阅读说明：本技术 基于BPEI-CuNCs荧光探针快速检测铜离子的方法 (Method for rapidly detecting copper ions based on BPEI-CuNCs fluorescent probe ) 是由 李胎花 宫磊 黄磊 于 2019-09-19 设计创作，主要内容包括：本发明公开了基于BPEI-CuNCs荧光探针快速检测铜离子的方法,包括以下步骤：支链聚乙烯亚胺BPEI在铜离子和抗坏血酸AA的共同作用下反应生成具有荧光性质的BPEI-CuNCs；将待测样品加入到含有BPEI-CuNCs的缓冲溶液中,基于BPEI-CuNCs荧光探针检测铜离子的浓度。通过荧光光谱仪,在激发波长为360nm,检测发射波长为430nm的荧光强度,根据Cu<Sup>2+</Sup>标准浓度梯度曲线,得到铜离子的浓度。铜离子的最低检出限为0.01μmol/L,加标回收率达96％-99％。该方法简单快速、高选择、高灵敏度。在生物和环境领域的选择性测定金属铜离子方面具有广阔的应用前景。(The invention discloses a method for rapidly detecting copper ions based on a BPEI-CuNCs fluorescent probe, which comprises the following steps: the branched polyethyleneimine BPEI reacts under the combined action of copper ions and ascorbic acid AA to generate BPEI-CuNCs with fluorescence; and adding a sample to be detected into a buffer solution containing BPEI-CuNCs, and detecting the concentration of copper ions based on a BPEI-CuNCs fluorescent probe. Detecting fluorescence intensity of 430nm emission wavelength at excitation wavelength of 360nm by fluorescence spectrometer according to Cu 2+ And (5) obtaining the concentration of the copper ions by a standard concentration gradient curve. The lowest detection limit of copper ions is 0.01 mu mol/L, and the recovery rate of the added standard reaches 96-99%. The method is simple, rapid, high in selectivity and high in sensitivity. Has wide application prospect in selectively measuring metal copper ions in the fields of biology and environment.)

1. The method for rapidly detecting the copper ions based on the BPEI-CuNCs fluorescent probe is characterized by comprising the following steps of:

1) the branched polyethyleneimine BPEI reacts under the combined action of copper ions and ascorbic acid AA to generate BPEI-CuNCs with fluorescence;

2) and adding a sample to be detected into a buffer solution containing BPEI-CuNCs, and detecting the concentration of copper ions based on a BPEI-CuNCs fluorescent probe.

2. The method of claim 1, wherein the BPEI-CuNCs are prepared by the following steps in step 1): mixing deionized water and BPEI uniformly, and then adding CuSO₄Placing the solution on an air constant temperature shaking table, and stirring for 10 min; and finally, adding AA, oscillating for two days at room temperature, and filtering to obtain a BPEI-CuNCs solution.

3. The method of claim 2, wherein the concentration of PEI in the BPEI-CuNCs solution is 0.36 mg/mL; the CuSO₄The molar ratio to the AA is 1: 1.

4. The method according to claim 1, wherein in step 2), the buffer solution is a citrate buffer solution containing 0.03% CTAB, and has a pH value of 4 and a concentration of 20 mmol/L.

5. The method according to claim 4, wherein the step 2) comprises the following steps: adding copper ions with different concentrations into BPEI-CuNCs and 20mmol/L citrate buffer solution with pH4 containing 0.03% CTAB, mixing uniformly, detecting the fluorescence intensity with emission wavelength of 430nm at excitation wavelength of 360nm after reaction, and plotting by taking the concentration of the copper ions as abscissa and the difference between the blank fluorescence intensity value and the fluorescence intensity value containing the copper ions as ordinate to obtain a linear regression equation to detect the concentration of the copper ions.

6. The method of claim 5, wherein the volume ratio of the copper ions, BPEI-CuNCs and the buffer solution is 1: 2: 16.

7. The method of claim 5, wherein the linear regression equation is y 1.3588x +10.744, R²The lowest detection limit of copper ions was 0.01 μmol/L, 0.9752.

Technical Field

The invention relates to the field of metal ion detection, in particular to a method for rapidly detecting copper ions based on a BPEI-CuNCs fluorescent probe.

Background

Copper (Copper) plays an important role in promoting the growth of animals and plants as a trace element necessary for the growth and development of animals, plants and human beings. The copper element is vital to human health, and has catalytic and auxiliary effects on a plurality of enzymes in the oxidation-reduction activity process of Cu (I)/Cu (II); it may also promote the generation of Reactive Oxygen Species (ROS), thereby interfering with the transduction of cell signals, disrupting cellular structures, and leading to apoptosis. High concentration of copper ions can also cause liver cirrhosis, vomiting, dyskinesia, and sensory nerve disorder, which affect the normal growth and development of organisms and may lead to death in severe cases. In addition, if copper accumulates in the neuronal cytoplasm for a long time, it causes dyskinesia and neurological disorders, and in severe cases, it causes diseases such as alzheimer's disease, parkinsonism and amyotrophic lateral sclerosis. Therefore, the detection of copper ions in a sample and the accurate determination of the content of the copper ions are of great significance for both environmental protection and human health.

The WHO of the world health organization specifies a maximum threshold value of 2mg/kg for copper content in drinking water and 1.0mg/L for EPA. The national sanitary standard for drinking water (GB5749-2006) also stipulates that the limit value of the copper content in the drinking water is 1.0mg/L

The detection methods of heavy metal copper ions are various, and in addition to the atomic absorption spectrophotometry specified by the environmental protection standard of the people's republic of china (HJ 486-. Thus, a simple, fast, highly selective, highly sensitive Cu is established²⁺Detection methods are necessary.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for rapidly detecting copper ions based on a BPEI-CuNCs fluorescent probe, which has the advantages of simple operation, high selectivity, high sensitivity, no need of depending on large-scale equipment and instruments, and no strict requirements on detection environment and time.

In order to achieve the purpose of the invention, the invention adopts the technical scheme that:

the method for rapidly detecting the copper ions based on the BPEI-CuNCs fluorescent probe comprises the following steps:

1) the branched polyethyleneimine BPEI reacts under the combined action of copper ions and ascorbic acid AA to generate BPEI-CuNCs with fluorescence;

2) and adding a sample to be detected into a buffer solution containing BPEI-CuNCs, and detecting the concentration of copper ions based on a BPEI-CuNCs fluorescent probe.

In the step 1), the BPEI-CuNCs are prepared by the following steps: mixing deionized water and BPEI uniformly, and then adding CuSO₄Placing the solution on an air constant temperature shaking table, and stirring for 10 min; and finally, adding AA, oscillating for two days at room temperature, and filtering to obtain a BPEI-CuNCs solution.

Further, the concentration of PEI in the BPEI-CuNCs solution is 0.36 mg/mL; CuSO₄The molar ratio to AA was 1: 1.

In step 2), the buffer solution is 0.03% CTAB-containing citrate buffer, the pH value of the buffer solution is 4, and the concentration of the buffer solution is 20 mmol/L.

The step 2) specifically comprises the following steps: adding copper ions with different concentrations into BPEI-CuNCs and 20mmol/L citrate buffer solution with pH4 containing 0.03% CTAB, mixing uniformly, detecting the fluorescence intensity with emission wavelength of 430nm at excitation wavelength of 360nm after reaction, and plotting by taking the concentration of the copper ions as abscissa and the difference between the blank fluorescence intensity value and the fluorescence intensity value containing the copper ions as ordinate to obtain a linear regression equation to detect the concentration of the copper ions.

Furthermore, the volume ratio of the copper ions, the BPEI-CuNCs and the buffer solution is 1: 2: 16.

Further, the linear regression equation is that y is 1.3588x +10.744, R²The lowest detection limit of copper ions was 0.01 μmol/L, 0.9752.

Has the advantages that: compared with the prior art, the invention has the following advantages:

1) the method has the advantages of simple operation, short time, sensitivity and convenience, no need of large-scale equipment and instruments, and no strict requirements on detection environment and time;

2) good specificity, good selectivity, and little interference to other metal ions, such as Al³⁺、Cd²⁺、Fe²⁺、Mg²⁺、Pb²⁺When the method is used for detecting the copper ions, the interference of other metal ions in the sample can be eliminated, and the result is more reliable;

3) the lowest detection limit of copper ions is 0.01 mu mol/L and is lower than the limit value of 1.0mg/L (about 15.74 mu mol/L) specified by the sanitary standard of drinking water (GB 5749-2006); the recovery rate of a copper ion labeling experiment reaches 96-99%, and the BPEI-CuNCs probe has accuracy and reliability in detecting ions in an actual sample and can be suitable for detecting Cu in life²⁺And (5) qualitatively and quantitatively detecting.

Drawings

FIG. 1 shows the detection of Cu by BPEI-CuNCs²⁺Working principle diagram of (1);

FIG. 2 is an electron micrograph of BPEI-CuNCs;

FIG. 3 is a fluorescence spectrum of BPEI-CuNCs; in the figure, A is a fluorescence spectrum obtained by diluting BPEI-CuNCs by 10 times; b is a fluorescence spectrum of BPEI-CuNCs (stock solution), and the set detection wavelength Em is 430nm and Ex is 360 nm;

FIG. 4 is a graph showing the relationship between the concentration of copper ions and the Δ fluorescence intensity;

FIG. 5 is a comparison graph of fluorescence intensity of BPEI-CuNCs detecting different heavy metal ions; in the figure, the concentrations of different heavy metal ions are all 50 mu mol/L;

FIG. 6 shows the recovery of each water sample in the copper ion labeling experiment; in the figure, the copper ion concentration of each water sample was 50. mu. mol/L.

Detailed Description

The present invention is further illustrated by the following specific examples, which are not intended to be limiting.