Nanoprobe for detecting 8-hydroxyquinoline without background interference and high sensitivity and preparation method thereof

Abstract

The application discloses a kind of nano-probes with no background interference, high sensitivity detects 8-hydroxyquinoline and preparation method thereof, it is related to analytical chemistry technical field, the nano-probe includes upconversion nanoparticle and diazonium salt, the diazonium salt is by p-aminobenzenesulfonic acid and sodium nitrite reaction and form.The application introduces diazonium salt as the specific recognition unit of 8-HQ, combines the green / red double-wavelength emission characteristics of UCNPs, constructs the ratio fluorescence detection system of near-infrared excitation, effectively eliminates environmental interference, avoids the risk of misjudgment of single signal detection;980nm near-infrared light is used as excitation light, combined with the upconversion luminescence characteristics of UCNPs, avoids the background fluorescence interference in complex matrix, realizes "no background" detection.

Description

Technical Field

[0001] The present invention relates to the technical field of analytical chemistry, and in particular to a nanoprobe for detecting 8-hydroxyquinoline with high sensitivity and without background interference, and a preparation method thereof. Background Art

[0002] 8-Hydroxyquinoline (8-HQ) is an important organic compound widely used in medicine, agriculture, and industry. It possesses excellent metal chelation and biological activity. However, long-term, low-dose exposure to 8-HQ may affect the nervous system and pose a threat to human health. Therefore, establishing accurate and efficient 8-HQ detection methods is crucial for safeguarding human health and environmental safety.

[0003] Currently, the main methods for detecting 8-HQ include chromatography, electrochemistry, and fluorescence. Although chromatography is highly accurate, the instrumentation is very expensive, the operation steps are cumbersome, and it is not suitable for on-site instant detection. Traditional fluorescence detection technology relies on excitation with short-wavelength light (such as ultraviolet light) and is susceptible to interference from natural fluorescent substances in the sample matrix, resulting in enhanced background signals. At the same time, the high energy of short-wavelength excitation light may induce photodegradation of target molecules, resulting in slow detection speed and poor reproducibility. Although there are existing 8-HQ detection schemes based on spectrophotometry, this method suffers from problems such as insufficient selectivity and low sensitivity, making it difficult to meet the detection needs of trace amounts of 8-HQ in complex samples. Therefore, the development of an 8-HQ detection technology that combines high sensitivity, anti-interference ability, and rapid response is urgent. Summary of the Invention

[0004] In order to solve the problems of large background interference, low sensitivity, slow detection speed and so on in the existing detection methods, the present invention provides a nanoprobe for 8-HQ detection and a preparation method thereof, which realizes high-sensitivity, anti-interference and rapid fluorescence detection of 8-HQ.

[0005] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0006] One of the purposes of the present invention is to provide an application of a nanoprobe in 8-HQ detection, wherein the nanoprobe comprises upconversion nanoparticles (UCNPs) and a diazonium salt.

[0007] Furthermore, the diazonium salt is formed by reacting p-aminobenzenesulfonic acid with sodium nitrite. Preferably, the molar ratio of p-aminobenzenesulfonic acid to sodium nitrite is 1:(3-3.2).

[0008] Furthermore, the UCNPs are NaYF4:Yb,Er@NaYF4 upconversion nanoparticles with a core-shell structure.

[0009] A second object of the present invention is to provide a method for preparing the nanoprobe, comprising the following steps:

[0010] (1) NaYF4:Yb,Er upconversion nanoparticles were prepared by solvothermal reaction of yttrium source, ytterbium source, erbium source, sodium source, fluorine source and ligand;

[0011] (2) NaYF4:Yb,Er upconversion nanoparticles, yttrium source, sodium source, fluorine source and ligand were reacted by solvothermal reaction to prepare NaYF4:Yb,Er@NaYF4 upconversion nanoparticles with core-shell structure;

[0012] (3) Surface modification of NaYF4:Yb,Er@NaYF4 upconversion nanoparticles to obtain hydrophilic UCNPs;

[0013] (4) The hydrophilic UCNPs, p-aminobenzenesulfonic acid and sodium nitrite were mixed evenly to obtain a nanoprobe.

[0014] Furthermore, the yttrium source includes but is not limited to at least one of yttrium chloride, yttrium sulfate, yttrium nitrate, yttrium acetate and hydrates thereof.

[0015] Furthermore, the ytterbium source includes but is not limited to at least one of ytterbium chloride, ytterbium sulfate, ytterbium nitrate, ytterbium acetate and hydrates thereof.

[0016] Furthermore, the erbium source includes but is not limited to at least one of erbium chloride, erbium sulfate, erbium nitrate, erbium acetate and hydrates thereof.

[0017] Furthermore, the sodium source is sodium hydroxide (NaOH), which provides both a sodium source and an alkaline environment.

[0018] Furthermore, the fluoride source includes but is not limited to at least one of ammonium fluoride, sodium fluoride, and potassium fluoride.

[0019] Furthermore, the ligand includes but is not limited to at least one of oleic acid and oleylamine. The ligand can also serve as a solvent.

[0020] Furthermore, the solvent includes but is not limited to at least one of 1-octadecene and cyclohexane.

[0021] Furthermore, the temperature of the solvent thermal reaction is 100-300° C., and the time is 30-60 min.

[0022] Furthermore, the solvent thermal reaction is carried out in an inert atmosphere (such as argon) to prevent oxidation and reduce impurity generation.

[0023] Furthermore, the surface modification includes acid treatment to remove ligands and surface modification with hydrophilic molecules. Preferably, the acid treatment uses dilute hydrochloric acid with a pH of 0.8 to 1.2; the hydrophilic molecules include but are not limited to at least one of polyacrylic acid (PAA) and polyethylene glycol (PEG).

[0024] The nanoprobe described in the present invention can be applied to the detection of 8-HQ in samples. Its applicability in complex matrices is verified by the standard addition method, enabling rapid quantitative detection of 8-HQ and providing a detection tool for industrial production compliance testing and chemical safety management.

[0025] Furthermore, the nanoprobe detects 8-HQ using a colorimetric reaction between a diazonium salt and 8-HQ under alkaline conditions. Preferably, the alkaline conditions are provided by at least one of sodium hydroxide (NaOH) and potassium hydroxide (KOH).

[0026] Furthermore, the 8-HQ detection is performed by fluorescence detection within the excitation wavelength range of 980 nm and the emission wavelength range of 500-700 nm; and colorimetric analysis is performed within the absorption wavelength range of 400-700 nm.

[0027] In the present invention, the UCNPs emit green (540 nm) and red (655 nm) upconversion luminescence (UCL) under 980 nm near-infrared light excitation. Under alkaline conditions, the diazonium salt undergoes a specific color development reaction (≤10 s) with 8-HQ to generate a red azo compound, which selectively quenches the green UCL through the inner filter effect (IFE), while the red UCL remains stable, forming a ratio detection signal.

[0028] The beneficial effects of the present invention are:

[0029] 1. The present invention introduces diazonium salt as the specific recognition unit of 8-HQ and combines it with the green / red dual-wavelength emission characteristics of UCNPs to construct a near-infrared excited ratio fluorescence detection system, which effectively eliminates environmental interference and avoids the risk of misjudgment in single signal detection.

[0030] 2. The present invention uses 980nm near-infrared light as the excitation light, combined with the up-conversion luminescence characteristics of UCNPs, to avoid background fluorescence interference in complex matrices and achieve "background-free" detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1Low-resolution TEM image of NaYF4:Yb,Er upconversion nanoparticles prepared in Example 1 of the present invention (A); low-resolution TEM image of NaYF4:Yb,Er@NaYF4 upconversion nanoparticles (B); high-resolution TEM image of NaYF4:Yb,Er@NaYF4 upconversion nanoparticles (C); XRD patterns of NaYF4:Yb,Er upconversion nanoparticles and NaYF4:Yb,Er@NaYF4 upconversion nanoparticles (D);

[0032] Figure 2 Schematic diagram of the principle of using the nanoprobe of the present invention for 8-HQ detection;

[0033] Figure 3 The luminescence mechanism diagram (A), UV-visible absorption spectrum and UCL spectrum (B), and luminescence kinetic curve (C) of the nanoprobe described in the present invention are shown;

[0034] Figure 4 The effect of different concentrations of 8-HQ on the UCL spectrum of the nanoprobe (A); I 540 / I 655 Linear fitting curve with 8-HQ concentration (B);

[0035] Figure 5 is the I of the nanoprobe in the presence of interfering substances 540 / I 655 UCL image (A) and UCL spectrum (B); 1-blank, 2-8-HQ, 3-glycine, 4-glucose, 5-oxalic acid, 6-Na + ,7-Cd 2+ , 8-K + ,9-Ca 2+ ,10-Fe 3+ , 11-Mg 2+ , 12-Cl - . DETAILED DESCRIPTION

[0036] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below with reference to specific embodiments and illustrations.

[0037] In the following examples, sodium nitrite, p-aminobenzenesulfonic acid, NaOH and interfering substances were prepared into solutions using deionized water; 8-HQ was prepared into a solution using a NaOH aqueous solution with a concentration of 20 μmol / L.

[0038] Example 1

[0039] The preparation methods of UCNPs and hydrophilic UCNPs solutions refer to Example 1 of patent CN119269488B "Reversible background hydrogel nanosensor and intelligent sensing platform for acetone detection".

[0040] Preparation of nanoprobes: 50 μL of sodium nitrite solution (25 mM), 10 μL of p-aminobenzenesulfonic acid solution (40 mM), 200 μL of the above-mentioned hydrophilic UCNPs solution (10 mg / mL) and 1540 μL of deionized water were mixed by ultrasonication to obtain a nanoprobe solution.

[0041] Examples 2-4

[0042] Nanoprobe solutions were prepared according to the method of Example 1, except that the concentrations of the sodium nitrite solution were adjusted to 50, 75, and 100 mM, respectively. 100 μL of 8-HQ solution (50 μM) and 100 μL of NaOH solution (200 mM) were added to the prepared nanoprobe solution, mixed thoroughly, and after waiting for 10 seconds, the absorbance spectrum of the mixed solution was recorded in the range of 400–700 nm using a Shimadzu UV-2550 spectrophotometer. The results showed that the absorbance spectrum did not change significantly when the sodium nitrite concentration ranged from 25 to 100 mM. To avoid the effect of high ionic strength on the luminescence intensity, 50 mM was selected as the optimal sodium nitrite concentration.

[0043] Example 5

[0044] To the nanoprobe solution prepared in Example 1, 100 μL of 50 μM 8-HQ solution and 100 μL of NaOH solutions of varying concentrations (0, 100, 200, 300, 400, and 500 mM) were added and mixed. After 10 seconds, the absorbance spectrum was recorded from 400 to 700 nm using a Shimadzu UV-2550 spectrophotometer. The results showed that within the NaOH concentration range of 0 to 500 mM, the maximum absorbance at 490 nm initially increased and then decreased, reaching its peak at 200 mM. Therefore, 200 mM was selected as the optimal NaOH concentration.

[0045] Example 6

[0046] 100 μL of 8-HQ solution (50 μM) and 100 μL of NaOH solution (200 mM) were added to the nanoprobe solution prepared in Example 1, mixed, and after waiting for 10 seconds, the UCL spectrum in the range of 500-700 nm was recorded using a Fluorolog-3 fluorescence spectrometer under 980 nm laser excitation, and the luminescence intensity was recorded at the same interval; the absorbance spectrum in the range of 400-700 nm was recorded using a Shimadzu UV-2550 spectrophotometer. The results showed that compared with the nanoprobe solution without the addition of 8-HQ, the green UCL at 540 nm of the nanoprobe solution after the addition of 8-HQ decreased significantly, while the red UCL at 655 nm remained unchanged; the nanoprobe solution did not have absorbance in the range of 400-700 nm, while the nanoprobe solution after the addition of 8-HQ produced an absorption peak at 490 nm, which overlapped with the UCL emission peak at 540 nm ( Figure 3 B). Luminescence intensity of the nanoprobe solution after adding 8-HQ 540 / I 655 It is rapidly quenched within 1 second and reaches stability, proving that the reaction kinetics are ultrafast and suitable for on-site instant detection ( Figure 3 C).

[0047] Example 7

[0048] To the nanoprobe solution prepared in Example 1, 100 μL of 8-HQ solution of different concentrations was added, followed by 100 μL of NaOH solution (10 mM), mixed, and then the fluorescence spectrum in the range of 500-700 nm was recorded using a fluorescence spectrometer under 980 nm laser excitation after 10 seconds. The results showed that as the 8-HQ concentration increased, the green fluorescence intensity at 540 nm gradually decreased, while the red fluorescence at 655 nm remained stable, and the fluorescence color changed from green to red ( Figure 4 A). I 540 / I 655 There was a good linear relationship between the concentration of 8-HQ and the concentration of 8-HQ in the range of 0~50μM (correlation coefficient R 2 =0.989, Figure 4 B), the detection limit of the luminescence mode was calculated to be 68 nM according to the formula LOD = 3δ / S (LOD is the limit of detection, δ is the standard deviation of 10 blank experiments, and S is the slope).

[0049] Example 8

[0050] 100 μL of 8-HQ solution (50 μM) or interfering substance solution (250 μM, interfering substances are glycine, glucose, oxalic acid, Na + , Cd 2+ , K + , Ca 2+ , Fe3+ , Mg 2+ , Cl - ), then add 100 μL of NaOH aqueous solution (200 mM), mix well, wait for 10 s, and use a Fluorolog-3 fluorescence spectrometer to record the UCL spectrum in the range of 500~700 nm under 980 nm laser excitation to evaluate the selective response of the nanoprobe to 8-HQ.

[0051] 100 μL of a mixed solution containing 8-HQ (50 μM) and interfering substances (250 μM) (the interfering substances were glycine, glucose, oxalic acid, and Na + , Cd 2+ , K + , Ca 2+ , Fe 3+ , Mg 2+ , Cl - ), mix well, then add 100 μL of NaOH aqueous solution (200 mM), mix well, wait for 10 s, and use a Fluorolog-3 fluorescence spectrometer to record the UCL spectrum in the range of 500~700 nm under 980 nm laser excitation to evaluate the anti-interference ability of the nanoprobe in detecting 8-HQ.

[0052] The luminescence intensity when the interfering substance is added alone is I 540 / I 655 As a selectivity test indicator (red), the luminescence intensity ratio when 8-HQ and interference are added simultaneously is I 540 / I 655 As the anti-interference test indicator (blue). The results show that when the interference is added alone, I 540 / I 655 There was no significant change, and the nanoprobe solution maintained a stable green luminescence ( Figure 5 A). When 8-HQ and interfering substances are added simultaneously, I 540 / I 655 The green UCL was significantly reduced, while the red UCL remained stable ( Figure 5 B). Even in the presence of 5-fold higher concentrations of interfering compounds, 8-HQ still triggered a significant signal change, without causing false positive responses. This demonstrates the probe's high specificity for 8-HQ and its ability to effectively exclude interference from common components in complex matrices.

[0053] Example 9

[0054] A commercially available hair conditioner sample was diluted 10-fold with deionized water. 8-HQ solutions at concentrations of 0, 15, 30, and 45 μM were added using the standard addition method to prepare sample solutions. 100 μL of the sample solution was then added to the nanoprobe solution prepared in Example 1 and 100 μL of a 200 mM aqueous NaOH solution. The mixture was mixed thoroughly and the 8-HQ concentration was analyzed using a Fluorolog-3 fluorescence spectrometer after 10 seconds. The results are shown in Table 1.

[0055] Table 1

[0056]

[0057] As shown in Table 1, the recovery rates measured by fluorescence spectrometer are 97.47-102.93% (relative standard error ≤ 2.34%), indicating that the nanoprobe provided by the present invention has good accuracy and reliability for detecting 8-HQ in actual samples.

[0058] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. Application of a nanoprobe in the detection of 8-HQ, the nanoprobe comprising hydrophilic UCNPs and a diazonium salt; The diazonium salt is formed by the reaction of p-aminobenzenesulfonic acid and sodium nitrite; The UCNPs are NaYF4:Yb,Er@NaYF4 upconversion nanoparticles with a core-shell structure.

2. The use according to claim 1, characterized in that The preparation method of the nanoprobe comprises the following steps: (1) NaYF4:Yb,Er upconversion nanoparticles were prepared by solvothermal reaction of yttrium source, ytterbium source, erbium source, sodium source, fluorine source and ligand; (2) NaYF4:Yb,Er upconversion nanoparticles, yttrium source, sodium source, fluorine source and ligand were reacted by solvothermal reaction to prepare NaYF4:Yb,Er@NaYF4 upconversion nanoparticles with core-shell structure; (3) Surface modification of NaYF4:Yb,Er@NaYF4 upconversion nanoparticles to obtain hydrophilic UCNPs; (4) The hydrophilic UCNPs, p-aminobenzenesulfonic acid, and sodium nitrite were mixed evenly to obtain the nanoprobe.

3. The use according to claim 2, characterized in that: The yttrium source is at least one of yttrium chloride, yttrium sulfate, yttrium nitrate, yttrium acetate and hydrates thereof; The ytterbium source is at least one of ytterbium chloride, ytterbium sulfate, ytterbium nitrate, ytterbium acetate and hydrates thereof; The erbium source is at least one of erbium chloride, erbium sulfate, erbium nitrate, erbium acetate and hydrates thereof; The sodium source is sodium hydroxide; The fluoride source is at least one of ammonium fluoride, sodium fluoride and potassium fluoride; The ligand is at least one of oleic acid and oleylamine; The solvent is selected from at least one of 1-octadecene and cyclohexane.

4. The use according to claim 2, characterized in that: The solvothermal reaction temperature is 100-300°C and the time is 30-60 min; The solvothermal reaction is carried out in an inert atmosphere.

5. The use according to claim 2, characterized in that: The surface modification includes acid treatment to remove ligands and surface modification with hydrophilic molecules; The acid treatment uses dilute hydrochloric acid with a pH value of 0.8 to 1.2; The hydrophilic molecule is selected from at least one of polyacrylic acid and polyethylene glycol.

6. The use according to claim 1, characterized in that: The nanoprobe detects 8-HQ using a colorimetric reaction between diazonium salt and 8-HQ under alkaline conditions; The alkaline condition is provided by at least one of sodium hydroxide and potassium hydroxide.

7. The use according to claim 1, characterized in that: The 8-HQ detection is performed by fluorescence detection at an excitation wavelength of 980 nm and an emission wavelength of 500-700 nm; and colorimetric analysis is performed at an absorption wavelength of 400-700 nm.

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