion, chromium ion, cadmium ion, lead ion and manganese ion. On the other hand, based on excellent fluorescence extinction and coloring for mercury and iron ions It is confirmed that dual channel detection selectivity is exhibited.

FIG. 6 shows fluorescence and color development of EB-PMO at a concentration of 0.1 g L ^-1 when 50 μM of metal ions and 5 mM of NO ₃ ^- , SO ₄ ^2- , and PO ₄ ^3- were added. Referring to the anion and buffer solutions such as nitrate ion, sulfate ion and phosphate ion, the EB-PMO was remarkably firm.

FIG. 7 is a graph showing fluorescence extinction of EB-PMO suspension having a concentration of 0.1 g L ^{-1 in the} presence of (a) mercury ion at 612 nm wavelength and (b) iron ion at a wavelength of 615 nm. Referring to FIG. 7, And colorimetric selectivity for various competitive metal ions. Heavy metal ions such as copper ions, cadmium ions, mercury ions, and lead ions tend to fluoresce through the electron or energy exchange process. The EB group in EB-PMO exhibits prominent fluorescence due to the photoinduced electron transfer (PET) action between the phenyl group and the nitrogen atom in the presence of ultraviolet light or the intramolecular proton transfer process. The remarkable fluorescence quenching and color change of EB-PMO is due to the formation of a complex of mercury and iron ions with PMO-Hg ²⁺ and EB-PMO-Fe ³⁺ . This is due to the interaction between the metal ion and the nitrogen atom of the EB group. As a result, intramolecular proton transfer or photoinduced electron transfer is blocked and fluorescence quenching occurs. As a result, it can be seen that EB-PMO is effective for detecting mercury and iron ions.

(B) - (a) in the absence of iron ions and (B) - (b) in the absence of mercury ions and in the presence of mercury ions at various pH values at room temperature, And the fluorescence intensity (? _Ex = 550 nm, [EB-PMO] = 0.1 gL ^-1 , [Hg ²⁺ , Fe ³⁺ ] = 6.25 x 10 ^-6 M) of EB-PMO in the presence of iron ions. Referring to FIG. 7, the emission peak of EB-PMO was observed at 625 nm at a neutral pH and the degree of fluorescence emission was decreased at a basic state (pH <5). However, when it was acidic, it showed complete fluorescence quenching. This may be due to competition of the counter ion of the bromine anion of the EB moiety with the hydrogen ion of the acidic medium. EB-PMO not only showed a color change from pink to pale green for mercury ions and pink to reddish for iron ions in a wide range of pH ranges (pH 1-14), but also showed enhanced fluorescence quenching. This phenomenon is due to the strong interaction of mercury and iron ions with the nitrogen atoms of EB-PMO. Therefore, EB-PMO-Hg ²⁺ and EB-PMO-Fe ³⁺ exhibit considerable fluorescence quenching with optical color change. As a result, it can be seen that EB-PMO is effective for detection of mercury and iron ions in a wide range of pH.

FIG. 9 is a photograph showing a confocal fluorescence image in MCF-7 cells, showing (a) absence of mercury ions, (b) presence of mercury ions, (D) fluorescence images in the presence of iron ions. Referring to FIG. 8, MCF-7 cells cultured with EB-PMO exhibit strong red fluorescence. However, when mercury and iron ions were present, the fluorescence intensity immediately decreased or no fluorescence appeared.

10 when observing the cell viability of MCF-7 cells (a) EB-PMO, Hg 2+, the case where the cells treated with ^{EB-PMO-Hg 2+, (} b) EB-PMO, Fe 3+, EB -PMO-Fe &lt; ^{3 +} &gt; was subjected to cell viability test by MMT method. As a result, the survival rate was 100%. Metal-free EB-PMO showed negligible cytotoxicity. Therefore, the present invention is a fluorescence chemical sensor suitable for a living body and is suitable for detection of mercury and iron ions in a biological system.

As described above, the organosilica-based adsorbent for removing metal cations according to the present invention exhibits excellent dual channel detection selectivity particularly for mercury and iron ions based on fluorescence extinction and color development for metal cations.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it should be understood that various changes and modifications may be made without departing from the scope of the present invention. The scope of which is defined in the claims.

Claims (8)

An adsorbent for removing metal cation based on organosilica, characterized in that a fluorescent bromine compound which selectively binds metal cations is formed by covalent bonding with an organic silica support,
Wherein the fluorescent bromine compound is ethidium bromide or magnesium bromide,
Wherein the metal cation is a mercury ion and an iron ion,
The adsorbent includes a first step of dissolving a fluorescent bromine compound in an organic solvent to prepare a solution; A second step of preparing an alkoxysilane precursor having a fluorescent bromine compound bonded thereto by reacting the solution with alkoxysilane; And a third step of preparing an organic silica to which a fluorescent bromine compound is covalently bonded by mixing and reacting the precursor with a tetraethylorthosilicate (TEOS) solution,
Wherein the adsorbent has dual ion selectivity for mercury and iron ions and exhibits double embolization due to adsorption. The method according to claim 1,
Wherein the silica support is any one of silica mesoporous, silica particles, silica nanotubes, and silica nanorods and periodic mesoporous organosilicones (PMOs). A first step of preparing a solution by dissolving a fluorescent bromine compound in an organic solvent;
A second step of preparing an alkoxysilane precursor having a fluorescent bromine compound bonded thereto by reacting the solution with alkoxysilane; And
And a third step of mixing the precursor with a solution of tetraethylorthosilicate (TEOS) and reacting to prepare an organosilica in which a fluorescent bromine compound is covalently bonded,
The fluorescent bromine compound is selectively bonded to a metal cation, and is etidium bromide or mathmidium bromide,
Wherein the metal cation is a mercury ion and an iron ion,
Wherein the adsorbent has a dual ion selectivity for mercury and iron ions and exhibits a double ion embolization by adsorption. The method of claim 3,
In the third step,
(1) mixing an aqueous surfactant solution and an aqueous ammonia solution with stirring to prepare a surfactant mixture;
(2) adding and stirring the precursor and the TEOS solution to the surfactant mixture; And
(3) purifying and washing the suspension, and adding an acidified alcohol and reacting to extract a surfactant in the suspension to prepare an organic silica having a fluorescent bromine compound covalently bonded thereto. A process for the preparation of adsorbents for silica based metal cation removal. The method of claim 3,
The alkoxysilane may be at least one selected from the group consisting of methyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, propyltriethoxysilane, methyltriethoxysilane, hexadecyltriethoxysilane and octadecyltriethoxysilane, 3-chloropropyl Triethoxysilane, and triethoxysilane. 2. The method of claim 1, wherein the organosilica-based adsorbent is selected from the group consisting of triethoxysilane and triethoxysilane. A metal cation double detection optical sensor according to claim 1 or 2, wherein the adsorbent adsorbs mercury ions and iron ions to exhibit double embolization. The method according to claim 6,
Wherein the sensor is a biosensor. A metal cation double detection device comprising the optical sensor according to claim 6.

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