A method for isotopically labeling glycerol to trace the thermal conversion behavior of cigarette sheet and a heat-not-burn tobacco sheet

Abstract

The application provides a method for tracking thermal conversion behavior of cigarette sheet by isotopically labeled glycerol and a heated cigarette tobacco sheet, and relates to tobacco detection. The method comprises the following steps: S1, preparing an isotopically labeled glycerol solution; S2, preparing a mixed smoking agent and applying the mixed smoking agent to a heated cigarette tobacco sheet substrate to prepare a tobacco sheet sample containing isotopically labeled glycerol; S3, heating the tobacco sheet sample and collecting a smoke sample; S4, detecting the smoke sample to obtain an isotopic ratio and calculating the generation amount of a target compound in the smoke sample which is derived from the labeled glycerol; and S5, drawing a thermal conversion path map of the glycerol, wherein the thermal conversion path map comprises a temperature-conversion rate relationship curve and a distribution map of each cracking product. The application has the beneficial effect of accurately distinguishing the material source of each volatile product in a complex smoke system with multiple components, clearly separating exogenous glycerol cracking products and endogenous tobacco matrix cracking products, and overcoming the technical bottleneck of distinguishing the source of cracking products in complex smoke.

Description

Technical Field

[0001] This invention relates to the field of tobacco detection technology, specifically to a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol and for heating cigarette tobacco sheets. Background Technology

[0002] Heated tobacco products (also known as heated cigarettes) are a mainstream new type of tobacco product. Their reconstituted tobacco system requires the addition of a large amount of glycerol as a smoke-generating agent, with glycerol accounting for more than 20% of the total mass of the reconstituted tobacco. The operating heating range for these products is typically 200℃ to 350℃, with a typical heating temperature of about 300℃. Under these thermal conditions, glycerol easily undergoes thermal decomposition, generating various volatile carbonyl harmful substances such as formaldehyde, acetaldehyde, and acrolein. Accurately analyzing the entire transformation pathway of glycerol during heating and quantitatively characterizing the proportion of various harmful carbonyl products generated are the core technological foundation for achieving targeted optimization of heated cigarette formulations and precisely reducing the release levels of harmful components in cigarette smoke.

[0003] However, existing analytical and detection technologies have significant shortcomings, lacking a reliable means to accurately distinguish between glycerol pyrolysis products and endogenous pyrolysis products of the tobacco matrix. The reconstituted tobacco sheet system of heated cigarettes is complex, containing natural macromolecules and small endogenous components such as cellulose, lignin, pectin, protein, fructose, and organic acids. All of these matrix components undergo thermal decomposition under heating conditions of 200℃–350℃, simultaneously generating various volatile carbonyl compounds such as acrolein, formaldehyde, acetaldehyde, and acetone. There is significant chemical overlap between the pyrolysis products of exogenous glycerol smoke-generating agents and the endogenous pyrolysis products of the tobacco matrix. For example, acrolein can be generated by the dehydration and cracking of glycerol molecules or by the thermal degradation of cellulose in the tobacco matrix. Conventional gas chromatography-mass spectrometry and other traditional flue gas analysis methods can only quantitatively detect the total release of carbonyl compounds in flue gas, failing to separate the contribution proportions of exogenous glycerol smoke-generating agents and endogenous tobacco matrix to a single target harmful substance.

[0004] This technological limitation severely restricts the refined research and development of harm-reduction formulas for heated cigarettes. When researchers adjust harm-reduction formulas by reducing the amount of glycerol or changing the type of smoke-generating agent, they cannot distinguish the source of harmful carbonyl compounds in the smoke, making it difficult to objectively quantify the actual harm-reduction benefits of formula adjustments. At the same time, they cannot accurately measure the actual conversion efficiency of glycerol to various harmful carbonyl compounds, resulting in a lack of quantitative data to support formula optimization.

[0005] Current research and patented technologies concerning glycerol in heated cigarette systems primarily focus on physical modifications such as glycerol application processes, tobacco sheet moisture retention, and glycerol adsorption efficiency. They do not address related technical solutions for tracing and quantifying the thermal conversion products of glycerol. For example, Chinese patent CN116210940A discloses a process for controlling the viscosity and promoting the absorption of glycerol in heated cigarette tobacco, which only optimizes the coating application method of glycerol on the tobacco surface; Chinese patent CN114343230A provides a special additive for tobacco sheets containing glycerol and a supporting preparation process; and Chinese patent CN112493528A discloses composite tobacco sheets containing glycerol functional components and their application in heated cigarettes. These existing patents all focus on the physical loading of glycerol in tobacco sheets and the improvement of the sheet matrix structure, without proposing a technical approach to trace and quantify the products from the thermal decomposition process of glycerol using tracer technology. This fails to address the detection challenge of mutual interference between exogenous glycerol and endogenous tobacco matrix pyrolysis products.

[0006] In summary, there is an urgent need in this field to develop an analytical method that can overcome the limitations of existing traceability and detection methods, and to achieve accurate identification of the thermal conversion pathway of glycerol in reconstituted tobacco leaves of heated cigarettes and quantitative analysis of the products, based on tracer technology, so as to provide quantitative and reliable detection technology basis for the targeted optimization of harm reduction formulas for heated cigarettes. Summary of the Invention

[0007] To address the challenges of accurately identifying thermal conversion pathways and quantitatively analyzing products in reconstituted tobacco leaves for heated cigarettes, this invention provides a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol, and a method for heating cigarette tobacco sheets.

[0008] This invention provides a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol, comprising: Step S1: Prepare an isotope-labeled glycerol solution, wherein the solute of the isotope-labeled glycerol solution is carbon-13 labeled glycerol or deuterated glycerol; Step S2: Mix the isotope-labeled glycerol solution with the unlabeled glycerol solution to prepare a mixed smoking agent, and apply the mixed smoking agent to a heated cigarette tobacco sheet substrate to prepare a tobacco sheet sample containing isotope-labeled glycerol; Step S3: Heat the tobacco sheet sample and collect the smoke sample generated during the heating process; Step S4: Detect the target compound in the flue gas sample to obtain the isotope ratio, and calculate the amount of the target compound in the flue gas sample originating from the labeled glycerol based on the isotope ratio; Step S5: Draw a thermal conversion pathway map of glycerol based on the amount of target compound generated from labeled glycerol. The thermal conversion pathway map includes a temperature-conversion curve and a distribution map of each cracking product.

[0009] Furthermore, in step S4, the target compound includes at least one of acrolein, formaldehyde, acetaldehyde, acetone, ethylene glycol, and hydroxyacetone.

[0010] Furthermore, The formula for calculating the amount of the target compound derived from labeled glycerol in step S4 is as follows:

[0011] in, The amount of labeled glycerol produced in the target compound. The total amount of the target compound produced. The isotopic ratio of the target compound in the sample. This represents the natural isotope abundance ratio. The isotopic abundance ratios of glycerol are used to label the glycerol.

[0012] Furthermore, in step S3, the heating temperature of the tobacco sheet sample is 200℃~350℃.

[0013] Furthermore, the carbon-13 labeled glycerol is glycerol-1,2,3-13C3 with a carbon-13 isotopic abundance ≥99 atom% The deuterated glycerol is glycerol-D8, with a deuterium isotope abundance of ≥98%.

[0014] Furthermore, if the solute in the isotopically labeled glycerol solution is carbon-13 labeled glycerol, the isotope ratio is the isotope ratio of carbon-13 to carbon-12. If the solute in the isotopically labeled glycerol solution is deuterated glycerol, the isotope ratio is the ratio of deuterium to hydrogen isotopes.

[0015] Furthermore, step S2 specifically includes: Step S201: Mix the isotope-labeled glycerol solution and the unlabeled glycerol solution in a preset ratio to obtain a mixed smoke generator; Step S202: The mixed smoke-generating agent is applied to the heated cigarette tobacco sheet substrate. The application method is selected from spraying, dipping or roller coating. The amount of the mixed smoke-generating agent applied is 5% to 25% of the mass of the heated cigarette tobacco sheet substrate. After application, the heated cigarette tobacco sheet substrate is dried and subjected to moisture balancing treatment to obtain a tobacco sheet sample containing isotope-labeled glycerol.

[0016] Further, in step S1, the concentration of the isotope-labeled glycerol solution is 0.1 mol / L to 2.0 mol / L; in step S2, the mass ratio of isotope-labeled glycerol to unlabeled glycerol in the mixed smoke-generating agent is 1:10 to 1:100.

[0017] Furthermore, the method for detecting the isotope ratio in step S4 is as follows: S401. Pre-treat the captured flue gas sample to obtain the sample solution to be tested. S402. Use gas chromatography-mass spectrometry or isotope ratio mass spectrometry to detect the target compound in the sample solution to obtain the isotope ratio value.

[0018] Furthermore, embodiments of the present invention also provide a method for tracking the thermal conversion behavior of heated cigarette tobacco sheets using the aforementioned isotope-labeled glycerol, quantitatively tracking the pyrolysis products derived from glycerol and the pyrolysis products derived from the tobacco matrix itself during the heating process of heated cigarette tobacco sheets.

[0019] The present invention has the following beneficial effects: 1. This invention provides a method for tracking the thermal conversion behavior of cigarette tobacco sheets using isotope-labeled glycerol, and a method for heating cigarette tobacco sheets. Stable isotopes (¹³C, deuterium) are used to molecularly label the smoking agent glycerol. Based on the isotope tracing mechanism, unique isotopic fingerprints are assigned to the pyrolysis products of glycerol, forming identifiable isotopic signal differences with the pyrolysis products of natural components in the tobacco matrix. Combined with gas chromatography-mass spectrometry and isotope ratio mass spectrometry, isotope ratio analysis of target carbonyl compounds in the smoke is performed. This allows for precise identification of the material sources of each volatile product in complex smoke systems with multiple components, clearly separating exogenous glycerol pyrolysis products from endogenous tobacco matrix pyrolysis products. Compared to traditional detection methods that can only measure the total release of smoke components and cannot achieve source traceability, this invention fundamentally overcomes the long-standing technical bottleneck of product source differentiation in the industry, accurately tracing and distinguishing exogenous glycerol from the thermal decomposition products of the tobacco matrix.

[0020] 2. This invention provides a method for tracking the thermal conversion behavior of cigarette tobacco sheets using isotope-labeled glycerol, and a method for heating cigarette tobacco sheets. It constructs a proprietary quantitative calculation formula based on the isotope ratio of the sample, the abundance of natural isotopes, and the abundance of the labeling reagent isotopes, directly calculating the absolute amount of glycerol-derived harmful substances in a single target. Furthermore, it can calculate the thermal conversion rate of glycerol to various carbonyl products, achieving a quantitative characterization of the glycerol thermal conversion pathway. This allows for precise quantification of the conversion efficiency of glycerol to volatile carbonyl harmful substances such as formaldehyde, acetaldehyde, and acrolein. Based on this quantitative data, a precise assessment of the harmful risks of heated cigarette formulations can be completed, providing direct and objective quantitative data for adjusting the proportion of smoking agents and improving formulation harm reduction. This supports quantitative optimization of formulations and completely overcomes the technical limitations of existing technologies that can only qualitatively predict and cannot quantitatively assess the harmful contribution of glycerol.

[0021] 3. This invention provides a method for tracking the thermal conversion behavior of cigarette tobacco sheets using isotope-labeled glycerol, and for heating cigarette tobacco sheets. This method allows for parallel gradient temperature experiments within a heating range of 200℃ to 350℃ to obtain kinetic characteristic curves showing the generation of various pyrolysis products as a function of temperature, thus constructing a complete distribution map of the thermal conversion pathways of glycerol. Based on this map, the main and side reaction pathways of glycerol thermal pyrolysis and the corresponding product distribution characteristics at different temperature ranges can be clarified. This provides theoretical and data support for optimizing the operating temperature range of the heated cigarette heat source, enabling the maximal suppression of harmful carbonyl compound generation while ensuring the basic smoking performance of the product. It also clarifies the temperature-dependent regulation of glycerol thermal conversion behavior and guides the optimization of heating conditions.

[0022] 4. This invention provides a method for tracking the thermal conversion behavior of cigarette tobacco sheets using isotope-labeled glycerol and a method for heating cigarette tobacco sheets. This invention is the first to fully apply isotope tracing and quantitative technology to the analysis of the thermal behavior of heated cigarette tobacco agents, filling a technological gap in this sub-field of research and providing a new set of analytical methods for the refined study of the harm reduction mechanism of heated cigarettes. The stable isotope labeling traceability and quantitative technology proposed in this invention has important reference and reuse value for the study of the thermal conversion mechanism of volatile components in other aerosol systems such as e-cigarettes and various aerosol generating products, and has a wide range of application scenarios. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol, according to the present invention. Detailed Implementation

[0025] The following detailed description of the features and advantages of this application is sufficient to enable any person skilled in the art to understand the technical content of this application and implement it accordingly. Based on the specification, claims and drawings disclosed in this specification, those skilled in the art can easily understand the related objectives and advantages of this application.

[0026] The invention will now be described with reference to the accompanying drawings, in which similar reference numerals denote similar elements. While specific structures and arrangements are discussed, it should be understood that this is done merely for illustrative purposes. Those skilled in the art will recognize that other structures and arrangements can be used without departing from the spirit and scope of the invention. It will be apparent to those skilled in the art that the invention can also be used in a variety of other applications.

[0027] In this specification and claims, several terms will be used, and unless otherwise indicated, these terms will be defined to have the following meanings: The singular forms “a” and “” include their corresponding plural forms. “At least one” means one or more, and “more” means two or more. “At least one of the following” or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can be expressed as: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0028] All figures used to represent component amounts, properties (e.g., molecular weight), reaction conditions, etc., should be considered to be modified in all cases by the terms "within the unavoidable margin of error" or "about". Therefore, the numerical values ​​set forth herein are approximate and may vary depending on the desired properties sought to be obtained by the present invention. The principles of equivalents, which are applied to a minimum and not intended to limit the scope of the claims, should be applied, for example, each value should be interpreted at least according to the reported significant digits and by applying conventional rounding techniques.

[0029] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0030] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product is usually placed during use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0031] Unless otherwise indicated, the following abbreviations have the following meanings, and any other abbreviations used herein but not defined have their generally accepted standard meanings: All other terms used herein for special definition are intended to have the general meaning understood by one of ordinary skill in the art, in particular meaning that one of ordinary skill in the art can directly and without doubt determine how the technical solutions of the invention can be implemented after reading the claims, specification and drawings.

[0032] Even if there are incomplete descriptions, omissions, or ambiguities in the grammar, words, punctuation, graphics, symbols, etc. of the claims, specification, and drawings of this patent, a person skilled in the art can still arrive at the only correct understanding by reading the claims, specification, and drawings as a whole without extensive reasoning or experimentation, and effectively exclude various incorrect interpretations that are not aimed at achieving the purpose of this patent.

[0033] Those skilled in the art would first choose to read the claims, specification, and drawings of this patent to reasonably interpret the terms; secondly, they would choose to refer to the relevant definitions in other documents published by the applicant before the filing date to reasonably interpret the terms; thirdly, they would choose the references cited in this patent to reasonably interpret the terms; and finally, they would choose to combine the technical dictionaries, technical manuals, reference books, textbooks, national or industry technical standards, etc., commonly used by those skilled in the art to reasonably interpret the terms.

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the following will describe in detail its implementation methods in conjunction with the specific structure and working process of the device of the present invention.

[0035] It can accurately identify which compounds in the mixed smoke composition originate from the pyrolysis of glycerol and which originate from the tobacco matrix itself.

[0036] Please refer to Figure 1 This invention provides a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol. It overcomes the shortcomings of existing conventional chromatography-mass spectrometry detection methods that cannot distinguish the source of carbonyl harmful substances in heated cigarette smoke. It accurately separates and quantitatively distinguishes which compounds in the smoke originate from the pyrolysis of glycerol and which originate from the tobacco matrix itself, and precisely quantifies the thermal conversion efficiency of glycerol. This provides quantitative data support for the harm reduction optimization of heated cigarette smoke-generating agent formulations and heating temperature processes.

[0037] This invention provides a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol, mainly comprising the following steps: Step S1: Prepare an isotope-labeled glycerol solution, wherein the solute of the isotope-labeled glycerol solution is carbon-13 labeled glycerol or deuterated glycerol; Step S2: Mix the isotope-labeled glycerol solution with the unlabeled glycerol solution to prepare a mixed smoking agent, and apply the mixed smoking agent to a heated cigarette tobacco sheet substrate to prepare a tobacco sheet sample containing isotope-labeled glycerol; Step S3: Heat the tobacco sheet sample and collect the smoke sample generated during the heating process; Step S4: Detect the target compound in the flue gas sample to obtain the isotope ratio, and calculate the amount of the target compound in the flue gas sample originating from the labeled glycerol based on the isotope ratio; Step S5: Draw a thermal conversion pathway map of glycerol based on the amount of target compound generated from labeled glycerol. The thermal conversion pathway map includes a temperature-conversion curve and a distribution map of each cracking product.

[0038] Specifically, step S1 includes: Preparation of stable isotope-labeled glycerol stock solution Stable isotope-labeled glycerol is selected, which can be either carbon-13 labeled glycerol or deuterated glycerol. For example, carbon-13 labeled glycerol is glycerol-1,2,3-13C3 with a carbon-13 isotope abundance ≥99 atom; deuterated glycerol is glycerol-D8 with a deuterium isotope abundance ≥98%.

[0039] The stable isotope-labeled glycerol is mixed with a solvent to prepare an isotope-labeled glycerol stock solution. For example, the concentration of the isotope-labeled glycerol solution is from 0.1 mol / L to 2.0 mol / L.

[0040] Step S2 specifically includes: Step S201: Prepare the mixed smoke generator A mixed smoke generator is obtained by mixing an isotopically labeled glycerol solution with an unlabeled glycerol solution in a predetermined ratio.

[0041] The mass ratio of isotopically labeled glycerol to unlabeled glycerol in the mixed smoke generator is 1:10 to 1:100.

[0042] Step S202: Prepare tobacco sheet samples containing labeled glycerol.

[0043] The mixed smoke-generating agent is applied to a heated cigarette tobacco sheet substrate by means of spraying, dipping, or roller coating. The amount of the mixed smoke-generating agent applied is 5% to 25% of the mass of the heated cigarette tobacco sheet substrate. The heated cigarette tobacco sheet substrate after application is dried and subjected to moisture balancing treatment to obtain a tobacco sheet sample containing isotopically labeled glycerol.

[0044] Step S3 specifically includes: Heating and Smoke Collection of Tobacco Sheet Samples Containing Isotope-Labeled Glycerol The prepared tobacco sheet sample containing isotopically labeled glycerol was placed in a heated cigarette heating device and heated at a preset heating temperature, while the aerosol / smoke generated during the heating process was captured simultaneously.

[0045] The preset heating temperature is 200℃ to 350℃, the heating rate is 5℃ / min to 50℃ / min, and the heating time is 1min to 10min.

[0046] The method for capturing flue gas samples is either the Cambridge filter method or the cold trap method.

[0047] Step S4 specifically includes: Isotope ratio detection: Step S401: Pre-treat the captured flue gas sample to obtain the sample solution to be tested.

[0048] Pretreatment of flue gas samples includes: placing the Cambridge filter containing the flue gas in an extraction solvent for ultrasonic extraction, followed by filtration through an organic phase membrane to obtain the sample solution to be tested. The extraction time is 10 to 60 minutes. Alternatively, the condensate obtained from the cold trap can be directly filtered through an organic phase membrane to obtain the sample solution to be tested.

[0049] Step S402: Use gas chromatography-mass spectrometry or isotope ratio mass spectrometry to detect the target compound in the sample solution to obtain the isotope ratio value.

[0050] The target compound is a cleavage product of glycerol, including at least one of acetaldehyde, acrolein, formaldehyde, acetone, and hydroxyacetone.

[0051] By analyzing the isotopic ratio of carbon-13 to carbon-12, or the isotopic ratio of deuterium to hydrogen, the cleavage products derived from isotopically labeled glycerol can be identified and quantified.

[0052] It should be noted that if the solute in the isotopically labeled glycerol solution is carbon-13 labeled glycerol, the isotope ratio is the ratio of carbon-13 to carbon-12 isotopes.

[0053] If the solute in the isotopically labeled glycerol solution is deuterated glycerol, the isotope ratio is the ratio of deuterium to hydrogen isotopes.

[0054] Step S403: Determination and Quantitative Calculation of Thermal Conversion Path

[0055] By analyzing the isotopic ratios of carbon-13 to carbon-12, or deuterium to hydrogen, in the target compound, pyrolysis products derived from isotopically labeled glycerol can be identified and quantified. The detected isotopic ratios can then be converted into calculations of the specific amounts of each pyrolysis product produced.

[0056] The specific formula for calculating the amount of the target compound derived from labeled glycerol is as follows:

[0057] in, The amount of labeled glycerol produced in the target compound. The total amount of the target compound produced. The isotopic ratio of the target compound in the sample. The values ​​represent the natural isotope abundance ratios (1.1% for carbon-13). The isotopic abundance ratios of glycerol are used to label the glycerol.

[0058] This calculation formula can accurately calculate the amount of various cracking products derived from glycerol and their proportion of the total glycerol addition. Further calculations were performed to determine the thermal conversion rates of glycerol to various carbonyl products, thus identifying the thermal conversion pathways and contribution percentages of glycerol.

[0059] Furthermore, a thermal conversion pathway map of glycerol can be plotted based on the amount of target compound derived from labeled glycerol. The thermal conversion pathway map includes a temperature-conversion curve and a distribution map of each cracking product.

[0060] Furthermore, embodiments of the present invention also provide a method for tracking the thermal conversion behavior of heated cigarette tobacco sheets using the above-mentioned isotope-labeled glycerol, quantitatively tracking the pyrolysis products derived from glycerol and the pyrolysis products derived from the tobacco matrix itself during the heating process of heated cigarette tobacco sheets.

[0061] This heated tobacco sheet introduces quantitatively labeled glycerol into the sheet smoking agent system. Combined with heating simulation, smoke capture, isotope ratio detection, and source-specific quantitative calculation, it can accurately distinguish whether carbonyl harmful substances such as acetaldehyde and acrolein originate from the thermal decomposition of exogenous glycerol or the thermal decomposition of the tobacco's endogenous cellulose / pectin / hemicellulose matrix during the heating process. It can be used to compare and evaluate the harmful performance of reconstituted tobacco under different smoking agent formulations, different processing techniques, and different heating conditions, and provide standardized test samples for the development of harmful reduction formulations for heated cigarettes.

[0062] In the following examples and comparative examples, the carbon-13 labeled glycerol used was glycerol-1,2,3-13C3 (Glycerol-13C3), purchased from Sigma-Aldrich, with a carbon-13 isotope abundance ≥99 atom%. Unlabeled glycerol was analytical grade, with a purity ≥99.5%. The heated tobacco sheet substrate used was commercially available reconstituted tobacco sheet for heated cigarettes, and its glycerol background content had been pre-determined.

[0063] Example 1: Tracking thermal conversion behavior of ¹³C-labeled glycerol at 300℃

[0064] Step S1: Prepare isotope-labeled glycerol solution: Weigh 1.0 g of Glycerol-13C3 (abundance 99 atom%), dissolve it in 10 mL of deionized water, and prepare a 0.82 mol / L C-13 labeled glycerol stock solution for later use.

[0065] Step S2: Prepare tobacco sheet samples containing labeled glycerol: Take 2.0 mL of the above C-13 labeled glycerol stock solution (containing approximately 0.2 g of Glycerol-13C3), mix it with 9.8 g of unlabeled glycerol, add deionized water to make up to 50 mL, and stir well to obtain a mixed smoke generator solution. In the mixed smoke generator, the mass ratio of isotopically labeled glycerol to unlabeled glycerol is 1:49.

[0066] Take 50g of heated cigarette tobacco sheet substrate (the background glycerol content has been pre-determined to be 2.5%), and apply the above-mentioned mixed smoking agent solution evenly to the surface of the sheet using a spraying method. The amount applied is 20% of the mass of the sheet substrate (i.e., the total amount of smoking agent applied is 10g). After application, place the sheet in a 40℃ oven to dry for 2 hours, and then place it in a constant temperature and humidity chamber at 22℃ and 60% relative humidity to equilibrate the moisture for 48 hours, thus obtaining a tobacco sheet sample containing C-13 labeled glycerol.

[0067] Step S3, Heating Simulation and Flue Gas Capture: Take 2.0 g of the tobacco sheet sample containing labeled glycerol obtained in step S2 and spread it evenly in the quartz sample boat of the tubular furnace. The tubular furnace is equipped with a programmable temperature controller and a digital gas mass flow controller. The tubular furnace is heated from room temperature to 300°C at a heating rate of 10°C / min, and then held at the set temperature for 5 min. Air is introduced as a carrier gas at a flow rate of 1.0 L / min during the heating process.

[0068] A Cambridge filter trapping method was used to capture aerosols / flue gas generated during the heating process. A Cambridge filter (44 mm in diameter) was placed in the flue gas trap, and the outlet of the quartz tube was connected to the airflow of the flue gas trap. The aerosols / flue gas generated during heating were carried by a carrier gas through the Cambridge filter, while particulate matter was trapped by the Cambridge filter. After heating, the Cambridge filter was removed, sealed, and stored for subsequent analysis.

[0069] Step S4: Isotope ratio detection and quantitative calculation

[0070] Sample pretreatment: A Cambridge filter containing particulate matter from the flue gas was placed in a 50 mL centrifuge tube, and 20 mL of methanol was added as the extraction solvent. The centrifuge tube was then placed in an ultrasonic cleaner and ultrasonically extracted for 30 min at room temperature. After extraction, the supernatant was filtered through a 0.22 μm organic phase filter membrane to obtain the sample solution to be tested.

[0071] Isotope ratio analysis: The sample solutions were analyzed using gas chromatography-mass spectrometry (GC-MS). The chromatographic conditions were as follows: DB-624 capillary column (60 m × 0.25 mm × 1.4 μm); injection port temperature 250 °C; carrier gas high-purity helium (purity ≥ 99.999%), flow rate 1.0 mL / min; temperature program: initial temperature 40 °C, held for 2 min, then increased to 240 °C at 8 °C / min, held for 5 min; injection volume 1 μL, split ratio 10:1. The mass spectrometry conditions were as follows: electron impact ionization (EI) source, ionization energy 70 eV; ion source temperature 230℃; quadrupole temperature 150℃; selected ion monitoring mode (SIM) was used, and the target ions monitored included: acrolein (m / z 56), acrolein-13C3 (m / z 59), acetone (m / z 58), acetone-13C3 (m / z 61), formaldehyde (m / z 30), and formaldehyde-13C (m / z 31).

[0072] By comparing the carbon-13 to carbon-12 isotope ratios of each target compound in the sample with their natural abundance (13C / 12C=1.1%), the cleavage products derived from carbon-13 labeled glycerol were identified and quantified.

[0073] Determination and quantitative calculation of thermal conversion pathway: Based on the detected isotope ratios, the amounts of various pyrolysis products derived from glycerol and their proportions in the total amount of glycerol added are calculated using the following formula:

[0074] in, The amount of the target compound derived from labeled glycerol (μg / g flake) is given. The total yield of the target compound (μg / g flakes). The 13C / 12C ratio of the target compound in the sample. The natural 13C / 12C ratio is 1.1%. The 13C / 12C ratio (99%) of glycerol is used to label the glycerol.

[0075] The detection and calculation results show that under heating conditions of 300℃, the total amount of acrolein generated in the flue gas is 12.8 μg / g flake, of which 0.010 μg / g flake originates from the pyrolysis of glycerol. The calculated conversion rate from glycerol to acrolein is approximately 0.08%. The total amount of acetone generated in the flue gas is 8.5 μg / g flake, of which 0.24 μg / g flake originates from the pyrolysis of glycerol. The total amount of formaldehyde generated is 15.2 μg / g flake, of which 0.18 μg / g flake originates from the pyrolysis of glycerol.

[0076] Example 2: Tracking thermal conversion behavior of ¹³C-labeled glycerol at 250°C

[0077] Example 2 follows the same basic steps as Example 1, except that the heating temperature of the tobacco sheet sample in step S3 is different. The heating temperature in Example 2 is set to 250°C, and the remaining steps are completely consistent with Example 1.

[0078] The detection and calculation results show that under heating conditions of 250℃, the total amount of acrolein generated in the flue gas is 5.6 μg / g flake, of which 0.002 μg / g flake originates from the pyrolysis of glycerol, and the conversion rate from glycerol to acrolein is approximately 0.016%. The total amount of acetone generated is 3.8 μg / g flake, of which 0.09 μg / g flake originates from the pyrolysis of glycerol. The total amount of formaldehyde generated is 8.1 μg / g flake, of which 0.07 μg / g flake originates from the pyrolysis of glycerol.

[0079] Compared with Example 1, it can be seen that when the heating temperature is increased from 250°C to 300°C, the conversion rate of glycerol to acrolein increases from 0.016% to 0.08%, indicating that increasing the heating temperature significantly promotes the reaction pathway of glycerol pyrolysis to acrolein.

[0080] Example 3: Tracking thermal conversion behavior of deuterated glycerol at 300℃

[0081] Example 3 follows the same basic steps as Example 1, except that the mixing ratio of isotopically labeled glycerol and unlabeled glycerol is different, and the target analyte includes a deuterated label.

[0082] In Example 3, deuterated glycerol (Glycerol-D8, deuterium isotope abundance ≥98%) was used as the isotope label in step S1. In step S2, 0.5 g of Glycerol-D8 was weighed and mixed with 9.5 g of unlabeled glycerol. Deionized water was added to bring the volume to 50 mL, and the mixture was stirred until homogeneous to obtain a mixed smoke-generating agent solution. In the mixed smoke-generating agent, the mass ratio of isotope-labeled glycerol to unlabeled glycerol was 1:19. The remaining steps were the same as in Example 1.

[0083] During the detection in step S4, the mass spectrometry detection mode is selected ion monitoring mode (SIM), and the target ions monitored include: acrolein (m / z 56), deuterated acrolein (m / z 60), acetone (m / z 58), and deuterated acetone (m / z 62).

[0084] The detection and calculation results show that under heating conditions of 300℃, the total amount of acrolein generated in the flue gas is 13.1 μg / g flake, of which 0.011 μg / g flake is derived from the pyrolysis of deuterated glycerol, and the conversion rate of glycerol to acrolein is approximately 0.084%. This result is basically consistent with the result obtained in Example 1 using carbon-13 labeled glycerol (0.08%), verifying the repeatability of the method of the present invention and the equivalence between different isotopic labels.

[0085] Example 4: Tracking thermal conversion behavior of tobacco sheets with smoke-generating agents applied by impregnation at 300°C

[0086] Example 4 follows the same basic steps as Example 1, except that the method of applying the mixed smoke-generating agent in step S2 is different. In Example 4, the mixed smoke-generating agent is applied to the tobacco sheet substrate by impregnation.

[0087] In step S2, 50g of heated cigarette tobacco sheet substrate was taken and immersed in the mixed smoking agent solution prepared in step S1. After soaking for 10 minutes, it was removed, excess solution was drained, and it was placed in a 40°C oven to dry for 2 hours. Then, it was placed in a constant temperature and humidity chamber at 22°C and 60% relative humidity to equilibrate the moisture for 48 hours. The amount of mixed smoking agent applied was calculated to be 18% of the mass of the sheet substrate. The remaining steps were the same as in Example 1.

[0088] The detection and calculation results show that under the heating condition of 300℃, the conversion rate of glycerol to acrolein is about 0.077%, which is not significantly different from the result of Example 1 (0.08%). This indicates that both spraying and impregnation methods can achieve uniform application of isotope-labeled glycerol in tobacco sheets. The method of the present invention has good adaptability to different application methods of mixed smoke-generating agents.

[0089] Example 5: Tracking thermal conversion behavior of flue gas samples captured in a cold trap at 300℃

[0090] Example 5 follows the same basic steps as Example 1, except that the flue gas collection method is different in step S3. Example 5 uses a cold trap collection method instead of the Cambridge filter collection method.

[0091] In step S3, the outlet of the tubular furnace is connected to two series-connected cold traps (placed in a -20°C low-temperature bath), with 10 mL of methanol added to each trap as the absorbent. During heating, the aerosol / flue gas generated is carried by a carrier gas through the two cold traps sequentially, and the gaseous and particulate matter are captured by the methanol absorbent. After heating, the absorbents from the two cold traps are combined and filtered through a 0.22 μm organic phase filter membrane to obtain the sample solution to be tested. The remaining steps are the same as in Example 1.

[0092] The detection and calculation results show that under the heating condition of 300℃, the conversion rate of glycerol to acrolein is about 0.079%, which is basically consistent with the result of Example 1 (0.08%), indicating that the Cambridge filter trapping method and the cold trapping method have equivalent trapping effects in this invention.

[0093] Comparative Example 1: Routine Detection Without Isotope Labeling

[0094] The difference between Comparative Example 1 and Example 1 is that in step S1, no isotopically labeled glycerol is added, but only an equal amount of unlabeled glycerol is added.

[0095] In step S1, 10.0 g of unlabeled glycerol was added to deionized water and brought to a final volume of 50 mL. The mixture was stirred until homogeneous to obtain a smoking agent solution. The smoking agent solution was then applied to 50 g of heated cigarette tobacco sheet substrate by spraying (the application amount was 20% of the substrate mass). The remaining processing steps were the same as in Example 1.

[0096] GC-MS analysis was performed on the heated flue gas to detect the total amount of target compounds such as acrolein, acetone, and formaldehyde. However, due to the lack of isotope labeling, it was impossible to distinguish which of these target compounds originated from the pyrolysis of glycerol and which originated from the pyrolysis of the tobacco matrix itself. Only total data (acrylaldehyde 12.8 μg / g flake, acetone 8.5 μg / g flake, formaldehyde 15.2 μg / g flake) could be obtained, and the conversion rate of glycerol to each pyrolysis product could not be calculated.

[0097] Comparing Comparative Example 1 with Example 1 reveals that, under the same heating conditions and glycerol addition amount, the total amount of target compounds obtained by both examples is basically consistent. However, Example 1, through isotope labeling technology, can further clarify the specific proportion of glycerol-derived components in each target compound, while Comparative Example 1 cannot achieve this distinction. This fully demonstrates the advantages of this invention in precise traceability and quantitative analysis.

[0098] Comparative Example 2: Tracking Thermal Conversion Behavior of Tobacco Sheets with Omitted Drying Balancing Process

[0099] The difference between Comparative Example 2 and Example 1 is that in step S2, isotopically labeled glycerol is directly added to the surface of the tobacco sheet, but without drying and moisture balancing treatment, and the heating simulation experiment is carried out immediately.

[0100] In step S2, 50g of heated cigarette tobacco sheet substrate was taken, and after applying the mixed smoking agent solution in the same manner as in Example 1, 2.0g was directly taken for heating simulation experiment (300℃) without drying and moisture balancing treatment, and the other conditions were the same as in Example 1.

[0101] The test results showed that the 13C / 12C ratio of acrolein in the flue gas was significantly lower than that in Example 1, and the calculated conversion rate of glycerol to acrolein was only 0.03%, significantly lower than 0.08% in Example 1. This indicates that without drying and moisture balancing treatment, the uniformity and permeability of isotope-labeled glycerol in tobacco sheets are poor, and some glycerol fails to fully participate in the pyrolysis reaction or is lost in other forms (such as direct volatilization) during heating, affecting the accuracy of quantitative analysis. Therefore, the drying and moisture balancing treatment in step (2) is an important step to ensure the accuracy of the method of the present invention.

[0102] Table 1 Test Results

[0103] Note: In Table 1, the units for total acrolein release, acrolein content from glycerol, total acetone content, acetone content from glycerol, total formaldehyde content, and formaldehyde content from glycerol are all μg / g. "—" in the table indicates that this indicator was not measured separately in this group of experiments. The core comparison indicator is acrolein conversion rate. Examples 3 to 5 mainly verify the universality of the method, with acrolein conversion rate as the core control parameter.

[0104] Comparing the test results of Examples 1-5 and Comparative Examples 1-2 in Table 1, it can be found that: 1. The present invention provides a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol. By using carbon-13 or deuterium-labeled glycerol as a tracer and combining it with GC-MS isotope ratio analysis, it is possible to accurately identify and quantify the pyrolysis products (such as acrolein, acetone, formaldehyde, etc.) originating from the pyrolysis of glycerol. This effectively solves the technical problem that the prior art cannot distinguish between the pyrolysis products of glycerol and the pyrolysis products of tobacco matrix (Examples 1-5).

[0105] 2. This invention provides a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol, which can accurately calculate the conversion rate of glycerol to various harmful substances. Under heating conditions of 300°C, the conversion rate of glycerol to acrolein is approximately 0.08%, to acetone is approximately 2.8%, and to formaldehyde is approximately 1.2% (Example 1).

[0106] 3. The present invention provides a method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol. The heating temperature has a significant impact on the thermal conversion behavior of glycerol. When the temperature increases from 250°C to 300°C, the conversion rate of glycerol to acrolein increases from 0.016% to 0.08%, which is about 5 times higher (comparison between Example 1 and Example 2). This indicates that the method of the present invention can effectively reveal the influence of temperature on the thermal conversion pathway of glycerol.

[0107] 4. The method of tracking the thermal conversion behavior of cigarette sheet with isotope-labeled glycerol of the present invention has good adaptability to different isotope labels (carbon-13 labeling and deuterium labeling), different application methods (spraying and impregnation), and different smoke collection methods (Cambridge filter and cold trap). The results are consistent and reproducible (Examples 1, 3, 4, 5).

[0108] 5. In practical application, the method of tracking the thermal conversion behavior of cigarette sheet with isotope-labeled glycerol of the present invention showed that the test results of the sample (Comparative Example 2) without drying and moisture balancing treatment deviated significantly from the true value, which verified the necessity and rationality of drying and moisture balancing treatment in step (2) of the technical solution of the present invention.

[0109] The device embodiments described above are merely illustrative. For example, the division of units is only a logical functional division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0110] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0111] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0112] In this specification, references to "an embodiment" or "a specific implementation" mean that a particular feature, structure, or characteristic described in connection with that embodiment / specific implementation is included in at least one embodiment / specific implementation of the invention. Therefore, the phrase "in one embodiment / specific implementation" appearing in various places in this specification does not necessarily refer to the same embodiment / setting, but rather to potentially different embodiments. Furthermore, specific features, structures, or characteristics may be combined in one or more embodiments / settings in any suitable manner, as will be apparent to those skilled in the art from this disclosure.

[0113] Similarly, it should be understood that in the above description of exemplary embodiments / specific implementations of the invention, various features of the invention are sometimes combined in a single embodiment / specific implementation or its figures and description, with the aim of simplifying the disclosure and aiding in the understanding of one or more of the various aspects of the invention. However, the method of description of the invention should not be construed as reflecting an intention that, except for expressly stated instructions to the contrary or obvious technical contradictions or exclusions, the claimed features of the invention are more than those expressly stated in each claim.

[0114] Conversely, the inventive aspect reflected in the claims lies in not all the features of a single foregoing disclosed embodiment / specification. Therefore, the claims following the detailed description are expressly incorporated herein, each claim existing independently as a separate embodiment / specification of the invention.

[0115] Furthermore, while some embodiments / specific implementations described herein include, but are not limited to, other features included in other embodiments / specific implementations, combinations of features from different embodiments / specific implementations are intended to be within the scope of the invention and form different embodiments / specific implementations, as will be understood by those skilled in the art. For example, in the following claims, embodiments / specific implementations of any claim can be used in any combination.

[0116] The terms and expressions used in this specification are for illustrative purposes and not for limitation. The use of these terms and expressions is not intended to exclude any equivalents of the features or portions thereof shown and described, but rather to allow for the understanding that various modifications may be made within the scope of the invention.

[0117] Therefore, it should be understood that although the invention has been specifically disclosed through preferred embodiments, exemplary embodiments and optional features, those skilled in the art may take variations or modifications of the concepts disclosed herein, and such variations and modifications are therefore considered to be within the scope of the invention as defined by the appended claims.

[0118] The specific embodiments given in this specification are examples of useful implementations of the present invention. It will be apparent to those skilled in the art that the present invention can be implemented using many variations of the devices, device components, and method steps disclosed in this specification.

[0119] The foregoing description of specific embodiments fully discloses the general features of the present invention, enabling others to easily modify and / or adapt such specific embodiments for various applications by applying knowledge within the scope of the art, without conducting excessive experimentation and without departing from the general concept of the present invention.

[0120] Therefore, based on the teachings and guidance provided herein, it is intended that such modifications and alterations be included within the meaning and scope of equivalents of the disclosed embodiments. It should be understood that the wording or terminology used herein is for descriptive purposes and is not intended to be limiting; thus, the wording or terminology in this specification will be interpreted by those skilled in the art based on the foregoing teachings and guidance.

[0121] Furthermore, the scope of this invention should not be limited to any of the exemplary embodiments described above, but only to the appended claims and their equivalents. The terminology and expressions used herein are for descriptive purposes only, and the invention should not be limited to these terms and expressions. The use of these terms and expressions does not imply the exclusion of any illustrative and descriptive equivalents (or parts thereof), and it should be recognized that various modifications that may exist should also be included within the scope of the claims. Other modifications, variations, and substitutions may also exist. Accordingly, the claims should be considered to cover all such equivalents.

[0122] Similarly, it should be noted that although the present invention has been described with reference to the specific embodiments described above, those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions can be made without departing from the spirit of the present invention. Therefore, any changes or modifications to the above embodiments within the scope of the essential spirit of the present invention will fall within the scope of the claims of the present invention.

Claims

1. A method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol, characterized in that, include: Step S1: Prepare an isotope-labeled glycerol solution, wherein the solute of the isotope-labeled glycerol solution is carbon-13 labeled glycerol or deuterated glycerol; Step S2: Mix the isotope-labeled glycerol solution with the unlabeled glycerol solution to prepare a mixed smoking agent, and apply the mixed smoking agent to a heated cigarette tobacco sheet substrate to prepare a tobacco sheet sample containing isotope-labeled glycerol; Step S3: Heat the tobacco sheet sample and collect the smoke sample generated during the heating process; Step S4: Detect the target compound in the flue gas sample to obtain the isotope ratio, and calculate the amount of the target compound in the flue gas sample originating from the labeled glycerol based on the isotope ratio; Step S5: Draw a thermal conversion pathway map of glycerol based on the amount of target compound generated from labeled glycerol. The thermal conversion pathway map includes a temperature-conversion curve and a distribution map of each cracking product.

2. The method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol according to claim 1, characterized in that: In step S4, the target compound includes at least one of acrolein, formaldehyde, acetaldehyde, acetone, ethylene glycol, and hydroxyacetone.

3. The method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol according to claim 2, characterized in that: The formula for calculating the amount of the target compound derived from labeled glycerol in step S4 is as follows: in, The amount of labeled glycerol produced in the target compound. The total amount of the target compound produced. The isotopic ratio of the target compound in the sample. This represents the natural isotope abundance ratio. The isotopic abundance ratios of glycerol are used to label the glycerol.

4. The method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol according to claim 1, characterized in that: In step S3, the heating temperature of the tobacco sheet sample is 200℃~350℃.

5. The method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol according to claim 1, characterized in that: Carbon-13 labeled glycerol is glycerol-1,2,3-13C3 with a carbon-13 isotopic abundance ≥99 atom% The deuterated glycerol is glycerol-D8, with a deuterium isotope abundance of ≥98%.

6. The method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol according to claim 1, characterized in that: If the solute in the isotopically labeled glycerol solution is carbon-13 labeled glycerol, the isotope ratio is the ratio of the carbon-13 to the carbon-12 isotopes. If the solute in the isotopically labeled glycerol solution is deuterated glycerol, the isotope ratio is the ratio of deuterium to hydrogen isotopes.

7. The method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol according to claim 1, characterized in that: Step S2 specifically includes: Step S201: Mix the isotope-labeled glycerol solution and the unlabeled glycerol solution in a preset ratio to obtain a mixed smoke generator; Step S202: The mixed smoke-generating agent is applied to the heated cigarette tobacco sheet substrate by spraying, dipping or roller coating. The amount of the mixed smoke-generating agent applied is 5% to 25% of the mass of the heated cigarette tobacco sheet substrate. The heated cigarette tobacco sheet substrate after application is dried and subjected to moisture balancing treatment to obtain a tobacco sheet sample containing isotope-labeled glycerol.

8. The method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol according to claim 1, characterized in that, In step S1, the concentration of the isotope-labeled glycerol solution is 0.1 mol / L to 2.0 mol / L; in step S2, the mass ratio of isotope-labeled glycerol to unlabeled glycerol in the mixed smoke generator is 1:10 to 1:

100.

9. The method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol according to claim 1, characterized in that, The method for detecting the isotope ratio in step S4 is as follows: S401. Pre-treat the captured flue gas sample to obtain the sample solution to be tested. S402. Use gas chromatography-mass spectrometry or isotope ratio mass spectrometry to detect the target compound in the sample solution to obtain the isotope ratio value.

10. A heated tobacco sheet for cigarettes, characterized in that: Using the method for tracking the thermal conversion behavior of cigarette sheets using isotope-labeled glycerol as described in any one of claims 1-9, the pyrolysis products derived from glycerol and the pyrolysis products derived from the tobacco matrix itself during the heating process of heated cigarette tobacco sheets are quantitatively tracked.

Images