Background-free fluorescence-colorimetry dual-modal hydrogel and portable sensing platform for promethazine detection

Abstract

The invention discloses a background-free fluorescence-colorimetric dual-modal hydrogel for promethazine detection and a portable sensing platform, and relates to the technical field of drug safety and environmental hazard detection. The fluorescence-colorimetric dual-modal hydrogel consists of a hydrogel matrix and nanoprobes, and the nanoprobes include UCNPs and bromate. The invention embeds the nanoprobes containing UCNPs and bromate into a PAM hydrogel matrix, and the red product generated by the oxidation reaction of PMZ and bromate quenches the green up-conversion luminescence of UCNPs, while the red emission remains unchanged, thereby realizing the fluorescence and colorimetric dual-mode detection of PMZ. In addition, the PAM hydrogel matrix provides a liquid detection environment and a high loading capacity of the nanoprobes. The near-infrared light excitation characteristics of UCNPs eliminate the interference of background fluorescence.

Description

Technical Field

[0001] The present invention relates to the technical field of drug safety and environmental hazard detection, and in particular to a background-free fluorescence-colorimetric dual-modal hydrogel and a portable sensing platform for promethazine detection. Background Art

[0002] Promethazine (PMZ) is a phenothiazine compound that is widely used in antihistamine therapy. In allergic reactions, histamine acts as a neurotransmitter and affects human activities. PMZ treats allergic reactions by competitively inhibiting the binding of histamine to H1 receptors, effectively blocking the action of histamine. However, excessive use of PMZ may induce anticholinergic syndrome. At the same time, PMZ is mainly used to enhance the hypnotic, anesthetic and sedative effects of animals. Adding PMZ can indirectly promote animal growth. When transporting animals over long distances, PMZ can relieve stress reactions, maintain body weight and reduce mortality. However, excessive use can cause PMZ to remain in edible tissues, posing a potential hazard to human health and animal production. Therefore, there is an urgent need to detect PMZ to protect human health and food safety.

[0003] Currently, a variety of methods have been developed to detect PMZ, including electrochemical methods, high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), spectrophotometry, and fluorescence analysis. Due to the advantages of low cost, simple operation, and visualization, fluorescent paper sensors combined with smartphones and 3D printing technology provide a novel, portable, and field-usable sensing platform for PMZ detection. However, fixing fluorescent probes on paper substrates often enhances the non-radiative relaxation of probes in the solid phase, resulting in reduced detection signals and sensitivity. In addition, the low loading capacity of fluorescent probes and the background fluorescence problem of paper substrates are also challenges that need to be addressed in the application of portable PMZ sensing.

[0004] Compared with paper substrates, hydrogels are ideal matrices for fluorescent probes due to their high optical transparency, adjustable size, high loading capacity, and stable 3D network structure. However, most existing fluorescent hydrogels rely on short-wave excitation, which can easily lead to background fluorescence and affect detection accuracy. In recent years, luminescent probes based on upconversion nanoparticles (UCNPs) have shown great potential in the fields of drug analysis and environmental monitoring. Their unique advantage is that they can effectively avoid background fluorescence interference by converting low-energy excitation light into high-energy emission light. In addition, the adjustable emission wavelength not only improves detection accuracy, but also meets diverse detection needs. Therefore, designing portable hydrogel nanosensors based on UCNPs is considered to be an ideal method for detecting PMZ. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a background-free fluorescence-colorimetric dual-modal hydrogel for promethazine detection, and to construct a portable sensing platform based on the fluorescence-colorimetric dual-modal hydrogel. The present invention embeds a nanoprobe containing UCNPs and bromate into a polyacrylamide (PAM) hydrogel matrix. The red product generated by the oxidation reaction of PMZ and bromate quenches the green upconversion luminescence (UCL) of UCNPs, while the red emission remains unchanged, thereby realizing the fluorescence and colorimetric dual-mode detection of PMZ. Among them, the fluorescence detection mode provides a sensitive quantitative method for PMZ, and the colorimetric detection mode provides an intuitive semi-quantitative method. In addition, the PAM hydrogel matrix provides a liquid detection environment and a high loading capacity of the nanoprobe. The near-infrared (NIR) light excitation characteristics of UCNPs reduce the interference of background fluorescence.

[0006] The technical problem to be solved by the present invention is achieved by adopting the following technical solutions:

[0007] The first object of the present invention is to provide a fluorescence-colorimetric dual-modal hydrogel, which is composed of a hydrogel matrix and nanoprobes, wherein the nanoprobes include UCNPs and bromate.

[0008] The second object of the present invention is to provide a portable sensing platform comprising the fluorescence-colorimetric dual-modal hydrogel.

[0009] The third object of the present invention is to provide application of the fluorescence-colorimetric dual-modal hydrogel or the portable sensing platform in PMZ detection.

[0010] The beneficial effects of the present invention are:

[0011] The present invention utilizes a three-dimensional hydrogel network structure to provide a liquid detection environment and a high loading capacity for the probe, providing a strong UCL signal and sensitive response for PMZ detection;

[0012] The hydrogel matrix will produce autofluorescence under short-wavelength excitation, thereby affecting the fluorescence detection signal. The present invention uses the UCL detection signal excited by near-infrared to eliminate the interference of background fluorescence and ensure the accuracy of detection;

[0013] The hydrogel of the present invention exhibits both colorimetric and fluorescent responses to PMZ. The colorimetric mode provides an intuitive and rapid detection method for PMZ, while the fluorescent mode provides a high-precision detection method for PMZ.

[0014] A portable sensing platform was developed for portable, on-site and highly sensitive PMZ detection, which showed satisfactory detection performance in standard addition experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1(A) is a schematic diagram showing the principle of using the nanoprobe of the present invention for PMZ detection; Figure 1 (B) is a schematic diagram showing the principle of using the hydrogel of the present invention for PMZ detection;

[0016] Figure 2 (A) is the energy transition mechanism diagram of UCNPs described in the present invention; Figure 2 (B) is the up-conversion luminescence spectrum and absorption spectrum of the nanoprobe used for PMZ detection according to the present invention;

[0017] Figure 3 (A) is a low-resolution TEM image of NaYF4:Yb,Er upconversion nanoparticles prepared in Example 1; Figure 3 (B) Figure 3 (C) Figure 3 (D) are low-resolution TEM images, high-resolution TEM images, and X-ray diffraction images of the NaYF4:Yb,Er@NaYF4 upconversion nanoparticles prepared in Example 1, respectively;

[0018] Figure 4 The responsiveness of the nanoprobe prepared in Example 1 to different concentrations of PMZ; (A) The effect of adding different concentrations of PMZ (0-200 µM) on the upconversion luminescence spectrum of the nanoprobe; (B) I 540 / I 655 Linear fitting curve of PMZ concentration; (C) Effect of adding different concentrations of PMZ (0~200 µM) on the absorption spectrum of the nanoprobe; (D) Linear fitting curve of absorbance and PMZ concentration;

[0019] Figure 5 The selectivity and anti-interference test results of the nanoprobe prepared in Example 1 in the presence of relevant interferents; (A) selectivity and anti-interference test results in fluorescence mode; (B) selectivity and anti-interference test results in colorimetric mode; wherein 1-PMZ; 2-blank; 3-Cl - ; 4-SO4 2- ; 5-S 2- ; 6-NO3 - ; 7-cysteine ​​(Cys); 8-glutathione (GSH); 9-glucose; 10-Ca 2+ ;11-H2O2;12-Mg 2+ ; 13-Fe 3+ ;

[0020] Figure 6Characterization diagram of the properties of the hydrogel prepared in Example 1; (A) Optical images of the hydrogel under natural light, 365 nm ultraviolet light and 980 nm near-infrared laser; (B) Color and fluorescence changes of the hydrogel after adding PMZ; (C) Colorimetric response of the hydrogel to PMZ concentration; (D) SEM image of the hydrogel;

[0021] Figure 7 (A) is a schematic diagram of the structure of the portable sensing platform of the present invention; Figure 7 (B) RGB analysis of UCL images using a smartphone color recognition application; Figure 7 (C) UCL luminescence changes of hydrogel in response to PMZ captured by smartphone; Figure 7 (D) is the linear relationship between PMZ concentration and G / R value; the inset is the evolution of the UCL color of the hydrogel in the CIE 1931 (x, y) chromaticity diagram. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments and diagrams.

[0023] The invention provides a fluorescence-colorimetry dual-modal hydrogel. The hydrogel consists of a hydrogel matrix and nanoprobes. The nanoprobes include UCNPs and bromate.

[0024] In the present invention, the hydrogel matrix is ​​a PAM hydrogel. The PAM hydrogel is synthesized by free radical induced polymerization. The present invention encapsulates the probe solution containing UCNPs and bromate into the three-dimensional network of PAM. The high optical transparency and stable 3D network structure of the PAM hydrogel provide a good detection environment for UCNPs, while achieving high loading capacity and rapid molecular diffusion.

[0025] In the present invention, the concentration of UCNPs in the nanoprobe is 0.8-1.2 mg / mL; the concentration of bromate is 2-3 mmol / L.

[0026] In the present invention, the pH value of the nanoprobe is 1.2-2, and the pH value can be adjusted by using a hydrochloric acid solution.

[0027] In the present invention, the UCNPs are prepared by a solvothermal method using rare earth chloride, oleic acid (OA), 1-octadecene (ODE), ammonium fluoride (NH4F) and sodium hydroxide (NaOH) as raw materials.

[0028] Furthermore, the rare earth chlorides include but are not limited to chlorides of yttrium, ytterbium and erbium.

[0029] Furthermore, the reaction temperature of the solvothermal method is 100-300° C., and the reaction time is 30-60 min to ensure uniform growth and good crystallinity of the nanoparticles.

[0030] The preparation of UCNPs of the present invention is to use rare earth chloride as a precursor, OA as a ligand, OA and ODE as a mixed solvent, and react with NH4F and NaOH under high temperature conditions. As a specific embodiment, the preparation method of UCNPs comprises the following steps:

[0031] (1) NaYF4:Yb,Er upconversion nanoparticles were prepared by reacting yttrium chloride hexahydrate (YCl3·6H2O), ytterbium chloride hexahydrate (YbCl3·6H2O), erbium chloride hexahydrate (ErCl3·6H2O), OA, ODE, NH4F and NaOH;

[0032] (2) The core-shell structured NaYF4:Yb,Er@NaYF4 upconversion nanoparticles were prepared by reacting NaYF4:Yb,Er upconversion nanoparticles, YCl3·6H2O, OA, ODE, NH4F and NaOH.

[0033] In order to avoid the influence of oxidation reaction on the nanoparticles, the preparation process of UCNPs is carried out in a protective atmosphere (such as argon).

[0034] In order to improve the water solubility and biocompatibility of UCNPs, the UCNPs are treated with acid to remove surface OA to obtain hydrophilic UCNPs. As a specific embodiment, the acid treatment uses dilute hydrochloric acid with a pH value of 0.8 to 1.2.

[0035] The present invention also provides a portable sensing platform, comprising the fluorescence-colorimetric dual-modal hydrogel.

[0036] Furthermore, the portable sensing platform also includes a smart phone, a 980 nm laser, a 3D printing platform, a dark box and a cuvette holder. A portable sensing platform based on a smart phone was developed using 3D printing technology, which can be efficiently used for on-site detection of PMZ in actual samples with high detection accuracy.

[0037] In the portable sensing platform, the smartphone is the core device that captures and records the upconversion luminescence emitted by the hydrogel through the camera. The built-in color recognition device of the smartphone is used to read and record the average RGB value of multiple points, thereby realizing the quantitative detection of PMZ concentration. At the same time, by observing the color change of the hydrogel, semi-quantitative detection of PMZ can also be achieved.

[0038] The present invention also provides the application of the fluorescence-colorimetric dual-modal hydrogel or the portable sensing platform in PMZ detection, which has the advantages of simple operation, visualization, high sensitivity and high accuracy, and has broad application prospects in the fields of human health and food quality monitoring.

[0039] Furthermore, the PMZ 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.

[0040] Example 1

[0041] (1) Preparation of NaYF4:Yb,Er upconversion nanoparticles

[0042] Weigh 3.9 mmol YCl3·6H2O, 1 mmol YbCl3·6H2O, 0.1 mmol ErCl3·6H2O, mix with 30 mLOA and 75 mL ODE, heat to 160℃ and stir for 1 h, and cool to room temperature; then add 50 mL of methanol solution containing 0.74 g NH4F and 0.5 g NaOH dropwise, heat to 40℃ and stir for 50 min, then heat to 100℃ in vacuum and keep warm for 20 min, then heat to 300℃ in argon atmosphere and keep warm for 1 h, cool to room temperature, take 5 mL of the reaction mixture, wash it three times with ethanol and cyclohexane to obtain NaYF4:Yb,Er upconversion nanoparticles for later use.

[0043] (2) Preparation of core-shell NaYF4:Yb,Er@NaYF4 upconversion nanoparticles

[0044] 1 mmol YCl3·6H2O was mixed with 6 mL OA and 15 mL ODE, and heated to 160°C in an argon-filled environment with stirring until the solution became transparent, and then cooled to room temperature; the NaYF4:Yb,Er upconversion nanoparticles prepared in step (1) were added under stirring, and 15 mL of a methanol solution containing 0.148 g NH4F and 0.1 g NaOH was added dropwise, and the mixture was heated to 50°C and stirred for 40 min, and then heated to 100°C in a vacuum and kept warm for 20 min, and then heated to 300°C in an argon atmosphere and kept warm for 1 h, and then cooled to room temperature, and the product was precipitated with ethanol, and the product was washed with ethanol three times to obtain NaYF4:Yb,Er@NaYF4 upconversion nanoparticles for later use.

[0045] Acid Treatment of NaYF4:Yb,Er@NaYF4 Upconversion Nanoparticles

[0046] 200 mg of the core-shell NaYF4:Yb,Er@NaYF4 upconversion nanoparticles prepared in step (2) were dispersed in 60 mL of dilute hydrochloric acid at pH = 1, ultrasonically treated for 1 h to accelerate the protonation and dissociation of the ligand OA, centrifuged, and washed twice with ultrapure water; the acid-treated UCNPs were redispersed in 20 mL of ultrapure water to obtain a hydrophilic UCNPs solution for later use.

[0047] Preparation of hydrogel

[0048] 3 g acrylamide, 0.05 g N,N'-methylenebisacrylamide, 0.3 g calcium chloride dihydrate and 45 mg ammonium persulfate were dissolved in 26.25 mL deionized water, and then 3 mL of the hydrophilic UCNPs solution prepared in step (3) and 0.75 mL of 10 mM bromate solution were added and mixed evenly. The pH value was adjusted to 1.5 with 2 mol / L hydrochloric acid solution. 2 mL of the obtained mixed solution was taken and injected into a mold with a size of 1 cm×1 cm×2 cm, and 20 μL of 0.1% (pH=6) tetramethylethylenediamine (TEMED) was added to promote gelation. The mixture was cured at room temperature to obtain a hydrogel.

[0049] from Figure 3 It can be observed that the UCNPs synthesized in this example exhibit a spherical morphology with uniform particle size distribution; after being encapsulated by the NaYF4 shell, the average diameter of the UCNPs increased from 26.03 nm ( Figure 3 A) increases to 28.06 nm ( Figure 3 B); NaYF4:Yb,Er@NaYF4 upconversion nanoparticles have uniformly distributed lattice fringes ( Figure 3 C); The XRD characteristic peaks of NaYF4:Yb,Er upconversion nanoparticles and NaYF4:Yb,Er@NaYF4 upconversion nanoparticles match well with the standard PDF card (powder diffraction file, JCPDS16-0334) ( Figure 3 D), this hexagonal crystal structure facilitates energy transfer between rare earth ions, thereby significantly improving the efficiency of upconversion luminescence (UCL).

[0050] Example 2

[0051] A portable sensing platform including a smartphone, a 980 nm laser, a 3D printing platform, a dark box, and a cuvette holder was designed and constructed. 3 The quartz tube of the hydrogel was placed on the sensing platform, and 2 mL of the PMZ solution to be tested was added and reacted for 30 min. Under 980 nm light excitation, the upconversion luminescence emitted by the hydrogel was recorded using the camera of a smartphone, and the RGB value was read and recorded using the built-in color recognition device of the smartphone.

[0052] Example 3

[0053] The preparation method of the hydrogel is the same as that of Example 1, except that the solvothermal reaction conditions for preparing NaYF4:Yb,Er@NaYF4 upconversion nanoparticles are first heated to 120°C in a vacuum for 30 min and then heated to 280°C in an argon atmosphere for 90 min.

[0054] Example 4

[0055] The preparation method of the hydrogel is the same as that of Example 1, except that the molar amounts of YCl3·6H2O, YbCl3·6H2O, and ErCl3·6H2O used in the preparation of NaYF4:Yb,Er upconversion nanoparticles are 3.85 mmol, 1 mmol, and 0.15 mmol, respectively.

[0056] Example 5

[0057] The preparation method of the hydrogel was the same as that of Example 1, except that 40 μL of 0.1% (pH=6) tetramethylethylenediamine (TEMED) was added during the preparation of the hydrogel to promote gelation.

[0058] Example 6

[0059] The preparation method of the hydrogel is the same as that of Example 1, except that calcium chloride dihydrate is not added during the preparation of the hydrogel.

[0060] Example 7

[0061] Fluorescence and colorimetric responsiveness tests:

[0062] PMZ aqueous solution was added to the nanoprobe prepared in Example 1 to make the final concentration of PMZ 0, 10, 20, 30, 40, 60, 80, 120, 160, 200 μM, respectively, and mixed evenly. After incubation for 20 min, the upconversion fluorescence spectrum of the probe solution in the range of 500-700 nm was recorded using a 980 nm laser to complete the fluorescence detection of PMZ ( Figure 4 A and 4B). At the same time, the absorbance of the solution was measured in the range of 400~800nm ​​to achieve colorimetric detection of PMZ ( Figure 4 C and 4D).

[0063] from Figure 4 It can be seen that as the PMZ concentration increases from 0 μM to 200 μM, the green UCL signal gradually weakens, while the red UCL signal remains constant, realizing the transition of UCL color from green to red. 540 / I 655As a detection index, this index shows a linear correlation with PMZ concentration in the PMZ concentration range of 0 to 200 μM. The limit of quantification (LOD) was calculated according to the formula LOD=3*δ / S, where δ represents the standard deviation (i.e., noise level) obtained based on 10 blank experiments, and S is the slope of the linear regression equation in the sensitivity test. The results show that in the fluorescence mode, the LOD reached an extremely low level of 10 nM. In addition, the probe solution exhibited a colorimetric response to PMZ. Potassium bromate reacts with PMZ to produce a red product, and the absorbance at 552 nm increases with the increase of PMZ concentration. The inset shows that the color of the probe solution changes from colorless to red, intuitively showing the presence and concentration change of PMZ. In addition, in the PMZ concentration range of 0 to 200 μM, the absorbance at 552 nm shows a good linear relationship with the PMZ concentration, and the LOD is as low as 25 nM (R²=0.996). In summary, the nanoprobe designed in the present invention exhibits sensitive and accurate detection capabilities for PMZ in both fluorescence and colorimetric modes.

[0064] Example 8

[0065] Selectivity and immunity test:

[0066] 200 μM PMZ aqueous solution and 500 μM interfering substances (the interfering substances were Cl - 、SO4 2+ , S 2- 、NO3 - 、Cys、GSH、glucose、Ca 2+ 、H2O2、Mg 2+ , Fe 3+ The aqueous solution of 20 μg / ml was added to the nanoprobe prepared in Example 1, mixed evenly, and incubated for 20 min. The up-conversion fluorescence spectrum of the probe solution in the range of 500-700 nm was recorded using a 980 nm laser to complete the fluorescence detection of PMZ ( Figure 5 At the same time, the absorbance of the solution was measured in the range of 400-700 nm to achieve colorimetric detection of PMZ ( Figure 5 red bars in B).

[0067] After adding the above interfering substances to the nanoprobe prepared in Example 1, 200 μM PMZ aqueous solution was further added, mixed evenly, and incubated for 10 min. The upconversion fluorescence spectrum of the solution in the range of 500-700 nm was recorded using a 980 nm laser to complete the fluorescence detection of PMZ ( Figure 5 The blue bar graph in A); at the same time, the absorbance of the solution was measured in the range of 400-700 nm to achieve colorimetric detection of PMZ ( Figure 5 blue bars in B).

[0068] from Figure 5 It can be seen that in the fluorescence mode, the addition of interfering substances did not affect the fluorescence intensity of UCNPs, while the addition of PMZ significantly changed the I 540 / I 655 Emission ratio ( Figure 5 A). In the colorimetric mode, the addition of the same concentration of PMZ resulted in a significant decrease in absorbance, demonstrating the selectivity of the probe ( Figure 5 B). Therefore, the nanoprobe designed in the present invention shows good selectivity and anti-interference ability for PMZ detection, and is suitable for quantitative analysis of PMZ in complex samples.

[0069] Example 9

[0070] Detection of PMZ in actual samples:

[0071] Milk and egg samples were purchased from local supermarkets, and serum samples were provided by Hefei Cancer Hospital, Chinese Academy of Sciences.

[0072] For milk samples, 10 mL of milk sample was centrifuged to remove the fat layer, and then the skim milk was filtered through a 0.22 μm microporous membrane and diluted with aqueous solution to a final volume of 10 mL.

[0073] For egg samples, add 10 g of well-mixed egg sample to a centrifuge tube and add 4 mL of ethyl acetate to mix well. Centrifuge at 6500 r / min for 5 min at room temperature, take the supernatant and dry it with nitrogen. Dilute the dried residue with aqueous solution to a final volume of 10 mL.

[0074] For serum samples, dilute 1 mL of serum sample to 10 mL.

[0075] In the standard spike experiment, PMZ aqueous solution with concentrations of 0, 20, 50, and 100 μmol / L was added to the sample to be tested. Each spiked sample was tested three times independently using the freshly prepared hydrogel of Example 1 to calculate the spike recovery and relative standard deviation (RSD). The results are shown in Table 1.

[0076] Table 1

[0077]

[0078] As can be seen from Table 1, the recovery rate of PMZ in milk samples is between 98.25% and 105.15%, the recovery rate of PMZ in egg samples is between 101.78% and 102.80%, and the recovery rate of PMZ in serum samples is between 101.98% and 108.25%, and the RSD of these three samples is between 1.34% and 4.35%. The results show that the hydrogel of the present invention exhibits high sensitivity and reliability in detecting PMZ in food and human fluid samples, which further verifies the feasibility of the hydrogel of the present invention in practical applications and its applicability in detecting complex real samples.

[0079] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. Application of a fluorescence-colorimetric dual-modal hydrogel in the detection of promethazine, wherein the fluorescence-colorimetric dual-modal hydrogel is composed of a hydrogel matrix and a nanoprobe, wherein the nanoprobe includes UCNPs and bromate; The hydrogel matrix is ​​a polyacrylamide hydrogel; The pH value of the nanoprobe is 1.2-2; The UCNPs are prepared by a solvothermal method using rare earth chloride, oleic acid, 1-octadecene, NH4F and NaOH as raw materials; The rare earth chlorides include chlorides of yttrium, ytterbium and erbium; The reaction temperature of the solvothermal method is 100-300°C, and the reaction time is 30-60 min; The preparation method of the UCNPs comprises the following steps: (1) NaYF4:Yb,Er upconversion nanoparticles were prepared by reaction of YCl3·6H2O, YbCl3·6H2O, ErCl3·6H2O, oleic acid, 1-octadecene, NH4F and NaOH; (2) NaYF4:Yb,Er@NaYF4 upconversion nanoparticles with core-shell structure were prepared by reacting NaYF4:Yb,Er upconversion nanoparticles, YCl3·6H2O, oleic acid, 1-octadecene, NH4F and NaOH; The UCNPs are treated with acid to remove surface oleic acid, thereby obtaining hydrophilic UCNPs.

2. The use according to claim 1, characterized in that: The concentration of UCNPs in the nanoprobe is 0.8-1.2 mg / mL; the concentration of bromate is 2-3 mmol / L.

3. The use according to claim 1, characterized in that: The preparation process of the UCNPs is carried out in a protective atmosphere.

4. Application of a portable sensing platform in the detection of promethazine, the portable sensing platform comprising the fluorescence-colorimetric dual-modal hydrogel described in any one of claims 1 to 3.

5. The use according to claim 4, characterized in that: The portable sensing platform also includes a smart phone, a 980nm laser, a 3D printing platform, a dark box and a cuvette holder.

6. The use according to claim 4, characterized in that: The promethazine detection is carried out by fluorescence detection at an excitation wavelength of 980 nm and an emission wavelength of 500-700 nm; and colorimetric analysis is carried out at an absorption wavelength of 400-700 nm.

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