1. A composite material for detecting borax content in crystal glue toys is characterized in that the composite materialThe molecular formula of (A) is as follows: y is_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃。

2. The composite material for borax content detection in crystal glue toy according to claim 1, wherein Y is_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃Composite Presence Tm³⁺Blue light level to Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃Energy transfer process of quantum dots.

3. The method for preparing the composite material for detecting the borax content in the crystal glue toy according to claim 1, wherein the method comprises the following steps:

adding 0.6 mmol of yttrium acetylacetonate, ytterbium acetate, thulium acetate, lanthanum acetylacetonate, 5-10 ml of oleic acid and 8-16 ml of octadecene into a 50 ml three-necked bottle at room temperature, and heating to 100-150%^oC, preserving the heat for 40-70 minutes; the total molar weight of ytterbium acetate, thulium acetate and lanthanum acetylacetonate is 1.4 millimole, wherein the molar percentage of ytterbium acetate is 5-15%, and the molar percentage of thulium acetate is 0.02-0.08%;

2) after the solution in the step (1) is cooled to room temperature, adding 3-6 mmol of sulfur powder and 5-10 ml of oleylamine, vacuumizing the three-necked bottle for 5-15 minutes by using a mechanical pump, and then heating to 100-120 DEG C ^oC, preserving the heat for 30 to 60 minutes, and then rapidly heating to 290 ℃ and 320 ℃ under the protection of nitrogen or argon^oC, preserving the heat for 50-90 minutes;

3) after the solution in the step (2) is cooled to room temperature, adding ethanol, centrifuging to obtain a precipitate, and adding ethanol: washing the product with the mixed solution of cyclohexane in the ratio of 3:1, and washing the product with the mixed solution of cyclohexane in the ratio of 40-80^ODrying C to obtain Y_0.6La_1.4O₂S: Yb/Tm；

4) Adding cesium carbonate, lithium carbonate, calcium carbonate, lead nitrate and ammonium bromide into a mixed solution of oleylamine and octadecene (the volume ratio is 1:2, and the total volume is 3-6 ml) at a molar ratio of 0.45: 0.05: 0.2:0.8: 3, grinding for 20-40 minutes at room temperature, then centrifugally washing with cyclohexane to remove excess solvent, and dispersing the centrifugal product in 4-8 ml of polyethylene glycol solvent;

5) y obtained in the step (3)_0.6La_1.4O₂S, adding Yb/Tm into the polyethylene glycol dispersion liquid in the step (4), carrying out ultrasonic treatment for 2-6 hours in an ultrasonic cleaning instrument with the power of more than 1 kilowatt, then adding 0.02-0.05 millimole of polyacrylic acid, stirring for 12-24 hours at room temperature, and finally carrying out centrifugal washing by using a mixed solution of cyclohexane and ethanol to obtain Y_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃And (c) a complex.

4. A detection method for borax content in a crystal glue toy is characterized by comprising the following steps:

pre-treatment, mixing crystal glue and deionized water, then shaking at a high speed, stirring at room temperature, filtering with a filter membrane, and drying in a muffle furnace;

and (3) mixing and detecting, namely mixing the pretreated crystal glue powder with deionized water, and detecting the borax content by using a ratio type fluorescent probe, wherein the ratio type fluorescent probe is made of the composite material for detecting the borax content in the crystal glue toy as claimed in claim 1.

5. The method for detecting the borax content in the crystal glue toy according to claim 4, wherein the mass ratio of the pretreated crystal glue powder, the deionized water and the probe material is 1: 10: 0.3-0.5.

Background

The crystal glue toy is a popular toy for children at present, and the crystal glue has crystal-clear and transparent appearance and is exactly like crystal beads. The crystal glue toy is made of PVA powder, water, borax, carbomer resin and propylene glycol, as described in Chinese patent publication No. CN102634156B, which is a red translucent crystal glue material. In the process of manufacturing the crystal glue, a trace amount of toxic substance borax is required to be added, the borax is white powder in appearance and is easy to dissolve in water, and the borax is added into the crystal glue and is used for improving the viscosity and the hardness of the crystal glue due to stable chemical property and soft texture.

At present, whether the borax content in the crystal glue toy exceeds the standard or not is generally detected by a special laboratory instrument. The conventional borax detection method mainly comprises a turmeric test paper characteristic test method, a pH test paper method and a sensory test method. The turmeric test paper characteristic inspection method has the disadvantages of complicated operation process, time and labor consumption and high cost, and cannot be used for real-time rapid detection; the detection accuracy of the pH test paper method is poor, and the pH is also changed due to other acid-base components in the product, so that the selectivity is not available; the sensory test method is based on hand feeling and smell feeling, and is not only poor in accuracy, but also only suitable for a few professionals with very rich experience. For children toys, inductive coupling plasma atomic emission spectrometry is generally adopted to analyze whether borax and the content of borax are contained in the toys, and the method is long in time consumption and high in cost. The fluorescence detection method based on the fluorescent probe material is a novel non-contact measurement technology, mainly realizes detection by representing the fluorescence intensity of a fluorescence center, the fluorescence life or the change of an emission peak position along with an object to be detected, and has the advantages of high spatial resolution, quick response, remote measurement and the like. The selective adsorption performance of the probe material is improved through surface ligand modification, and the detection accuracy can be further improved. However, the detection of borax by using fluorescent probe materials is only rarely reported at present. The molecular formula of borax is Na₂B₄O₇·10H₂O, in aqueous solution, containing B₄O₇ ^2-，BO₂ ^-，H₃BO₃All of which are capable of reacting with heavy metal ions such as Pb²⁺Or Mn²⁺The ions are combined to form a new compound, and the combination can further promote the hydrolysis of the borax. Although the content of borax in the reaction product can be detected to a certain extent by detecting the content of the new generated compound, the accuracy is still low, and the detection cannot be carried out in situ in real time. By arrangingThe fluorescent probe material is modified by a surface ligand, can be specifically combined with borax, detects the content of the borax by the change of fluorescence, and has good feasibility and high accuracy. According to the analysis, aiming at the detection of borax, the novel probe material is explored in the detection field of borax content in crystal glue, and the method has good application prospect.

The detection method of borax content in the existing toy is described in a test method of borax content in toy clay material of Chinese patent (publication number: CN 106442374A). The defects of the detection method and the detection material are as follows: the content of the boric acid in the sample is obtained through quantitative analysis, and the content of the borax in the sample is obtained through conversion.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a composite material Y for detecting borax content in a crystal glue toy_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃The approximate concentration range of the borax can be qualitatively judged by naked eyes, and whether the content of the borax in the crystal glue toy exceeds the standard or not can be conveniently detected.

In order to achieve the above object, the present application adopts the following technical solutions:

a composite material for detecting borax content in a crystal glue toy has the following molecular formula: y is_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃。

Preferably, Y is_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃Composite Presence Tm³⁺Blue light level to Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃The quantum dot energy transfer process is further characterized in that the application provides a detection method for borax content in a crystal glue toy, and the preparation method of the used probe material comprises the following steps:

1) adding 0.6 mmol of yttrium acetylacetonate, ytterbium acetate, thulium acetate, lanthanum acetylacetonate, 5-10 ml of oleic acid and 8-16 ml of octadecene into a 50 ml three-necked bottle at room temperature, and heating to 100-150%^oC, preserving the heat for 40-70 minutes; the total molar weight of ytterbium acetate, thulium acetate and lanthanum acetylacetonate is 1.4 millimole, wherein the molar percentage of ytterbium acetate is 5-15%, and the molar percentage of thulium acetate is 0.02-0.08%;

2) after the solution in the step (1) is cooled to room temperature, adding 3-6 mmol of sulfur powder and 5-10 ml of oleylamine, vacuumizing the three-necked bottle for 5-15 minutes by using a mechanical pump, and then heating to 100-120 DEG C ^oCAnd the temperature is kept for 30-60 minutes, and then the temperature is rapidly raised to 290-320 ℃ under the protection of nitrogen or argon^oC, preserving the heat for 50-90 minutes;

3) after the solution in the step (2) is cooled to room temperature, adding ethanol, centrifuging to obtain a precipitate, and adding ethanol: washing the product with the mixed solution of cyclohexane in the ratio of 3:1, and washing the product with the mixed solution of cyclohexane in the ratio of 40-80^ODrying C to obtain Y_0.6La_1.4O₂S: Yb/Tm；

4) Adding cesium carbonate, lithium carbonate, calcium carbonate, lead nitrate and ammonium bromide into a mixed solution of oleylamine and octadecene (the volume ratio is 1:2, and the total volume is 3-6 ml) at a molar ratio of 0.45: 0.05: 0.2:0.8: 3, grinding for 20-40 minutes at room temperature, then centrifugally washing with cyclohexane to remove excess solvent, and dispersing the centrifugal product in 4-8 ml of polyethylene glycol solvent;

5) y obtained in the step (3)_0.6La_1.4O₂S, adding Yb/Tm into the polyethylene glycol dispersion liquid in the step (4), carrying out ultrasonic treatment for 2-6 hours in an ultrasonic cleaning instrument with the power of more than 1 kilowatt, then adding 0.02-0.05 millimole of polyacrylic acid, stirring for 12-24 hours at room temperature, and finally carrying out centrifugal washing by using a mixed solution of cyclohexane and ethanol to obtain Y_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃And (c) a complex.

A detection method for borax content in a crystal glue toy comprises the following steps:

(1) pre-treatment, mixing crystal glue and deionized water, then shaking at a high speed, stirring at room temperature, filtering with a filter membrane, and drying in a muffle furnace;

(2) and (3) mixing and detecting, namely mixing the pretreated crystal glue powder with deionized water, and detecting the borax content by using a ratio type fluorescent probe, wherein the ratio type fluorescent probe is made of the composite material for detecting the borax content in the crystal glue toy as claimed in claim 1.

Preferably, the mass ratio of the pretreated crystal glue powder, the deionized water and the probe material is 1: 10: 0.3-0.5.

The composite material for detecting the borax content in the crystal glue toy disclosed by the patent emits bright green light under the excitation condition of 980 nm laser, the luminous color and the luminous intensity have good response characteristics to borax, and after excessive borax is added into the aqueous solution of the composite material, as borax hydrolysate can react with Cs (Cs)_0.9Li_0.1Pb_0.8Ca_0.2Br₃Pb in Quantum dots²⁺Ionic interactions, combined with the formation of borax lead-like compounds, disrupt Tm³⁺Blue light level to Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃The energy transfer process of the quantum dots enables the product to emit blue light. By fitting Tm³⁺Blue light and Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃The relationship curve of the fluorescence intensity ratio of the green light of the quantum dots and the concentration of the borax can be accurately used for quantitative detection of the borax. After borax is added into the crystal glue toy, the content of the borax in the crystal glue toy can be accurately detected by utilizing the change of the luminous performance of the probe material, the approximate concentration range of the borax can be qualitatively judged by naked eyes, and the detection is convenient.

Drawings

FIG. 1Y_0.6La_1.4O₂S is the result of atomic emission spectrometry of inductively coupled plasma of Yb/Tm.

FIG. 2Y_0.6La_1.4O₂X-ray diffraction spectrum of Yb/Tm.

FIG. 3Y_0.6La_1.4O₂S: Yb/TmSpectrogram under excitation condition of 980 nm laser.

FIG. 4Y_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃X-ray diffraction pattern of the complex.

FIG. 5Y_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃Compound, spectrogram under 980 nm laser excitation condition.

FIG. 6Y_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃In the solution, the relationship curve of the ratio of the intensity of blue light to the intensity of green light to the concentration of borax.

FIG. 7 at Y_0.6La_1.4O₂S: Yb/Tm-Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃The ratio of the blue light intensity to the green light intensity under different types of cations or pH conditions is added to the solution.

FIG. 8 at Y_0.6La_1.4O₂S: Yb/Tm- Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃Adding different masses of the treated crystal glue powder into the solution, wherein the ratio of the blue light intensity to the green light intensity is higher than that of the crystal glue powder.

Detailed Description

Experimental part

The main reagents are as follows: yttrium acetylacetonate, ytterbium acetate, thulium acetate, lanthanum acetylacetonate, oleic acid, oleylamine, octadecene (90%), polyacrylic acid (99%), cesium carbonate, lithium carbonate, calcium carbonate, lead nitrate and ammonium bromide were purchased from Sigma-Aldrich, and borax, sulfur powder, cyclohexane, ethanol and deionized water were purchased from national pharmaceutical group chemicals, ltd.

Y_0.6La_1.4O₂S: Yb/Tm- Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃Preparation of the Complex

0.6 millimole of yttrium acetylacetonate, 0.14 millimole of ytterbium acetate, 0.07 millimole of thulium acetate, 1.19 millimole of lanthanum acetylacetonate,10 ml of oleic acid and 12 ml of octadecene are added into a 50 ml three-neck flask at room temperature, and the temperature is raised to 130 DEG^oC, and keeping the temperature for 50 minutes; after the solution is cooled to room temperature, 4 mmol of sulfur powder and 8 ml of oleylamine are added, the three-necked bottle is vacuumized by a mechanical pump for 10 minutes, and then the temperature is raised to 100 DEG ^oCAnd the temperature is kept for 50 minutes, and then the temperature is quickly increased to 310 ℃ under the protection of nitrogen^oC, and keeping the temperature for 70 minutes; after the above solution was cooled to room temperature, ethanol was added and centrifuged to obtain a precipitate, which was purified with ethanol: the product was washed with a 3:1 mixture of cyclohexane and then at 40^ODrying C to obtain Y_0.6La_1.4O₂S is Yb/Tm; adding 0.45 mmol of cesium carbonate, 0.05 mmol of lithium carbonate, 0.2 mmol of calcium carbonate, 0.8 mmol of lead nitrate and 3 mmol of ammonium bromide into a mixed solution of 1 ml of oleylamine and 2 ml of octadecene, grinding at room temperature for 20 minutes, then centrifugally washing with cyclohexane to remove excess solvent, and dispersing the centrifuged product in 6 ml of polyethylene glycol solvent; subjecting the obtained Y to_0.6La_1.4O₂S, Yb/Tm is added into the polyethylene glycol dispersion liquid, ultrasonic treatment is carried out for 4 hours in an ultrasonic cleaner with the power of more than 1 kilowatt, then 0.04 millimole of polyacrylic acid is added, stirring is carried out for 16 hours at room temperature, and finally, the mixed solution of cyclohexane and ethanol is used for centrifugal washing to obtain Y_0.6La_1.4O₂S: Yb/Tm- Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃And (c) a complex.

Characterization apparatus and method

Inductively coupled plasma atomic emission spectroscopy (ZX-Z5000-WLD5000, powder sample, frequency 50/60 Hz), X-ray diffraction pattern (Bruker D8 Advance, Cu-K α (λ = 1.5405)), transmission electron microscope (TEM, FEI Tecnai G2F 20), spectrometer (FLAROHUB-B, HORIBA JOBIN YVON), 980 nm laser at a power of 1-3W.

Preparation of X-ray diffraction samples: paving the dried composite material in the groove of the sample support;

preparation of transmission electron microscope samples: dissolving a little of the composite material in 4 ml of ethanol solution, and dropping 3-6 drops of liquid on the ultrathin carbon film after ultrasonic treatment for 5 minutes.

The detection method of borax comprises the following steps: taking a certain mass of compound, dividing the compound into a plurality of groups, adding 5 ml of deionized water into each group, then adding borax with different molar weights, representing the change of the fluorescence intensity by a fluorescence spectrometer, and fitting a standard curve.

Data analysis and discussion

As shown in FIG. 1, the results of atomic emission spectroscopy analysis of inductively coupled plasma showed that the mole percentages of the rare earth elements Y, La, Yb and Tm in the oxysulfide were 29.36%, 60.35%, 6.86% and 3.43%, respectively, which were substantially the same as the mole percentages added to the raw materials, indicating that the obtained product was Y_0.6La_1.4O₂S is Yb/Tm. It should be noted that, since the air contains much oxygen, the content of oxygen element is not measured, and only the percentage of cations is measured, which is mainly used for analyzing the mole percentage of the rare earth doped ions, and is closely related to the luminous intensity. As shown in FIG. 2, the results of X-ray diffraction spectrum analysis show that the product can be well matched with cards 26-1422 in the standard database, which shows that the product is pure hexagonal phase, and the crystal faces corresponding to the three strongest diffraction peaks are (100), (101) and (110), respectively.

As shown in FIG. 3, rare earth doped oxysulfide Y_0.6La_1.4O₂Yb/Tm, emitting bright up-converted blue light corresponding to Tm under excitation of 980 nm laser³⁺F-f transition of (2) by sensitizing ion Yb³⁺Absorb incident light energy and transfer the energy to the active ion Tm through a three-photon or four-photon process³⁺And filling the high-energy level excited state, and generating up-conversion luminescence after the excited state electrons return to the ground state. In order to further research the influence rule of the concentrations of the sensitizing ions and the activating ions on the upconversion luminescence intensity, samples with different rare earth ion doping concentrations are prepared.

As shown in fig. 4, the X-ray diffraction spectrum contains diffraction peaks of both sulfur oxide and halogen perovskite quantum dots, indicating that the final product is a two-phase composite, consistent with expectations. As shown in fig. 5, under the excitation condition of 980 nm laser, Tm is divided³⁺In addition to the blue light emission peak of the ion, also appearsThe emission peak of the halogen perovskite quantum dot in a green light region has the central wavelength of about 516 nm. Because the single quantum dot does not emit light by up-conversion under the excitation condition of a 980 nm laser, the fact that the high-efficiency Tm exists after the sulfur oxide and the perovskite quantum dot are compounded in two phases can be inferred³⁺The energy transfer of the ions to the conduction band energy level of the quantum dots, and thus the green emission peak occurs.

The composite material is dispersed in the aqueous solution, when borax is added into the solution, the up-conversion luminous intensity of green light is obviously weakened, the up-conversion luminous intensity of blue light is gradually enhanced, and the ratio of the intensity of the blue light to the intensity of the green light is in a direct proportional relation with the concentration of the borax, as shown in fig. 6. The method can be applied to the quantitative detection of the borax by fitting a relation curve of the ratio of the intensity of the blue light to the intensity of the green light to the concentration of the borax. In order to show that the fluorescence detection method has high stability and accuracy, different metal cations are added into the solution and the pH value of the solution is regulated, so that a borax detection experiment is further developed. As shown in FIG. 7, the concentration of fixed borax was 4X 10^-8mol/L by adding 0.2 mmol Li to the solution⁺，Na⁺，Ca₂₊，Sr²⁺，Cu²⁺Or the pH value of the solution is adjusted to 3, 5 or 7, and under the excitation condition of a 980 nm laser, the fluorescence intensity ratio of blue light to green light is almost unchanged, which shows that the change of the ratio is only related to the borax concentration.

A detection method for borax content in a crystal glue toy comprises the following steps:

(1) pre-treatment, rolling 0.2 g of crystal glue sample for dissolving, putting into a plastic centrifuge tube, adding 20 ml of deionized water, and adding 40 ml of deionized water^oShaking in water bath at high speed for 10 min, stirring at room temperature for 2-4 hr, filtering with 0.45 μm filter membrane, and filtering at 60 deg.C^oC, drying in a muffle furnace; the pretreated crystal glue is easy to dissolve, and the detection accuracy is improved.

(2) And mixing the pretreated crystal glue powder with deionized water, and detecting the content of borax by using a ratio type fluorescent probe material.

The crystal glue is pretreated to obtain crystal glue powder which is easy to dissolve, and the detection accuracy is improved. As shown in fig. 8, different quality of crystal glue powders were added to the aqueous solution containing the composite material, and the ratio of the blue light to green light fluorescence intensity was substantially unchanged, indicating that the commercially available crystal glue meeting the safety standards did not contain borax; when the crystal glue powder and the borax are added simultaneously, the fluorescence intensity ratio of blue light to green light is gradually enhanced and basically consistent with that in figure 6, which shows that the composite material can be well applied to the detection of the borax content in the treated crystal glue. The simple pretreatment method of the crystal glue is combined, and when the mass ratio of the pretreated crystal glue powder, the deionized water and the probe material is 1: 10: 0.4, the detection accuracy is optimal.

The fluorescent composite material has good response characteristics of luminous color and luminous intensity to borax, and Tm is fitted³⁺Blue light and Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃The relationship curve of the fluorescence intensity ratio of the green light of the quantum dots and the concentration of the borax can be well applied to the quantitative detection of the borax. Further, the chemical components in the crystal glue do not influence Tm due to the compliance with the safety standard³⁺Blue light level to Cs_0.9Li_0.1Pb_0.8Ca_0.2Br₃In the energy transfer process of the quantum dots, after borax is added into the pretreated crystal glue, the borax content in the crystal glue can be detected by utilizing the change of the luminescence property of the probe material. In addition, with the increase of the borax concentration, the green light intensity is gradually reduced, the blue light intensity is gradually increased, the overall luminescent color of the compound is obviously converted from green light to blue light under the excitation condition of a 980 nm laser, and the approximate concentration range of the borax can be qualitatively judged by naked eyes. After the commercially available crystal glue is subjected to simple pretreatment, the borax content in the crystal glue can be detected by using the composite material provided by the invention. Compared with a single fluorescence peak detection method, the ratio type fluorescence detection method has high accuracy and can be well applied to the detection of the borax content in the crystal glue toy.