Method for simultaneously determining contents of water, ethanol, 1, 2-propylene glycol and glycerol in tobacco essence and perfume

Abstract

The invention provides a method for simultaneously determining the content of water, ethanol, 1, 2-propylene glycol and glycerol in tobacco flavors and fragrances, and belongs to the technical field of tobacco detection, analysis and application. By adopting the gas chromatography double-column double-detector system, the response degree, sensitivity and accuracy of water, ethanol, 1, 2-propylene glycol and glycerol in the tobacco flavors and fragrances can be remarkably improved, the time, labor, reagents and consumables of pretreatment and gas chromatography are saved, and the defects of water, ethanol, 1, 2-propylene glycol and glycerol in the tobacco flavors and fragrances are overcome. The blank of simultaneous determination of 1, 2-propylene glycol and glycerol is realized.

Description

Technical Field

[0001] This application relates to the technical field of tobacco detection and analysis applications, and particularly to a method for simultaneously determining the contents of water, ethanol, 1,2-propanediol, and glycerol in tobacco flavorings. Background Art

[0002] Tobacco flavorings play a crucial role in cigarette production. Their quality directly affects the taste and smoking flavor of cigarettes, and thus determines the consumer experience and the market competitiveness of products.

[0003] Water, ethanol, 1,2-propanediol, and glycerol, as important components of tobacco flavorings, have a significant impact on the performance of flavorings and cigarette quality. The water content affects the stability and volatility of tobacco flavorings. Excessive water may cause hydrolysis, mildew, and other reactions in flavorings, shortening the shelf life; too little water may affect its dispersibility and wettability in cigarettes, resulting in uneven aroma release. Ethanol can regulate the volatility of flavorings. Appropriate ethanol helps the uniform release of aroma and improves the aroma coordination during cigarette smoking; if the ethanol content is inappropriate, it will cause the aroma to volatilize too fast or too slow, affecting the smoking quality. 1,2-Propanediol and glycerol have good moisture retention and solubilization properties. They can maintain the moisture of tobacco leaves, prevent the tobacco leaves from drying, improve the combustion performance of cigarettes, and at the same time assist in dissolving flavor components, enhancing the stability and persistence of aroma. Differences in their contents will significantly affect the taste and combustion characteristics of cigarettes.

[0004] Therefore, accurately determining the contents of water, ethanol, 1,2-propanediol, and glycerol in tobacco flavorings helps to improve the component consistency of each batch of flavorings, stabilize the quality of cigarette products, provide accurate data support for cigarette formula research and development, assist researchers in optimizing the flavoring formula according to different needs, and develop cigarette products that better meet consumer preferences. It is of great significance for controlling the quality of flavorings and ensuring the stability of cigarette quality.

[0005] However, the current methods for determining the contents of water, ethanol, 1,2-propanediol, and glycerol in tobacco flavorings have many deficiencies. Traditional methods usually use the Karl Fischer method to measure water, gas chromatography to measure ethanol, and liquid chromatography to measure 1,2-propanediol and glycerol. Detecting the four components separately using different methods requires a lot of time and labor. The pretreatment operation of reagents needs to be carried out multiple times, and the analysis efficiency is low. Multiple injections for detection are prone to introducing errors, affecting the accuracy of the results. In addition, different detection methods require different instrument equipment, increasing the enterprise's detection costs and the difficulty of equipment maintenance. Therefore, developing an efficient and accurate method that can simultaneously and accurately determine the contents of water, ethanol, 1,2-propanediol, and glycerol in tobacco flavorings has become an urgent problem to be solved in the tobacco industry. Summary of the Invention

[0006] Based on this, the main object of the present application is to provide a method for simultaneously determining the contents of water, ethanol, 1,2 - propanediol and glycerol in tobacco flavorings, so as to improve the accuracy, sensitivity and detection efficiency of the detection results.

[0007] In the first aspect of the present application, a method for simultaneously determining the contents of water, ethanol, 1,2 - propanediol and glycerol in tobacco flavorings is provided, including:

[0008] Quantitatively analyzing water, ethanol, 1,2 - propanediol and glycerol in tobacco flavorings by using a gas chromatography dual - column and dual - detector system;

[0009] The gas chromatography dual - column and dual - detector system includes a water detection system and an alcohol detection system;

[0010] The water detection system is used to detect water, the stationary phase of the chromatographic column is bonded polystyrene - divinylbenzene, and the detector is a TCD detector;

[0011] The alcohol detection system is used to detect ethanol, 1,2 - propanediol and glycerol, the stationary phase of the chromatographic column is bonded polyethylene glycol, and the detector is an FID detector.

[0012] In some embodiments, the conditions of the water detection system include one or more of the following features:

[0013] (1) Detector temperature: 260 - 280 °C;

[0014] (2) Injection port temperature: 250 - 270 °C;

[0015] (3) Injection mode: split injection, split ratio 5 - 15:1;

[0016] (4) Injection volume: 1.0 - 2 μL;

[0017] (5) Carrier gas: helium, constant flow mode, flow rate 5 - 10 mL / min;

[0018] (6) Make - up gas: helium, 5 - 15 mL / min;

[0019] (7) Reference flow rate: 20 - 30 mL / min.

[0020] In some embodiments, the conditions of the water detection system include one or more of the following features:

[0021] (1) Detector temperature: 270 °C;

[0022] (2) Injection port temperature: 260 °C;

[0023] (3) Injection mode: split injection, split ratio 10:1;

[0024] (4) Injection volume: 1.0 μL;

[0025] (5) Carrier gas: helium, constant flow mode, flow rate 6.0 mL / min;

[0026] (6) Make-up gas: helium, 10 mL / min;

[0027] (7) Reference flow rate: 25 mL / min.

[0028] In some embodiments, the conditions of the alcohol detection system include one or more of the following features:

[0029] (1) Detector temperature: 260 - 280 °C;

[0030] (2) Injection port temperature: 250 - 270 °C;

[0031] (3) Injection mode: split injection, split ratio 15 - 30:1;

[0032] (4) Injection volume: 1.0 - 2.0 µL;

[0033] (5) Carrier gas: helium, constant flow mode, flow rate 1 - 2 mL / min;

[0034] (6) Air: 300 - 500 mL / min;

[0035] (7) Hydrogen: 30 - 50 mL / min;

[0036] (8) Make-up gas: helium, 10 - 30 mL / min.

[0037] In some embodiments, the conditions of the alcohol detection system include one or more of the following features:

[0038] (1) Detector temperature: 270 °C;

[0039] (2) Injection port temperature: 260 °C;

[0040] (3) Injection mode: split injection, split ratio 25:1;

[0041] (4) Injection volume: 1.0 µL;

[0042] (5) Carrier gas: helium, constant flow mode, flow rate 1.2 mL / min;

[0043] (6) Air: 400 mL / min;

[0044] (7) Hydrogen: 40 mL / min;

[0045] (8)Tail blowing: Helium, 20 mL / min.

[0046] In some embodiments, the column temperature of the chromatographic column in the gas chromatography dual-column and dual-detector system is programmed temperature rise, and the programmed temperature rise includes:

[0047] Initial temperature 50 - 70 °C, hold for 3 - 6 min;

[0048] Raise the temperature to 150 - 180 °C at a rate of 40 - 60 °C / min, hold for 0 - 1 min;

[0049] Raise the temperature to 180 - 220 °C at a rate of 10 - 30 °C / min, hold for 0 - 1 min;

[0050] Raise the temperature to 220 - 260 °C at a rate of 30 - 50 °C / min, hold for 3 - 8 min;

[0051] Raise the temperature to 230 - 270 °C at a rate of 40 - 60 °C / min, hold for 5 - 10 min.

[0052] In some embodiments, the column temperature of the chromatographic column in the gas chromatography dual-column and dual-detector system is programmed temperature rise, and the programmed temperature rise includes:

[0053] Initial temperature 60 °C, hold for 4.5 min;

[0054] Raise the temperature to 160 °C at a rate of 50 °C / min, hold for 0 min;

[0055] Raise the temperature to 200 °C at a rate of 20 °C / min, hold for 0 min;

[0056] Raise the temperature to 240 °C at a rate of 40 °C / min, hold for 5 min;

[0057] Raise the temperature to 250 °C at a rate of 50 °C / min, hold for 8 min.

[0058] In some embodiments, the chromatographic column of the water detection system is an Agilent HP-PLOT Q gas chromatographic column.

[0059] In some embodiments, the specifications of the Agilent HP-PLOT Q gas chromatographic column are: length 30 m, inner diameter 0.53 mm, film thickness 40.00 µm.

[0060] In some embodiments, the chromatographic column of the alcohol detection system is an Agilent HP-INNOWax gas chromatographic column.

[0061] In some embodiments, the specifications of the HP-INNOWax gas chromatography column are as follows: length 30 m, inner diameter 0.25 mm, and film thickness 0.25 µm.

[0062] In some embodiments, an internal standard is added to the tobacco flavor and fragrance, and the internal standard is n-propanol.

[0063] Compared with the traditional technology, the present application has at least the following beneficial effects:

[0064] The present application uses a gas chromatography dual-column and dual-detector system to quantitatively analyze water, ethanol, 1,2-propanediol, and glycerol in tobacco flavor and fragrance, which can significantly improve the response degree, detection sensitivity, accuracy, and detection efficiency of water, ethanol, 1,2-propanediol, and glycerol. Description of the Drawings

[0065] Figure 1 It is a schematic diagram of a method for simultaneously detecting the contents of water, ethanol, 1,2-propanediol, and glycerol using a dual-column and dual-detector;

[0066] Figure 2 It is a gas chromatograph used in Example 1;

[0067] Figure 3 It is a gas chromatogram of a standard working solution of 2.5 mg / mL water;

[0068] Figure 4 It is a gas chromatogram of ethanol, 1,2-propanediol, and glycerol in a standard working solution (containing 0.25 mg / mL ethanol, 3.0 mg / mL 1,2-propanediol, and 0.4 mg / mL glycerol);

[0069] Figure 5 It is a gas chromatogram of water in the sample solution of Example 1;

[0070] Figure 6 It is a gas chromatogram of ethanol, 1,2-propanediol, and glycerol in the sample solution;

[0071] Figure 7 It is a detection chromatogram of Comparative Example 3. Detailed Embodiments

[0072] The following will further elaborate on the present application in combination with the embodiments and examples. These embodiments and examples are only used to illustrate the present application and not to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the understanding of the disclosed content of the present application more thorough and comprehensive. It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various changes or modifications without departing from the connotation of the present application, and the equivalent forms obtained also fall within the protection scope of the present application. In addition, in the following description, a large number of specific details are given to provide a more thorough understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0073] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0074] Aiming at the deficiencies of the traditional methods for measuring the contents of four components, namely water, ethanol, 1,2-propanediol, and glycerol, in tobacco flavorings, such as low analysis efficiency, easy introduction of errors in multiple injections for detection, affecting the accuracy of results, different detection methods requiring different instrument equipment, increasing the detection cost and equipment maintenance difficulty of enterprises, etc., the present application adopts a method for simultaneously determining the contents of water, ethanol, 1,2-propanediol, and glycerol in tobacco flavorings by using a gas chromatography dual-column dual-detector system, which can significantly improve the response degree and detection sensitivity of water, ethanol, 1,2-propanediol, and glycerol, and reduce the equipment maintenance difficulty.

[0075] In the first aspect of the present application, a method for simultaneously determining the contents of water, ethanol, 1,2-propanediol, and glycerol in tobacco flavorings is provided, including:

[0076] Performing quantitative analysis on water, ethanol, 1,2-propanediol, and glycerol in tobacco flavorings by using a gas chromatography dual-column dual-detector system;

[0077] The gas chromatography dual-column dual-detector system includes a water detection system and an alcohol detection system;

[0078] The water detection system is used to detect water, the stationary phase of the chromatographic column is bonded polystyrene-divinylbenzene, and the detector is a TCD detector;

[0079] The alcohol detection system is used to detect ethanol, 1,2-propanediol, and glycerol, the stationary phase of the chromatographic column is bonded polyethylene glycol, and the detector is an FID detector.

[0080] By adopting a gas chromatography dual-column and dual-detector system, this application can significantly improve the response degree, quantitative limit, and detection limit of water, ethanol, 1,2-propanediol, and glycerol in tobacco flavorings, and enhance the sensitivity, accuracy, and detection efficiency of detection.

[0081] In some embodiments, the conditions of the water detection system include one or more of the following features:

[0082] (1) Detector temperature: 260 - 280 °C;

[0083] (2) Injection port temperature: 250 - 270 °C;

[0084] (3) Injection mode: split injection, split ratio 5 - 15:1;

[0085] (4) Injection volume: 1.0 - 2 μL;

[0086] (5) Carrier gas: helium, constant flow mode, flow rate 5 - 10 mL / min;

[0087] (6) Make-up gas: helium, 5 - 15 mL / min;

[0088] (7) Reference flow rate: 20 - 30 mL / min.

[0089] In some embodiments, the conditions of the water detection system include one or more of the following features:

[0090] (1) Detector temperature: 270 °C;

[0091] (2) Injection port temperature: 260 °C;

[0092] (3) Injection mode: split injection, split ratio 10:1;

[0093] (4) Injection volume: 1.0 μL;

[0094] (5) Carrier gas: helium, constant flow mode, flow rate 6.0 mL / min;

[0095] (6) Make-up gas: helium, 10 mL / min;

[0096] (7) Reference flow rate: 25 mL / min.

[0097] In some embodiments, the conditions of the alcohol detection system include one or more of the following features:

[0098] (1) Detector temperature: 260 - 280 °C;

[0099] (2) Injection port temperature: 250 - 270 °C;

[0100] (3) Injection mode: split injection, split ratio 15 - 30:1;

[0101] (4) Injection volume: 1.0 - 2.0 µL;

[0102] (5) Carrier gas: helium, constant flow mode, flow rate 1 - 2 mL / min;

[0103] (6) Air: 300 - 500 mL / min;

[0104] (7) Hydrogen: 30 - 50 mL / min;

[0105] (8) Make-up gas: helium, 10 - 30 mL / min.

[0106] In some embodiments, the conditions of the alcohol detection system include one or more of the following features:

[0107] (1) Detector temperature: 270 °C;

[0108] (2) Injector temperature: 260 °C;

[0109] (3) Injection mode: split injection, split ratio 25:1;

[0110] (4) Injection volume: 1.0 µL;

[0111] (5) Carrier gas: helium, constant flow mode, flow rate 1.2 mL / min;

[0112] (6) Air: 400 mL / min;

[0113] (7) Hydrogen: 40 mL / min;

[0114] (8) Make-up gas: helium, 20 mL / min.

[0115] In some embodiments, the column temperature of the chromatographic column in the gas chromatography dual-column dual-detector system uses programmed temperature rise, and the programmed temperature rise includes:

[0116] Initial temperature 50 - 70 °C, hold for 3 - 6 min;

[0117] Rise to 150 - 180 °C at a rate of 40 - 60 °C / min, hold for 0 - 1 min;

[0118] Rise to 180 - 220 °C at a rate of 10 - 30 °C / min, hold for 0 - 1 min;

[0119] Rise to 220 - 260 °C at a rate of 30 - 50 °C / min, hold for 3 - 8 min;

[0120] Raise the temperature to 230 - 270 °C at a rate of 40 - 60 °C / min and hold for 5 - 10 min.

[0121] In some embodiments, the column temperature of the chromatographic column in the gas chromatography dual-column dual-detector system uses programmed temperature elevation, and the programmed temperature elevation includes:

[0122] Initial temperature 60 °C, hold for 4.5 min;

[0123] Raise the temperature to 160 °C at a rate of 50 °C / min and hold for 0 min;

[0124] Raise the temperature to 200 °C at a rate of 20 °C / min and hold for 0 min;

[0125] Raise the temperature to 240 °C at a rate of 40 °C / min and hold for 5 min;

[0126] Raise the temperature to 250 °C at a rate of 50 °C / min and hold for 8 min.

[0127] In some embodiments, the column temperature of the chromatographic column in both the water detection system and the alcohol detection system uses programmed temperature elevation, and the programmed temperature elevation includes:

[0128] Initial temperature 60 °C, hold for 4.5 min;

[0129] Raise the temperature to 160 °C at a rate of 50 °C / min and hold for 0 min;

[0130] Raise the temperature to 200 °C at a rate of 20 °C / min and hold for 0 min;

[0131] Raise the temperature to 240 °C at a rate of 40 °C / min and hold for 5 min;

[0132] Raise the temperature to 250 °C at a rate of 50 °C / min and hold for 8 min;

[0133] The running time of one program of the programmed temperature elevation is 22.7 min.

[0134] In some embodiments, in the water detection system, the stationary phase of the chromatographic column is bonded polystyrene-divinylbenzene, and the chromatographic column is at least one of an elastic fused silica capillary column and an equivalent column.

[0135] In some embodiments, the chromatographic column of the water detection system is an Agilent HP-PLOT Q gas chromatography column.

[0136] In some embodiments, the specifications of the Agilent HP-PLOT Q gas chromatography column are: length 30 m, inner diameter 0.53 mm, and film thickness 40.00 µm.

[0137] In some embodiments, in the alcohol detection system, the stationary phase of the chromatographic column is bonded polyethylene glycol, and the chromatographic column is at least one of an elastic fused silica capillary column and an equivalent column.

[0138] In some embodiments, the chromatographic column of the alcohol detection system is an Agilent HP-INNOWax gas chromatography column.

[0139] In some embodiments, the specifications of the Agilent HP-INNOWax gas chromatography column are: length 30m, inner diameter 0.25mm, and film thickness 0.25µm.

[0140] In some embodiments, an internal standard is added to the tobacco flavoring and fragrance, and the internal standard is n-propanol.

[0141] In some embodiments, a tobacco flavor and fragrance sample is pretreated, and the pretreatment includes extracting water, ethanol, 1,2-propylene glycol, and glycerol in the tobacco flavor and fragrance sample into a methanol solution containing an internal standard to prepare a sample solution, and injecting the sample solution into two injection towers of the same gas chromatograph respectively, and simultaneously detecting the water, ethanol, 1,2-propylene glycol, and glycerol contents in the sample solution using a dual-column dual detector. Specifically, water is separated using a gas chromatography column with a bonded polystyrene-divinylbenzene stationary phase, detected using a thermal conductivity detector (TCD detector), and the water content in the sample solution is calculated using the peak area according to the internal standard method; ethanol, 1,2-propylene glycol, and glycerol are separated using a gas chromatography column with a bonded polyethylene glycol stationary phase, detected using a hydrogen flame ionization detector (FID detector), and the ethanol, 1,2-propylene glycol, and glycerol contents in the sample solution are calculated using the peak area according to the internal standard method. In view of the characteristics of alcohols and water having large differences in polarity, being suitable for different types of gas chromatography columns, and having different response sensitivities to different gas chromatography detectors, the present application establishes a sample pretreatment method that can simultaneously extract alcohols and water, and uses a gas chromatograph and the instrument's built-in thermal conductivity detector and hydrogen flame ionization detector to respectively detect water and ethanol, 1,2-propylene glycol, and glycerol. The sample pretreatment is reduced from two pretreatments to one pretreatment, and the gas chromatography analysis is reduced from two to one, which greatly saves the time, labor, reagents, and consumables of pretreatment and gas chromatography, and fills the gap in the simultaneous determination of water, ethanol, 1,2-propylene glycol, and glycerol in tobacco flavors and fragrances. The instruments used are commonly used and general, and the measurement results are accurate and reliable.

[0142] The implementation solutions of the present application will be described in detail below in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. For the experimental methods without specific conditions indicated in the following embodiments, priority is given to the guidance given in the present application, and it can also be carried out according to the experimental manuals or conventional conditions in the art, or according to the conditions recommended by the manufacturer, or by referring to the experimental methods known in the art.

[0143] Example 1

[0144] A method for simultaneously determining the contents of water, ethanol, 1,2 - propylene glycol and glycerol in tobacco flavor and fragrance, comprising the following steps:

[0145] 1. Prepare a standard solution

[0146] n - propanol internal standard stock solution: Weigh 10 g of n - propanol, accurate to 0.001 g, place it in a 100 mL volumetric flask, dilute it to volume with methanol and mix well to prepare a 100 mg / mL n - propanol internal standard stock solution. Store it sealed and protected from light at a temperature below 4 °C, with a validity period of 3 months. When taking it for use, it should be equilibrated to room temperature before use.

[0147] n - propanol extractant: Precisely measure 50 mL of the n - propanol internal standard stock solution, place it in a 1000 mL volumetric flask, dilute it to volume with methanol and mix well to prepare a 5 mg / mL n - propanol extractant. Store it sealed and protected from light at a temperature below 4 °C, with a validity period of 3 months. When taking it for use, it should be equilibrated to room temperature before use.

[0148] Water standard stock solution: Weigh 5 g of water, accurate to 0.001 g, place it in a 100 mL volumetric flask, dilute it to volume with methanol to prepare a 50 mg / mL water standard stock solution, and use it immediately after preparation.

[0149] Water standard working solution: Precisely measure 8 portions of 0.5 mL of the n - propanol internal standard stock solution into 10 mL volumetric flasks respectively, and precisely add 0 mL, 0.1 mL, 0.2 mL, 0.5 mL, 1.0 mL, 2.0 mL, 4.0 mL and 6.0 mL of the water standard stock solution respectively, dilute them to volume with methanol and mix well to prepare 8 - level water standard working solutions with water concentrations of 0 mg / mL, 0.5 mg / mL, 1 mg / mL, 2.5 mg / mL, 5 mg / mL, 10 mg / mL, 20 mg / mL and 30 mg / mL respectively, and use them immediately after preparation.

[0150] Mixed standard stock solution of ethanol, 1,2 - propanediol and glycerol: Weigh 5 g of ethanol, 6 g of 1,2 - propanediol, and 4 g of glycerol (4.6) accurately to 0.001 g. Place them together in a 100 - mL volumetric flask, dilute to the mark with methanol and mix well to prepare a mixed standard stock solution with an ethanol concentration of 50 mg / mL, a 1,2 - propanediol concentration of 60 mg / mL, and a glycerol concentration of 40 mg / mL. Store it sealed and protected from light at a temperature below 4 °C. The validity period is 3 months. When using, it should be equilibrated to room temperature before use.

[0151] Mixed standard working solution of ethanol, 1,2 - propanediol and glycerol: Accurately pipette 7 portions of 0.5 mL of the internal standard stock solution into 10 - mL volumetric flasks. Then accurately add 0.01 mL, 0.05 mL, 0.25 mL, 0.5 mL, 1.0 mL, 2.5 mL, and 5.0 mL of the mixed standard stock solution respectively. Dilute to the mark with methanol and mix well to prepare 7 - level mixed standard working solutions of ethanol, 1,2 - propanediol and glycerol. Store it sealed and protected from light at a temperature below 4 °C. The validity period is 3 months. When using, it should be equilibrated to room temperature before use.

[0152] 2. Preparation of sample solution

[0153] Sample solution: Weigh 0.15 g of the sample (the sample is from tobacco raw materials of Sichuan China Tobacco Industry Co., Ltd.) accurately to 0.001 g. Place it in a 50 - mL stoppered Erlenmeyer flask, accurately add 5 mL of n - propanol extractant, tighten the ground - glass stopper, place it in a shaking table - type speed - adjustable oscillator, and shake at a speed of 160 r / min for 20 min. Take the extract. After taking 2 mL of the extract and passing it through an organic - phase filter membrane, a sample solution is prepared for gas chromatography analysis. Repeat the preparation of 3 sample solutions for the same sample.

[0154] The three pure solvents of ethanol, 1,2 - propanediol, and glycerol are samples that need to be detected. If the samples are taken according to the conventional sampling amount for detection, it may exceed the standard curve range. Therefore, the recommended sampling amounts (Table 1) for the detection of these three pure - solvent samples are provided, and the other pretreatment methods are the same.

[0155] Table 1 Recommended sampling amounts for ethanol, 1,2 - propanediol, and glycerol pure - solvent samples

[0156]

[0157] Blank solution: Prepare a blank solution according to the preparation method of the sample solution. The difference from the preparation method of the sample solution is that no sample is added. The prepared blank solution is used for gas chromatography analysis. Make 3 parallel samples of the blank control solution.

[0158] 3. Gas chromatography detection method

[0159] The contents of water, ethanol, 1,2 - propanediol and glycerol are detected simultaneously by using a dual - column and dual - detector system. As Figure 1 shown, Figure 1 Figure Figure 1 is a schematic diagram of the method for simultaneously detecting the contents of water, ethanol, 1,2 - propanediol and glycerol by using a dual - column and dual - detector system. The method for simultaneously detecting the contents of water, ethanol, 1,2 - propanediol and glycerol by using a dual - column and dual - detector system includes the following steps: Pretreat the water and alcohol determination sample (the extractant is a methanol solution containing n - propanol) to prepare a test solution, and then detect the test solution with a gas chromatograph ( Figure 2 ). Specifically, use a water - detecting chromatographic column and a TCD detector to detect water, and use an alcohol - detecting chromatographic column and an FID detector to detect alcohols. Figure 2 One of the GC instruments (gas chromatograph) has two injection towers, two chromatographic columns, an FID detector, a TCD detector and a sample tray. Among them, chromatographic column 2 and the TCD detector are used to detect water, and chromatographic column 1 and the FID detector are used to detect alcohols.

[0160] When performing gas chromatographic analysis on the same solution by using a dual - column and dual - detector system, first detect water and then detect alcohols (ethanol, 1,2 - propanediol and glycerol) by using gas chromatography, that is, place the water determination of the sample in front of the alcohol determination when editing the determination sequence list.

[0161] Among them, the conditions for gas chromatographic detection of water include:

[0162] Detector: TCD detector, temperature is 270 °C;

[0163] Injection port temperature: 260 °C;

[0164] Injection mode: split injection, split ratio 10:1;

[0165] Injection volume: 1.0 μL;

[0166] Carrier gas: helium (99.99%), constant - flow mode, flow rate 6.0 mL / min;

[0167] Make - up gas: helium, 10 mL / min;

[0168] Reference flow rate: 25 mL / min;

[0169] Programmed temperature - rising conditions: initial temperature 60 °C, hold for 4.5 min; rise to 160 °C at a rate of 50 °C / min, hold for 0 min; rise to 200 °C at a rate of 20 °C / min, hold for 0 min; rise to 240 °C at a rate of 40 °C / min, hold for 5 min; rise to 250 °C at a rate of 50 °C / min, hold for 8 min (note: the running time of one program is 22.7 min);

[0170] Gas Chromatography Column for Water Detection:

[0171] Agilent HP-PLOT Q Gas Chromatography Column (Purchase Information: Part Number 19095P-Q04, J&W HP-PLOT Q Gas Chromatography Column, length 30m, inner diameter 0.53mm, film thickness 40.00µm, column cage size 7 inches), elastic fused silica capillary column, stationary phase is bonded polystyrene-divinylbenzene (DVB);

[0172] Conditions for Gas Chromatography Detection of Ethanol, 1,2-Propanediol and Glycerol include:

[0173] Detector: FID detector, temperature 270°C;

[0174] Injector Temperature: 260°C;

[0175] Injection Mode: Split Injection, split ratio 25:1;

[0176] Injection Volume: 1.0µL;

[0177] Carrier Gas: Helium (99.99%), constant flow mode, flow rate 1.2mL / min;

[0178] Air: 400mL / min;

[0179] Hydrogen: 40mL / min;

[0180] Makeup Gas: Helium, 20mL / min;

[0181] Programmed Temperature Conditions: Initial temperature 60°C, hold for 4.5min; increase to 160°C at a rate of 50°C / min, hold for 0min; increase to 200°C at a rate of 20°C / min, hold for 0min; increase to 240°C at a rate of 40°C / min, hold for 5min; increase to 250°C at a rate of 50°C / min, hold for 8min (Note: One program run time is 22.7min);

[0182] Gas Chromatography Column for Detection of Ethanol, 1,2-Propanediol and Glycerol: Agilent HP-INNOWax Gas Chromatography Column (Purchase Information: Part Number 19091N-133I, J&W HP-INNOWax, length 30m, inner diameter 0.25mm, film thickness 0.25µm, column cage size 7 inches), elastic fused silica capillary column, stationary phase is bonded polyethylene glycol.

[0183] 4. Prepare Standard Curves for Water, Ethanol, 1,2-Propanediol and Glycerol

[0184] Preparation of water standard curve: The water standard working solution is determined according to the water determination conditions, and the water standard curve is established (the abscissa is the ratio of the water concentration to the concentration of the internal standard n-propanol, and the ordinate is the ratio of the water peak area to the n-propanol peak area of the internal standard); the linear correlation coefficient R of the water standard curve 2 should be greater than 0.995. Among them, the gas chromatogram of the 2.5 mg / mL water standard working solution is as shown in Figure 3 shown

[0185] To ensure the accuracy of the water content determination, the standard curve is prepared once for each inspection batch. In addition, after every 20 sample determinations, a working standard solution with a concentration close to that of the sample is added. If the measured value differs from the value of the original standard working solution by more than 5%, the standard curve should be prepared again.

[0186] Preparation of standard curves for ethanol, 1,2-propanediol, and glycerol: The mixed standard working solution of ethanol, 1,2-propanediol, and glycerol is determined according to the determination conditions of ethanol, 1,2-propanediol, and glycerol, and the standard curves of ethanol, 1,2-propanediol, and glycerol are established respectively (the abscissas are the ratios of the concentrations of ethanol, 1,2-propanediol, and glycerol to the concentration of the internal standard n-propanol, and the ordinates are the ratios of the peak areas of ethanol, 1,2-propanediol, and glycerol to the peak area of the internal standard n-propanol). The linear correlation coefficients R of the three standard curves 2 should all be greater than 0.999. The gas chromatograms of ethanol, 1,2-propanediol, and glycerol in the standard working solution (containing 0.25 mg / mL ethanol, 3.0 mg / mL 1,2-propanediol, and 0.4 mg / mL glycerol) are as shown in Figure 4 shown

[0187] To ensure the accuracy of the determinations of the contents of ethanol, 1,2-propanediol, and glycerol, the standard curve is prepared once for each inspection batch. In addition, after every 20 sample determinations, the original mixed standard working solution with a concentration close to that of the sample is added. If the measured value differs from the original value by more than 5%, the standard curve should be prepared again.

[0188] 5. Determination of the contents of water, ethanol, 1,2-propanediol, and glycerol in the sample solution

[0189] The water in the reagent (methanol, n-propanol extractant), blank solution, and sample solution of this inspection batch is determined according to the water determination conditions, and the corresponding water concentration is calculated through the water standard curve (if the measured value of water exceeds the range of the standard curve, a suitable standard curve should be prepared again; the water content in methanol is lower than 1.0 mg / mL). The gas chromatogram of water in the sample solution is as shown in Figure 5 shown

[0190] The sample solution is detected under the determination conditions of ethanol, 1,2-propanediol, and glycerol, and the concentrations of ethanol, 1,2-propanediol, and glycerol in the sample solution are calculated through the corresponding standard curve (if the measured value of the target substance in the sample exceeds the range of the standard curve, the sample solution should be appropriately diluted before measurement, and the final concentration result should be calculated according to the actual dilution ratio). The gas chromatograms of ethanol, 1,2-propanediol, and glycerol in the sample solution are as shown in Figure 6 shown.

[0191] The arithmetic mean of the determination results of three parallel samples is used as the determination result of the sample, accurate to 0.1%. The RSD value of the determination results of three parallel samples should be ≤10.0%.

[0192] The mass percentage of water in the sample is calculated according to formula (1):

[0193]

[0194] In formula (1),

[0195] W: The mass percentage of water in the sample, unit is percentage (%);

[0196] c t : The water concentration of the sample solution, unit is milligram per milliliter (mg / mL);

[0197] c b : The water concentration of the blank solution, unit is milligram per milliliter (mg / mL);

[0198] V: The volume of the sample solution, unit is milliliter (mL);

[0199] m: The mass of the sample, unit is milligram (mg).

[0200] The mass percentage of ethanol, 1,2-propanediol, and glycerol in the sample is calculated according to formula (2):

[0201]

[0202] In formula (2),

[0203] ω: The mass percentage of the target compound in the sample, unit is percentage (%);

[0204] c: The concentration of the target compound in the sample solution, unit is milligram per milliliter (mg / mL);

[0205] V: The volume of the sample solution, unit is milliliter (mL);

[0206] m: The mass of the sample, unit is milligram (mg).

[0207] 6. Method Validation for Detecting the Contents of Water, Ethanol, 1,2 - Propylene Glycol and Glycerol

[0208] The validation experiment of the method was carried out with reference to the "General Technical Requirements" in the 2020 Edition of the Chinese Pharmacopoeia, specifically the "Guidelines for Validation of Analytical Methods" numbered 9101. The main evaluation indicators were the linearity, repeatability, accuracy, quantitation limit and detection limit of the method.

[0209] The linearity of the method was evaluated by the correlation coefficient R of the standard curve 2 for evaluation.

[0210] The repeatability of the method was expressed by the relative standard deviation (RSD) of the results obtained from repeated sampling and determination of the actual flavor and fragrance samples for 6 times.

[0211] The accuracy of the method was determined by adding the standard substance to the actual flavor and fragrance samples. The recovery rate was calculated by dividing the difference between the measured value and the content in the sample by the amount of the added standard substance; it was determined 6 times in parallel, and the accuracy of the method was judged by the recovery rate values of the 6 determination results.

[0212] The quantitation limit and detection limit of the method were determined by the signal - to - noise ratio method. The signal measured from the known low - concentration sample was compared with the noise signal measured from the blank sample. When the signal - to - noise ratios were 10:1 and 3:1 respectively, the corresponding concentrations (or mass percentages) were the quantitation limit and detection limit.

[0213] The determination results of the linearity, repeatability, accuracy, quantitation limit and detection limit of this method are shown in Table 2 - 5 respectively.

[0214] Table 2 Linearity of the Method

[0215]

[0216] Table 3 Repeatability of the Method (n = 6)

[0217]

[0218] Table 4 Accuracy of the Method (n = 6)

[0219]

[0220] Table 5 Quantitation Limit and Detection Limit of the Method

[0221]

[0222] Example 2

[0223] Different types of flavor and fragrance were used as samples. Different sample solutions were prepared according to the sample solution preparation method in Example 1, and the contents of water, ethanol, 1,2 - propylene glycol and glycerol in different samples were detected by the gas chromatography detection method in Example 1.

[0224] Samples: From the standard substances of the flavor and fragrance procurement project (the second batch) from 2024 to 2026, different types of fragrance raw materials were selected (including 7 types: extracts, oils, fragrances, monomers, functional materials, fragrance bases, and concretes).

[0225] The test results are shown in Table 6.

[0226] Table 6 Detection results of the contents of water, ethanol, 1,2 - propanediol, and glycerol in different types of flavors and fragrances

[0227]

[0228]

[0229]

[0230] The results in Table 6 show that among the 8 oil - type fragrance raw materials (tree moss essential oil, peppermint oil, Zimbabwe tobacco absolute, star anise oil, geranium oil, Zimbabwe tobacco essential oil, tobacco supercritical essential oil, juniper berry absolute), the solvent contents of 3 samples, namely tree moss essential oil, juniper berry absolute, and tobacco supercritical essential oil, are all higher than 90%, and among them, the solvent contents of juniper berry absolute and tobacco supercritical essential oil are as high as 99% respectively; among the remaining 42 different types of fragrance raw materials, 23 have a solvent content higher than 70%. Through these data, the approximate content of the fragrance components in the sample can be calculated, achieving the purpose of more comprehensively evaluating the quality of the tender samples and avoiding the situation of passing off inferior products by diluting the samples.

[0231] The detection results of the contents of water, ethanol, 1,2 - propanediol, and glycerol in different types of flavors and fragrances indicate that the gas chromatography detection method established in this application is applicable to the detection of solvents (water, ethanol, 1,2 - propanediol, and glycerol) in different types of flavors and fragrances.

[0232] Therefore, mastering the solvent information of fragrance raw materials can provide data reference for dissolving, diluting, and blending with appropriate solvents in the work of self - made fragrance, further improving the knowability and controllability of flavors and fragrances.

[0233] Comparative Example 1

[0234] Prepare a mixed standard working solution of two alcohol compounds, ethanol, 1,2 - propanediol, and glycerol (internal standard n - propanol) according to the method of Example 1, and use the gas chromatography detection method to detect the contents of ethanol, n - propanol, 1,2 - propanediol, and glycerol in the mixed standard working solution. The gas chromatography detection conditions are as follows:

[0235] Detector: TCD detector, temperature is 260°C;

[0236] Injector temperature: 250 °C;

[0237] Injection mode: split injection, split ratio 30:1;

[0238] Injection volume: 1.0 μL;

[0239] Carrier gas: helium; flow rate 2.0 mL / min;

[0240] Reference flow rate: 20 mL / min;

[0241] Make-up gas flow rate: 9 mL / min;

[0242] Programmed temperature rise: 40 °C, hold for 4 min, ramp at 60 K / min to 250 °C, hold for 5 min;

[0243] HP-INNOWAX capillary column (elastic fused silica capillary column with polyethylene glycol as the stationary phase).

[0244] Under the gas chromatography detection conditions of Comparative Example 1 and Example 1, the peak areas of ethanol, n-propanol, 1,2-propanediol, and glycerol in the same mixed standard working solution are shown in Table 7.

[0245] The results in Table 7 show that the detection values (peak areas) of ethanol, n-propanol, 1,2-propanediol, and glycerol by the TCD detector are much lower than those by the FID detector. This indicates that, compared with using the TCD detector in Comparative Example 1, the detection sensitivity of the FID detector used in Example 1 for these three alcohol compounds is significantly improved and is suitable for routine quality control detection.

[0246] Table 7 Detection results of alcohol compounds under the gas chromatography detection conditions of Comparative Example 1 and Example 1

[0247]

[0248] Comparative Example 2

[0249] In Comparative Example 2, a mixed standard working solution of ethanol, 1,2-propanediol, and glycerol was prepared according to the method of Example 1, except that the solvent of the internal standard stock solution was isopropanol.

[0250] The contents of ethanol, n-propanol, 1,2-propanediol, and glycerol in the mixed standard working solution were detected according to the gas chromatography detection method of Example 1. The detection results of Comparative Example 3 are as Figure 7 shown. The results show that when isopropanol is used as the internal standard for determining water, due to the similar molecular weights and boiling points, it is difficult to completely separate the water internal standard isopropanol from the ethanol peak.

[0251] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0252] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method for simultaneously determining the contents of water, ethanol, 1,2 - propanediol and glycerol in tobacco flavorings, characterized in that, Comprising: Quantitatively analyzing water, ethanol, 1,2 - propanediol, and glycerol in tobacco flavorings using a gas chromatography dual - column dual - detector system; The gas chromatography dual - column dual - detector system includes a water detection system and an alcohol detection system; The water detection system is used to detect water. The stationary phase of the chromatographic column is bonded polystyrene - divinylbenzene, and the detector is a TCD detector; The alcohol detection system is used to detect ethanol, 1,2 - propanediol, and glycerol. The stationary phase of the chromatographic column is bonded polyethylene glycol, and the detector is an FID detector.

2. The method according to claim 1, wherein The conditions of the water detection system include one or more of the following characteristics: (1) Detector temperature: 260 - 280 °C; (2) Injector port temperature: 250 - 270 °C; (3) Injection mode: Split injection, split ratio 5 - 15:1; (4) Injection volume: 1.0 - 2 μL; (5) Carrier gas: Helium, constant - flow mode, flow rate 5 - 10 mL / min; (6) Make - up gas: Helium, 5 - 15 mL / min; (7) Reference flow rate: 20 - 30 mL / min.

3. The method according to claim 2, wherein The conditions of the water detection system include one or more of the following characteristics: (1) Detector temperature: 270 °C; (2) Injector port temperature: 260 °C; (3) Injection mode: Split injection, split ratio 10:1; (4) Injection volume: 1.0 μL; (5) Carrier gas: Helium, constant - flow mode, flow rate 6.0 mL / min; (6) Make - up gas: Helium, 10 mL / min; (7) Reference flow rate: 25 mL / min.

4. The method according to any one of claims 1 to 3, characterized in that, The conditions of the alcohol detection system include one or more of the following characteristics: (1) Detector temperature: 260 - 280 °C; (2) Injector port temperature: 250 - 270 °C; (3) Injection mode: Split injection, split ratio 15 - 30:1; (4) Injection volume: 1.0 - 2.0 µL; (5) Carrier gas: Helium, constant - flow mode, flow rate 1 - 2 mL / min; (6) Air: 300 - 500 mL / min; (7) Hydrogen: 30 - 50 mL / min; (8) Make - up gas: Helium, 10 - 30 mL / min.

5. The method according to claim 4, wherein The conditions of the alcohol detection system include one or more of the following characteristics: (1) Detector temperature: 270 °C; (2) Injector port temperature: 260 °C; (3) Injection mode: Split injection, split ratio 25:1; (4) Injection volume: 1.0 µL; (5) Carrier gas: Helium, constant - flow mode, flow rate 1.2 mL / min; (6) Air: 400 mL / min; (7) Hydrogen: 40 mL / min; (8) Make - up gas: Helium, 20 mL / min.

6. The method according to any one of claims 1-5, characterized in that, The column temperature of the chromatographic column in the gas chromatography dual - column dual - detector system uses programmed temperature rise, and the programmed temperature rise includes: Initial temperature 50 - 70 °C, hold for 3 - 6 min; Raise the temperature to 150 - 180 °C at a rate of 40 - 60 °C / min, hold for 0 - 1 min; Raise the temperature to 180 - 220 °C at a rate of 10 - 30 °C / min, hold for 0 - 1 min; Raise the temperature to 220 - 260 °C at a rate of 30 - 50 °C / min, hold for 3 - 8 min; Raise the temperature to 230 - 270 °C at a rate of 40 - 60 °C / min and hold for 5 - 10 min.

7. The method according to claim 6, wherein The temperature programming includes: Initial temperature 60 °C, hold for 4.5 min; Raise the temperature to 160 °C at a rate of 50 °C / min and hold for 0 min; Raise the temperature to 200 °C at a rate of 20 °C / min and hold for 0 min; Raise the temperature to 240 °C at a rate of 40 °C / min and hold for 5 min; Raise the temperature to 250 °C at a rate of 50 °C / min and hold for 8 min.

8. The method according to any one of claims 1 to 3, characterized in that The chromatographic column of the water detection system is an Agilent HP-PLOT Q gas chromatographic column; the specifications of the Agilent HP-PLOT Q gas chromatographic column are: length 30 m, inner diameter 0.53 mm, film thickness 40.00 µm.

9. The method according to any one of claims 1-3, characterized in that, The chromatographic column of the alcohol detection system is an Agilent HP-INNOWax gas chromatographic column; the specifications of the Agilent HP-INNOWax gas chromatographic column are: length 30 m, inner diameter 0.25 mm, film thickness 0.25 µm.

10. The method according to any one of claims 1-9, characterized in that, An internal standard is added to the tobacco flavor and fragrance, and the internal standard is n-propanol.

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