Method for rapidly screening illegally added propranolol in functional beverage

Abstract

The invention provides a method for rapidly screening illegally added propranolol in a functional beverage, which adopts a liquid phase microextraction technology to separate and enrich a sample, adopts an ultraviolet visible spectrophotometer to detect illegally added propranolol, and adopts an external standard method to quantify, the established method has good linearity, the correlation coefficient of propranolol is greater than 0.999, and the result shows that the method can be used for rapidly screening the illegally added propranolol. The detection limit is 97.2 [mu] g / L, the recovery rate is 95.5%-108.1%, and the relative standard deviation (RSD) is 0.99%-5.59%. The method is good in accuracy, high in precision and sensitivity and suitable for rapidly, qualitatively and quantitatively screening the propranolol illegally added in the functional beverage.

Description

Technical Field

[0001] The present invention relates to the technical field of analysis and detection, and in particular to a method for rapidly screening functional drinks for illegally added propranolol. Background Art

[0002] Functional drinks are popular among consumers for their claims of improving fluid circulation and enhancing athletic performance. However, to enhance their effectiveness, illegal vendors are illegally adding stimulants, such as beta-agonists and beta-blockers, to these drinks. Propranolol, a non-selective beta-1 and beta-2 adrenergic receptor blocker, has become a prominent high-risk drug illegally added to food products due to its sedative and heart rate-lowering properties.

[0003] Chinese patent document CN201711154932.1 discloses a method for rapid screening of 132 illegally added chemical drugs in traditional Chinese medicines and health products. This method uses high-performance liquid chromatography-tandem mass spectrometry to detect illegally added drugs in traditional Chinese medicines or health products. However, at low spike levels, the recovery rate is only 43.36%, and the RSD is greater than 10%, indicating poor accuracy. Chinese patent document CN202311011333.X discloses a sample pretreatment method for simultaneously detecting 24 food-derived stimulants in food. Although it can detect 24 stimulants, the pretreatment process includes enzymatic hydrolysis, extraction, and purification, which is time-consuming and cumbersome to operate. The document "UPLC-MS / MS Simultaneous Determination of Multiple Illegally Added Chemical Drugs in Functional Beverages" discloses a method for detecting 40 illegally added chemical drugs in functional beverages using high-performance liquid chromatography-tandem mass spectrometry, but still uses the QuEChERS sample treatment method to purify the matrix, which is cumbersome to operate and has high technical requirements.

[0004] Liquid-phase microextraction (LPME), developed from supported liquid membrane technology, combines high recovery rates, low solvent consumption, and environmental friendliness. It can purify and enrich target compounds through selective extraction via the supported liquid membrane. Ultraviolet spectrophotometry (UV-Vis) has attracted widespread attention due to its ease of use and affordability, but it still has significant shortcomings in detecting low-concentration targets and eliminating interference from complex matrices. Currently, there is no method for detecting illegally added drugs using the combined combination of LPME and UV spectrophotometry.

[0005] In view of this, the present invention combines liquid phase microextraction and ultraviolet spectrophotometry to provide a method for quickly screening functional drinks for illegally added propranolol with simple operation, high sample recovery rate and high accuracy.

[0006] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0007] In order to solve the problems in the above-mentioned background technology, the main purpose of the present invention is to provide a method for quickly screening functional beverages for illegally added propranolol, which has the advantages of simple operation, high sample recovery rate and high accuracy.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: A method for rapidly screening functional drinks for illegally added propranolol comprises the following steps: Preparation of S1 standard solution Accurately weigh 100 mg of propranolol standard into a 100 mL volumetric flask, add methanol, dissolve, and dilute to the mark. Mix well to obtain a standard stock solution with a mass concentration of 1 mg / mL. Store at 4°C in the dark. S2 sample preparation The sample is pre-treated by liquid phase microextraction to obtain the sample solution to be tested; S3 establishes a standard curve A propranolol standard working solution was prepared, and after pretreatment, detection was performed using an ultraviolet spectrophotometer. A linear regression was performed with the absorbance of propranolol as the ordinate and the various mass concentrations of propranolol as the abscissa to establish a standard curve for propranolol. S4 content determination Under the same test conditions as in step S3, the sample solution to be tested is subjected to ultraviolet detection, and the content of propranolol in the sample to be tested is calculated according to the standard curve.

[0009] Furthermore, the preparation of the propranolol standard working solution includes: respectively aspirating 0 mL, 0.010 mL, 0.025 mL, 0.050 mL, 0.100 mL, 0.250 mL, 0.500 mL, 1.000 mL, and 2.500 mL of a 1 mg / mL propranolol standard stock solution into a 50 mL centrifuge tube, diluting the volume to the scale with NaOH solution, and shaking well to prepare 0, 0.2, 0.5, 1.0, 2.0, 5.0, 10.0, 20.0, and 50.0 mg / L propranolol standard solutions.

[0010] Furthermore, the liquid phase microextraction method includes: taking 20 mL of sample and placing it in a 50 mL centrifuge tube, adding NaOH solution to adjust the pH to alkaline, shaking and ultrasonicating for 15 minutes, taking the supernatant and placing it in a 2 mL centrifuge tube as the sample phase solution; 10 μL of organic membrane solvent was applied to a 200 μm thick polypropylene flat membrane as a support liquid membrane. The pipette tip with the support liquid membrane was embedded in the sample phase solution to construct an extraction system. 500 μL of 10 mM hydrochloric acid solution was taken as the receiving phase and placed in a constant temperature oscillator for extraction. After the extraction was completed, the receiving phase solution was filtered using a 0.22 μm filter membrane to obtain the sample solution to be tested. Furthermore, the organic membrane solvent includes at least one of dinitrophenyl octyl ether, hexyl ether, n-heptanol, n-octanol, n-nonanol, n-decanol, octanone, nonanone, undecanone or tributyl phosphate.

[0011] Furthermore, NaOH was used to adjust the pH to 9-13. The alkaline environment promoted the existence of propranolol in an alkaline form, which was beneficial to subsequent extraction.

[0012] Furthermore, the pH of the hydrochloric acid solution is 1-5.

[0013] Furthermore, the rotation speed of the oscillator is 0-300 r / min, the extraction time is 5-25 min, and during the oscillation process, propranolol is transferred from the sample phase to the receiving phase through the supported liquid membrane.

[0014] Furthermore, the detection wavelength of the ultraviolet spectrophotometer is 215 nm.

[0015] Further, the standard curve of adding propranolol is , with a correlation coefficient of 0.9995. The detection limit of the method is 97.2 μg / L, and the quantification limit is 320 μg / L. This method accurately quantifies propranolol in an addition range of 0.2-10 mg / L. Since propranolol is added to functional drinks to stimulate their effect, the addition amount is not too high. This method, targeting an addition range of 0.2-10 mg / L, is sufficient to cover the actual amount of propranolol added to functional drinks.

[0016] The present invention utilizes the advantages of high recovery rate, low solvent consumption and environmental friendliness of liquid-phase microextraction technology to perform extraction analysis of illegally added propranolol trace substances, and combines ultraviolet determination to achieve qualitative and quantitative judgment of propranolol. The method has the advantages of high sensitivity, good accuracy and precision, and has strong applicability for the separation and detection of propranolol in functional beverages.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention first achieves separation and enrichment of the target through selective extraction of the supported liquid membrane, and then performs ultraviolet spectrophotometric detection on the target. It has strong targeting and anti-interference ability, greatly reduces the occurrence of false positives, and improves the accuracy of qualitative judgment and quantitative determination.

[0018] 2. The method of the present invention has high sensitivity, good accuracy and precision, and fast detection speed. The entire process from extraction to quantitative detection does not exceed 30 minutes. The sample does not require complex pretreatment, which lowers the technical threshold and simplifies the operation process. In addition, it does not require the use of highly toxic or carcinogenic dangerous reagents, and has low harm to the experimental environment and personnel. It does not require large-scale analytical instruments, the equipment cost is low, and it can be widely used in grassroots institutions.

[0019] 3. The detection limit of the method provided by the present invention is 97.2 μg / L, the quantification limit is 320 μg / L, and the correlation coefficient R is within the range of 0.2-10 mg / L. 2 The linear relationship of this method is good and the qualitative and quantitative results are reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings and examples: Figure 1 This is the UV spectrum of the illegally added propranolol of the present invention; Figure 2 is a schematic diagram of a liquid-phase microextraction device of the present invention; Figure 3 It is the standard curve diagram of propranolol of the present invention; Figure 4 Graph showing the effect of organic membrane solvent on propranolol recovery in sample pretreatment of the present invention; Figure 5 3. It is a graph showing the effect of sample phase pH on propranolol recovery in the sample pretreatment of the present invention; Figure 6 3. This is a graph showing the effect of the pH of the receiving phase on the recovery of propranolol in the sample pretreatment of the present invention; Figure 7 Graph showing the effect of oscillator speed on propranolol recovery in sample pretreatment of the present invention; Figure 8 Graph showing the effect of extraction time on propranolol recovery in sample pretreatment of the present invention; Figure 9 It is the interference diagram of the recovery rate of propranolol by different drug combinations of the present invention, In the figure: 1. Propranolol + sertraline, 2. Propranolol + clozapine, 3. Propranolol + amoxicillin, 4. Propranolol, 5. Propranolol + amitriptyline, 6. Propranolol + ampicillin. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the following embodiments and drawings, but they should not be construed as limiting the scope of protection of the present invention.

[0022] In the following examples, the calculation formulas for the detection limit, quantification limit and recovery rate are as follows: The limit of detection (LOD) is calculated as:

[0023] ; The limit of quantitation (LOQ) is calculated as: ; The recovery rate calculation formula is: ; In the above formula, C A is the concentration of the analyte transferred to the receiving phase after extraction, C D is the concentration of analyte added to the sample phase before extraction, V D Refers to the volume of the sample phase solution, V A refers to the volume of the receiving phase solution; σ refers to the standard deviation of the results obtained from 11 extractions of blank samples; and k refers to the slope of the standard curve corresponding to analyte concentration and absorbance.

[0024] Example 1. Instruments and Reagents U-1901 double-beam UV-visible spectrophotometer, Beijing Puxi General Instrument Co., Ltd.; SHA-B dual-function digital display constant temperature oscillator, Changzhou Yineng Experimental Instrument Factory; BSM-220.4 analytical balance (accuracy 0.0001g), Shanghai Zhuojing Electronic Technology Co., Ltd.; 44531PHS-3E pH meter, Shanghai Yidian Scientific Instrument Co., Ltd.; 2300TH CNC ultrasonic cleaner (Shanghai Anpu Experimental Technology Co., Ltd.); Milli-Q pure water system (Merck, Germany).

[0025] Propranolol hydrochloride standard, purity 99.5%, batch number PTI-1119287, was purchased from Northern Weiye Metrology Group Co., Ltd.; hexyl ether, analytical grade, was purchased from Shanghai MacLean Biochemical Co., Ltd.; 2-nitrophenyl octyl ether, n-heptanol, n-octanol, n-nonanol, n-decanol, 2-octanone, 2-nonanone, 5-undecanone, and tributyl phosphate, analytical grade, were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; sodium hydroxide and hydrochloric acid were all analytical grade.

[0026] 2. Methods and testing: 2.1 UV detection conditions Using a UV-visible spectrophotometer, with hydrochloric acid solution as the blank reference solution, propranolol was scanned in the full wavelength range of 190-300 nm (e.g. Figure 1 The characteristic absorption peak of propranolol was determined to be 215 nm.

[0027] 2.2 Standard solution configuration: Accurately weigh 100 mg of propranolol standard into a 100 mL volumetric flask, dissolve it in methanol and dilute to the mark. Shake well to obtain a standard stock solution with a mass concentration of 1 mg / mL. Store at 4°C in the dark. Dilute with sodium hydroxide solution to the desired concentration before use.

[0028] 2.3 Sample pretreatment: The sample was pre-treated by liquid phase microextraction, specifically: 20 mL of sample was placed in a 50 mL centrifuge tube, 1 M NaOH solution was added to adjust the pH to 11, shaken and ultrasonicated for 15 minutes, and the supernatant was placed in a 2 mL centrifuge tube as the sample phase solution; 500 μL of 10 mM pH = 2 hydrochloric acid solution was taken as the receiving phase, 10 μL of organic membrane solvent was applied to a 200 μm thick polypropylene flat membrane as a supporting liquid membrane, and the tip of the gun with the supporting liquid membrane was embedded in the sample phase solution, leaving a small gap between the liquid membrane and the sample solution, the oscillator was turned on and the speed was adjusted to 240 rpm for extraction for 20 minutes. After the extraction was completed, the target was transferred from the sample phase solution to the receiving phase solution, the receiving phase solution was taken out, and then filtered with a 0.22 μm filter membrane. The filtrate obtained was the sample solution to be tested. The liquid phase microextraction device is as follows: Figure 2 shown.

[0029] 2.4 Establish a standard curve: 0 mL, 0.010 mL, 0.025 mL, 0.050 mL, 0.100 mL, 0.250 mL, 0.500 mL, 1.000 mL, and 2.500 mL of 1 mg / mL propranolol standard stock solution were respectively drawn into 50 mL centrifuge tubes, diluted to the mark with NaOH solution, and shaken to prepare 0, 0.2, 0.5, 1.0, 2.0, 5.0, 10.0, 20.0, and 50.0 mg / L propranolol standard solutions. After pretreatment, the solutions were detected by UV spectrophotometer at 215 nm. Linear regression was performed with the absorbance of propranolol (y) as the ordinate and the mass concentration of propranolol (x) as the abscissa to establish a standard curve for propranolol (see Figure 2). Figure 3 shown).

[0030] 2.5 Content determination: Under the same test conditions as in step 2.4, perform UV detection on the sample solution and calculate the propranolol content in the sample based on the standard curve. If the absorbance of the sample solution is above the standard curve, dilute the sample solution and perform UV detection again.

[0031] 3. Optimization of sample pretreatment conditions In order to improve the recovery rate of the target substance propranolol and achieve the purpose of rapid, accurate and efficient screening, the experiment used single-factor optimization to investigate the effects of organic membrane solvent, sample phase pH, receiving phase pH, rotation speed and extraction time on the extraction efficiency of propranolol in liquid phase microextraction.

[0032] 3.1 Organic membrane solvent optimization Preparation of the sample phase (2 mg / L propranolol solution): Accurately transfer 100 μL of the propranolol standard stock solution into a 100 mL volumetric flask, add NaOH solution at a pH of 12 and dilute to the mark, mix well to obtain a 10 mg / L intermediate solution; accurately transfer 20 mL of the intermediate solution into a 100 mL volumetric flask, dilute to the mark with NaOH solution, and shake thoroughly to obtain a 2 mg / L propranolol standard solution.

[0033] Take 1mL of propranolol standard solution (2mg / L, pH=12) as the sample phase solution, inject 500μL of hydrochloric acid solution with pH=2 into the pipette tip as the receiving phase solution, apply 10μL of organic membrane solvent on a 200μm thick polypropylene flat membrane as a supporting liquid membrane, and embed the pipette tip with the supporting liquid membrane into the sample phase solution, leaving a small gap between the liquid membrane and the sample solution; turn on the oscillator and adjust the speed to 180rpm for extraction for 20min. After the extraction is completed, take out the receiving phase solution, filter it with a 0.22μm filter membrane, and detect the filtrate.

[0034] The above organic membrane solvents include: dinitrophenyl octyl ether (NPOE), hexyl ether (DHE), n-heptanol (1-Heptanol), n-octanol (1-Octanol), n-nonanol (1-Nonanol), n-decanol (1-Decanol), octanone (2-Octanone), nonanone (2-Nonanone), undecanone (2-Undecanone) and tributyl phosphate (TBP). The effects of different organic membrane solvents on the extraction efficiency of propranolol are shown in Figure 4 .

[0035] 3.2 Optimization of sample phase pH Based on the optimization in 3.1, 1 mg / mL propranolol standard solution was diluted to 2 mg / L with 1 M NaOH solution and the pH values ​​were adjusted to 9, 10, 11, 12, and 13 respectively. The effect of different sample phase pH on the extraction efficiency of propranolol was investigated. The results are shown in Table 1. Figure 5 .

[0036] 3.3 Optimization of pH of the receiving phase Based on the optimization in 3.2, hydrochloric acid solutions with different pH values ​​(1, 2, 3, 4, and 5) were selected as the receiving phase to investigate the effect of different receiving phase pH values ​​on the extraction efficiency of propranolol. Figure 6 .

[0037] 3.4 Optimization of speed Based on the optimization in 3.3, the shaker speed was adjusted to 0, 60, 120, 180, 240, and 300 r / min respectively to investigate the effect of different speeds on the extraction efficiency of propranolol. Figure 7 .

[0038] 3.5 Optimization of extraction time Based on the optimization in 3.4, the extraction time was adjusted to 5, 10, 15, 20, and 25 min respectively to investigate the effect of different extraction times on the extraction efficiency of propranolol. Figure 8 .

[0039] 4. Results and Analysis 4.1 Determination of sample pretreatment conditions Liquid-phase microextraction has the characteristics of high recovery rate, low solvent consumption and environmental friendliness. The purification and enrichment of the target compound can be achieved through the selective extraction of supported liquid membrane.

[0040] The present invention adopts liquid phase microextraction pretreatment technology to enrich the illegally added propranolol in functional beverages, and optimizes the pretreatment conditions. Final determination: take 20mL functional beverage and place it in a 50mL centrifuge tube, add 1M NaOH solution to adjust pH=11, shake well and ultrasonicate for 15min, take the supernatant in a 2mL centrifuge tube, as sample phase solution; take 500μL10mM hydrochloric acid solution with pH of 2 as receiving phase, 10μL TBP organic film solvent is smeared on a polypropylene flat membrane with a thickness of 200μm as a supporting liquid membrane, the gun head with the supporting liquid membrane is embedded in the sample phase solution, leaving a little gap between the liquid membrane and the sample solution, turn on the oscillator and adjust the speed to 240rpm for extraction 20min, after the extraction is completed, propranolol is transferred from the sample phase solution to the receiving phase solution, the receiving phase solution is taken out, and 0.22μm filter membrane is filtered and detected. Propranolol extraction is carried out under the above conditions, and propranolol can be efficiently recovered.

[0041] 4.2 Linear Relationship 0 mL, 0.010 mL, 0.025 mL, 0.050 mL, 0.100 mL, 0.250 mL, 0.500 mL, 1.000 mL, and 2.500 mL of 1 mg / mL propranolol standard stock solution were respectively drawn into 50 mL centrifuge tubes, diluted to the mark with NaOH solution, and shaken to prepare 0, 0.2, 0.5, 1.0, 2.0, 5.0, 10.0, 20.0, and 50.0 mg / L propranolol standard solutions. After pretreatment, the solution was analyzed by UV spectrophotometry. The detection was performed by a linear regression between the absorbance (y) of propranolol and each mass concentration (x) to establish a standard equation. A certain concentration of propranolol standard solution was added to the blank sample, and LPME-UV-Vis separation and detection were performed according to the pretreatment conditions in 4.1 (organic membrane solvent: TBP, sample phase pH: 11, receiving phase pH: 2, rotation speed: 240 rpm, extraction time: 20 min). The detection limit and quantification limit of propranolol were measured using a signal-to-noise ratio (S / N) of 3 and 10, respectively. The results are shown in Table 1.

[0042] Table 1

[0043] As can be seen from Table 1, propranolol in the range of 0.2-10 mg·L -1 Within the concentration range of 1.577 μg / L, the linear correlation coefficient was greater than 0.995, indicating a good linear relationship. The detection limit of this method was 97.2 μg / L, and the quantification limit was 320 μg / L, indicating that it had good sensitivity and accuracy.

[0044] 4.3 Selective Inspection: Propranolol was mixed with common illegally added drugs such as ampicillin, amoxicillin, amitriptyline, clozapine, and sertraline in a 1:1 ratio to obtain a 2 mg / L, pH=11 mixed drug solution. The solution was extracted under the above optimized pretreatment conditions and analyzed by UV spectrophotometry. Figure 8 .

[0045] Depend on Figure 8 As can be seen, the differences in recovery rates between different drug combinations and propranolol alone were small (relative deviation less than 5%), indicating that the extraction method of the present invention has strong selectivity for propranolol. This suggests that the method can effectively eliminate interference from other drug components in functional beverages, reduce the occurrence of false positives, and has good method specificity.

[0046] 4.4 Spiked recovery and precision: Two functional beverages (a sparkling functional beverage and a non-sparkling functional beverage) without illegally added propranolol were selected. 50 μL of a 2000 mg / L and 5000 mg / L propranolol standard solution were added to 50 mL of beverage A and 50 mL of beverage B, respectively. The pH was adjusted to 11 with sodium hydroxide solution to obtain spiked samples with concentrations of 2 mg / L and 5 mg / L, respectively. Six replicates were performed at each concentration, and the spiked recovery and precision were calculated. The results are shown in the table below.

[0047] Table 1 Average recovery and relative standard deviation of illegally added propranolol

[0048] Note: ND means not detected, - means none.

[0049] As can be seen from the above table, the average recovery of propranolol is 95.5%~108.1%, and the relative standard deviation (RSD) is 0.99%~5.59%, indicating that the method established in the present invention has high accuracy and good precision.

[0050] 4.5 Actual effect verification: The above test method was used to conduct actual verification on six functional beverages produced by different manufacturers on the market (Scream, Jianlibao, Pulse, Water-soluble C100, Vitamin Water, and Yuanqi Forest). The test results are shown in the following table:

[0051] Note: - indicates not detected.

[0052] From the above test results, it can be seen that there is no illegal conditional propranolol in the six functional drinks, which shows that the functional drinks on the market are relatively safe.

[0053] In summary, the present invention combines liquid-phase microextraction with ultraviolet spectrophotometry. By optimizing the liquid-phase microextraction conditions, a rapid screening method for propranolol in functional beverages using liquid-phase microextraction-ultraviolet spectrophotometry has been established. Propranolol exhibits good linearity within the concentration range of 0.2-10.0 mg / L, with a correlation coefficient greater than 0.995, meeting the accuracy and precision requirements of the analytical method. The method has a limit of detection (LOD) of 97.2 μg / L and a limit of quantification (LOQ) of 320 μg / L. This method exhibits high sensitivity, good accuracy, precision, high detection throughput, rapid detection, and strong specificity. It is suitable for rapid screening of illegally added propranolol in functional beverages, providing technical support for combating illegal additions and regulating the functional beverage market.

[0054] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for rapidly screening functional drinks for the illegal addition of propranolol, characterized by: The following steps are involved: Preparation of S1 standard solution Accurately weigh 100 mg of propranolol standard into a 100 mL volumetric flask, dissolve it in methanol and dilute to the mark. Mix well to obtain a standard stock solution with a mass concentration of 1 mg / mL. Store at 4°C in the dark. S2 sample pretreatment The sample is pre-treated by liquid phase microextraction to obtain the sample solution to be tested; S3 establishes a standard curve A propranolol standard working solution was prepared and detected using an ultraviolet spectrophotometer. A linear regression was performed with the absorbance of propranolol as the ordinate and the mass concentrations of propranolol as the abscissa to establish a standard curve for propranolol. S4 content determination Under the same test conditions as in step S3, the sample solution to be tested is subjected to ultraviolet detection, and the content of propranolol in the sample to be tested is calculated according to the standard curve.

2. The method for rapidly screening for illegal addition of propranolol in functional beverages according to claim 1, wherein: The preparation of the propranolol standard working solution includes: respectively aspirating 0 mL, 0.010 mL, 0.025 mL, 0.050 mL, 0.100 mL, 0.250 mL, 0.500 mL, 1.000 mL, and 2.500 mL of a 1 mg / mL propranolol standard stock solution into a 50 mL centrifuge tube, diluting the solution to the mark with a NaOH solution, and shaking the solution to prepare 0, 0.2, 0.5, 1.0, 2.0, 5.0, 10.0, 20.0, and 50.0 mg / L propranolol standard solutions.

3. The method for rapidly screening for illegal addition of propranolol in functional beverages according to claim 1, wherein: The liquid phase microextraction method comprises: taking 20 mL of sample and placing it in a 50 mL centrifuge tube, adding NaOH solution to adjust the pH to alkaline, shaking and ultrasonicating for 15 minutes, taking the supernatant and placing it in a 2 mL centrifuge tube as the sample phase solution; 10 μL of organic membrane solvent was applied to a 200 μm thick polypropylene flat membrane as a supporting liquid membrane, and the gun tip with the supporting liquid membrane was embedded in the sample phase solution; 500 μL of 10 mM hydrochloric acid solution was taken as the receiving phase, and the constant temperature oscillator was turned on and the speed was adjusted for extraction. After the extraction was completed, the receiving phase solution was filtered using a 0.22 μm filter membrane to obtain the sample solution to be tested.

4. The method for rapidly screening for illegal addition of propranolol in functional drinks according to claim 3, wherein: The organic membrane solvent includes at least one of dinitrophenyl octyl ether, hexyl ether, n-heptanol, n-octanol, n-nonanol, n-decanol, octanone, nonanone, undecanone or tributyl phosphate.

5. The method for rapidly screening for illegal addition of propranolol in functional beverages according to claim 3, characterized in that: The pH was adjusted to 9-13 using NaOH.

6. The method for rapidly screening for illegal addition of propranolol in functional beverages according to claim 3, characterized in that: The pH of the hydrochloric acid solution is 1-5.

7. The method for rapidly screening for illegal addition of propranolol in functional beverages according to claim 3, characterized in that: The rotation speed of the oscillator is 0-300 r / min, and the extraction time is 5-25 min.

8. The method for rapidly screening for illegal addition of propranolol in functional beverages according to claim 1, characterized in that: The detection wavelength of the ultraviolet spectrophotometer is 215 nm.

9. The method for rapidly screening for illegal addition of propranolol in functional beverages according to claim 1, characterized in that: The standard curve of propranolol is , the correlation coefficient is 0.9995.

10. The method for rapidly screening functional drinks for illegal addition of propranolol according to claim 1, characterized in that: The detection limit of the method was 97.2 μg / L, and the quantification limit was 320 μg / L.

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