CN111961463A - Multifunctional fluorescent sensor and preparation method and application thereof - Google Patents

Abstract

The invention discloses a multifunctional fluorescent sensor, and preparation and application thereof, and the prepared multifunctional fluorescent sensor is prepared by using carboxylic acid modified tetraphenylethylene to form fluorescent material tetrabenzylenetetracarboxylic acid (H)₄tcbpe), wherein tetraphenylethylene is used as a fluorescent core, and carboxylic acid is used as a recognition functional group of heavy metal ions. Heavy metal ion Zn²⁺Can be reacted with H₄the fluorescence is enhanced by the aggregation-induced luminescence effect of tcbpe, however, the heavy metal ion Cu²⁺Can disperse H₄the distribution of tcbpe in the solvent thereby quenches the fluorescence. Thus, detection of Zn can be achieved²⁺And Cu²⁺And the detected concentration is low. Can be developed and designed into a kit or a test strip.

Description

Multifunctional fluorescent sensor and preparation method and application thereof

Technical Field

The invention belongs to the technical field of rapid detection of food safety, relates to a detection probe, and particularly relates to a multifunctional fluorescent sensor, preparation and application thereof in detection of heavy metal ions.

Background

Heavy metals, metals having a relative density of 5 or more, are a ubiquitous environmental pollutant, such as zinc, copper, nickel, cobalt, mercury, and the like. At present, heavy metal pollution is increasingly serious along with the development of human economy, great influence is generated on atmosphere, soil and water, and heavy metals in the environment can be enriched in plants and animals through a food chain. Human beings, as the end of the food chain, will have a greater toxic effect on human health if eating heavy metal contaminated foods. In recent years, with the exposure of media to heavy metal contamination events such as cadmium rice, arsenic poison and blood lead, the heavy metal contamination has become an important factor harming food safety and human health, has a destructive effect on a plurality of organs of a human body, and even induces cancer.

Most heavy metals such as lead, mercury, cadmium and the like are necessary for non-life activities, while some heavy metals such as zinc, iron and copper are necessary trace elements for human bodies, which play a vital role in stabilizing ecological environment and human and animal metabolic health, but the heavy metal ions necessary for human bodies in food exceed a certain concentration and can denature proteins in the human bodies, thereby causing certain harm to the human bodies. Such as:

1. zinc and copper ions are two of the most abundant transition metal ions present in human physiology and pathology, and play an indispensable role in many biological processes.

2. Zinc ion (Zn)²⁺) Is a trace element essential to microorganisms, animals and plants, but excess Zn is taken in human body²⁺Can induce relevant diseases such as epilepsy, Alzheimer disease, cerebral arterial thrombosis, etc.

3. Copper ion (Cu)²⁺) Can enhance body functions including bone formation, red blood cell formation, normal functioning of nerve cells, etc. And excessive Cu²⁺Can cause various diseases, such as hypothyroidism, Alzheimer disease, Hashimoto's disease, emesis, gastrospasm, diarrhea, hypomnesis, liver pathological change, acute renal failure and tissue ischemia.

For humans and animals, heavy metal contaminated foods can cause poisoning of the human body and, in severe cases, death. Therefore, the food-derived food safety problem caused by heavy metals exceeding the normal range has become the focus of attention at home and abroad, and at present, the development of a simple and convenient detection method still has a challenge.

Multi-functional chemical sensors are designed, which have great advantages in terms of reduced analysis time and cost-effectiveness compared to single-target response sensors. Chemical sensors for single target response systems are common in the literature, however, designing and synthesizing multifunctional probes for two or more different analytes remains a formidable challenge. In addition, the chemical sensor which is simple and portable in design has very important significance for practical application, can conveniently carry out semi-quantitative detection in families, and reduces the possibility that a human body is polluted by heavy metal ions.

Since the aggregation-induced emission effect (AIE) discovered by the university of hong kong science and technology (HKUST) down-loyalty academy team in 2001, AIE is becoming the subject of popular research on fluorescent probes because AIE effect can overcome the defect that chromophores do not emit in a high concentration or aggregation state (ACQ), and AIE can widen the practical application range of fluorescent sensors.

Disclosure of Invention

In order to solve the technical problems of single function and inconvenience for practical application in the existing detection method, the invention aims to provide a multifunctional fluorescent sensor, preparation thereof and application thereof in detection of heavy metal ions Zn²⁺And Cu²⁺The use of (1).

In order to realize the task, the invention adopts the following technical solution:

a multifunctional fluorescent sensor is characterized in that a fluorescent material of tetra-styrene tetracarboxylic acid (H) is composed of carboxylic acid (COOH) modified Tetraphenylethylene (TPE)₄tcbpe), wherein tetraphenylethylene is used as a fluorescent core, and carboxylic acid is used as a recognition functional group of heavy metal ions.

The preparation method of the multifunctional fluorescence sensor is characterized in that 50 mg-350 mg of iodotetraphenylethylene (TPE-I), 100 mg-500 mg of p-methyl phenylboronic acid and 5 mg-30 mg of catalyst palladium tetrakistriphenylphosphine are sequentially added into 10 ml-100 ml of THF under the nitrogen atmosphere, and 5 ml-30 ml of 1.0-10.0M K is continuously added into the THF under the nitrogen atmosphere₂CO₃Aqueous solution in a sealing conditionReacting for 3-6 days at 60-90 ℃; after the reaction is completed, extracting with dichloromethane to obtain solid tetraphenyl ethylene formic ether; finally, the tetraphenylethylene formate is acidized to obtain the fluorescent material of the tetradiphenylethylene tetracarboxylic acid (H)₄tcbpe)。

Further, the acidification treatment is to add tetraphenyl ethylene formic ether into 1-10 mL of KOH solution with the concentration of 0.1-0.5M and reflux for 1-8 h; after the reflux is finished and the pressure is reduced and the concentration is carried out, concentrated hydrochloric acid is added into the reaction system for acidification, the fluorescent material of the tetra-distyryl tetracarboxylic acid (H) is obtained₄tcbpe)。

Experiments of the applicant show that the multifunctional fluorescent sensor can be used for detecting heavy metal ions Zn²⁺And Cu²⁺The use of (1).

Preferably, tetrakisvinyltetracarboxylic acid (H)₄tcbpe) as an identification unit in a mixed solution of ethanol and water; then heavy metal ions Zn²⁺And Cu²⁺Adding into an identification unit, detecting with a fluorescence spectrophotometer, and directly obtaining heavy metal ion Zn²⁺And Cu²⁺The linear range of the fluorescence intensity variation and the concentration of (a); heavy metal ion Zn²⁺Can generate aggregation-induced emission effect with the recognition unit to enhance fluorescence, and heavy metal ions Cu²⁺The distribution of the recognition unit in the solvent can be dispersed, thereby quenching fluorescence.

Wherein the fluorescence intensity variation value and the heavy metal ion Zn²⁺The linear curve relationship between concentrations is:

ΔF/F₀＝0.03C_Zn2++0.03(C_Zn2+0-0.45 μ g/L) and

ΔF/F₀＝0.08C_Zn2++1.80(C_Zn2+＝0.53-1.06μg/L)(ΔF/F₀＝(F₁-F₀)/F₀)；

the heavy metal ion Cu²⁺The linear curve relationship between concentration and fluorescence intensity is:

ΔF/F₀＝-0.02C_Cu2+-0.01(C_Cu2+＝0-0.70μg/L)(ΔF/F₀＝(F₁-F₀)/F₀)；

wherein, C_Zn2+Represents a heavy metal ion Zn²⁺In μ M; c_Cu2+Represents heavy metal ion Cu²⁺In μ M; Δ F represents the change in fluorescence of the multifunctional fluorescent molecule bound to the target in a.u.; f₀The fluorescence intensity before addition of the analyte.

In the mixed solution of ethanol and water, water is a poor solvent and accounts for 20-80% of the volume of the mixed solution so as to adjust the light-emitting characteristic of the functional fluorescent molecules.

Compared with the prior art, the multifunctional fluorescence sensor of the invention has the following beneficial effects:

(1) the same fluorescence sensing platform can be used for detecting two different target objects, namely heavy metal ions Zn²⁺And Cu²⁺. And the detection concentration is low.

Through the experiments of the applicant, Zn²⁺The linear range is 0-0.45 mu g/L and 0.53 mu g/L-1.06 mu g/L, and the detection limit can reach 0.39 mu g/L; cu²⁺The linear range is 0-0.70 μ g/L, and the detection limit is 0.01 μ g/L.

(2) The multifunctional fluorescence sensor can realize detection through a fluorescence spectrophotometer and has the advantages of convenience, rapidness, simple operation and high repeatability.

(3) Under the excitation of ultraviolet light, can realize semi-quantitative detection on micropore board and test paper through the naked eye, easy operation, convenient quick.

Drawings

FIG. 1 shows the multi-functional fluorescent sensor of the present invention for measuring Zn²⁺/Cu²⁺Schematic diagram of the principle of (1).

FIG. 2 is the pair of multifunctional fluorescent sensors Zn in example 1²⁺And Cu²⁺A detection graph and a linear graph of (a). Wherein, the graph A shows that the constructed multifunctional fluorescence sensor is used for Zn with different concentrations²⁺(ii) a fluorescent response of; panel B shows Zn in the concentration range of 0-1.06. mu.g/L²⁺The fluorescence intensity variation value is in a good linear relation; panel C shows a constructed fluorescence sensor for different concentrationsCu of (2)²⁺(ii) a fluorescent response of; panel D shows Cu at a concentration in the range of 0-0.70. mu.g/L²⁺Has good linear relation with the change value of fluorescence intensity.

FIG. 3 is a schematic diagram of the practical application mode-microplate (left) and test paper (right).

The present invention will be described in further detail with reference to the following drawings and examples.

Detailed Description

The applicant researches and discovers that among most AIE fluorescent cores, tetraphenyl ethylene (TPE) and derivatives thereof have the characteristics of simple synthesis, easy modification and the like, and the applicant develops a multifunctional fluorescent sensor for directly detecting heavy metal ions Zn in food by combining the advantages of AIE²⁺And Cu²⁺The content of (a).

This example provides a multifunctional fluorescence sensor, which is a fluorescent material of tetra-vinyl-tetra-carboxylic acid (hereinafter abbreviated as H) composed of carboxylic acid (COOH) -modified Tetraphenylethylene (TPE)₄tcbpe), wherein Tetraphenylethylene (TPE) is used as a fluorescent core, and carboxylic acid (COOH) is a heavy metal ion recognition functional group.

According to the experiments of the applicant, H is shown₄tcbpe can be used for detecting heavy metal ions Zn²⁺And Cu²⁺The application of (a), namely:

h is to be₄tcbpe was dissolved in a mixed solution of ethanol and water as an identification unit; then heavy metal ions Zn²⁺And Cu²⁺Adding into an identification unit, detecting with a fluorescence spectrophotometer, and directly obtaining heavy metal ion Zn²⁺And Cu²⁺The linear range of the fluorescence intensity variation and the concentration of (a); heavy metal ion Zn²⁺Can generate aggregation-induced emission effect with the recognition unit to enhance fluorescence, and heavy metal ions Cu²⁺The distribution of the recognition unit in the solvent can be dispersed, thereby quenching fluorescence.

For the specific application of the multifunctional fluorescence sensor described above, the applicant also carried out the following experiments:

before the detection of the fluorescent core, the aggregation-induced emission characteristic is researched, and the process is as follows: fluorescent material H₄tcbpe solutionIn pure ethanol, the fluorescence intensity was barely observed; when the content of water (poor solvent) was gradually increased in ethanol, it was found that water (poor solvent) was present against H₄the molecular rotation of tcbpe is hindered and fluorescence gradually increases. Therefore, ethanol and water are selected as the mixed solution, wherein the content of the water is in the range of 20-80%.

As shown in FIG. 1 as H₄Schematic diagram of the detection principle of tcbpe. H₄Fluorescence emission enhancement and fluorescence quenching of tcbpe can be measured by heavy metal ion Zn respectively²⁺And Cu²⁺Is adjusted, H₄tcbpe and Zn²⁺The binding causes the fluorescent molecules to aggregate and thereby induces the emission of strong fluorescence, while Cu²⁺Can disperse H₄tcbpe is distributed in a mixed solvent of ethanol and water, thus H₄Intramolecular spin activation of tcbpe resulted in fluorescence quenching.

The inventor uses the multifunctional fluorescent sensor for detecting the heavy metal ions Zn²⁺And Cu²⁺The experiment specifically comprises the following steps:

step 1, study H₄the selectivity test of tcbpe on different cations is carried out by a fluorescence photometer, and the experiment shows that H₄tcbpe can be reacted with Zn²⁺The binding leads to an increase in fluorescence, while Cu²⁺So that H₄Tcbpe quench, addition of additional cation did not affect H₄tcbpe fluorescence intensity;

step 2, 10 mM-30 mM H₄Dissolving tcbpe in a mixed solvent of ethanol and water, and adding Zn with different concentrations²⁺/Cu²⁺And detecting on a fluorescence spectrophotometer.

Application of multifunctional fluorescent sensor in detection of heavy metal ions Zn²⁺And Cu²⁺First, it is necessary to establish H by means of a fluorescence spectrophotometer₄Change in tcbpe fluorescence intensity and Zn²⁺/Cu²⁺The method for preparing the linear curve between the concentrations comprises the following steps: mixing 10-30mM of H₄Dissolving tcbpe in a mixed solvent of ethanol and water, and adding heavy metal ions Zn with different concentrations²⁺/Cu²⁺Detecting on a fluorescence spectrophotometer; obtaining the variation of fluorescence intensity and the concentration of heavy metal ionsA linear curve; according to the obtained linear curve, Zn in the sample to be detected²⁺And Cu²⁺And (5) carrying out quantitative detection.

Specific application examples of the multifunctional fluorescence sensor are given below, it should be noted that these examples are preferred examples, the present invention is not limited to these examples, and all equivalent changes or additions of technical features on the basis of the technical solution of the present application are within the protection scope of the present invention.

Example 1: multifunctional fluorescent sensor and application thereof in detection of heavy metal ions Zn²⁺And Cu²⁺

Step 1, preparing a multifunctional fluorescent sensor:

under the nitrogen atmosphere, 50 mg-350 mg of iodotetraphenylethylene (TPE-I), 100 mg-500 mg of p-methyl phenylboronic acid and 5 mg-30 mg of catalyst tetrakistriphenylphosphine palladium are sequentially added into 10 ml-100 ml of THF, and 5 ml-30 ml of 1.0M-10.0M K is continuously added under the nitrogen atmosphere₂CO₃Reacting the aqueous solution at 60-90 ℃ for 3-6 days under a sealed condition; after the reaction is completed, extracting with dichloromethane to obtain yellow green solid tetraphenyl ethylene formic ether (under the optimal condition, the yield is 63%); finally, carrying out acidification treatment on tetraphenyl ethylene formic ether to obtain a yellow fluorescent material H₄tcbpe. Under optimum conditions, fluorescent material H₄the yield of tcbpe was 90%.

In the embodiment, the acidification treatment is to add tetraphenyl ethylene formic ether into 1-10 mL of 0.1-0.5M KOH solution and reflux for 1-8 h; after the reflux is finished and the decompression concentration is carried out, concentrated hydrochloric acid is added into the reaction system for acidification, and the yellow fluorescent material H is obtained₄tcbpe。

Step 2, 10 mM-30 mM of fluorescent material H₄tcbpe was dissolved in a mixed solvent of ethanol and water as an identification unit; wherein, water is a poor solvent and accounts for 20-80% of the volume of the mixed solution so as to adjust H₄Luminescence characteristics of tcbpe fluorescent material.

Step 3, adding heavy metal ions Zn with different concentrations into the mixed solvent²⁺Detecting on a fluorescence spectrophotometer to obtain the fluorescence intensityDegree of change and heavy metal ion Zn²⁺A linear relationship of concentration of (c);

step 4, adding heavy metal ions Cu with different concentrations into the identification unit (mixed solvent)²⁺Detecting on a fluorescence spectrophotometer to obtain the variation of fluorescence intensity and heavy metal ion Cu²⁺Is linear with respect to concentration.

In this example, H₄Tcbpe heavy metal ion Zn²⁺And Cu²⁺The detection curve and the linear graph of (2) are shown in fig. 2, wherein, the graph A shows that the constructed fluorescence sensor has different Zn concentrations²⁺(ii) a fluorescent response of; panel B shows Zn in the concentration range of 0-1.06. mu.g/L²⁺The fluorescence intensity variation value is in a good linear relation; panel C shows a constructed fluorescence sensor for different concentrations of Cu²⁺(ii) a fluorescent response of; panel D shows Cu at a concentration in the range of 0-0.70. mu.g/L²⁺Has good linear relation with the change value of fluorescence intensity.

Change value of fluorescence intensity and heavy metal ion Zn²⁺The linear relationship of the concentrations is:

ΔF/F₀＝0.03C_Zn2++0.03(C_Zn2+0-0.45. mu.g/L) and. DELTA.F/F₀＝0.08C_Zn2++1.80(C_Zn2+＝0.53-1.06μg/L)(ΔF/F₀＝(F₁-F₀)/F₀)；

Change in fluorescence intensity and Cu²⁺Linear relationship of concentration:

ΔF/F₀＝-0.02C_Cu2+-0.01(C_Cu2+＝0-0.70μg/L)(ΔF/F₀＝(F₁-F₀)/F₀)；

wherein, C_Zn2+Represents Zn²⁺In μ M; c_Cu2+Represents Cu²⁺In μ M; Δ F represents the change in fluorescence of the multifunctional fluorescent molecule bound to the target in a.u.; f₀The fluorescence intensity before addition of the analyte.

Example 2: for Zn in edible tree fungus²⁺And Cu²⁺Performing the measurement

The agaric is purchased from a local supermarket in the great Khingan region, and is washed for 2-3 times by using tap water and secondary distilled water, dried in the air, dried in an oven at 50-150 ℃, crushed after being dried, and sieved by a sieve of 100-200 meshes for later use. Then, weighing 0.02 g-0.03 g of agaric undersize, grinding and crushing in a mortar, adding 5-20 mL of nitric acid: perchloric acid was mixed with 4:1 acid solution and left overnight. Digesting for 0.5-2 h on an electric heating furnace at 100-180 ℃, and supplementing if the acid is not enough. Next, water was added and boiled to remove the residual acid. And after cooling, diluting the digestive juice to 10-100 mL, selecting a mixed solvent of ethanol and water as a solvent system, shaking and uniformly mixing, and dividing into two parts for later use. Wherein, sodium thiosulfate is added into the reagent 1 for masking copper ions; adding dithio propanol into the reagent 2 for masking zinc ions; and simultaneously performing a blank test.

For heavy metal ions Zn in the agaric²⁺And Cu²⁺Detecting, and comparing the detection result (the change value of fluorescence) with the linear curve to obtain the heavy metal ion Zn in the actual agaric sample²⁺And Cu²⁺The contents of (A) are shown in Table 1 below:

table 1: detection of Zn in black fungus²⁺And Cu²⁺In an amount of

Of course, as shown in fig. 3, the multifunctional fluorescence sensor of the present embodiment can also be developed into two detection application modes, i.e., a microplate and a test strip.

Claims (7)

1. A multifunctional fluorescent sensor is characterized in that a fluorescent material of tetrabenzylenetetracarboxylic acid is formed by carboxylic acid modified tetraphenylethylene, wherein tetraphenylethylene is used as a fluorescent nucleus, and carboxylic acid is used as a recognition functional group of heavy metal ions.

2. The method of claim 1, wherein 50-350 mg of iodotetraphenylethylene (TPE-I) is mixed with 100-500 mg of iodotetraphenylethylene (TPE-I) under nitrogen atmosphereSequentially adding p-methyl phenylboronic acid and 5-30 mg of catalyst palladium tetratriphenylphosphine into 10-100 ml of THF, and continuously adding 5-30 ml of 1.0-10.0M K under the nitrogen atmosphere₂CO₃Reacting the aqueous solution at 60-90 ℃ for 3-6 days under a sealed condition; after the reaction is completed, extracting with dichloromethane to obtain solid tetraphenyl ethylene formic ether; and finally, carrying out acidification treatment on the tetraphenylethylene formate to obtain the fluorescent material of the tetrabenzylenetetracarboxylic acid.

3. The method of claim 2, wherein the acidification treatment is to add tetraphenyl ethylene formate to 1-10 mL of 0.1-0.5M KOH solution, reflux for 1-8 h; after the reflux is finished and the pressure is reduced and the concentration is carried out, adding concentrated hydrochloric acid into the reaction system for acidification, and obtaining the fluorescent material of the tetra-distyryl tetracarboxylic acid.

4. The multifunctional fluorescent sensor of claim 1 for detecting heavy metal ions Zn²⁺And Cu²⁺The use of (1).

5. The use according to claim 4, wherein a fluorescent material, tetrabenzyltetracarboxylic acid, is dissolved in a mixed solution of ethanol and water as an identification unit; then heavy metal ions Zn²⁺And Cu²⁺Adding into an identification unit, detecting with a fluorescence spectrophotometer, and directly obtaining heavy metal ion Zn²⁺And Cu²⁺The linear range of the fluorescence intensity variation and the concentration of (a); heavy metal ion Zn²⁺Can generate aggregation-induced emission effect with the recognition unit to enhance fluorescence, and heavy metal ions Cu²⁺The distribution of the recognition unit in the solvent can be dispersed, thereby quenching fluorescence.

6. The use according to claim 5, wherein the change in fluorescence intensity is correlated with the presence of a heavy metal ion Zn²⁺The linear curve relationship between concentrations is:

ΔF/F₀＝0.03C_Zn2++0.03(C_Zn2+0-0.45 μ g/L) and

ΔF/F₀＝0.08C_Zn2++1.80(C_Zn2+＝0.53-1.06μg/L)(ΔF/F₀＝(F₁-F₀)/F₀)；

the heavy metal ion Cu²⁺The linear curve relationship between concentration and fluorescence intensity is:

ΔF/F₀＝-0.02C_Cu2+-0.01(C_Cu2+＝0-0.70μg/L)(ΔF/F₀＝(F₁-F₀)/F₀)；

wherein, C_Zn2+Represents a heavy metal ion Zn²⁺In μ M; c_Cu2+Represents heavy metal ion Cu²⁺In μ M; Δ F represents the change in fluorescence of the multifunctional fluorescent molecule bound to the target in a.u.; f₀The fluorescence intensity before addition of the analyte.

7. The use according to claim 5, wherein the mixed solution of ethanol and water, water is a poor solvent and accounts for 20-80% of the volume of the mixed solution, so as to adjust the light-emitting property of the functional fluorescent molecule.

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