A high-sensitivity spectral analysis method for rapidly determining 1.2-propylene glycol content

Abstract

The application discloses a high-sensitivity spectral analysis method for rapidly determining 1.2-propylene glycol content, and relates to the technical field of spectral analysis. ‑1 The C-O stretching vibration peak of PG is shifted to 1078 cm The signal-to-noise ratio is improved, high-selectivity detection effect is generated, the interference of ethanol in liquor and glycerol in cosmetics is effectively avoided, the SERS detection parameters and the internal standard method are optimized, the sensitivity is improved, the detection effect is effectively improved through a standardized rapid pretreatment process and a 5-minute borate ester bond reaction, and the accuracy of the determination is improved through verification of the applicability of complex matrixes.

Description

Technical Field

[0001] This invention relates to the field of spectroscopic analysis technology, specifically to a highly sensitive spectroscopic analysis method for rapidly determining the content of 1,2-propanediol. Background Technology

[0002] Existing high-sensitivity spectroscopic methods for rapid determination of 1,2-propanediol content still have the following drawbacks in practical applications:

[0003] 1,2-Propanediol (PG), an important small-molecule alcohol compound, is widely used in food, pharmaceuticals, cosmetics, and industrial production due to its excellent water solubility, moisturizing properties, and solvent characteristics. In the food industry, 1,2-Propanediol is often added to baked goods, beverages, and dairy products as a humectant, thickener, and solvent to improve product texture and extend shelf life. In the pharmaceutical field, it is a common excipient in injections and oral liquids, serving as a cosolvent and humectant to regulate drug stability. In the cosmetics industry, it is widely used as a moisturizing ingredient in lotions, creams, and toners, effectively maintaining skin hydration. In industrial production, 1,2-Propanediol is a key raw material for antifreeze and coatings, playing a role in antifreeze and solubilization.

[0004] However, excessive use or improper addition of 1,2-propanediol may pose safety risks. For example, excessive levels of 1,2-propanediol in food may cause gastrointestinal discomfort and other health problems in consumers. The Codex Alimentarius Commission (CAC) has clearly defined the maximum amount it can be used in food. In pharmaceutical preparations, deviations in the concentration of 1,2-propanediol may affect the efficacy of the drug and even cause adverse reactions. In cosmetics, excessively high levels may damage the skin barrier function and lead to allergies.

[0005] Currently, common methods for detecting 1,2-propanediol include gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), and traditional spectroscopic methods, but these methods have obvious limitations.

[0006] In recent years, surface-enhanced Raman spectroscopy (SERS) has attracted attention in the analysis of small molecule compounds due to its high sensitivity, fingerprint recognition ability, and rapid detection advantages. However, existing SERS-based methods for the detection of 1,2-propanediol still have bottlenecks: on the one hand, the 1,2-propanediol molecule lacks strong Raman-active groups, resulting in weak direct detection signals and insufficient signal-to-noise ratio; on the other hand, existing SERS substrates have poor specific adsorption capacity for 1,2-propanediol and are easily interfered with by complex matrices, making it difficult to meet the requirements of trace analysis. Summary of the Invention

[0007] The purpose of this invention is to provide a highly sensitive spectroscopic analysis method for the rapid determination of 1,2-propanediol content, in order to solve the aforementioned problems.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a highly sensitive spectroscopic analysis method for rapid determination of 1,2-propanediol content, comprising the following steps:

[0009] S1: Preparation of 4-mercaptophenylboronic acid (4-MPBA) modified silver nanocube substrate;

[0010] S2: The sample to be tested is brought into contact with the substrate and reacted to form a borate ester complex with 1,2-propanediol (PG) and 4-MPBA;

[0011] S3: The SERS spectrum of the complex was acquired using 785nm laser excitation;

[0012] S4: Based on 1078cm -1 The intensity of the characteristic peak of PG-4MPBA was used to quantify the PG content.

[0013] Furthermore, the preparation of the silver nanocube substrate includes:

[0014] Sodium borohydride with a concentration of 0.01-0.05 mol / L is used to reduce silver nitrate with a concentration of 0.05-0.1 mol / L to form seed crystals, wherein the molar ratio of sodium borohydride to silver nitrate is 1:1-1:3;

[0015] In the presence of ascorbic acid at a concentration of 0.02-0.08 mol / L, a cube with a side length of 50±5 nm was obtained by hydrothermal growth at 45±2℃ for 30 minutes.

[0016] A 10 mM 4-MPBA ethanol solution was mixed with a cubic colloid at a volume ratio of 1:5 to 1:10 and shaken for 2 hours to form a monomolecular modified layer.

[0017] When preparing silver nanocube substrates, the hydrothermal growth process is carried out in a polytetrafluoroethylene reactor with a reactor filling degree of 60-80%.

[0018] Furthermore, the reaction conditions in step S2 are as follows: a phosphate buffer system with a pH of 8.0 ± 0.2 and a concentration of 0.01-0.05 mol / L; a reaction time of 5 minutes; and the reaction must be carried out under constant temperature conditions of 25-30℃.

[0019] The formation of the boronic acid ester bond shifts the CO stretching vibration peak of PG to 1078 cm⁻¹. -1 The signal-to-noise ratio is improved by 20 times;

[0020] The volume ratio of the sample to the substrate is 1:1 to 1:5, and the contact reaction is carried out using a shaker with an oscillation rate of 100-150 r / min.

[0021] Furthermore, in step S3, the SERS parameters are set as follows:

[0022] Laser power: 10mW, laser spot diameter on the sample is 1-3μm;

[0023] Integration time: 10s, integrate 3 times consecutively for each spectrum acquisition and take the average value;

[0024] Spectral range: 600–1800 cm⁻¹ -1 ;

[0025] Resolution: 2cm -1 ;

[0026] When collecting SERS spectra, the sample is placed in a quartz cuvette with an optical path of 1 cm, and the instrument needs to be calibrated for dark current before each measurement.

[0027] Furthermore, in step S4, baseline correction and Savitzky-Golay smoothing are used to preprocess the spectrum, where the Savitzky-Golay smoothing window size is 5-11 points and the polynomial order is 2; through a 1078 cm⁻¹... -1 Peak area and internal standard peak (1580 cm⁻¹ of 4-MPBA) -1 A standard curve is established based on the ratio of ).

[0028] Furthermore, the method for establishing the standard curve is as follows:

[0029] Prepare PG standard solutions of 0.1–1000 ppm, with at least 3 parallel samples for each concentration gradient;

[0030] The SERS intensity ratio (I) of each parallel sample was measured. 1078 / I 1580 ), and calculate the average value;

[0031] Plotting the concentration of the PG standard solution on the x-axis and the corresponding average SERS intensity ratio on the y-axis, a linear equation was fitted: y = 0.0185x + 0.0032(R²). 2 =0.9993).

[0032] Furthermore, the limit of detection (LOD) is 0.1 ppm and the limit of quantitation (LOQ) is 0.3 ppm;

[0033] The LOD was determined by the 3-fold blank standard deviation method, wherein the blank sample was the corresponding matrix solution without PG, and the parallel determination was performed more than 10 times; the LOQ was determined by the 10-fold blank standard deviation method.

[0034] Furthermore, precision is characterized by relative standard deviation (RSD):

[0035] Intra-day RSD ≤ 2.1%, n = 6, concentration 10 ppm, intra-day precision determination is to measure 6 times consecutively on the same day for a PG sample with a concentration of 10 ppm;

[0036] The daytime RSD is ≤3.5%, n=3 days. The daytime precision is determined by measuring the PG sample with a concentration of 10 ppm twice a day for 3 consecutive days.

[0037] Furthermore, accuracy was evaluated using spiked recovery rates:

[0038] Recovery rates in the baijiu matrix were 98.2–102.5%, with spiked concentrations of 1 ppm, 10 ppm, and 100 ppm, and three parallel samples were set up for each concentration.

[0039] Recovery rates in cosmetic matrix: 96.8–101.3%, with spiking concentrations of 1 ppm, 10 ppm, and 100 ppm, and three parallel samples for each concentration.

[0040] Furthermore, it applies to the following samples:

[0041] Baijiu (Chinese liquor), wine, moisturizing cosmetics, and antifreeze industrial products;

[0042] The detection time is ≤8 minutes (including pretreatment), which includes simple dilution or filtration of the sample. The dilution factor is determined according to the estimated concentration of PG in the sample, usually 1:10-1:100.

[0043] For antifreeze industrial product samples, an equal amount of ethanol should be added for demulsification before subsequent dilution.

[0044] Compared with existing technologies, the high-sensitivity spectroscopic analysis method for rapid determination of 1,2-propanediol content provided by this invention has the following advantages:

[0045] This rapid and highly sensitive spectroscopic method for determining 1,2-propanediol content utilizes a 4-MPBA-modified silver nanocube substrate to specifically form boronic acid ester bonds with PG, shifting the CO stretching vibration peak of PG to 1078 cm⁻¹. -1Furthermore, the improved signal-to-noise ratio results in highly selective detection, effectively avoiding interference from ethanol in liquor and glycerol in cosmetics; the optimized SERS detection parameters and internal standard quantification improve sensitivity; the standardized rapid pretreatment process and 5-minute borate ester bond reaction effectively enhance detection performance; and the verification of applicability to complex matrices improves the accuracy of the determination. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0047] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0049] Please see Figure 1 A rapid and highly sensitive spectroscopic analysis method for determining the content of 1,2-propanediol includes the following steps:

[0050] S1: Preparation of 4-mercaptophenylboronic acid (4-MPBA) modified silver nanocube substrate;

[0051] S2: The sample to be tested is brought into contact with the substrate and reacted to form a borate ester complex with 1,2-propanediol (PG) and 4-MPBA;

[0052] S3: The SERS spectrum of the complex was acquired using 785nm laser excitation;

[0053] S4: Based on 1078cm -1 The intensity of the characteristic peak of PG-4MPBA was used to quantify the PG content.

[0054] The preparation of the silver nanocube substrate includes:

[0055] Sodium borohydride with a concentration of 0.01-0.05 mol / L is used to reduce silver nitrate with a concentration of 0.05-0.1 mol / L to form seed crystals, wherein the molar ratio of sodium borohydride to silver nitrate is 1:1-1:3;

[0056] In the presence of ascorbic acid at a concentration of 0.02-0.08 mol / L, a cube with a side length of 50±5 nm was obtained by hydrothermal growth at 45±2℃ for 30 minutes.

[0057] A 10 mM 4-MPBA ethanol solution was mixed with a cubic colloid at a volume ratio of 1:5 to 1:10 and shaken for 2 hours to form a monomolecular modified layer.

[0058] When preparing silver nanocube substrates, the hydrothermal growth process is carried out in a polytetrafluoroethylene reactor with a reactor filling degree of 60-80%.

[0059] The reaction conditions in step S2 are as follows: a phosphate buffer system with a pH of 8.0 ± 0.2 and a concentration of 0.01-0.05 mol / L; a reaction time of 5 minutes; and the reaction must be carried out under constant temperature conditions of 25-30℃.

[0060] The formation of boronic acid ester bonds shifts the CO stretching vibration peak of PG to 1078 cm⁻¹. -1 The signal-to-noise ratio is improved by 20 times;

[0061] The volume ratio of the sample to the substrate is 1:1 to 1:5, and the contact reaction is carried out by shaking on a shaker at a speed of 100-150 r / min.

[0062] In step S3, the SERS parameters are set as follows:

[0063] Laser power: 10mW, laser spot diameter on the sample is 1-3μm;

[0064] Integration time: 10s, integrate 3 times consecutively for each spectrum acquisition and take the average value;

[0065] Spectral range: 600–1800 cm⁻¹ -1 ;

[0066] Resolution: 2cm -1 ;

[0067] When collecting SERS spectra, the sample is placed in a quartz cuvette with an optical path of 1 cm, and the instrument needs to be calibrated for dark current before each measurement.

[0068] In step S4, baseline correction and Savitzky-Golay smoothing are used to preprocess the spectrum. The Savitzky-Golay smoothing window size is 5-11 points, and the polynomial order is 2. The spectrum is then processed through a 1078 cm⁻¹ spectral depth. -1 Peak area and internal standard peak (1580 cm⁻¹ of 4-MPBA) -1 A standard curve is established based on the ratio of ).

[0069] The method for establishing a standard curve is as follows:

[0070] Prepare PG standard solutions of 0.1–1000 ppm, with at least 3 parallel samples for each concentration gradient;

[0071] The SERS intensity ratio (I) of each parallel sample was measured. 1078 / I 1580 ), and calculate the average value;

[0072] Plotting the concentration of the PG standard solution on the x-axis and the corresponding average SERS intensity ratio on the y-axis, a linear equation was fitted: y = 0.0185x + 0.0032(R²). 2 =0.9993).

[0073] The limit of detection (LOD) is 0.1 ppm, and the limit of quantitation (LOQ) is 0.3 ppm.

[0074] LOD was determined using the 3-fold blank standard deviation method, where the blank sample was the corresponding matrix solution without PG, and the determination was performed in parallel more than 10 times; LOQ was determined using the 10-fold blank standard deviation method.

[0075] Precision is characterized by relative standard deviation (RSD):

[0076] Intra-day RSD ≤ 2.1%, n = 6, concentration 10 ppm, intra-day precision determination is to measure 6 times consecutively on the same day for a PG sample with a concentration of 10 ppm;

[0077] The daytime RSD is ≤3.5%, n=3 days. The daytime precision is determined by measuring the PG sample with a concentration of 10 ppm twice a day for 3 consecutive days.

[0078] Accuracy is evaluated using spiked recovery rate:

[0079] Recovery rates in the baijiu matrix were 98.2–102.5%, with spiked concentrations of 1 ppm, 10 ppm, and 100 ppm, and three parallel samples were set up for each concentration.

[0080] Recovery rates in cosmetic matrix: 96.8–101.3%, with spiking concentrations of 1 ppm, 10 ppm, and 100 ppm, and three parallel samples for each concentration.

[0081] Applicable to the following samples:

[0082] Baijiu (Chinese liquor), wine, moisturizing cosmetics, and antifreeze industrial products;

[0083] The detection time is ≤8 minutes (including pretreatment), which includes simple dilution or filtration of the sample. The dilution factor is determined according to the estimated concentration of PG in the sample, usually 1:10-1:100.

[0084] For antifreeze industrial product samples, an equal amount of ethanol should be added for demulsification before subsequent dilution.

[0085] Example 1: Preparation of silver nanocube substrates modified with 4-mercaptophenylboronic acid (4-MPBA)

[0086] (1) Seed preparation: Take 5 mL of 0.025 mol / L silver nitrate solution and place it in a beaker. Under magnetic stirring, slowly add 5 mL of 0.01 mol / L sodium borohydride solution (the molar ratio of sodium borohydride to silver nitrate is 1:2.5). Continue stirring for 10 minutes to obtain a brownish-yellow silver nanocrystal seed solution, and store it in a refrigerator at 4℃ for later use.

[0087] (2) Growth of silver nanocubes: 100 mL of deionized water was added to a 250 mL three-necked flask, followed by 5 mL of the above seed solution and 8 mL of 0.05 mol / L ascorbic acid solution. After stirring evenly, the three-necked flask was placed in a constant temperature water bath at 45 °C for hydrothermal growth for 30 minutes. The reaction was carried out in a polytetrafluoroethylene reactor with a filling degree of 70%. After the reaction was completed, the mixture was naturally cooled to room temperature to obtain a colloidal solution of silver nanocubes. The side length of the solution was 50 ± 5 nm, as determined by transmission electron microscopy.

[0088] (3) 4-MPBA modification: Take 10 mL of silver nanocube colloidal solution into a centrifuge tube, add 2 mL of 10 mM 4-MPBA ethanol solution (volume ratio 5:1), and shake at 120 r / min for 2 hours at 25 °C; after shaking, centrifuge at 8000 r / min for 10 minutes, discard the supernatant, wash the precipitate 3 times with deionized water to obtain 4-MPBA modified silver nanocube substrate, redisperse it in 10 mL of deionized water for later use.

[0089] Example 2: Detection of 1,2-propanediol in Baijiu Samples

[0090] (1) Sample pretreatment: Take 1 mL of liquor sample, add 9 mL of deionized water for dilution (dilution ratio is 1:10), stir evenly, filter with a 0.22 μm filter membrane to remove impurities and obtain the sample solution to be tested.

[0091] (2) Reaction process: Take 2 mL of the sample solution to be tested into a centrifuge tube, add 2 mL of the 4-MPBA modified silver nanocube substrate (volume ratio of 1:1) prepared above, and then add 0.5 mL of phosphate buffer solution with a concentration of 0.02 mol / L and a pH of 8.0. Shake the reaction at 120 r / min at 25 °C for 5 minutes to form a borate ester bond complex between 1,2-propanediol and 4-MPBA.

[0092] (3) SERS spectral acquisition: The reacted mixed solution was transferred into a quartz cuvette with a 1 cm optical path and detected using a 785 nm laser Raman spectrometer. The instrument parameters were set as follows: laser power 10 mW, laser spot diameter on the sample 2 μm, integration time 10 s, and the average value was taken after three consecutive integrations for each spectral acquisition. The spectral range was 600–1800 cm⁻¹. -1 2cm resolution -1 Dark current calibration of the instrument is performed before each measurement.

[0093] (4) Data Processing: The acquired SERS spectra were preprocessed using professional spectral analysis software, including baseline correction and Savitzky-Golay smoothing (window size of 7 points, polynomial order of 2); the 1078 cm⁻¹ was calculated using the software. -1 Peak area and internal standard peak (1580 cm⁻¹ of 4-MPBA) -1 The ratio of (I) 1078 / I 1580 ).

[0094] (5) Quantitative analysis: Based on the pre-established standard curve (y = 0.0185x + 0.0032, R0), 2 =0.9993), substitute the intensity ratio obtained above into the equation to calculate the concentration of 1,2-propanediol in the diluted sample, and then multiply by the dilution factor of 10 to obtain the actual content of 1,2-propanediol in the liquor sample.

[0095] (6) Accuracy verification: The spiked recovery experiment was conducted. 1 ppm, 10 ppm and 100 ppm of 1,2-propanediol standard solution were added to the liquor samples respectively. Three parallel samples were set up for each concentration. The detection was carried out according to the above method, and the spiked recovery rate was calculated. The result was 98.2-102.5%.

[0096] Example 3: Detection of 1,2-propanediol in cosmetic samples

[0097] (1) Sample pretreatment: Take 1g of moisturizing cosmetic sample, add 9mL of deionized water, and extract by ultrasonication at 50℃ for 10 minutes to fully dissolve the sample; after cooling to room temperature, centrifuge at 5000r / min for 10 minutes, take the supernatant, filter it with a 0.22μm filter membrane to obtain the sample solution to be tested.

[0098] (2) Reaction process: Take 2 mL of the sample solution to be tested into a centrifuge tube, add 1 mL of the 4-MPBA modified silver nanocube substrate (volume ratio of 2:1) prepared above, and then add 0.5 mL of phosphate buffer solution with a concentration of 0.02 mol / L and a pH of 8.0. Shake at 120 r / min for 5 minutes at 25 °C.

[0099] (3) SERS spectral acquisition and data processing: Same as steps (3) and (4) in Example 2.

[0100] (4) Quantitative analysis: Same as step (5) in Example 2.

[0101] (5) Accuracy verification: 1 ppm, 10 ppm and 100 ppm of 1,2-propanediol standard solution were added to the cosmetic samples respectively. Three parallel samples were set up for each concentration. The detection was carried out according to the above method, and the spiked recovery rate was calculated. The results were 96.8–101.3%.

[0102] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A rapid and highly sensitive spectroscopic analysis method for determining the content of 1,2-propanediol, characterized in that, Includes the following steps: S1: Preparation of 4-mercaptophenylboronic acid modified silver nanocube substrate; S2: The sample to be tested is brought into contact with the substrate and reacted to form a borate ester complex with 1,2-propanediol and 4-MPBA; S3: The SERS spectrum of the complex was acquired using 785nm laser excitation; S4: Based on 1078cm -1 The intensity of the characteristic peak of PG-4MPBA was used to quantify the PG content.

2. The high-sensitivity spectroscopic analysis method for rapid determination of 1,2-propanediol content according to claim 1, characterized in that, The preparation of the silver nanocube substrate includes: Sodium borohydride with a concentration of 0.01-0.05 mol / L is used to reduce silver nitrate with a concentration of 0.05-0.1 mol / L to form seed crystals, wherein the molar ratio of sodium borohydride to silver nitrate is 1:1-1:3; In the presence of ascorbic acid at a concentration of 0.02-0.08 mol / L, a cube with a side length of 50±5 nm was obtained by hydrothermal growth at 45±2℃ for 30 minutes. A 10 mM 4-MPBA ethanol solution was mixed with a cubic colloid at a volume ratio of 1:5 to 1:10 and shaken for 2 hours to form a monomolecular modified layer. When preparing silver nanocube substrates, the hydrothermal growth process is carried out in a polytetrafluoroethylene reactor with a reactor filling degree of 60-80%.

3. The high-sensitivity spectroscopic analysis method for rapid determination of 1,2-propanediol content according to claim 1, characterized in that, The reaction conditions in step S2 are as follows: a phosphate buffer system with a pH of 8.0 ± 0.2 and a concentration of 0.01-0.05 mol / L; a reaction time of 5 minutes; and the reaction must be carried out under constant temperature conditions of 25-30℃. The formation of the boronic acid ester bond shifts the CO stretching vibration peak of PG to 1078 cm⁻¹. -1 The signal-to-noise ratio is improved by 20 times; The volume ratio of the sample to the substrate is 1:1 to 1:5, and the contact reaction is carried out by shaking on a shaker at a rate of 100-150 r / min.

4. The high-sensitivity spectroscopic analysis method for rapid determination of 1,2-propanediol content according to claim 1, characterized in that, In step S3, the SERS parameters are set as follows: Laser power: 10mW, laser spot diameter on the sample is 1-3μm; Integration time: 10s, integrate 3 times consecutively for each spectrum acquisition and take the average value; Spectral range: 600–1800 cm⁻¹ -1 ; Resolution: 2cm -1 ; When acquiring SERS spectra, the sample is placed in a quartz cuvette with an optical path of 1 cm, and the instrument must be calibrated for dark current before each measurement.

5. The highly sensitive spectroscopic analysis method for rapid determination of 1,2-propanediol content according to claim 1, characterized in that, In step S4, baseline correction and Savitzky-Golay smoothing are used to preprocess the spectrum. The Savitzky-Golay smoothing window size is 5-11 points, and the polynomial order is 2. The spectrum is then processed through a 1078 cm⁻¹ spectral depth. -1 A standard curve is established by the ratio of peak area to internal standard peak.

6. The highly sensitive spectroscopic analysis method for rapid determination of 1,2-propanediol content according to claim 5, characterized in that, The method for establishing the standard curve is as follows: Prepare PG standard solutions of 0.1–1000 ppm, with at least 3 parallel samples for each concentration gradient; The SERS intensity ratio (I) of each parallel sample was measured. 1078 / I 1580 ), and calculate the average value; Plotting the concentration of the PG standard solution on the x-axis and the corresponding average SERS intensity ratio on the y-axis, a linear equation is fitted: y = 0.0185x + 0.0032.

7. The high-sensitivity spectroscopic analysis method for rapid determination of 1,2-propanediol content according to claim 1, characterized in that, The limit of detection is 0.1 ppm, and the limit of quantitation is 0.3 ppm. The LOD was determined by the 3-fold blank standard deviation method, wherein the blank sample was the corresponding matrix solution without PG, and the parallel determination was performed more than 10 times; the LOQ was determined by the 10-fold blank standard deviation method.

8. The high-sensitivity spectroscopic analysis method for rapid determination of 1,2-propanediol content according to claim 1, characterized in that, Precision is characterized by relative standard deviation: Intra-day RSD ≤ 2.1%, n = 6, concentration 10 ppm, intra-day precision determination is to measure 6 times consecutively on the same day for a PG sample with a concentration of 10 ppm; The daytime RSD is ≤3.5%, n=3 days. The daytime precision is determined by measuring the PG sample with a concentration of 10 ppm twice a day for 3 consecutive days.

9. The high-sensitivity spectroscopic analysis method for rapid determination of 1,2-propanediol content according to claim 1, characterized in that, Accuracy is evaluated using spiked recovery rate: Recovery rates in baijiu matrix: 98.2–102.5%, with baijiu matrix spiked at concentrations of 1 ppm, 10 ppm, and 100 ppm, and three parallel samples set up for each concentration; Recovery rates in cosmetic matrix: 96.8–101.3%, with spiking concentrations of 1 ppm, 10 ppm, and 100 ppm, and three parallel samples for each concentration.

10. A highly sensitive spectroscopic analysis method for rapid determination of 1,2-propanediol content according to any one of claims 1-9, characterized in that, Applicable to the following samples: Baijiu (Chinese liquor), wine, moisturizing cosmetics, and antifreeze industrial products; The detection time is ≤8 minutes, including pretreatment including simple dilution or filtration of the sample. The dilution factor is determined according to the estimated concentration of PG in the sample, usually 1:10-1:

100. For antifreeze industrial product samples, an equal amount of ethanol should be added for demulsification before subsequent dilution.

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