CN103833944B - A kind of detect mercury ion amphipathic nature polyalcohol nanoparticle, preparation method and application - Google Patents

Abstract

The invention discloses a kind of detect mercury ion amphipathic nature polyalcohol nanoparticle, preparation method and application.Standby amphipathic rhodamine B graft copolymer is prepared from redeposition to water with simple reprecipitation method by it under ultrasonic condition.And prepared amphipathic rhodamine B graft copolymer is grafted on amphipathic multipolymer polyoxyethylene-<i>b</iGreatT.Gr eaT.GT-poly-(vinylbenzene-<i>co</iGreatT.G reaT.GT-p-chloromethyl styrene) by methylation reaction with quadrol thio lactam rhodamine B.This amphipathic nature polyalcohol nanoparticle has well dispersed and less size in water, can realize the change of highly sensitive, highly selective fluorescence and colorimetric detect mercury ion in water.Compared with prior art, the present invention can realize the rapid detection to Trace Mercury ion in pure water medium, and synthetic route is simple, easy to use, consumption is few, is suitable for amplifying synthesis and production application, has huge application prospect in biological and environment measuring field.

Description

An amphiphilic polymer nanoparticle for detecting mercury ions, its preparation method and application

technical field

The invention relates to the technical field of material preparation and biological and environmental ion detection, in particular, it relates to amphiphilic polymer nanoparticles with the function of detecting mercury ions through fluorescence and colorimetric changes and a preparation method thereof, and the amphiphilic polymer Application of nanoparticles to the detection of mercury ions in water.

Background technique

Mercury is a highly toxic heavy metal element widely present in the environment and distributed in all corners of the globe. Elemental Hg and Hg ²⁺ can be converted into methylmercury by aquatic microorganisms after being discharged into the environment. It can be enriched in organisms and finally absorbed by the human body through the food chain. After reaching the human body, it will damage the human central nervous system. It causes severe nausea, vomiting, abdominal pain, and severe renal damage, which has a huge impact on human health. Therefore, the selective and rapid detection of mercury ions, especially the detection of mercury ion residues in environmental pollutants and the monitoring of food safety, has an extremely important role in environmental science, medical and biological research.

Currently, common methods for detecting mercury ions include atomic absorption/emission spectrometry, dithizone colorimetry, inductively coupled plasma-mass spectrometry, and electrochemical methods. However, the cost of these methods is high, the detection process is cumbersome, and requires more complicated instruments and equipment. Therefore, inventing a simple, direct, efficient and low-cost detection technology undoubtedly has very important practical significance and application prospects. In recent years, the chemical sensor method to detect metal ions through fluorescence or colorimetric changes has received more and more attention due to its advantages of simplicity, rapidity, high sensitivity, high selectivity, no damage to samples, and identification in water. The hotspots in ion detection and identification research are discussed. Most of the reported chemical sensors based on mercury ions are concentrated in the field of small organic molecules. However, most small-molecule sensors are not water-soluble, which is not conducive to the detection of metal ions in water and biological environments; and most of the water-soluble small-molecule sensors have low quantum yields in water, so the detection sensitivity is not high; In addition, Small organic molecule systems are often biologically toxic and prone to self-aggregation, which leads to instability of the detection system. Therefore, it is a great challenge to develop a simple and highly sensitive sensor that can rapidly detect Hg ions in water.

In the present invention, the amphiphilic rhodamine B graft copolymer is formed by grafting ethylenediamine thiolactamized rhodamine B onto the amphiphilic copolymer, and then it is reprecipitated into water to form a mercury ion-detecting copolymer. amphiphilic polymer nanoparticles. The amphiphilic polymer nanoparticle prepared by the method has the characteristics of convenient synthesis, stable structure, small particle size, no need to use other surfactants and dispersants, and the like. Through the specific complexation between mercury ions and the probe groups on the nanoparticles, the spiro ring structure of the probe groups is induced to open, so that a color reaction occurs and a fluorescent signal is generated, which can achieve high detection of mercury ions in water. Rapid detection with sensitivity and high selectivity.

Contents of the invention

The object of the present invention is to provide an amphiphilic polymer nanoparticle with mercury ion detection function, a preparation method and an application thereof. It adopts the strategy of combining functional polymer grafting technology and reprecipitation method to obtain amphiphilic fluorescent polymer nanoparticles with a particle diameter of about 20nm. Further applications show that the amphiphilic polymer nanoparticles can achieve High sensitivity and high selectivity detection function for mercury ions.

In order to achieve the above object, the technical solution of the present invention is: a kind of amphiphilic polymer nano-particles with mercury ion detection function, which is prepared by re-precipitating into water under ultrasonic condition from amphiphilic rhodamine B graft copolymer. Form, the structural formula of described amphiphilic rhodamine B graft copolymer is:

In the formula, a/b/x is 16:8:1~7:3.5:1.

The preparation method comprises: quickly adding the tetrahydrofuran solution of the amphiphilic rhodamine B graft copolymer into the water being ultrasonicated, and after ultrasonicating for 10 minutes, the tetrahydrofuran in the solution is removed by rotary evaporation at room temperature, and the obtained product is obtained at constant volume. The required amphiphilic polymer nanoparticle solution has a particle diameter of about 20nm.

The synthetic route of described amphiphilic rhodamine B graft copolymer is:

The preparation method of described amphiphilic rhodamine B graft copolymer comprises the following steps:

(1) Put the solvent dimethylformamide, polyoxyethylene macromolecular chain transfer reagent, styrene, p-chloromethylstyrene and azobisisobutyronitrile in the reaction bottle, and fill it with nitrogen at low temperature-vacuumize Repeat three times, seal, and react in an oil bath at 90 degrees for 4 hours. The product is precipitated in a mixed solvent of petroleum ether and ether, and then dissolved in dichloromethane. Repeat three times to remove unreacted monomers and small molecular impurities, and vacuum dry to obtain Amphiphilic copolymer polyethylene oxide- b -poly(styrene- co -p-chloromethylstyrene), its structural formula is as follows:

Where a/b/x is 16:8:1~7:3.5:1,

The structural formula of the polyoxyethylene macromolecular chain transfer reagent is as follows:

In the formula, a is 112;

(2) Add the tetrahydrofuran solution containing the amphiphilic copolymer polyethylene oxide- b -poly(styrene- co -p-chloromethylstyrene) to the solution containing ethylenediamine thiolactamized rhodamine B and diiso In the tetrahydrofuran solution of propylethylamine, react in the dark at room temperature under the protection of nitrogen for 24 hours. The product is precipitated in a mixed solvent of petroleum ether, ether and ethanol, and then dissolved in tetrahydrofuran. Repeat three times to remove unreacted ethylenediamine Rhodamine B and other small molecule impurities are thiolactamized and vacuum-dried to obtain an amphiphilic rhodamine B graft copolymer.

In step (1), the molar ratio of polyethylene oxide macromolecular chain transfer reagent, hydrophobic monomer, p-chloromethylstyrene and azobisisobutyronitrile is 3.5:1400:140:1~3.5:1400:420: 1.

In step (1), the volume ratio of the mixed solvent of petroleum ether and diethyl ether is: petroleum ether:diethyl ether=1:1.

In step (2), the amphiphilic copolymer polyethylene oxide- b -poly(styrene- co -p-chloromethylstyrene), ethylenediamine thiolactamized rhodamine B and diisopropyl ethyl The molar ratio of amines is 1:20:60.

In step (2), the volume ratio of the mixed solvent of petroleum ether, diethyl ether and ethanol is: petroleum ether:diethyl ether:ethanol=5:5:1.

In step ( ₂ ), the preparation method of the ethylenediamine thiolactamized rhodamine B is: under the condition of avoiding light, dissolve 3.0g of rhodamine B in 130ml of methanol, and quickly add 7.5g of ethylenediamine was heated to 85 ^o C for 24 hours. Then rotary evaporation removes most of the methanol, precipitates in a large amount of water, filters, and vacuum-dries the precipitate to obtain a light red powder, which is ethylenediamine lactamized rhodamine B; mix 1.0 g of ethylenediamine lactamized rhodamine B with 1.6 g Lawson's reagent was dissolved in 250ml of refined toluene, heated to reflux under _N2 protection, reacted for 6 hours, then removed the solvent, and the mixture was developed with a mixed solvent of petroleum ether and ethyl acetate with a volume ratio of 3:1 , using column chromatography to separate the desired ethylenediamine thiolactamized rhodamine B.

The amphiphilic polymer nanoparticles provided by the present invention can be used for the detection of mercury ions in water. The method is generally to prepare the amphiphilic polymer nanoparticles into an aqueous dispersion with a certain concentration, and to control the pH value to be 6-8. , which can detect mercury ions in water by detecting changes in its absorption and fluorescence. The concentration can be determined according to the test conditions and the degree of absorption change. For the amphiphilic polymer nanoparticles of the present invention, the concentration of the polymer can be formulated as 0.1g/L~0.5g/L, and the conventional test method is 0.2g/L ~0.4g/L. The detection and identification of mercury ions is achieved by detecting the changes in absorption and fluorescence of the dispersion. Specific tests can use absorption or fluorescence emission curves to detect the presence and concentration changes of mercury ions.

In the invention, the rhodamine B derivative is grafted onto the amphiphilic copolymer, and then reprecipitated under ultrasonic conditions to form amphiphilic polymer nanoparticles required for detecting mercury ions. In water, through the specific complexation between mercury ions and the rhodamine sulfide group on the particles, the spiro ring structure of the probe group is induced to open, so that the nanoparticles produce a color reaction and the fluorescence intensity gradually increases, thereby realizing the in water. Highly sensitive and selective identification and detection of mercury ions. Compared with the prior art, the amphiphilic polymer nanoparticles in the present invention have a simple synthesis route, convenient post-treatment, stable structure, smaller particle size, less dosage, and can directly perform high sensitivity and specificity on mercury ions in water. Identification, suitable for scale-up synthesis and practical production applications.

Description of drawings

Figure 1 is a particle size distribution diagram measured by a laser particle size analyzer for amphiphilic polymer nanoparticles.

Fig. 2 is the change graph of the absorption spectrum of adding different concentrations of mercury ions in the amphiphilic polymer nanoparticle aqueous solution (0.4g/L) prepared in the embodiment. Mercury ion concentration ranges from 0 to 2.4×10 ^-4 mol/L.

Fig. 3 is a change diagram of the fluorescence emission spectrum of the amphiphilic polymer nanoparticle aqueous solution (0.4g/L) prepared in the embodiment by adding different concentrations of mercury ions. The excitation wavelength is 520nm, and the mercury ion concentration ranges from 0 to 2.4×10 ^-4 mol/L.

Fig. 4 is a change diagram of the fluorescence emission spectrum of the amphiphilic polymer nanoparticle aqueous solution (0.4g/L) prepared in the example when various cations (concentration: 4×10 ^-5 mol/L) are added. The excitation wavelength is 520nm.

Fig. 5 is a comparison chart of fluorescence intensity of the amphiphilic polymer nanoparticle aqueous solution (0.4g/L) prepared in the embodiment while adding mercury ions and other cations (both at a concentration of 4×10 ^-5 mol/L). (The excitation wavelength is 520nm, the emission wavelength is 594nm, 0=Hg ²⁺ ; 1=Hg ²⁺ +Cu ²⁺ ; 2=Hg ²⁺ +Ca ²⁺ ; 3=Hg ²⁺ +Mg ²⁺ ; 4= Hg ²⁺ +Co ²⁺ ; 5=Hg ²⁺ +Ni ²⁺ ; 6=Hg ²⁺ +Zn ²⁺ ; 7=Hg ²⁺ +Fe ²⁺ ; 8=Hg ²⁺ +Pb ²⁺ ; 9= Hg ²⁺ +Mn ²⁺ ; 10=Hg ²⁺ +K ⁺ ; 11=Hg ²⁺ +Na ⁺ ).

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments, but the present invention is not limited thereto.

Example 1:

(1) Synthesis of amphiphilic copolymer polyethylene oxide- b -poly(styrene- co -p-chloromethylstyrene) [referred to as PEO-bP(St-co-VBC)]: 0.50g (0.1 mmol) polyethylene oxide macromolecular chain transfer reagent, 4.16g (40mmol) styrene, 1.22g (2mmol) p-chloromethylstyrene and 4.69mg (0.028mmol) azobisisobutyronitrile (AIBN) and 5ml dimethyl Dimethylformamide DMF was placed in a reaction flask, nitrogen-filled-vacuum was repeated three times at a low temperature, sealed, and reacted for 4 hours in an oil bath at 90°C. The product was precipitated in a mixed solvent of petroleum ether and diethyl ether with a volume ratio of 1:1, then dissolved in dichloromethane, and repeated three times to remove unreacted monomers and small molecular impurities, and vacuum-dried to obtain the desired product.

(2) Synthesis of amphiphilic rhodamine B graft copolymer: 200 mg of the above-prepared amphiphilic copolymer PEO-b-P (St-co-VBC) was dissolved in 10 ml of tetrahydrofuran (THF), and added to 146 mg Ethylenediamine thiolactamized rhodamine B (SRhB) and 113 mg of diisopropylethylamine (DIEA) in tetrahydrofuran (THF) (5 ml) were reacted under nitrogen protection at room temperature and protected from light for 24 hours. The product was precipitated in a mixed solvent of petroleum ether, diethyl ether and ethanol (the volume ratio of the three was 5:5:1), and then dissolved in THF, and repeated three times to remove unreacted ethylenediamine thiolactamized rhodamine B ( SRhB) and other small molecular impurities, vacuum-dried to obtain the desired product amphiphilic rhodamine B graft copolymer.

(3) Preparation of amphiphilic polymer nanoparticles with mercury ion detection function: the above-prepared amphiphilic rhodamine B graft copolymer was made into 8mg/ml THF solution, and 0.5ml solution was quickly added to the Sonicate 10ml of water for 10 minutes (ultrasonic power is 100W), then remove THF in the solution by rotary evaporation at room temperature, and obtain the required amphiphilic polymer nanoparticle solution after constant volume, with a concentration of 0.4g/ L.

Example 2: The particle size and distribution of the amphiphilic polymer nanoparticles prepared in Example 1 were tested.

The specific test instrument is MalvernNano-ZS90 laser particle size analyzer, the test concentration is (0.4g/L), and the test temperature is 25oC. The results are shown in Figure 1. It is about 20nm, and the monodispersity of the particles is good.

Embodiment 3: detection experiment of mercury ion.

(1) Take 12 5ml sample bottles, add 3ml of the amphiphilic polymer nanoparticles with a concentration of (0.4g/L) obtained in Example 1, and then add the mercury ion aqueous solution with a concentration of 0~0.24mol/L 3ul were added to 12 sample vials. After stirring for 3 minutes at room temperature, the absorption spectrum and fluorescence emission spectrum of these samples were sequentially measured (excitation wavelength is 520nm). The results are shown in Figure 2 and Figure 3. The measurement results show that the absorption intensity and fluorescence intensity of the amphiphilic polymer nanoparticles gradually increase with the increase of the mercury ion concentration, and when the mercury ion concentration is > 5 μmol/l, the fluorescence intensity of the amphiphilic polymer nanoparticles There is a significant increase.

(2) Take 12 5ml sample bottles, respectively add 3ml of the amphiphilic polymer nanoparticles with a concentration of (0.4g/L) obtained in Example 1, and then add the amphiphilic polymer nanoparticles with a concentration of 4×10 ^-2 mol/L Mercury ions and 11 other common metal ions (Mg ²⁺ , Cu ²⁺ , Pb ²⁺ , Ca ²⁺ , Zn ²⁺ , Co ²⁺ , Mn ²⁺ , Fe ²⁺ , Ni ²⁺ , K ⁺ , Na ⁺ ) 3ul of aqueous solution were added to 12 sample bottles. After stirring for 3 minutes at room temperature, the fluorescence emission spectra of these samples were sequentially measured (excitation wavelength is 520nm), and the change diagram of the fluorescence emission spectra of twelve samples was obtained. See Figure 4. The measurement results show that among many common metal ions, the amphiphilic polymer nanoparticles only have high selectivity to mercury ions.

(3) Take twelve 5ml sample bottles, numbered 0-11, and add 3ml of the amphiphilic polymer nanoparticles obtained in Example 1 at a concentration of (0.4g/L) respectively. Add ^3ul of mercury ^ion aqueous solution with a concentration of 4×10 ^-2 mol/L into No. , Cu ²⁺ , Pb ²⁺ , Ca ²⁺ , Zn ²⁺ , Co ²⁺ , Mn ²⁺ , Fe ²⁺ , Ni ²⁺ , K ⁺ , Na ⁺ ) aqueous solution 3ul was added to other 11 sample bottles at the same time . After stirring for 3 minutes at room temperature, the fluorescence emission spectra of these samples were sequentially measured (excitation wavelength is 520nm), and a comparison chart of the relative intensity of fluorescence emission of twelve samples was obtained. See Figure 5. The measurement results show that the amphiphilic polymer nanoparticles have a strong ability to resist interference from other cations in the detection of mercury ions.

The above-mentioned embodiments are used to illustrate the present invention, rather than to limit the present invention. Within the spirit of the present invention and the scope of protection of the claims, any modifications and changes made to the present invention will fall within the protection scope of the present invention.

Claims (10)

1. detect an amphipathic nature polyalcohol nanoparticle for mercury ion, it is characterized in that, be prepared from by amphipathic rhodamine B graft copolymer under ultrasonic condition in redeposition to water, the structural formula of described amphipathic rhodamine B graft copolymer is:

In formula, a/b/x is 16:8:1 ~ 7:3.5:1.

2. one kind is detected the preparation method of the amphipathic nature polyalcohol nanoparticle of mercury ion as claimed in claim 1, it is characterized in that, step comprises: joined fast by the tetrahydrofuran solution of amphipathic rhodamine B graft copolymer just in ultrasonic water, after ultrasonic 10 minutes, the method of tetrahydrofuran (THF) in solution by normal temperature rotary evaporation removed, constant volume obtains required amphipathic nature polyalcohol nano-particle solution again.

3. the preparation method of the amphipathic nature polyalcohol nanoparticle of detection mercury ion according to claim 2, is characterized in that, the preparation method of described amphipathic rhodamine B graft copolymer comprises the following steps:

(1) solvent dimethylformamide, polyoxyethylene macromolecular chain transfering reagent, vinylbenzene, p-chloromethyl styrene and Diisopropyl azodicarboxylate are placed in reaction flask, inflated with nitrogen at low temperatures-vacuumize three times repeatedly, sealing, the lower reaction of oil bath 90 degree 4 hours, product precipitates in sherwood oil and ether mixed solvent, then dissolves with methylene dichloride, in triplicate, remove unreacted monomer and small molecular weight impurity, vacuum-drying, obtain amphipathic multipolymer polyoxyethylene- b-poly-(vinylbenzene- co-p-chloromethyl styrene), its structural formula is as follows:

In formula, a/b/x is 16:8:1 ~ 7:3.5:1,

The structural formula of described polyoxyethylene macromolecular chain transfering reagent is as follows:

In formula, a is 112;

(2) will containing amphipathic multipolymer polyoxyethylene- b-poly-(vinylbenzene- co-p-chloromethyl styrene) tetrahydrofuran solution join in the tetrahydrofuran solution containing quadrol thio lactam rhodamine B and diisopropylethylamine; under room temperature, lucifuge reacts 24 hours under nitrogen protection; product precipitates in the mixed solvent of sherwood oil, ether and ethanol; dissolve with tetrahydrofuran (THF) again; in triplicate; remove unreacted quadrol thio lactam rhodamine B and other small molecular weight impurity, vacuum-drying, obtains amphipathic rhodamine B graft copolymer.

4. the preparation method of the amphipathic nature polyalcohol nanoparticle of detection mercury ion according to claim 3, it is characterized in that, in step (1), the mol ratio of polyoxyethylene macromolecular chain transfering reagent, hydrophobic monomer, p-chloromethyl styrene and Diisopropyl azodicarboxylate is 3.5:1400:140:1 ~ 3.5:1400:420:1.

5. the preparation method of the amphipathic nature polyalcohol nanoparticle of detection mercury ion according to claim 3, is characterized in that, in step (1), the volume proportion of described sherwood oil and ether mixed solvent is sherwood oil: ether=1:1.

6. the preparation method of the amphipathic nature polyalcohol nanoparticle of detection mercury ion according to claim 3, is characterized in that, in step (2), and wherein amphipathic multipolymer polyoxyethylene- b-poly-(vinylbenzene- co-p-chloromethyl styrene), the mol ratio of quadrol thio lactam rhodamine B and diisopropylethylamine is 1:20:60.

7. the preparation method of the amphipathic nature polyalcohol nanoparticle of detection mercury ion according to claim 3, is characterized in that, in step (2), the volume proportion of the mixed solvent of sherwood oil, ether and ethanol is: sherwood oil: ether: ethanol=5:5:1.

8. the preparation method of the amphipathic nature polyalcohol nanoparticle of detection mercury ion according to claim 3, it is characterized in that, in step (2), the preparation method of described quadrol thio lactam rhodamine B is: under the condition of lucifuge, 3.0g rhodamine B is dissolved in 130ml methyl alcohol, at N ₂add 7.5g quadrol fast under protection, be warming up to 85 ^oc reacts 24 hours; Then rotary evaporation removes most of methyl alcohol, precipitates in large water gaging, and filter, throw out vacuum-drying obtains incarnadine powder, is quadrol lactamize rhodamine B; 1.0g quadrol lactamize rhodamine B and 1.6g lawesson reagent are dissolved in the refining toluene of 250ml, at N ₂be warming up to backflow under protection, react 6 hours, then remove solvent, mixture take volume ratio as the sherwood oil of 3:1 and ethyl acetate mixed solvent is developping agent, utilizes pillar layer separation to obtain required quadrol thio lactam rhodamine B.

9. an amphipathic nature polyalcohol nanoparticle as claimed in claim 1 is detecting the application in water in mercury ion.

10. amphipathic nature polyalcohol nanoparticle according to claim 9 is detecting the application in water in mercury ion, it is characterized in that, the detection and indentification of mercury ion is realized by the enhancing of observation solution colour/Change of absorption and fluorescence.