Fluorescence quenching detection method for sulfide in Baijiu

Abstract

The invention discloses a fluorescence quenching detection method for sulfides in Baijiu, and the fluorescence quenching detection method comprises the following steps: (1) mixing a Baijiu sample to be detected with a nanocrystal solution, and reacting to obtain a liquid to be detected; (2) determining the fluorescence intensity value of the to-be-detected liquid by using a luminoscope; and (3) substituting the fluorescence intensity value into the standard linear equation to obtain the sulfide content in the white spirit sample to be detected, the nano crystal is a perovskite nano crystal. The invention provides a novel, simple, rapid, efficient and low-cost method for detecting sulfide in white spirit, the application range of the perovskite nanocrystal is expanded, and a basis is provided for application of the perovskite nanocrystal in the field of food safety.

Description

Technical Field

[0001] The present application relates to a fluorescence quenching detection method for sulfide in liquor, belonging to the technical field of nanomaterials. Background Art

[0002] Liquor plays an important role in Chinese culture. It is regarded as one of the symbols of traditional Chinese culture, an important part of the Chinese dining table, and a common drink in social occasions. Sulfur compounds are produced during the brewing and aging process of liquor, and sulfide is an important flavor component of liquor. Some sulfur compounds can provide special fragrance to liquor in appropriate amounts, for example, some thiol compounds may have the smell of flowers, fruits or vegetables. 3-Methylthiopropanol and ethyl 3-methylthiopropionate in liquor have antioxidant activity and are one of the functional factors that are beneficial to human health. Excessive sulfur compounds will cause liquor to have odors, such as sulfur, hydrogen sulfide or onion, which reduce the quality and taste of liquor. In the liquor industry, one of the goals of quality control and technological improvement is to ensure that the content of sulfur compounds is within an appropriate range and does not have a negative impact on the quality of liquor. Sulfur compounds in liquor are volatile and have a low threshold. Common methods for determining the content of sulfur compounds in liquor include gas chromatography (GC), high performance liquid chromatography (HPLC), atomic absorption spectrometry (AAS) and mass spectrometry (MS). These methods require expensive instruments, are complex to operate, and are time-consuming. Moreover, most of these methods are only qualitative and not quantitative.

[0003] In recent years, perovskite nanocrystals have attracted people's attention and research due to their excellent optoelectronic properties. Compared with traditional inorganic semiconductor nanocrystals, perovskite nanocrystals have higher fluorescence quantum efficiency (PLQY), wider adjustable emission wavelength range, excellent photoelectric transmission performance, simple synthesis, low cost and other advantages, and have good application prospects in optoelectronic devices. At the same time, because of its high quantum yield and strong fluorescence signal and adjustable wavelength, it can be used as a light source to construct highly sensitive fluorescence sensors and applied in analytical chemistry or bioanalytical chemistry. However, perovskite nanocrystals are greatly affected by the environment and have poor stability. Factors such as air, humidity, temperature, and polar substances can cause the luminescence efficiency of perovskite nanocrystals to decrease or even completely quench. Taking advantage of the unique property of being sensitive to sulfides, perovskite nanocrystals can be used for qualitative and quantitative analysis of sulfides. At present, there is no relevant report on the use of perovskite nanocrystals for the detection of sulfides in liquor. Summary of the invention

[0004] The purpose of the present invention is to make up for the shortcomings of the existing methods for detecting sulfide in liquor, and propose a new method for determining sulfide in liquor by using a nanocrystal fluorescence quenching method.

[0005] The present invention discloses a method for determining sulfide in liquor by using perovskite nanocrystal fluorescence quenching method. The main steps include: mixing a liquor sample containing sulfide with nanocrystals for reaction, determining the fluorescence intensity of the liquor sample, establishing a linear relationship between the fluorescence intensity and the sulfide content in the liquor sample, determining the fluorescence intensity of an unknown liquor sample and obtaining the sulfide content according to a fitted linear equation.

[0006] According to one aspect of the present application, a fluorescence quenching detection method for sulfide in liquor is provided, and the fluorescence quenching detection method comprises the following steps:

[0007] (1) mixing a liquor sample to be tested with a nanocrystal solution, reacting the mixture, and obtaining a test solution;

[0008] (2) using a fluorimeter to measure the fluorescence intensity of the test solution;

[0009] (3) Substituting the fluorescence intensity value into the standard linear equation, the sulfide content in the liquor sample to be tested is obtained;

[0010] The nanocrystals are perovskite nanocrystals.

[0011] Optionally, the perovskite nanocrystals are selected from at least one of CH3NH3PbX3, CH(NH2)2PbX3, and CsPbX3.

[0012] Among them, X=Cl, Br, I.

[0013] Optionally, the perovskite nanocrystals are organic-inorganic hybrid perovskite nanocrystals CH3NH3PbX3, CH(NH2)2PbX3, all-inorganic perovskite nanocrystals CsPbX3, wherein (X=Cl, Br, I) is one or more.

[0014] Optionally, in step (1), the liquor is selected from at least one of light-flavor liquor, strong-flavor liquor, and sauce-flavor liquor.

[0015] Optionally, in step (1), the volume ratio of the liquor sample to the nanocrystal solution is 0.1-1 mL: 0.1-3 mL.

[0016] Optionally, the concentration of the nanocrystal solution is 10-30 mg / mL.

[0017] Optionally, the concentration of the nanocrystal solution is selected from any value of 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL or a range between any two of the above values.

[0018] Optionally, the method for constructing the standard linear equation includes:

[0019] Add the same amount of nanocrystal solution to the liquor sample solutions with different sulfide contents, mix them, and after the reaction, use a fluorescence meter to measure the fluorescence intensity value;

[0020] The corresponding sulfide content and fluorescence intensity values ​​were analyzed to construct a standard linear equation.

[0021] Optionally, the number of samples of the sulfide liquor sample solution is 5 to 20.

[0022] Optionally, in step (2), the fluorescence excitation wavelength λex during measurement by the fluorescence instrument is in the range of 350 to 370 nm.

[0023] Optionally, in step (2), the fluorescence detection emission wavelength λem during measurement by the fluorescence instrument is 512nm to 520nm.

[0024] Optionally, the reaction time is 1 to 10 minutes.

[0025] Optionally, the reaction time is selected from any value of 1 min, 2 min, 4 min, 5 min, 7 min, 10 min or a range between any two of the above.

[0026] Optionally, the solvent in the nanocrystal solution is selected from at least one of n-hexane, cyclohexane and toluene.

[0027] As a specific implementation, the present application is implemented through the following technical solutions:

[0028] The method of the present invention is used to determine the sulfide in liquor, and the specific steps are as follows:

[0029] Step (1): a series of liquor samples with known sulfide content are added into a centrifuge tube containing the nanocrystal solution and mixed thoroughly;

[0030] Step (2): Pipette the mixed solution into a cuvette and place it in a fluorescence meter to measure the fluorescence intensity. Due to the different sulfide contents, different wine samples have different degrees of quenching of the nanocrystal fluorescence, and the measured fluorescence intensities are also different. Record the fluorescence intensities of all wine samples after the reaction with the nanocrystal solution.

[0031] Step (3): using the sample sulfide content as the independent variable X and the fluorescence intensity as the dependent variable Y, a linear equation between the sample sulfide content and the fluorescence intensity is established by regression analysis;

[0032] Step (4): According to the operation methods of steps (1) and (2) and the linear equation obtained in step (3), the fluorescence intensity of the wine sample with unknown sulfide content after reacting with the nanocrystals is determined, and the obtained fluorescence intensity is substituted into the obtained linear equation to obtain the sulfide content in the wine sample, and the sulfide content in the liquor is verified by gas chromatography.

[0033] Optionally, in step (2), the volume absorbed into the cuvette after the reaction is 1 mL to 2 mL.

[0034] The beneficial effects of this application include:

[0035] 1) Compared with gas chromatography, the method provided in this application is simple to operate, greatly shortens the detection time, reduces the amount of organic reagents used, is based on the fluorescence quenching principle of nanocrystals, has high reaction sensitivity, higher precision and good reproducibility.

[0036] 2) The method provided in this application is simple to operate, the experimental results are clear and intuitive, it is operator-friendly, and the accuracy is improved.

[0037] 3) This application provides a new, simple, rapid, efficient and low-cost method for detecting sulfide in liquor, and expands the application scope of perovskite nanocrystals, providing a basis for the application of perovskite nanocrystals in the field of food safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a graph showing the relationship between the sulfide content and fluorescence intensity of Luzhou-flavor liquor in Example 1 of the present application.

[0039] Figure 2 This is a graph showing the relationship between the sulfide content and fluorescence intensity of the Maotai-flavor liquor in Example 2 of the present application.

[0040] Figure 3 This is a graph showing the relationship between the sulfide content and fluorescence intensity of the light-fragrance liquor in Example 3 of the present application. DETAILED DESCRIPTION

[0041] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0042] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0043] Fluorescence spectrometer: FL4600, Hitachi, Japan.

[0044] Example 1

[0045] 52%vol Luzhou-flavor liquor: purchased from supermarket;

[0046] 1 mL of wine samples with sulfide contents of 20, 50, 80, 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 μg / L were taken and added into a centrifuge tube containing 2 mL of CsPbBr3 10 mg / mL nanocrystal toluene solution. The mixture was fully mixed at room temperature. After reacting for 3 minutes, 1 mL of the mixed solution was taken into a quartz cuvette. The fluorescence intensity was measured with a fluorescence meter. The excitation wavelength λex = 365 nm, the emission wavelength λem = 512 nm, and each group was measured in parallel 3 times. A linear equation between the fluorescence intensity and the sulfide content of olive-flavor liquor was established, as follows: Figure 1 As shown in Figure 2, as the sulfide content increases, the fluorescence intensity gradually decreases, and the resulting linear equation is y = -7.0817x + 7408.1, R 2 =0.9872.

[0047] According to the above method, the sulfide content of the Luzhou-flavor liquor with unknown sulfide content was found to be 869 μg / L, and then the liquor sample was verified by column chromatography, and the result was 870 μg / L. Thus, the sulfide content of Luzhou-flavor liquor was measured by CsPbBr3 nanocrystal fluorescence quenching method.

[0048] Example 2

[0049] 53%vol Maotai-flavor liquor: purchased from supermarket;

[0050] Fluorescence spectrometer: FL4600, Hitachi, Japan.

[0051] 0.5 mL of Maotai-flavor liquor samples with sulfide contents of 20, 50, 80, 100, 200, 300, 400, 500, 1000, 1500, 2000, and 2500 μg / L were taken and added into a centrifuge tube containing 1 mL of CsPbBr314 mg / mL nanocrystal toluene solution. The mixture was fully mixed at room temperature. After reacting for 1 minute, 1 mL of the mixed solution was taken into a quartz cuvette. The fluorescence intensity was measured with a fluorescence meter. The excitation wavelength λex=365 nm and the emission wavelength λem=512 nm. Each group was measured in parallel 3 times. A linear equation between the fluorescence intensity and the sulfide content of Maotai-flavor liquor was established, as follows: Figure 2 As shown in Figure 2, as the sulfide content increases, the fluorescence intensity gradually decreases, and the resulting linear equation is y = -2.8615x + 7280, R 2 =0.9942.

[0052] According to the above method, the sulfide content of the sauce-flavor liquor with unknown sulfide content was found to be 1847 μg / L, and then the liquor sample was verified by column chromatography, and the result was 1837 μg / L. Thus, the sulfide content of the sauce-flavor liquor was measured by CsPbBr3 nanocrystal fluorescence quenching method.

[0053] Example 3

[0054] 53% Light-flavor liquor: purchased in supermarkets;

[0055] Fluorescence spectrometer: FL4600, Hitachi, Japan.

[0056] 0.9 mL of light-flavor liquor samples with sulfide contents of 20, 50, 80, 100, 200, 300, 400, 500, 600, 700, and 800 μg / L were taken and added into a centrifuge tube containing 1 mL of 25 mg / mL nanocrystal toluene solution of CsPbBr3. The mixture was fully mixed at room temperature. After reacting for 2 minutes, 1 mL of the mixed solution was taken into a quartz cuvette. The fluorescence intensity was measured with a fluorescence meter. The excitation wavelength λex = 365 nm, the emission wavelength λem = 512 nm, and each group was measured three times in parallel. A linear equation between the fluorescence intensity and the sulfide content was established, as follows: Figure 3 As shown in Figure 2, as the sulfide content increases, the fluorescence intensity gradually decreases, and the resulting linear equation is y = -8.3709x + 7808.5, R 2 =0.9914.

[0057] According to the above method, the sulfide content of the light-flavor wine sample with unknown sulfide content was measured to be 569μg / L, and then the wine sample was verified by gas chromatography, and the result was 561μg / L. Thus, the sulfide content of the light-flavor wine sample was measured by CsPbBr3 nanocrystal fluorescence quenching method.

[0058] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A fluorescence quenching detection method for sulfide in liquor, characterized in that: The fluorescence quenching detection method comprises the following steps: (1) mixing a liquor sample to be tested with a nanocrystal solution, reacting the mixture, and obtaining a test solution; (2) using a fluorimeter to measure the fluorescence intensity of the test solution; (3) Substituting the fluorescence intensity value into the standard linear equation, the sulfide content in the liquor sample to be tested is obtained; The nanocrystals are perovskite nanocrystals.

2. The fluorescence quenching detection method according to claim 1, characterized in that: The perovskite nanocrystals are selected from at least one of CH3NH3PbX3, CH(NH2)2PbX3, and CsPbX3, Among them, X=Cl, Br, I.

3. The fluorescence quenching detection method according to claim 1, characterized in that: In the step (1), the volume ratio of the liquor sample to the nanocrystal solution is 0.1-1 mL: 0.1-3 mL.

4. The fluorescence quenching detection method according to claim 1, characterized in that: The concentration of the nanocrystal solution is 10-30 mg / mL.

5. The fluorescence quenching detection method according to claim 1, characterized in that: The method for constructing the standard linear equation includes: Add the same amount of nanocrystal solution to the liquor sample solutions with different sulfide contents, mix them, and after the reaction, use a fluorescence meter to measure the fluorescence intensity value; The corresponding sulfide content and fluorescence intensity values ​​were analyzed to construct a standard linear equation.

6. The fluorescence quenching detection method according to claim 5, characterized in that: The number of samples of the sulfide liquor sample solution is 5 to 20.

7. The fluorescence quenching detection method according to claim 1, characterized in that: In the step (2), the fluorescence excitation wavelength λex during measurement by the fluorescence instrument is in the range of 350 to 370 nm.

8. The fluorescence quenching detection method according to claim 1, characterized in that: In the step (2), the fluorescence detection emission wavelength λem during the fluorescence measurement by the fluorescence instrument is 512nm~520nm.

9. The fluorescence quenching detection method according to claim 1, characterized in that: The reaction time is 1 to 10 minutes.

10. The fluorescence quenching detection method according to claim 1, characterized in that: The solvent in the nanocrystal solution is selected from at least one of n-hexane, cyclohexane and toluene.

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