Sweetener thermal cracking analysis method and application thereof

Abstract

The invention discloses a sweetener thermal cracking analysis method and application thereof, and belongs to the field of sweet additive analys.The sweetener and an alkylating reagent are mixed and placed in a thermal cracking instrument for thermal cracking, a cracking product is subjected to GC-MS analysis, and the cracking product is detected. Compared with a conventional sweetener thermal cracking method (direct cracking method), the sweetener methylation thermal cracking analysis method has the advantages that more components can be detected, and more cracking product information can be supplemented. The cracking products detected by the sweetener thermal cracking and tetramethylammonium hydroxide methylation method are more than the cracking products detected by direct cracking of the sweetener. Methylation is carried out while thermal cracking is carried out, the total time of analysis is 35 minutes, and the analysis efficiency is high.

Description

Technical Field

[0001] The present invention relates to the technical field of sweetening additive analysis, and in particular to a sweetening agent thermal cracking analysis method and application thereof. Background Art

[0002] Electronic atomization liquid is composed of propylene glycol, glycerin, aromatic compounds and sweeteners. It is heated and atomized to enter the human body in the form of aerosol. During the atomization process, most components will exist in an evaporated state, and some components will undergo thermal cracking reactions at high temperatures. Therefore, analyzing the possible cracking products is helpful to understand the safety of the added raw materials, facilitate the subsequent understanding of the product optimization direction, and thus improve product performance and consumer satisfaction.

[0003] At present, dipeptide sweeteners such as neotame and adventitium are commonly used sweeteners in e-cigarette liquids. According to existing literature, neotame will undergo thermal cracking at a temperature of about 200°C, and the cracking products are L-phenylalanine methyl ester and 3,3-dimethylbutylamine. The atomization temperature of e-cigarette oil is generally 220-260°C, and the working temperature of some areas of the smoking device can reach 300°C. However, the existing literature does not record what cracking products neotame will produce after exceeding 200°C. In order to more comprehensively analyze the thermal cracking products of neotame, a new analysis method needs to be proposed. Summary of the invention

[0004] Purpose of the Invention

[0005] In order to overcome the above shortcomings, the purpose of the present invention is to provide a sweetener thermal cracking analysis method and its application. The present invention provides a theoretical basis for controlling the reaction in the production process by deeply understanding the stability of various sweeteners under high temperature conditions; and analyzes the composition and properties of cracking products, which can provide a solution for reducing the generation of cracking products.

[0006] Solution

[0007] To achieve the purpose of the present invention, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a sweetener thermal cracking analysis method, wherein a sweetener and an alkylating agent are mixed and introduced into a thermal cracking instrument for thermal cracking, and the cracking products are analyzed by GC-MS to detect the cracking products.

[0009] Furthermore, the sweetener is a dipeptide sweetener and / or sucralose, and optionally the dipeptide sweetener includes one or more of neotame, advantame, and alitame.

[0010] Further, the alkylating agent is a methylating agent or an ethylating agent, and the methylating agent may optionally include one or more of tetraalkylammonium hydroxide, phenyltrimethylammonium hydroxide or trimethylsulfide hydroxide; may optionally be tetraalkylammonium hydroxide; and may optionally include one or both of tetramethylammonium hydroxide and tetraethylammonium hydroxide.

[0011] Furthermore, the weight ratio of the sweetener to the alkylating agent is 1:(0.5-10), optionally 1:(1-10); and the mixing method is optionally shaking mixing.

[0012] Further, the cracking temperature is 200°C to 500°C, optionally 250°C to 500°C, optionally 250°C, 350°C or 500°C.

[0013] Further, the cracking includes thermal cracking in an aerobic atmosphere and / or thermal cracking in an anaerobic atmosphere; optionally, the cracking in an aerobic atmosphere includes introducing air or other oxygen-containing gas into the cracking reaction chamber; optionally, no air is introduced during the anaerobic atmosphere cracking.

[0014] Furthermore, the lysis time is 1 to 30 seconds, optionally 12 seconds.

[0015] Further, the sweetener undergoes an alkylation reaction with an alkylating agent during the cleavage process, and optionally the sweetener undergoes a methylation reaction with a methylating agent during the cleavage process.

[0016] Furthermore, after the target pyrolysis temperature of the pyrolysis instrument and the cold trap temperature are stabilized and the GC-MS is ready, the pyrolysis reaction is carried out.

[0017] Further, the pyrolysis products are cooled (can be liquid nitrogen cooled) and pumped to the GC-MS system.

[0018] Furthermore, in GC-MS analysis, the chromatography uses a capillary chromatographic column, and optionally a UA-1MS capillary chromatographic column.

[0019] Furthermore, the chromatographic conditions were as follows: injection port temperature: 250°C; detector temperature: 250°C; carrier gas: helium, flow rate 3 mL / min; injection volume: 0.2 μL; programmed temperature: initial temperature 50°C for 2 min, then increased to 280°C at a rate of 10°C / min for 10 min; split ratio: 50:1.

[0020] Furthermore, in the GC-MS analysis, the mass spectrometer is a high-sensitivity EI source; optionally, the mass spectrometer conditions are: in the mass spectrometer, ion source temperature: 230°C, MS quadrupole high temperature: 150°C, solvent delay time: 0min, scanning mode: full scan.

[0021] Furthermore, other electronic cigarette additives are added to the sweetener before cracking.

[0022] In a second aspect, an analysis method for evaluating the safety of sweeteners for electronic cigarettes is provided, wherein the sweetener pyrolysis analysis method described in the first aspect is used to detect the pyrolysis products of the sweeteners to evaluate the safety of the pyrolysis products.

[0023] In a third aspect, an analysis system for evaluating the safety of sweeteners for electronic cigarettes is provided, which inputs the pyrolysis products of sweeteners detected by the pyrolysis analysis method for sweeteners described in the first aspect, and outputs an evaluation result of whether the pyrolysis products are safe.

[0024] Beneficial Effects

[0025] (1) The present invention uses a simulation experiment by using an analytical method (PY-GCMS) that combines thermal cracking technology with gas chromatography-mass spectrometry technology to explore the cracking behavior and generated products of dipeptide sweeteners at high temperatures, and understand the mechanism of the cracking reaction of dipeptide sweeteners. By selecting a suitable methylation reagent and optimizing the reaction conditions, the reaction products can be analyzed to provide theoretical guidance for the production and application of electronic cigarettes. The thermal cracking analysis method of the present invention for methylation of sweeteners detects more components than the conventional thermal cracking method (direct cracking method) of sweeteners, and can supplement more cracking product information. The method of thermal cracking of sweeteners with methylation by tetramethylammonium hydroxide can detect more cracking products than the cracking products detected by direct cracking of sweeteners. The methylation reaction is carried out while the sweetener is thermally cracked, and the total analysis time is 35 minutes, with high analysis efficiency.

[0026] (2) The present invention provides a theoretical basis for controlling the reaction in the production process by deeply understanding the stability of various sweeteners under high temperature conditions; and analyzes the composition and properties of the pyrolysis products to provide a solution for reducing the generation of pyrolysis products. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] One or more embodiments are exemplarily described by the pictures in the accompanying drawings, and these exemplary descriptions do not constitute limitations on the embodiments. The special word "exemplary" here means "used as an example, embodiment or illustrative". Any embodiment described as "exemplary" here is not necessarily interpreted as being superior or better than other embodiments.

[0028] Figure 1 to Figure 3 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of neotame pyrolysis-methylation (tetramethylammonium hydroxide) and thermal cracking of pure neotame at different cracking temperatures of 250°C, 350°C, and 500°C under oxygen-free atmosphere conditions in Example 1 of the present invention.

[0029] Figures 4 to 6, chromatogram overlay comparison of thermal cracking experiments of thermal cracking of neotame pyrolysis-methylation (tetramethylammonium hydroxide) and thermal cracking of pure neotame at different cracking temperatures of 250°C, 350°C, and 500°C in an aerobic atmosphere.

[0030] Figure 7 to Figure 9 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of neotame pyrolysis-methylation (phenyltrimethylammonium hydroxide) and thermal cracking of pure neotame at different cracking temperatures of 250°C, 350°C, and 500°C under oxygen-free atmosphere conditions in Example 2 of the present invention.

[0031] Figure 10 to Figure 12 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of neotame pyrolysis-methylation (phenyltrimethylammonium hydroxide) and thermal cracking of pure neotame at different cracking temperatures of 250°C, 350°C, and 500°C in an aerobic atmosphere.

[0032] Figure 13 to Figure 15 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of neotame pyrolysis-methylation (trimethyl sulfide hydroxide) and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an oxygen-free atmosphere, respectively, in Example 3 of the present invention.

[0033] Figure 16 to Figure 18 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of neotame pyrolysis-methylation (trimethyl sulfide hydroxide) and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an aerobic atmosphere, respectively, in Example 3 of the present invention.

[0034] Figure 19 to Figure 21 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation (tetramethylammonium hydroxide) of Advantame of Example 4 of the present invention and thermal cracking of pure neotame at 250°C, 350°C, and 500°C under oxygen-free atmosphere conditions, respectively.

[0035] Figure 22 to Figure 24 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation (tetramethylammonium hydroxide) of Advantame of Example 4 of the present invention and thermal cracking of pure neotame under aerobic atmosphere conditions of 250°C, 350°C, and 500°C, respectively.

[0036] Figure 25 to Figure 27 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of Advantame pyrolysis-methylation (phenyltrimethylammonium hydroxide) and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an oxygen-free atmosphere, respectively, in Example 5 of the present invention.

[0037] Figure 28 to Figure 30 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of Advantame pyrolysis-methylation (phenyltrimethylammonium hydroxide) and thermal cracking of pure neotame in Example 5 of the present invention under aerobic atmosphere conditions of 250°C, 350°C, and 500°C, respectively.

[0038] Figure 31 to Figure 33 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation (trimethyl sulfide hydroxide) of Advantame in Example 6 of the present invention and thermal cracking of pure neotame at 250°C, 350°C, and 500°C under oxygen-free atmosphere conditions, respectively.

[0039] Figure 34 to Figure 36 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation (trimethyl sulfide hydroxide) of Advantame in Example 6 of the present invention and thermal cracking of pure neotame under aerobic atmosphere conditions of 250°C, 350°C, and 500°C, respectively.

[0040] Figure 37 to Figure 39 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation (tetramethylammonium hydroxide) of alitame in Example 7 of the present invention and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an oxygen-free atmosphere, respectively.

[0041] Figure 40 to Figure 42 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation (tetramethylammonium hydroxide) of alitame in Example 7 of the present invention and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an aerobic atmosphere, respectively.

[0042] Figure 43 to Figure 45 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of alitame in Example 8 of the present invention - methylation (phenyltrimethylammonium hydroxide) and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an oxygen-free atmosphere, respectively.

[0043] Figure 46-48 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking of alitame in Example 8 of the present invention - methylation (phenyltrimethylammonium hydroxide) and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an aerobic atmosphere, respectively.

[0044] Figures 49 to 51 , chromatogram overlay comparison of thermal cracking experiments of alitame thermal cracking-methylation (trimethyl sulfide hydroxide) and pure neotame thermal cracking at 250°C, 350°C, and 500°C in an oxygen-free atmosphere, respectively, in Example 9 of the present invention.

[0045] Figure 52 to Figure 54 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation (trimethyl sulfide hydroxide) of alitame in Example 9 of the present invention and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an aerobic atmosphere, respectively.

[0046] Figure 55 to Figure 57, chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation (tetramethylammonium hydroxide) of sucralose in Example 10 of the present invention and thermal cracking of pure neotame at 250°C, 350°C, and 500°C under oxygen-free atmosphere conditions, respectively.

[0047] Figures 58 to 60 , chromatogram overlay comparison of thermal cracking experiments of sucralose thermal cracking-methylation (tetramethylammonium hydroxide) of Example 10 of the present invention and thermal cracking of pure neotame under aerobic atmosphere conditions of 250°C, 350°C, and 500°C, respectively.

[0048] Figure 61 to Figure 63 , chromatogram overlay comparison of thermal cracking experiments of thermal cracking-methylation of sucralose (phenyltrimethylammonium hydroxide) in Example 11 of the present invention and thermal cracking of pure neotame at 250°C, 350°C, and 500°C in an oxygen-free atmosphere, respectively.

[0049] Figure 64 to Figure 66 , chromatogram overlay comparison of thermal cracking experiments of sucralose thermal cracking-methylation (phenyltrimethylammonium hydroxide) of Example 11 of the present invention and thermal cracking of pure neotame under aerobic atmosphere conditions of 250°C, 350°C, and 500°C, respectively.

[0050] Figure 67 to Figure 69 , chromatogram overlay comparison of thermal cracking experiments of sucralose thermal cracking-methylation (trimethyl sulfide hydroxide) of Example 12 of the present invention and thermal cracking of pure neotame under oxygen-free atmosphere conditions of 250°C, 350°C, and 500°C, respectively.

[0051] Figure 70 to Figure 72 , chromatogram overlay comparison of thermal cracking experiments of sucralose thermal cracking-methylation (trimethyl sulfide hydroxide) of Example 12 of the present invention and thermal cracking of pure neotame under aerobic atmosphere conditions of 250°C, 350°C, and 500°C, respectively. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] In addition, in order to better illustrate the present invention, numerous specific details are provided in the specific embodiments below. It should be understood by those skilled in the art that the present invention can also be implemented without certain specific details. In some embodiments, raw materials, elements, methods, means, etc. well known to those skilled in the art are not described in detail, so as to highlight the main purpose of the present invention.

[0054] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0055] The pre-treatment method of thermal cracking-alkylation (e.g., methylation) of the present invention is as follows: before the thermal cracking experiment of the sweetener sample, during the sample preparation process, an alkylating agent such as tetramethylammonium hydroxide, phenyltrimethylammonium hydroxide or trimethyl sulfide hydroxide is added, and the thermal cracking experiment is performed after sufficient oscillation and mixing, so that the cracking products can be effectively alkylated (e.g., methylated) under high temperature conditions.

[0056] In the following examples, the products of thermal cracking-methylation of sweeteners and thermal cracking of pure sweeteners may be different in whether they are methylated or not. The products of thermal cracking-methylation of a certain sweetener may be analyzed according to the product groups (for example, some products may be demethylated after being decomposed to analyze related products) to obtain the cracking products of the sweetener. If other alkylating agents are used, similar decomposition is performed.

[0057] In the following examples, Examples 1 to 3 are methylation analyses of cleavage products of neotame mixed with different methylating agents (tetramethylammonium hydroxide, phenyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide).

[0058] In the following examples, Examples 4 to 6 are methylation analyses of cleavage products of adventitone mixed with different methylating agents (tetramethylammonium hydroxide, phenyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide).

[0059] In the following examples, Examples 7 to 9 are methylation analyses of cleavage products of alitame mixed with different methylating agents (tetramethylammonium hydroxide, phenyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide).

[0060] In the following examples, Examples 10 to 12 are methylation analyses of cleavage products of sucralose mixed with different methylation agents (tetramethylammonium hydroxide, phenyltrimethylammonium hydroxide, phenyltrimethylammonium hydroxide).

[0061] The method steps of the online pyrolysis-methylation analysis of sweetener pyrolysis products of the present invention are as follows:

[0062] 1) Weigh the target sweetener sample and place it in a special sample cup for thermal cracking;

[0063] 2) adding a methylating agent into the sample cup of the above step, gently shaking it to mix it with the sample, and obtaining a sample to be tested; wherein the methylating agent includes one or more of tetramethylammonium hydroxide (TMAH), other tetraalkylammonium hydroxides, trimethylaniline or trimethylammonium hydroxide;

[0064] 3) Turn on the pyrolysis instrument, set the pyrolysis target temperature and pyrolysis time; (the pyrolysis instrument is Frontier (Japan) PY-Rx-3050SR pyrolysis instrument); turn on the GC-MS gas phase mass spectrometer, and set the separation conditions and mass spectrometry conditions respectively; among which, the GC-MS conditions are: UA-1MS capillary column (30m×250μm×2μm); carrier gas He (99.999%), flow rate 3mL / min, split ratio 50:1; temperature program, 50℃ for 2min, increase to 280℃ at 10℃ / min and hold for 10min; mass spectrometry conditions: ion source (EI), electron energy 70Ev; ion source temperature 230℃; quadrupole temperature 150℃; scanning range 35~450amu; transmission line temperature 280℃);

[0065] 4) When the target pyrolysis temperature and cold trap temperature of the pyrolysis instrument are stable and the GC-MS is ready, the sample to be tested is injected into the reaction chamber of the pyrolysis instrument to perform a pyrolysis-methylation reaction; at a preset temperature (e.g., 250° C.), the methylation reaction occurs instantly, and after the preset reaction time is over, liquid nitrogen enters the reaction chamber to cool and capture the pyrolysis product and pump it to the GC-MS injection area; pyrolysis reactions and pyrolysis product analyses are performed at different temperatures respectively;

[0066] Among them, the method of cracking under an aerobic atmosphere is: open the gas valve to introduce air into the reaction chamber of the thermal cracking instrument (for example, ventilation for 10 seconds), and then close the gas valve to allow the cracking reaction to proceed (for example, reaction for 12 seconds), that is, the sweetener is cracked in an aerobic atmosphere and the methylation reaction occurs simultaneously.

[0067] The method of cracking in an anaerobic atmosphere is: do not open the gas valve for ventilation, and directly carry out the cracking reaction in an anaerobic atmosphere (for example, react for 12 seconds), that is, complete the cracking of the sweetener in an anaerobic atmosphere and the methylation reaction at the same time.

[0068] The experiments were carried out at temperature gradients of 250°C, 350°C, and 500°C, respectively, with a total operating time of approximately 35 min.

[0069] 5) GC-MS separation and analysis of pyrolysis products;

[0070] 6) in step 4), the methylation cleavage reaction is carried out in an aerobic atmosphere by introducing air (or the methylation cleavage reaction is carried out in an anaerobic atmosphere without introducing air);

[0071] 7) Analyze the GC-MS result data.

[0072] Example 1 Neotame thermal cracking-methylation

[0073] A pyrolysis-methylation (methylation reagent: tetramethylammonium hydroxide) experiment was conducted on a dipeptide sweetener neotame sample, and a pyrolysis instrument was used to perform pyrolysis experiments under different temperature conditions. The specific method steps are as follows:

[0074] 1) Sample pretreatment: Place the sample cup on a 1 / 10,000 balance weighing pan, weigh 0.1 mg of neotame sample, add 0.1 mg of tetramethylammonium hydroxide solution, shake gently to allow the neotame sample to fully contact with the methylating agent tetramethyl sodium hydroxide, place it on the sample table, and insert the sampling needle for use.

[0075] 2) Turn on the pyrolysis instrument, set the pyrolysis reactor temperature to 250°C, 350°C, and 500°C, the interface temperature to 300°C, and the pyrolysis time to 12s.

[0076] 3) Fix the injection cup to the injection port at the upper end of the cracking furnace through the sampling needle, and the handle is in the state of waiting for injection; run GC-MS, and after the GC conditions are ready, run the pyrolysis instrument, and after the cold trap temperature reaches about -180°C, which means that the cold trap temperature is stable (used to cool and capture the pyrolysis products), that is, the target pyrolysis temperature of the pyrolysis instrument, the cold trap temperature is stable, and the GC-MS is ready, inject the sample pre-treated in step 1) into the reaction chamber of the pyrolysis instrument to perform pyrolysis-methylation reaction; perform pyrolysis in an aerobic atmosphere at a preset temperature of 250°C (the method of pyrolysis in an aerobic atmosphere is: open the gas valve to pass air into the reaction chamber of the pyrolysis instrument for 10 seconds, then close the gas valve, and perform pyrolysis reaction for 12 seconds), the methylation reaction occurs instantly, and after the preset reaction time is over, liquid nitrogen enters the reaction chamber to cool and capture the pyrolysis products and pump them to the GC-MS injection area; perform pyrolysis reactions and pyrolysis product analyses at different temperatures respectively.

[0077] A blank sample should be run after each single sample experiment to eliminate the interference caused by the previous sample.

[0078] 4) The composition of the products of thermal cracking and methylation of neotame was determined by gas chromatography-mass spectrometry.

[0079] The analysis conditions were as follows: chromatographic column: UA-1MS capillary column (30m×250μm×2μm; injection port temperature: 250℃; detector temperature: 250℃; carrier gas: helium, flow rate 3mL / min; injection volume: 0.2μL; programmed temperature: initial temperature 50℃ for 2min, then raised to 280℃ at a rate of 10℃ / min and held for 10min; split ratio: 50:1; mass spectrometer was a high-sensitivity EI source, ion source temperature: 230℃, MS quadrupole high temperature: 150℃, solvent delay time: 0min, and scanning mode: full scan.

[0080] Thermal cracking was performed in an oxygen atmosphere at 350° C. and 500° C., respectively, according to the above method.

[0081] Referring to the above method, pyrolysis and thermal cracking were carried out in an anaerobic atmosphere at different pyrolysis temperatures (250°C, 350°C, 500°C), the difference being that the corresponding thermal cracking temperature was adjusted, and in the above step 3), the aerobic atmosphere was adjusted to an anaerobic atmosphere, and the method for the anaerobic atmosphere was as follows: the gas valve was not opened for ventilation, and the pyrolysis reaction was directly carried out in an anaerobic atmosphere for 12 seconds.

[0082] Comparative Example 1 (Pure Neotame Cracking)

[0083] The difference from Example 1 is that in step 1), no methylating agent is added, and 0.1 mg of a single neotame sample is directly placed in a sample injection cup, and the subsequent steps 2) to 4) are performed.

[0084] Neotame thermal cracking-methylation (Example 1, tetramethylammonium hydroxide) and neotame (Comparative Example 1) were cracked at different cracking temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatographic superposition comparison results are shown as follows: Figures 1 to 6 .

[0085] Figure 1 to Figure 6 The results showed that the thermal cracking products detected after thermal cracking of neotame in Example 1 and methylation with tetramethylammonium hydroxide were more than those detected by direct thermal cracking of neotame.

[0086] Specifically, Figure 1 It shows that the main cleavage products detected under anaerobic conditions at 250°C for pure neotame (Comparative Example 1) are 3-phenylpropionic acid methyl ester, L-phenylalanine methyl ester, N-methyl-L-phenylalanine benzyl ester, and N-acetyl-L-phenylalanine benzyl ester. The main cleavage products detected under anaerobic conditions at 250°C for neotame methylation (tetramethylammonium hydroxide) of Example 1 are N,N-dimethyl-D-phenylalanine methyl ester, N-acetyl-phenylalanine methyl ester, and other products.

[0087] Figure 2It shows that the main cleavage products detected under anaerobic conditions at 350°C for pure neotame (Comparative Example 1) are methyl cinnamate, L-phenylalanine methyl ester, N-methyl-L-phenylalanine benzyl ester, and N-acetyl-L-phenylalanine benzyl ester. The main cleavage products detected under anaerobic conditions at 350°C for the methylation of neotame (tetramethylammonium hydroxide) in Example 1 are N-acetyl-phenylalanine methyl ester, N-methyl-N-propoxycarbonyl-L-phenylalanine methyl ester, and other products.

[0088] Figure 3 It shows that the main pyrolysis products detected under 500°C conditions of pure neotame (Comparative Example 1) are 3-phenylpropionic acid methyl ester, cinnamic acid methyl ester, L-phenylalanine methyl ester, N-methyl-L-phenylalanine benzyl ester, and N-acetyl-L-phenylalanine benzyl ester. The main pyrolysis products detected under 500°C anaerobic conditions of neotame methylation (tetramethylammonium hydroxide) of Example 1 are more than those under aerobic conditions.

[0089] Example 2 Neotame Pyrolysis-Methylation

[0090] The difference between Example 2 and Example 1 is that the formate reagent used is phenyltrimethylammonium hydroxide, and the cleavage and analysis methods refer to steps 1) to 4) of Example 1.

[0091] The chromatographic superposition comparison results of thermal cracking-methylation of neotame (Example 2, phenyltrimethylammonium hydroxide) and comparative example 1 at different cracking temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere are shown in Figure 2. Figures 7 to 12 .

[0092] Figure 7 to Figure 12 The results show that the products detected by thermal cracking in Example 2 are slightly more than those detected by thermal cracking in Comparative Example 1, but the methylation treatment effect is not significant, and the methylation effect is slightly worse than that of the methylation agent tetramethylammonium hydroxide.

[0093] Specifically, Figure 7 It shows that the main cleavage products detected under 250°C anaerobic conditions of pure neotame (Comparative Example 1) are 3-phenylpropionic acid methyl ester, L-phenylalanine methyl ester, N-methyl-L-phenylalanine benzyl ester, and N-acetyl-L-phenylalanine benzyl ester. The main cleavage products detected under 250°C anaerobic conditions of neotame methylation (phenyltrimethylammonium hydroxide) in Example 2 are N,N-dimethylaniline.

[0094] Figure 8It shows that the main cleavage products detected under anaerobic conditions at 350°C for pure neotame (Comparative Example 1) are methyl cinnamate, L-phenylalanine methyl ester, N-methyl-L-phenylalanine benzyl ester, and N-acetyl-L-phenylalanine benzyl ester. The main cleavage products detected under anaerobic conditions at 350°C for the methylated neotame (phenyltrimethylammonium hydroxide) of Example 2 are N,N-dimethylaniline.

[0095] Fig. 9 It shows that the main cleavage products detected under anaerobic conditions at 500°C for pure neotame (Comparative Example 1) are 3-phenylpropionic acid methyl ester, cinnamic acid methyl ester, L-phenylalanine methyl ester, N-methyl-L-phenylalanine benzyl ester, and N-acetyl-L-phenylalanine benzyl ester. The main cleavage products detected under anaerobic conditions at 500°C for neotame thermal cracking-methylation (phenyltrimethylammonium hydroxide) of Example 2 are N,N-dimethylaniline and some unknown products. Among them, N,N-dimethylaniline is a cleavage product of the methylating agent phenyltrimethylammonium hydroxide. And the cleavage products under anaerobic conditions are more than those under aerobic conditions.

[0096] Example 3 Neotame thermal cracking-methylation

[0097] The difference between Example 3 and Example 1 is that the formate reagent used is trimethyl sulfide hydroxide, and the cracking and analysis methods refer to steps 1) to 4) of Example 1.

[0098] Neotame methylation (Example 3, trimethyl sulfide hydroxide) and neotame (Comparative Example 1) were pyrolyzed at different pyrolysis temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatographic superposition comparison results are shown in FIG. Figures 13 to 18 .

[0099] Figure 13 to Figure 18 The results showed that the products detected after thermal cracking of neotame and methylation with trimethylsulfoxide were almost the same as those of direct thermal cracking of neotame, and the methylation effect was not significant; the methylation effect was poorer than that of the methylation agent tetramethylammonium hydroxide.

[0100] The main cleavage products and structures of neotame and methylating agents are shown in Table 1.

[0101] Table 1. Main pyrolysis products of neotame and GC-MS analysis retention time

[0102]

[0103] In summary, at the same pyrolysis temperature, the methylation agent tetramethylammonium hydroxide has the best methylation effect on the thermal pyrolysis product of neotame, and more methylated pyrolysis products are detected, while trimethyl sulfhydryl hydroxide and phenyltrimethylammonium hydroxide have no significant methylation effect on the thermal pyrolysis product of neotame.

[0104] Under aerobic and anaerobic conditions, the cleavage products differ slightly, for example:

[0105] 1. When neotame is cracked at 500℃ and methylated with tetramethylammonium hydroxide, more products such as N-(2-phenylethyl)maleimide will be produced under anaerobic conditions than under aerobic conditions (see Figure 3 and Figure 6 ).

[0106] 2. When neotame is cracked at 500℃ and methylated with phenyltrimethylammonium hydroxide, more products such as 3-phenylpyridine, methyl cinnamate, and 1-benzylindole will be produced under anaerobic conditions than under aerobic conditions (see Fig. 9 and Fig.12 ).

[0107] 3. When neotame is cracked at 500℃ and treated with trimethylthiohydroxide, the products under anaerobic conditions are the same as those under aerobic conditions (see Fig.15 and Fig.18 ).

[0108] Among them, under the temperature gradient of 250℃, 350℃ and 500℃, the higher the temperature, the more products obtained by cracking.

[0109] Example 4 Thermal cleavage-methylation of Advantame:

[0110] A thermal cracking-methylation (methylation reagent: tetramethylammonium hydroxide) experiment was performed on a sample of the dipeptide sweetener Advantane. A thermal cracking experiment was performed on the sample under different temperature conditions using a thermal cracking instrument (model Rx-3050SR).

[0111] 1) Sample pretreatment: Place the sample cup on a 1 / 10,000 balance weighing pan, weigh 0.1 mg of the Advantamine sample, and add 0.1 mg of tetramethylammonium hydroxide solution. Grasp the sample cup with tweezers, shake it gently to allow the Advantamine sample to fully contact with the methylation reagent tetramethylammonium hydroxide, place it on the sample table, and insert the sampling needle for use.

[0112] 2) The lysis and analysis methods refer to steps 2) to 4) of Example 1.

[0113] Comparative Example 2: Thermal Cracking of Advantine

[0114] The difference from Example 4 is that the methylation treatment of the thermal cracking product of adavantame in step 1) is not performed, and 0.1 mg of a single adavantame sample is directly placed in a sample injection cup to perform the subsequent steps 2) to 4).

[0115] Advantine methylation (Example 4, trimethyl sulfide hydroxide) and Advantine (Comparative Example 2) were pyrolyzed at different pyrolysis temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatographic superposition comparison results are shown in FIG. Figures 19 to 24 .

[0116] Figure 19 to Figure 24 The results showed that the products detected after thermal pyrolysis of advantame with methylation by tetramethylammonium hydroxide were more than those detected after direct thermal pyrolysis of advantame.

[0117] Fig.19 The results show that the main cleavage products detected from pure Advantine under anaerobic conditions at 250°C are L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 4-hydroxy-3-methoxymethamphetamine, 5-benzyl-3,6-dioxo-2-piperazineacetic acid, 2-methoxy-5-propyl-2-aminophenol, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, etc. The main cleavage products detected from the thermal cleavage-methylation (tetramethylammonium hydroxide) of Advantine in Example 4 are N,N-dimethyl-D-phenylalanine methyl ester relative to the pure Advantine under anaerobic conditions at 250°C. The results of the reaction under an aerobic atmosphere are the same (see Fig. 22 ).

[0118] Fig. 20 The results show that the main cleavage products detected from pure Advantine under anaerobic conditions at 350°C are L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 4-hydroxy-3-methoxymethylamphetamine, 5-benzyl-3,6-dioxo-2-piperazineacetic acid, 6-methoxy-3-methylbenzofuran, 2-methoxy-5-propyl-2-aminophenol, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, etc. The main cleavage products detected from the methylation of Advantine (tetramethylammonium hydroxide) in Example 4 are N,N-dimethyl-D-phenylalanine methyl ester relative to pure Advantine under anaerobic conditions at 350°C. The results of the reaction under an aerobic atmosphere are the same (see Fig.23 ).

[0119] Fig.21The results show that the main cleavage products detected from pure Advantine under anaerobic conditions at 500°C are 5-ethyl-2-methoxyphenol, L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 6-methoxy-3-methylbenzofuran, 2-methoxy-5-propyl-2-aminophenol, 4-hydroxy-3-methoxymethylamphetamine, 5-benzyl-3,6-dioxo-2-piperazineacetic acid, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, N-(4-methylpentyl)phenylalanine, etc. The main cleavage products detected from the methylated Advantine (tetramethylammonium hydroxide) of Example 4 at 500°C anaerobic conditions are N,N-dimethyl-2-phenylethylamine. However, this is not the case for the cracking reaction in an oxygen atmosphere (i.e., no additional N,N-dimethyl-2-phenylethylamine is produced in an oxygen atmosphere at 500°C) (see Fig.24 ).

[0120] Example 5 Thermal cleavage-methylation of Advantame:

[0121] The difference between Example 5 and Example 4 is that the formate reagent used is phenyltrimethylammonium hydroxide, and the cleavage and analysis methods refer to steps 1) to 4) of Example 1.

[0122] Thermal cracking-methylation of edavantin (Example 5, phenyltrimethylammonium hydroxide) and edavantin (Comparative Example 2) were cracked at different cracking temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatographic superposition comparison results are shown in FIG. Figures 25-30 .

[0123] Figures 25-30 The results show that the products detected after the thermal cracking of advantame in Example 5 and methylation with phenyltrimethylammonium hydroxide are slightly more than the products of direct thermal cracking of advantame, and the methylation effect is not significant, which is slightly worse than the methylation effect of tetramethylammonium hydroxide.

[0124] Fig.25 The results show that the main cleavage products detected under anaerobic conditions at 250°C for pure Advantine are L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 4-hydroxy-3-methoxymethamphetamine, 5-benzyl-3,6-dioxo-2-piperazineacetic acid, 2-methoxy-5-propyl-2-aminophenol, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, etc. The main cleavage products detected under anaerobic conditions at 250°C for the thermal cleavage-methylation of Advantine in Example 5 (phenyltrimethylammonium hydroxide) are basically the same as those detected for pure Advantine. The results of the reaction under an aerobic atmosphere are also the same (see Fig.28 ).

[0125] Fig.26 The results show that the main cleavage products detected under anaerobic conditions at 350°C for pure Advantine are L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 4-hydroxy-3-methoxymethylamphetamine, 5-benzyl-3,6-dioxo-2-piperazineacetic acid, 6-methoxy-3-methylbenzofuran, 2-methoxy-5-propyl-2-aminophenol, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, etc. The main cleavage products detected under anaerobic conditions at 350°C for the thermal cleavage-methylation of Advantine in Example 5 (phenyltrimethylammonium hydroxide) are basically the same as those detected for pure Advantine. The results of the reaction under an aerobic atmosphere are also the same (see Fig.29 ).

[0126] Fig. 27 The results show that the main cleavage products detected under 500°C anaerobic conditions of pure Advantine are 5-ethyl-2-methoxyphenol, L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 6-methoxy-3-methylbenzofuran, 2-methoxy-5-propyl-2-aminophenol, 4-hydroxy-3-methoxymethylamphetamine, 5-benzyl-3,6-dioxo-2-piperazineacetic acid, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, N-(4-methylpentyl)phenylalanine, etc. The main cleavage products detected under 500°C anaerobic conditions of the methylation of Advantine in Example 5 (phenyltrimethylammonium hydroxide) are basically the same as those of pure Advantine. The results of the reaction under an aerobic atmosphere are also the same (see Fig.30 ).

[0127] Example 6 Thermal cleavage-methylation of Advantame:

[0128] The difference between Example 6 and Example 4 is that the formate reagent used is trimethyl sulfide hydroxide, and the cracking and analysis methods refer to steps 1) to 4) of Example 1.

[0129] Advantine methylation (Example 6, trimethyl sulfide hydroxide) and Advantine (Comparative Example 2) were pyrolyzed at different pyrolysis temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatographic superposition comparison results are shown in FIG. Figures 31-36 .

[0130] Figures 31-36 The results showed that the products detected after thermal cracking of adventitia with trimethylthiohydroxide methylation were almost indistinguishable from the products of direct thermal cracking of adventitia, and the methylation effect was not significant, which was worse than that of the methylation agent tetramethylammonium hydroxide.

[0131] Fig.31The results show that the main cleavage products detected under anaerobic conditions at 250°C for pure Advantine are L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 4-hydroxy-3-methoxymethamphetamine, 5-benzyl-3,6-dioxy-2-piperazineacetic acid, 2-methoxy-5-propyl-2-aminophenol, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, etc. The main cleavage products detected under anaerobic conditions at 250°C for Advantine thermal cleavage-methylation (trimethyl sulfide hydroxide) of Example 6 are basically the same as the main cleavage products detected for pure Advantine. The results of the reaction under an aerobic atmosphere are also the same (see Fig.34 ).

[0132] Fig.32 The results show that the main cleavage products detected under anaerobic conditions at 350°C for pure Advantine are L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 4-hydroxy-3-methoxymethylamphetamine, 5-benzyl-3,6-dioxo-2-piperazineacetic acid, 6-methoxy-3-methylbenzofuran, 2-methoxy-5-propyl-2-aminophenol, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, etc. The main cleavage products detected under anaerobic conditions at 350°C for the thermal cleavage-methylation of Advantine in Example 6 (trimethyl sulfide hydroxide) are basically the same as those detected for pure Advantine. The results of the reaction under an aerobic atmosphere are also the same (see Fig.35 ).

[0133] Fig.33 The results show that the main cleavage products detected from pure Advantine under anaerobic conditions at 500°C are 5-ethyl-2-methoxyphenol, L-phenylalanine methyl ester, α-methyl-phenylalanine methyl ester, 6-methoxy-3-methylbenzofuran, 2-methoxy-5-propyl-2-aminophenol, 4-hydroxy-3-methoxymethamphetamine, 5-benzyl-3,6-dioxy-2-piperazineacetic acid, L-phenylalanine, N-cyclobutylcarbonylmethyl ester, N-methyl 2-cyclohexyl-N-(4-methoxyphenyl)acetamide, N-(4-methylpentyl)phenylalanine, etc. The main cleavage products detected from the thermal cleavage-methylation (trimethyl sulfide hydroxide) of Advantine in Example 6 are basically the same as those detected from pure Advantine under anaerobic conditions at 500°C. The main cleavage product of Advantine methylation (trimethyl sulfide hydroxide) under an aerobic atmosphere at 500°C will include α-phenylcinnamonitrile (see Fig.36 ).

[0134] The main cleavage products and structures of Advantine and methylating agents are shown in Table 2.

[0135] Table 2. Main pyrolysis products of Advantine and GC-MS analysis retention time

[0136]

[0137]

[0138] In summary, among the three methylation reagents, tetramethylammonium hydroxide has the best methylation effect, and more products are detected by thermal cracking of tetramethylammonium hydroxide and adventitium. The methylation effects of trimethyl sulfhydryl hydroxide and phenyltrimethylammonium hydroxide are not significant.

[0139] Under aerobic and anaerobic conditions, the cleavage products differ slightly, for example:

[0140] 1. When Advantine was pyrolyzed at 500°C and methylated with tetramethylammonium hydroxide, the products detected under anaerobic conditions were the same as those under aerobic conditions (see Fig.19 and Fig. 22 ).

[0141] 2. When Advantine was pyrolyzed at 500°C and methylated with phenyltrimethylammonium hydroxide, the products detected under anaerobic conditions were the same as those under aerobic conditions (see Fig.25 and Fig.28 ).

[0142] 3. When Advantine is cracked at 500℃ and treated with trimethylthiohydroxide, more products such as α-phenylcinnamonitrile will be produced under anaerobic conditions than under aerobic conditions (see Fig.31 and Fig.34 ).

[0143] Among them, under the temperature gradient of 250℃, 350℃ and 500℃, the higher the temperature, the more cracking products are detected.

[0144] Example 7 Alitame thermal cracking-methylation:

[0145] A thermal cracking-methylation (methylation reagent: tetramethylammonium hydroxide) experiment was carried out on a sample of the dipeptide sweetener alitame, and a thermal cracking experiment was carried out under different temperature conditions using a thermal cracking instrument (model Rx-3050SR).

[0146] 1) Place the sample cup on a 1 / 10,000 balance weighing pan, weigh 0.1 mg of alitame sample, and add 0.1 mg of tetramethyl sodium hydroxide solution. Grasp the sample cup with tweezers, shake it gently to make the alitame sample fully contact with the methylation reagent tetramethyl sodium hydroxide, place it on the sample table, and insert the sampling needle for use.

[0147] 2) The lysis and analysis methods refer to steps 2) to 4) of Example 1.

[0148] Comparative Example 3: Thermal Decomposition of Alitame

[0149] The difference from Example 7 is that the methylation treatment of the thermal cracking product of alitame in step 1) is not performed, and 0.1 mg of alitame sample alone is directly placed in the sample injection cup to perform the subsequent steps 2) to 4).

[0150] Alitame methylation (Example 7, tetramethylammonium hydroxide) and Alitame (Comparative Example 3) were pyrolyzed at different pyrolysis temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatographic superposition comparison results are shown in FIG. Figures 37-42 .

[0151] Figures 37-42 The results showed that the products detected after thermal pyrolysis of alitame with tetramethylammonium hydroxide methylation were more than those detected after direct thermal pyrolysis of alitame.

[0152] Fig.37 The results show that the main cracking products of pure alitame under anaerobic conditions at 250°C are 2,2-dimethylpentane, 5-methyl furanaldehyde, 2H-pyran-2,6(3H)-dione, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one, 5-hydroxymethylfurfural, 4-hydroxy-3-methoxymethamphetamine, levulose ketone, 1,6-anhydro-α-d-galactofuranose, etc. The main cracking products of alitame thermal cracking-methylation (tetramethylammonium hydroxide) detected at 250°C for pure alitame are methyl acetate and methyl lactate. In an aerobic atmosphere, the reaction products include methyl acetate, methyl lactate, methyl levulinate, 2-phenylethyl isocyanate, etc. (see Fig.40 ).

[0153] Fig.38 The results show that the main pyrolysis products detected from pure alitame at 350°C in the absence of oxygen are 2,2-dimethylbutene, furan, 2,2-dimethylpentane, 2-furanone, 3-furfural, 5-methyl furanaldehyde, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, levulose ketone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one, α-methyl-phenylalanine methyl ester, 1,6-anhydro-β-D-glucose, 1,6-anhydro-α-D-galactofuranose, etc. The main pyrolysis products detected from the methylated alitame (tetramethylammonium hydroxide) of Example 7 relative to pure alitame at 350°C in the absence of oxygen are methyl formate, methyl acetate, methyl lactate, methyl levulinate, dimethyl fumarate, etc. In an oxygen atmosphere, the reaction products will include methyl formate, methyl glycolate, methyl lactate, dimethyl fumarate, etc. (see Fig.41 ).

[0154] The main cracking products of pure alitame under anaerobic conditions at 500°C are 2-butene, neopentane, 3,3-dimethyl-1-butene, 2,2-dimethylbutene, 2-methylfuran, 2,2-dimethylpentane, 2,5-dimethylfuran, 2-furanone, 2-acetylfuran, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2,4-dihydroxy-2,5-dimethyl-3(2H)-furan-3-one, 2-phenylethyl isocyanate, 1,6-anhydro-β-D-glucose, 1,6-anhydro-α-D-galactofuranose, etc. The main cracking products of alitame and tetramethylammonium hydroxide under anaerobic conditions at 500°C are isobutane, 2-methylpropylene, methyl acetate, methyl glycolate, dimethyl fumarate, etc. The reaction results under aerobic atmosphere are the same as those under anaerobic conditions (see Fig.42 ).

[0155] Example 8 Alitame thermal cracking-methylation:

[0156] The difference between Example 8 and Example 7 is that the formate reagent used is phenyltrimethylammonium hydroxide, and the cleavage and analysis methods refer to steps 1) to 4) of Example 1.

[0157] Alitame thermal cracking-methylation (Example 8, phenyltrimethylammonium hydroxide) and Alitame (Comparative Example 3) were cracked at different cracking temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatographic superposition comparison results are shown as follows: Figures 43 to 48 .

[0158] Figures 43 to 48 The results show that the products detected after the thermal decomposition of alitame in Example 8 and methylation treatment with phenyltrimethylammonium hydroxide are slightly more than the products of direct thermal decomposition of alitame, but the methylation effect is not significant, and is slightly worse than the methylation effect of the methylation agent tetramethylammonium hydroxide.

[0159] Fig.43 The results show that the main cleavage products detected from pure alitame under anaerobic conditions at 250°C are 2,2-dimethylpentane, 5-methyl furanaldehyde, 2H-pyran-2,6(3H)-dione, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one, 5-hydroxymethylfurfural, 4-hydroxy-3-methoxymethamphetamine, levulose ketone, 1,6-anhydro-α-d-galactofuranose, etc. The main cleavage products detected from the thermal cleavage-methylation of alitame in Example 8 (phenyltrimethylammonium hydroxide) are basically the same as those detected from pure alitame under anaerobic conditions at 250°C. The same is true for the reaction under an aerobic atmosphere (see Fig.46 ).

[0160] Fig.44The results show that the main cracking products detected in the pure alitame under anaerobic conditions at 350°C are 2,2-dimethylbutene, furan, 2,2-dimethylpentane, 2-furanone, 3-furfural, 5-methylfuranaldehyde, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, levulinic acid ketone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one, α-methyl-phenylalanine methyl ester, 1,6-anhydro-β-D-glucose, 1,6-anhydro-α-D-galactofuranose, etc. The main cracking products detected in the thermal cracking-methylation of alitame in Example 8 (phenyltrimethylammonium hydroxide) are basically the same as those detected in the pure alitame under anaerobic conditions at 350°C. The results of the reaction in an aerobic atmosphere are the same (see Fig.47 ).

[0161] Fig.45 The results show that the main cracking products detected in the pure alitame under anaerobic conditions at 500°C are 2-butene, neopentane, 3,3-dimethyl-1-butene, 2,2-dimethylbutene, 2-methylfuran, 2,2-dimethylpentane, 2,5-dimethylfuran, 2-furanone, 2-acetylfuran, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2,4-dihydroxy-2,5-dimethyl-3(2H)-furan-3-one, 2-phenylethyl isocyanate, 1,6-anhydro-β-D-glucose, 1,6-anhydro-α-D-galactofuranose, etc. The main cracking products detected in the thermal cracking-methylation of alitame in Example 8 (phenyltrimethylammonium hydroxide) are basically the same as those detected in the pure alitame under anaerobic conditions at 500°C. The results of the reaction in an aerobic atmosphere are the same (see Fig.48 ).

[0162] Example 9 Alitame thermal cracking-methylation:

[0163] The difference between Example 9 and Example 7 is that the formate reagent used is trimethyl sulfide hydroxide, and the cracking and analysis methods refer to steps 1) to 4) of Example 1.

[0164] Alitame thermal cracking-methylation (Example 9, trimethyl sulfide hydroxide) and Alitame (Comparative Example 3) were cracked at different cracking temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatograms were superimposed and compared as shown in FIG. Figures 49 to 54 .

[0165] Figures 49 to 54 The results showed that the products detected after the thermal decomposition of alitame with trimethylthiohydroxide methylation were slightly more than those of direct thermal decomposition of alitame, and the methylation effect was not significant, which was slightly worse than that of the methylation agent tetramethylammonium hydroxide.

[0166] Fig.49The results show that the main pyrolysis products detected in the pure alitame under 250°C anaerobic conditions are 2,2-dimethylpentane, 5-methyl furanaldehyde, 2H-pyran-2,6(3H)-dione, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one, 5-hydroxymethylfurfural, 4-hydroxy-3-methoxymethamphetamine, levulose ketone, 1,6-anhydro-α-d-galactofuranose, etc. The main pyrolysis products detected in the thermal pyrolysis-methylation (trimethyl sulfide hydroxide) of alitame in Example 8 are basically the same as the main pyrolysis products detected in the pure alitame under 250°C anaerobic conditions.

[0167] Fig.50 The results show that the main pyrolysis products detected from pure alitame at 350°C in the absence of oxygen are 2,2-dimethylbutene, furan, 2,2-dimethylpentane, 2-furanone, 3-furfural, 5-methyl furanaldehyde, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, levulose ketone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one, α-methyl-phenylalanine methyl ester, 1,6-anhydro-β-D-glucose, 1,6-anhydro-α-D-galactofuranose, etc. The main pyrolysis products detected from the thermal pyrolysis-methylation (trimethyl sulfide hydroxide) of alitame in Example 8 are basically the same as those of pure alitame at 350°C in the absence of oxygen.

[0168] Fig.51 The results show that the main cracking products of pure alitame under anaerobic conditions at 500°C are 2-butene, neopentane, 3,3-dimethyl-1-butene, 2,2-dimethylbutene, 2-methylfuran, 2,2-dimethylpentane, 2,5-dimethylfuran, 2-furanone, 2-acetylfuran, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 2,4-dihydroxy-2,5-dimethyl-3(2H)-furan-3-one, 2-phenylethyl isocyanate, 1,6-anhydro-β-D-glucose, 1,6-anhydro-α-D-galactofuranose, etc. The main cracking products detected by thermal cracking-methylation (trimethyl hydroxide sulfide) of alitame in Example 8 are basically the same as those of pure alitame under anaerobic conditions at 500°C. In an aerobic atmosphere, the main cracking product will have an additional α-phenylcinnamonitrile (see Fig.54 ).

[0169] In summary, among the three methylation reagents, tetramethylammonium hydroxide has the best methylation effect. More products are detected after thermal decomposition of alitame and methylation with tetramethylammonium hydroxide. The methylation effects of trimethyl sulfhydryl hydroxide and phenyltrimethylammonium hydroxide are not significant.

[0170] The main cleavage products and structures of alitame and methylating agents are shown in Table 3.

[0171] Table 3. Main pyrolysis products of alitame and GC-MS analysis retention time

[0172]

[0173]

[0174] Under aerobic and anaerobic conditions, the cleavage products differ slightly, for example:

[0175] 1. When Alitame is cracked at 250℃ and methylated with tetramethylammonium hydroxide, methyl acetate and methyl lactate will be produced under anaerobic conditions, and methyl acetate, methyl lactate, methyl levulinate, 2-phenylethyl isocyanate, etc. will be produced in the aerobic atmosphere; when it is cracked with tetramethylammonium hydroxide at 350℃, methyl formate, methyl acetate, methyl lactate, levulinic acid, dimethyl fumarate, etc. will be produced in the aerobic atmosphere. (See Fig.37 and Fig.40 ).

[0176] 2. When alitame is cracked at 500℃ and methylated with phenyltrimethylammonium hydroxide, the products under anaerobic conditions are the same as those under aerobic conditions. (See Fig.43 and Fig.46 ).

[0177] 3. When alitame is cracked at 500℃ and treated with trimethylthiohydroxide, more products such as α-phenylcinnamonitrile will be produced under anaerobic conditions than under aerobic conditions. (See Fig.47 and Fig.50 ).

[0178] Example 10 Thermal cleavage-methylation of sucralose:

[0179] The dipeptide sweetener sucralose sample was subjected to a thermal cracking-methylation (methylation reagent: tetramethylammonium hydroxide) experiment, and a thermal cracking experiment was performed under different temperature conditions using a thermal cracking instrument (model Rx-3050SR).

[0180] 1) Place the sample cup on the weighing pan of a 1 / 10,000 balance, weigh 0.1 mg of sucralose sample, and add 0.1 mg of tetramethyl sodium hydroxide solution. Grasp the sample cup with tweezers and shake it gently to make the sucralose sample fully contact with the methylation reagent tetramethyl sodium hydroxide. Place it on the sample table and insert the sampling needle for use.

[0181] 2) The lysis and analysis methods refer to steps 2) to 4) of Example 1.

[0182] Comparative Example 4: Thermal Decomposition of Sucralose

[0183] The difference from Example 10 is that the methylation treatment of sucralose in step 1) is not performed, and 0.1 mg of a single sucralose sample is directly placed in the sample injection cup to perform the subsequent operations of steps 2) to 4).

[0184] Sucralose methylation (Example 10, tetramethylammonium hydroxide) and sucralose (Comparative Example 4) were pyrolyzed at different pyrolysis temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatograms were superimposed and compared as shown in FIG. Figures 55-60 .

[0185] Figures 55-60 The results showed that the products detected after thermal pyrolysis of sucralose with tetramethylammonium hydroxide methylation were more than those of direct thermal pyrolysis of sucralose.

[0186] Fig.55 The results show that the main cleavage products of pure sucralose under anaerobic conditions at 250°C are levoglucosone, 1,4:3,6-anhydro-α-d-pyranose glucose, 5-chloromethylfuran-2-carboxaldehyde, and 1,6-anhydro-βd-4-chloro-4-deoxypyranose galactose. The main cleavage products of the sucralose thermal cleavage-methylation (tetramethylammonium hydroxide) in Example 10 are more than those of pure sucralose under anaerobic conditions at 250°C, including isomalt, 2,5-diformylfuran, and 4-O-β-D-pyranose galactose-α-D-pyranose glucose. In an aerobic atmosphere, the main cleavage products include isomalt, 2-furanoylhydrazide, 4-O-β-D-pyranose galactose-α-D-pyranose glucose, 5-hydroxymethylfurfural, and dihydromannitol (see Fig.58 ).

[0187] Fig.56 The results show that the main cleavage products of pure sucralose under anaerobic conditions at 350°C are hydrochloric acid, 1,4:3,6-anhydro-α-d-pyranose glucose, levuloglucosone, and 1,6-anhydro-βd-4-chloro-4-deoxypyranose galactose. The main cleavage products of sucralose thermal cleavage-methylation (tetramethylammonium hydroxide) in Example 10 are more than those of pure sucralose under anaerobic conditions at 350°C, including isomalt, 2-furanoylhydrazide, dihydromannitol, and 4-O-β-D-pyranose galactose-α-D-pyranose glucose. In an aerobic atmosphere, the main cleavage products are more isomalt (see Fig.59 ).

[0188] Fig.57The results show that the main cleavage products of pure sucralose under 500°C anaerobic conditions are 1,4:3,6-anhydro-α-d-glucopyranose, furfural, 1,4:3,6-anhydro-α-d-glucopyranose, 2-acetylfuran, etc. The main cleavage products of sucralose thermal cleavage-methylation (tetramethylammonium hydroxide) relative to pure sucralose under 500°C anaerobic conditions are basically the same as the cleavage products of the pure product. The reaction under an aerobic atmosphere is the same (see Fig.60 ).

[0189] Example 11 Thermal cleavage-methylation of sucralose:

[0190] The difference between Example 11 and Example 10 is that the formate reagent used is phenyltrimethylammonium hydroxide, and the cleavage and analysis methods refer to steps 1) to 4) of Example 1.

[0191] Sucralose thermal cracking-methylation (Example 11, phenyltrimethylammonium hydroxide) and sucralose (Comparative Example 4) were cracked at different cracking temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatograms were superimposed and compared as shown in FIG. Figures 61-66 .

[0192] Figures 61-66 The results showed that the products detected after methylation of sucralose by phenyltrimethylammonium hydroxide were slightly more than those of direct pyrolysis of sucralose, but the methylation effect of phenyltrimethylammonium hydroxide was not significant and was slightly worse than that of the methylation agent tetramethylammonium hydroxide.

[0193] Fig.61 The results showed that the main cleavage products of pure sucralose under anaerobic conditions at 250°C were levoglucosone, 1,4:3,6-anhydro-α-d-pyranose glucose, 5-chloromethylfuran-2-carboxaldehyde, and 1,6-anhydro-βd-4-chloro-4-deoxypyranose galactose. The main cleavage products of sucralose thermal cleavage-methylation (phenyltrimethylammonium hydroxide) relative to pure sucralose under anaerobic conditions at 250°C were basically the same as those of the pure product. In an aerobic atmosphere, the main cleavage products included dihydromannitol, 4-O-β-D-pyranose galactose-α-D-pyranose glucose (see Fig.64 ).

[0194] Fig.62The results show that the main cleavage products of pure sucralose under anaerobic conditions at 350°C are hydrochloric acid, 1,4:3,6-anhydro-α-d-pyranose glucose, levulin, and 1,6-anhydro-βd-4-chloro-4-deoxypyranose galactose. The main cleavage products of methylated sucralose (phenyltrimethylammonium hydroxide) in Example 11 are dihydromannitol and 4-O-β-D-pyranose galactose-α-D-pyranose glucose compared to pure sucralose under anaerobic conditions at 350°C. The results of the reaction under an aerobic atmosphere do not have this situation (see Fig.65 ).

[0195] Fig.63 The results show that the main cleavage products of pure sucralose under 500°C anaerobic conditions are 1,4:3,6-anhydro-α-d-glucopyranose, furfural, 1,4:3,6-anhydro-α-d-glucopyranose, and 2-acetylfuran. The main cleavage products of sucralose thermal cleavage-methylation (phenyltrimethylammonium hydroxide) in Example 11 are 4-O-β-D-galactopyranose-α-D-glucopyranose, which are detected as the main cleavage products of pure sucralose under 500°C anaerobic conditions. The results of the reaction under an aerobic atmosphere do not have this situation (see Fig.66 ).

[0196] Example 12 Thermal cleavage-methylation of sucralose:

[0197] The difference between Example 12 and Example 10 is that the formate reagent used is trimethyl sulfide hydroxide, and the cracking and analysis methods refer to steps 1) to 4) of Example 1.

[0198] Sucralose thermal cracking-methylation (Example 12, trimethyl sulfide hydroxide) and sucralose (Comparative Example 4) were cracked at different cracking temperatures (250°C, 350°C, 500°C) in an anaerobic atmosphere and an aerobic atmosphere, respectively. The chromatograms were superimposed and compared as shown in FIG. Figures 67-72 .

[0199] Figures 67-72 The results showed that the products detected after thermal pyrolysis of sucralose and methylation with trimethylthiohydroxide were slightly more than those detected after direct thermal pyrolysis of sucralose, and the methylation effect was not significant, which was slightly worse than that of the methylation agent tetramethylammonium hydroxide.

[0200] Fig.67The results show that the main cleavage products of pure sucralose under anaerobic conditions at 250°C are levulose ketone, 1,4:3,6-anhydro-α-d-pyranose glucose, 5-chloromethyl furan-2-carboxaldehyde, and 1,6-anhydro-βd-4-chloro-4-deoxypyranose galactose. The main cleavage products detected by thermal cleavage-methylation (trimethyl hydroxide sulfide) of sucralose in Example 11 are isomaltol and 2,3-dichlorotetrahydrofuran compared to pure sucralose under anaerobic conditions at 250°C. The conclusions of the reaction under aerobic atmosphere are the same as those under anaerobic atmosphere (see Fig.70 ).

[0201] Fig.68 The results show that the main cleavage products detected under anaerobic conditions at 350°C for pure sucralose are hydrochloric acid, 1,4:3,6-anhydro-α-d-glucopyranose, levuloglucosone, and 1,6-anhydro-βd-4-chloro-4-deoxygalactopyranose. The main cleavage products detected under anaerobic conditions at 350°C for sucralose methylation (trimethyl hydroxide sulfide) relative to pure sucralose in Example 11 are the same as those of pure sucralose under the same conditions. The conclusions of the reaction under aerobic atmosphere are the same as those under anaerobic atmosphere (see Fig.71 ).

[0202] Fig.69 The results show that the main cleavage products of pure sucralose under 500°C anaerobic conditions are 1,4:3,6-anhydro-α-d-glucopyranose, furfural, 1,4:3,6-anhydro-α-d-glucopyranose, and 2-acetylfuran. The main cleavage products of sucralose methylation (trimethyl hydroxide sulfide) relative to pure sucralose under 500°C anaerobic conditions are the same as the cleavage products of pure sucralose under the same conditions. In an aerobic atmosphere, the main cleavage products will have some unknown substances (see Fig.72 ).

[0203] The main cleavage products and structures of sucralose and methylating agents are shown in Table 4.

[0204] Table 4. Main cleavage products of sucralose and GC-MS analysis retention time

[0205]

[0206]

[0207] Under aerobic and anaerobic conditions, the cleavage products differ slightly, for example:

[0208] 1. When sucralose is cracked at 250℃ and methylated with tetramethylammonium hydroxide, more isomaltol, 2,5-diformylfuran, and 4-O-β-D-galactopyranose-α-D-glucopyranose will be produced under anaerobic conditions, and more isomaltol, 2-furancarboxylic acid hydrazide, 4-O-β-D-galactopyranose-α-D-glucopyranose, 5-hydroxymethylfurfural, dihydromannitol, etc. will be produced under aerobic atmosphere; when cracked with tetramethylammonium hydroxide at 350℃, more products will be produced, such as isomaltol, 2-furancarboxylic acid hydrazide, dihydromannitol, 4-O-β-D-galactopyranose-α-D-glucopyranose, etc. More isomaltol will be produced under aerobic conditions.

[0209] 2. When sucralose is cracked at 350℃ and 500℃ and methylated with phenyltrimethylammonium hydroxide, dihydromannitol and 4-O-β-D-pyranose-α-D-pyranose glucose will be produced under anaerobic conditions.

[0210] 3. When sucralose is cracked at 250℃ and treated with trimethylthiohydroxide, the product will contain more isomaltol and 2,3-dichlorotetrahydrofuran under anaerobic conditions.

[0211] In summary, among the three methylation reagents, tetramethylammonium hydroxide has the best methylation effect. More products are detected after thermal decomposition of sucralose and methylation treatment with tetramethylammonium hydroxide, while the methylation effects of trimethylsulfhydryl hydroxide and phenyltrimethylammonium hydroxide are not significant.

[0212] The present invention uses a simulation experiment by using an analysis method (PY-GCMS) that combines thermal cracking technology with gas chromatography-mass spectrometry technology to explore the cracking behavior and generated products of dipeptide sweeteners at high temperatures, and understand the mechanism of the cracking reaction of dipeptide sweeteners. By selecting a suitable methylation reagent and optimizing the reaction conditions, the reaction products can be analyzed to provide theoretical guidance for the production and application of electronic cigarettes. The thermal cracking analysis method of the present invention for methylation of sweeteners detects more components than the conventional thermal cracking method of sweeteners (direct cracking method), and can supplement more cracking product information. The method of thermal cracking of sweeteners + methylation of tetramethylammonium hydroxide can detect more cracking products than the cracking products detected by direct cracking of sweeteners. The sweetener is methylated while being thermally cracked, and the total analysis time is 35 minutes, with high analysis efficiency.

[0213] The above results show that among the three methylation reagents, tetramethylammonium hydroxide has the best methylation effect. After the sweeteners (neotame, edvantame, alitame, or sucralose) are thermally cracked and methylated with methylammonium hydroxide, more products are detected.

[0214] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sweetener thermal cracking analysis method, characterized in that: The sweetener and the alkylating agent are mixed and introduced into a thermal cracking instrument for thermal cracking, and the cracking products are analyzed by GC-MS to detect the cracking products.

2. The sweetener thermal decomposition analysis method according to claim 1, characterized in that: The sweetener is a dipeptide sweetener and / or sucralose, and the dipeptide sweetener may include one or more of neotame, advantame, and alitame.

3. The sweetener pyrolysis analysis method according to claim 1 or 2, characterized in that: The alkylating agent is a methylating agent or an ethylating agent, and the methylating agent may be selected from one or more of tetraalkylammonium hydroxide, phenyltrimethylammonium hydroxide or trimethylsulfide hydroxide; may be selected from tetraalkylammonium hydroxide; and may be selected from one or both of tetramethylammonium hydroxide and tetraethylammonium hydroxide.

4. The sweetener pyrolysis analysis method according to any one of claims 1 to 3, characterized in that: The weight ratio of the sweetener to the alkylating agent is 1:(0.5-10), optionally 1:(1-10).

5. The sweetener pyrolysis analysis method according to any one of claims 1 to 4, characterized in that: The cracking temperature is 200°C to 500°C, optionally 250°C to 500°C, optionally 250°C, 350°C or 500°C; And / or, the cracking includes thermal cracking in an aerobic atmosphere and / or thermal cracking in an anaerobic atmosphere; optionally, the aerobic atmosphere cracking includes introducing air or other oxygen-containing gas into the cracking reaction chamber; optionally, the anaerobic atmosphere cracking does not introduce air; and / or, the lysis time is 1 to 30 s, optionally 12 s; And / or, the sweetener undergoes an alkylation reaction with an alkylating agent during the cleavage process, and optionally the sweetener undergoes a methylation reaction with a methylating agent during the cleavage process.

6. The sweetener pyrolysis analysis method according to any one of claims 1 to 5, characterized in that: After the target pyrolysis temperature and cold trap temperature of the pyrolysis instrument are stable and the GC-MS is ready, the pyrolysis reaction can be carried out.

7. The sweetener pyrolysis analysis method according to any one of claims 1 to 6, characterized in that: The pyrolysis products were cooled and pumped to the GC-MS system; And / or, in GC-MS analysis, the chromatography uses a capillary column, optionally a UA-1MS capillary column; Optionally, the chromatographic conditions are: injection port temperature: 250°C; detector temperature: 250°C; carrier gas: helium, flow rate 3mL / min; injection volume: 0.2μL; program temperature: initial temperature 50°C for 2min, increase to 280°C at a rate of 10°C / min for 10min; split ratio: 50:1; And / or, in GC-MS analysis, the mass spectrometer is a high-sensitivity EI source; optionally, the mass spectrometer conditions are: in the mass spectrometer, ion source temperature: 230°C, MS quadrupole high temperature: 150°C, solvent delay time: 0min, scanning mode: full scan.

8. The sweetener pyrolysis analysis method according to any one of claims 1 to 7, characterized in that: Before cracking, add other e-cigarette additives to the sweetener.

9. An analytical method for evaluating the safety of sweeteners on electronic cigarettes, characterized in that: The sweetener pyrolysis analysis method according to any one of claims 1 to 8 is used to detect the pyrolysis products of the sweetener and evaluate the safety of the pyrolysis products.

10. An analytical system for evaluating the safety of sweeteners on electronic cigarettes, characterized in that: The sweetener pyrolysis product detected by the sweetener pyrolysis analysis method according to any one of claims 1 to 8 is input, and an evaluation result of whether the pyrolysis product is safe is output.

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