Preparation method of a ratio type fluorescent probe and application thereof in detection of bromohexadecyl pyridine

Abstract

The application discloses a preparation method of a ratio type fluorescent probe and application of the ratio type fluorescent probe in detection of bromohexadecylpyridine, and first, sulfur quantum dots SQDS@beta-CD are prepared by taking thiourea as a sulfur source, beta-cyclodextrin as a protective agent and hydrogen peroxide as an oxidant; then, the ratio type fluorescent probe EY-SQDS@beta-CD is prepared by taking the sulfur quantum dots and eosin Y as design materials. The ratio type probe has two emission peaks at 412 nm and 548 nm, and bromohexadecylpyridine can reduce the emission peak fluorescence intensity at 548 nm, while the emission peak fluorescence intensity at 412 nm is basically unchanged. Meanwhile, the application constructs a new method for detecting bromohexadecylpyridine based on the ratio type fluorescent probe. The ratio type fluorescent probe developed by the application can effectively overcome the interference of instruments and environment and the like on the determination of bromohexadecylpyridine, and further improve the reliability of the determination result.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of fluorescent probes and fluorescent detection technology, and particularly relates to a preparation method of a ratio-type fluorescent probe and application of the ratio-type fluorescent probe in detection of CPB. BACKGROUND

[0002] Cationic surfactants are widely used in daily chemical industry, industrial detergents and other fields, and the application process often causes water pollution. The cationic surfactants in water samples are mainly determined by titration analysis, electrochemistry, high performance liquid chromatography and other methods. However, these methods often need pretreatment such as extraction, and have low sensitivity. Therefore, it is urgent to develop a simple, rapid and high-sensitivity detection method for determining cationic surfactants in water samples.

[0003] Cetylpyridinium bromide (CPB) is a cationic surfactant with a quaternary ammonium salt structure, which is widely used in chemical industry, food and medicine fields, and is often detected in environmental water samples. Research on the determination method of cetylpyridinium bromide will effectively promote the development of production and environmental protection. The application designs and develops a ratio-type fluorescent probe for detecting cetylpyridinium bromide, which can realize simple, rapid and high-sensitivity determination of cetylpyridinium bromide in environmental water samples. However, there is no relevant report in this regard at present. SUMMARY

[0004] The technical problem solved by the application is to provide a preparation method of a ratio-type fluorescent probe. The method prepares a ratio-type fluorescent probe EY-SQDS@beta-CD based on sulfur quantum dots SQDS@beta-CD and eosin Y (EY), and the prepared ratio-type fluorescent probe can realize simple, rapid and high-sensitivity determination of cetylpyridinium bromide in environmental water samples.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for preparing a ratiometric fluorescent probe, characterized by the following specific steps: 1.50 mL of 0.20 mol / L thiourea, 14.50 mL of water, and 0.25 g of β-cyclodextrin (β-CD) are sequentially added to a reaction vessel at room temperature and stirred until homogeneous. Then, 4.0 mL of 3 wt% hydrogen peroxide solution is added dropwise, and the mixture is stirred at 130 °C for 4 h to obtain pale yellow sulfur quantum dots SQDS@β-CD. 0.80 mL of sulfur quantum dots SQDS@β-CD and 0.70 mL of 0.1 g of β-cyclodextrin are then taken. mmol / L Eosin Y was placed in 0.50 mL of BR buffer solution at pH 7.0 and reacted at 25 °C for 30 minutes to obtain the ratiometric fluorescent probe EY-SQDS@β-CD. The fluorescence characteristics of the ratiometric fluorescent probe EY-SQDS@β-CD are as follows: when the excitation wavelength is 325 nm, there are two emission peaks at 412 nm and 548 nm. Hexadecyl bromopyridine can reduce the fluorescence intensity of the emission peak at 548 nm, while the fluorescence intensity of the emission peak at 412 nm remains basically unchanged.

[0006] The application of the ratiometric fluorescent probe of the present invention in the detection of hexadecylpyridine bromide is characterized by the following specific steps:

[0007] Step S1, plotting the standard curve: Mix 0.80 mL of sulfur quantum dots SQDS@β-CD, 0.70 mL of 0.1 mmol / L eosin Y, and 0.50 mL of BR buffer solution at pH 7.0 thoroughly. Add a series of bromohexadecylpyridine standard solutions of different concentrations, bring the volume to 4.00 mL, mix well, and react at 25 °C for 30 min. Measure the fluorescence intensity at 412 nm and 548 nm at an excitation wavelength of 325 nm, and calculate the fluorescence intensity ratio I. 412 / I 548 The concentration of hexadecyl bromopyridine is C CPB In the range of 0-60μM, with I 412 / I 548 The linear relationship is well observed, and the linear regression equation is: I 412 / I 548 =0.05426C CPB +0.48825, R 2 =0.9821, the detection limit was 0.30 μM, and 15 parallel determinations were performed on the detection systems of 10 μM and 50 μM bromohexadecylpyridine, with RSDs of 1.68% and 3.75%, respectively.

[0008] Step S2, Detection of hexadecylpyridine bromide in environmental water sample: Mix 0.80 mL of sulfur quantum dot SQDS@β-CD, 0.70 mL of 0.1 mmol / L eosin Y, and 0.50 mL of BR buffer solution at pH 7.0 thoroughly. Add a certain volume of environmental water sample, bring the volume to 4.00 mL, mix well, and react at 25℃ for 30 min. Measure the fluorescence intensity at 412 nm and 548 nm under an excitation wavelength of 325 nm, and calculate the fluorescence intensity ratio I. 412 / I 548 The calculated fluorescence intensity ratio is substituted into the linear regression equation obtained in step S1 to calculate the concentration of hexadecyl pyridine bromide in the environmental water sample.

[0009] Furthermore, the ratiometric fluorescent probe EY-SQDS@β-CD, used in the determination system of hexadecylpyridine bromide, possesses the unique characteristics of highly selective recognition of hexadecylpyridine bromide and strong anti-interference ability. The detection system formed by this ratiometric fluorescent probe EY-SQDS@β-CD is effective against high concentrations of Al. 3+ Fe 3+ Only then can it exhibit a significant response, and can eliminate Fe by adding sodium fluoride to the water sample to be tested. 3+ Al 3+ Interference.

[0010] Furthermore, both hexadecyl bromide and hexadecyl chloropyridine are cationic surfactants with quaternary ammonium salt structures and the same cationic structure and properties. The ratiometric fluorescent probe EY-SQDS@β-CD has essentially the same fluorescence characteristics for both hexadecyl chloropyridine and hexadecyl bromide, and can also be used for the fluorescence detection of hexadecyl chloropyridine.

[0011] Compared with fluorescent probes based on single fluorescence emission, the ratiometric fluorescent probe developed in this invention can effectively overcome the interference of instrument and environmental factors on the determination of hexadecylpyridine bromide, and further improve the reliability of the determination results. Attached Figure Description

[0012] Figure 1 To assess the feasibility of synthesizing sulfur quantum dots.

[0013] Figure 2 To assess the feasibility of synthesizing ratiometric fluorescent probes.

[0014] Figure 3 The fluorescence intensity corresponds to different concentrations of hexadecylpyridine bromide standard solutions.

[0015] Figure 4 shows the selectivity and anti-interference performance of the ratiometric fluorescent probe assay method. Detailed Implementation

[0016] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0017] Example

[0018] Figure 1 To investigate the feasibility of synthesizing sulfur quantum dots, the optimal conditions for synthesizing sulfur quantum dots were as follows: 1.50 mL of thiourea (0.20 mol / L), 14.50 mL of water, and 0.25 g of β-cyclodextrin (β-CD) were sequentially added to a round-bottom flask at room temperature and stirred for 5 min. Then, 4.0 mL of hydrogen peroxide solution (3 wt%) was added dropwise, and the reaction was carried out at 130 °C with stirring for 4 h to obtain pale yellow sulfur quantum dots, i.e., SQDS@β-CD. Under the optimal experimental conditions, while keeping the reaction temperature, time, and reaction system volume constant, the possibility of synthesizing sulfur quantum dots under different combinations of thiourea, β-cyclodextrin, thiourea + hydrogen peroxide, β-cyclodextrin + hydrogen peroxide, thiourea + β-cyclodextrin, and thiourea + β-cyclodextrin + hydrogen peroxide was investigated. Figure 1 As shown, sulfur quantum dots SQDS@β-CD can only be successfully synthesized under the condition that thiourea, hydrogen peroxide and β-cyclodextrin coexist.

[0019] Figure 2 To assess the feasibility of synthesizing a ratiometric fluorescent probe, the optimal conditions for synthesizing the ratiometric fluorescent probe EY-SQDS@β-CD were as follows: 0.80 mL of sulfur quantum dots SQDs@β-CD, 0.70 mL of 0.1 mmol / L eosin Y, and 0.50 mL of BR buffer solution (pH = 7.0) were added, and the volume was adjusted to 4.00 mL. The reaction was carried out at 25 °C for 30 min to obtain the ratiometric fluorescent probe, EY-SQDS@β-CD. Under these optimal experimental conditions, while maintaining the type and volume of the buffer solution, reaction temperature, time, and reaction system volume, the indispensability of sulfur quantum dots SQDs@β-CD and eosin Y in the synthesis of the ratiometric fluorescent probe EY-SQDS@β-CD was investigated. Figure 2 As shown, the ratiometric fluorescent probe EY-SQDS@β-CD can only be successfully synthesized under the condition that sulfur quantum dots SQDs@β-CD and eosin Y coexist.

[0020] Figure 3The fluorescence intensity corresponds to different concentrations of hexadecylpyridine bromide standard solutions. 0.80 mL of sulfur quantum dots SQDS@β-CD, 0.70 mL of 0.1 mmol / L eosin Y, and 0.50 mL of BR buffer solution (pH = 7.0) were mixed thoroughly. A series of hexadecylpyridine bromide standard solutions of different concentrations were added, and the volume was adjusted to 4.00 mL. The mixture was then incubated at 25 °C for 30 min. The fluorescence intensity at 412 nm and 548 nm was measured at an excitation wavelength of 325 nm, and the fluorescence intensity ratio I was calculated. 412 / I 548 Concentration of hexadecyl bromide pyridine (C CPB ) in the range of 0-60μM with I 412 / I 548 The linear relationship is well observed, and the linear regression equation is: I 412 / I 548 =0.05426C CPB +0.48825, R 2 =0.9821, the detection limit was 0.30 μM. The parallel determination of the detection system with 10 μM and 50 μM bromide was performed 15 times, and the RSDs were 1.68% and 3.75%, respectively.

[0021] Figure 4 shows the selectivity and anti-interference performance of the ratiometric fluorescent probe assay. 0.80 mL of sulfur quantum dots SQDS@β-CD, 0.70 mL of 0.1 mmol / L eosin Y, and 0.50 mL of BR buffer solution (pH = 7.0) were mixed thoroughly. Then, hexadecylpyridine bromide or the interfering substance was added, and the volume was adjusted to 4.00 mL. The mixture was stirred and reacted at 25 °C for 30 min. The fluorescence intensity at 412 nm and 548 nm was measured at an excitation wavelength of 325 nm, and the fluorescence intensity ratio I was calculated. 412 / I 548 The CPB concentration was 30 μM, and Na+ was a common ion in the environmental water sample. + Mg + K + Ba 2+ Ca 2+ F - ,Br - NO3 - NO2 - Cl - I - The concentration is 100 μM, Cd 2+ Pb 2+ Cu 2+ Sn 2 + Co 2+ Hg 2+ Zn 2+Ni 2+ Mn 2+ Fe 3+ Al 3+ The concentrations of hexadecylpyridine chloride (CPC), hexadecyltrimethylammonium bromide (CTMAB), tetradecyltrimethylammonium bromide (TTMAB), sodium dodecyl sulfonate (SBS), sodium dodecyl sulfate (SDS), and dodecylbenzenesulfonic acid (SDBS) were all 30 μM, as shown in Figures 4(A), 4(B), and 4(C). The detection system based on the ratiometric fluorescent probe EY-SQDS@β-CD exhibits unique characteristics of high selectivity in recognizing CPB and strong anti-interference capabilities. 3+ And Al 3+ Ions significantly affect the determination, but this can be masked and eliminated by adding sodium fluoride to the environmental water sample. Both hexadecyl chloride and hexadecyl bromide are cationic surfactants with quaternary ammonium salt structures; their cationic structures and properties are identical, differing only in their anions. Therefore, the ratiometric fluorescent probe EY-SQDS@β-CD exhibits essentially the same fluorescence characteristics for both hexadecyl chloride and hexadecyl bromide, and thus this ratiometric fluorescent probe EY-SQDS@β-CD method can also be used for the fluorescence detection of hexadecyl chloride.

[0022] Application of the test method in environmental water samples:

[0023] Water samples were collected from tap water (sample 1), groundwater (sample 2), river water (sample 3), and lake water (sample 4), and filtered before use. 0.80 mL of sulfur quantum dots SQDS@β-CD, 0.70 mL of 0.1 mmol / L eosin Y, and 0.50 mL of BR buffer solution (pH = 7.0) were mixed thoroughly. A certain volume of the environmental water sample to be tested was added, and the volume was adjusted to 4.00 mL. The mixture was then incubated at 25°C for 30 min. The fluorescence intensity at 412 nm and 548 nm was measured at an excitation wavelength of 325 nm, and the fluorescence intensity ratio I was calculated. 412 / I 548 The calculated fluorescence intensity ratio was substituted into the linear regression equation to calculate the concentration of hexadecylpyridine bromide in the environmental water samples. Hexadecylpyridine bromide was not detected in any of the environmental water samples. Further spiked recovery experiments were conducted, with 10 μM, 30 μM, and 50 μM of hexadecylpyridine added, and the results are shown in Table 1. The recoveries ranged from 95.1% to 100.4%, and the RSDs ranged from 0.13% to 3.03%. This indicates that the ratiometric fluorescent probe EY-SQDS@β-CD provided by this invention can be successfully applied to the determination of hexadecylpyridine bromide in environmental water samples.

[0024] Table 1. Measurement of actual environmental water samples

[0025]

[0026] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. The application of a ratiometric fluorescent probe in the detection of hexadecylpyridine bromide, characterized in that... The specific steps are as follows: Step S1, plotting the standard curve: Mix 0.80 mL of sulfur quantum dots SQDS@β-CD, 0.70 mL of 0.1 mmol / L eosin Y, and 0.50 mL of BR buffer solution at pH 7.0 thoroughly. Add a series of standard solutions of hexadecylpyridine bromide at different concentrations, bring the volume to 4.00 mL, mix well, and react at 25 °C for 30 min. Measure the fluorescence intensity at 412 nm and 548 nm at an excitation wavelength of 325 nm, and calculate the fluorescence intensity ratio I. 412 / I 548 The concentration of hexadecyl bromopyridine is C CPB In the range of 0-60 µM, with I 412 / I 548 The linear relationship is well observed, and the linear regression equation is: I 412 / I 548 = 0.05426C CPB +0.48825, R 2 =0.9821, the limit of detection was 0.30 µM. Fifteen parallel determinations were performed on the detection systems of 10 µM and 50 µM brominated hexadecylpyridine, with RSDs of 1.68% and 3.75%, respectively. Step S2, Detection of hexadecylpyridine bromide in environmental water sample: Mix 0.80 mL of sulfur quantum dots SQDS@β-CD, 0.70 mL of 0.1 mmol / L eosin Y, and 0.50 mL of BR buffer solution at pH=7.0 thoroughly. Add a certain volume of environmental water sample, bring the volume to 4.00 mL, mix well, and react at 25℃ for 30 min. Measure the fluorescence intensity at 412 nm and 548 nm at an excitation wavelength of 325 nm, and calculate the fluorescence intensity ratio I. 412 / I 548 Substitute the calculated fluorescence intensity ratio into the linear regression equation obtained in step S1 to calculate the concentration of hexadecylpyridine bromide in the environmental water sample. The detection system formed by the ratiometric fluorescent probe is effective against high concentrations of Al. 3+ Fe 3+ It exhibits a significant response, and Fe is eliminated by masking with sodium fluoride added to the water sample being tested. 3+ Al 3+ Interference; The specific preparation steps of the ratiometric fluorescent probe are as follows: At room temperature, 1.50 mL of 0.20 mol / L thiourea, 14.50 mL of water, and 0.25 g of β-cyclodextrin are sequentially added to a reaction vessel and stirred until homogeneous. Then, 4.0 mL of 3wt% hydrogen peroxide solution is added dropwise, and the mixture is stirred at 130℃ for 4 h to obtain pale yellow sulfur quantum dots SQDS@β-CD. 0.80 mL of sulfur quantum dots SQDS@β-CD and 0.70 mL of 0.1 mmol / L eosin Y are placed in 0.50 mL of pH=7.0 BR buffer solution and reacted at 25℃ for 30 minutes to obtain the ratiometric fluorescent probe EY-SQDS@β-CD. The fluorescence characteristics of this ratiometric fluorescent probe EY-SQDS@β-CD are: when the excitation wavelength is 325 nm, there are two emission peaks at 412 nm and 548 nm. Hexadecyl bromopyridine can reduce the fluorescence intensity of the emission peak at 548 nm, while the emission peak at 412 nm... The fluorescence intensity of the emission peak at nm remains essentially unchanged.

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