Method for detecting content of vinyl alcohol groups in water-based adhesive for cigarettes

Abstract

The invention provides a method for detecting the content of vinyl alcohol groups in a water-based adhesive for cigarettes. The method comprises the following steps: mixing a to-be-detected water-based adhesive sample for cigarettes, a solvent and an internal standard substance to prepare a to-be-detected solution; detecting a nuclear magnetic resonance hydrogen spectrum of the to-be-detected solution, and obtaining an integral area of a methylene hydrogen characteristic peak in the to-be-detected water-based adhesive sample for cigarettes and an integral area of a benzyl hydrogen characteristic peak in the internal standard substance; acquiring a correction factor of the internal standard substance; and determining the content of vinyl alcohol groups in the to-be-detected water-based adhesive sample for cigarettes according to the integral area of the methylene hydrogen characteristic peak in the to-be-detected water-based adhesive sample for cigarettes, the integral area of the benzyl hydrogen characteristic peak in the internal standard substance, the correction factor of the internal standard substance and the content of the internal standard substance in the to-be-detected solution. The detection method at least has the advantages of rapidness, high efficiency, high repeatability, low detection limit and the like.

Description

Technical Field

[0001] The present application relates to the technical field of chemical analysis, and in particular to a method for detecting the content of vinyl alcohol groups in water-based adhesives for cigarettes. Background Art

[0002] Cigarette adhesives are a key material for cigarette splicing and packaging. They are widely used in a variety of applications, including cigarette lap joints, filter tip attachment, small box and carton packaging, and filter rod forming. They are an indispensable and crucial component of tobacco materials. For example, for rigid pack cigarettes with a cigarette length of 84mm and a filter tip of 24mm, approximately 170g of adhesive is used per 10,000 cigarettes, a relatively low amount. Despite this low amount, adhesive is an essential and crucial component of tobacco materials, providing sufficient adhesion to ensure product quality during cigarette production, packaging, transportation, and consumer use.

[0003] Water-based adhesive for cigarettes is a commonly used adhesive. Polymers are the core chemical component, accounting for the majority of the adhesive's mass, and the types and content of these fragments vary. The main polymer component of water-based adhesives for cigarettes has gradually transitioned from polyvinyl acetate emulsion to ethylene-vinyl acetate copolymer. These main components, combined with several other functional additives, can create water-based adhesives for cigarettes. In recent years, water-based adhesives doped with other polymer fragments, such as acrylic acid and acrylates, have emerged, enriching the product range and improving the adhesive properties of water-based adhesives for cigarettes.

[0004] Adhesion strength is one of the most important properties of water-based adhesives. If the adhesion strength is insufficient, it will affect the overall quality of the cigarette and the consumer experience. The chemical composition of water-based adhesives for cigarettes is the material basis that affects its adhesive properties. Quantitative analysis of the chemical composition of water-based adhesives for cigarettes is important for explaining the differences in adhesive properties between different samples, controlling the quality of purchased materials, and further studying the compatibility between paper and adhesive and their applicability to machines. However, due to the diversity and complexity of the main polymer components, and the different types and contents of fragments, there is currently no method for quickly and easily achieving quantitative analysis of the main components in water-based adhesives for cigarettes.

[0005] The colloid protection function and some bonding properties of the main components of water-based adhesives are closely related to the mass proportion of vinyl alcohol groups. Therefore, it is of great significance to clarify the content of vinyl alcohol groups in the main components of polymers. Summary of the Invention

[0006] Based on this, one or more embodiments of the present application provide a method for detecting the vinyl alcohol content in water-based glue for cigarettes, which is simple to operate, efficient and accurate.

[0007] According to a first aspect of an embodiment of the present application, a method for detecting the vinyl alcohol content in a water-based adhesive for cigarettes is provided, comprising the following steps:

[0008] Mixing the water-based adhesive sample of the cigarette to be tested, a solvent and an internal standard to prepare a test solution;

[0009] Detecting the hydrogen nuclear magnetic resonance spectrum of the test solution to obtain the integrated area of ​​the characteristic peak of methylene hydrogen in the water-based gum sample for the test cigarette and the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard;

[0010] obtaining a correction factor for the internal standard; and

[0011] The content of vinyl alcohol groups in the water-based glue sample for the cigarette to be tested is determined based on the integrated area of ​​the methylene hydrogen characteristic peak in the water-based glue sample for the cigarette to be tested, the integrated area of ​​the benzyl hydrogen characteristic peak in the internal standard, the correction factor of the internal standard, and the content of the internal standard in the solution to be tested.

[0012] In some embodiments, the step of obtaining the correction factor of the internal standard comprises:

[0013] The n-hexane standard and the internal standard were mixed to prepare a mixed solution;

[0014] Detecting the H NMR spectrum of the mixed solution to obtain the integrated area of ​​the characteristic peak of methylene hydrogen in the n-hexane standard and the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard; and

[0015] The correction factor is obtained according to the integrated area of ​​the characteristic peak of methylene hydrogen in the n-hexane standard and the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard.

[0016] In some embodiments, the correction factor is 1.0-1.2.

[0017] In some embodiments, the methylene hydrogen characteristic peaks in the water-based gum sample for the cigarette to be tested include a 2# hydrogen characteristic peak, a 4# hydrogen characteristic peak, and a 5# hydrogen characteristic peak.

[0018] In some embodiments, the molar number M of the vinyl alcohol group in the water-based glue sample of the cigarette to be tested is used. 乙烯醇基 The content of vinyl alcohol groups in the water-based adhesive sample to be tested is calculated using the following formula:

[0019] M 乙烯醇基 =M 内标物 ×[(I2+I5) / 2-I4 / 3] / (A 苄基氢 / 2)×correction factor;

[0020] Among them, M 内标物 is the molar number of the internal standard in the solution to be tested, I2 is the integrated area of ​​the characteristic peak of hydrogen #2, I5 is the integrated area of ​​the characteristic peak of hydrogen #5, I4 is the integrated area of ​​the characteristic peak of hydrogen #4, and A 苄基氢is the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard.

[0021] In some embodiments, the concentration of the water-based adhesive sample for the cigarette to be tested in the test solution is 10 ppm to 10000 ppm; and / or,

[0022] The concentration of the internal standard in the test solution is 10 ppm to 10000 ppm.

[0023] In some embodiments, the solvent comprises deuterated dimethyl sulfoxide.

[0024] In some embodiments, the internal standard comprises one or more of benzyl benzoate, styrene, 3-nitrostyrene and 4-nitrostyrene.

[0025] In some embodiments, before mixing the water-based adhesive sample, solvent and internal standard of the cigarette to be tested, the following steps are also included:

[0026] The water-based adhesive sample for the cigarette to be tested is dried and ground to prepare a powder sample.

[0027] In some embodiments, during the detection of the hydrogen nuclear magnetic resonance spectrum of the test solution, the frequency of the nuclear magnetic resonance is 300 MHz to 600 MHz.

[0028] Compared with traditional technologies, this application has the following beneficial effects:

[0029] The present application uses the nuclear magnetic resonance method to obtain the integral area of ​​the characteristic peak of methylene hydrogen in the water-based glue sample to be tested and the integral area of ​​the characteristic peak of benzyl hydrogen in the internal standard, and combines the correction factor and the content of the internal standard to accurately obtain the content of vinyl alcohol groups in the water-based glue sample to be tested; the above method has at least the advantages of being fast and efficient, highly repeatable, and having a low detection limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the specific implementation methods of this application, the following is a brief introduction to the drawings required for the description of the specific implementation methods. Obviously, the drawings described below are some implementation methods of this application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0031] Figure 1 This is the nuclear magnetic resonance spectrum of the water-based adhesive sample A for cigarettes in Example 1 of the present application;

[0032] Figure 2 This is the nuclear magnetic resonance spectrum of the water-based adhesive sample B for cigarettes in Example 1 of the present application;

[0033] Figure 3This is the nuclear magnetic resonance spectrum of the water-based glue sample C used for cigarettes in Example 1 of the present application. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotations of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art in the technical field of this application. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or can be prepared by existing methods.

[0036] The terms "and / or", "or / and", and "and / or" used herein include any one of two or more related listed items, and also include any and all combinations of the related listed items, wherein the arbitrary and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical and" and also undoubtedly includes technical solutions connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution of all being connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the four-item combination of A, B, C, and D (that is, the technical solution of all being connected by "logical AND").

[0037] In this application, "plurality", "multiple", "multiple times", "multiples", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0038] As used herein, "combination thereof", "any combination thereof", "any combination thereof" and the like include all suitable combinations of any two or more of the listed items.

[0039] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc. shall be based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0040] Herein, "preferred", "better", "more preferred" and "suitable" are merely used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of this application.

[0041] In this application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0042] In this application, the terms "optionally," "optional," and "optional" mean optional or dispensable, i.e., they refer to either option being selected from two parallel options: "with" or "without." If a technical solution contains multiple "optional" clauses, each "optional" clause is independent unless otherwise specified and there are no contradictions or constraints.

[0043] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0044] In this application, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the optional numerical distribution within the numerical interval is considered continuous and includes the two numerical endpoints of the numerical range (i.e., the minimum and maximum values), as well as every numerical value between these two numerical endpoints. Unless otherwise specified, when a numerical interval refers only to integers within the numerical interval, it includes the two numerical endpoints of the numerical range, as well as every integer between the two numerical endpoints. In this document, this is equivalent to directly listing each integer. For example, "t is an integer selected from 1-10" means that t is any integer selected from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. In addition, when multiple ranges are provided to describe a feature or characteristic, these ranges may be combined. In other words, unless otherwise specified, ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0045] Unless otherwise specified, the temperature parameters in this application allow for both constant temperature treatment and temperature fluctuations within a certain temperature range. It should be understood that the constant temperature treatment allows for temperature fluctuations within the accuracy range of instrument control. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are permitted.

[0046] In this application, %(w / w) and wt% both refer to weight percentage, %(v / v) refers to volume percentage, and %(w / v) refers to mass volume percentage.

[0047] Currently, the main polymer component of water-based adhesives for cigarettes is ethylene vinyl acetate copolymer (EVA). The molecular structure of ethylene vinyl acetate copolymer is shown in formula (a). Currently, there is no effective method to determine the content of vinyl alcohol groups in ethylene vinyl acetate copolymer.

[0048]

[0049] Some embodiments of the present application provide a method for detecting the content of vinyl alcohol groups in water-based adhesive for cigarettes, including S10 to S40.

[0050] S10: Mixing the water-based adhesive sample of the cigarette to be tested, the solvent and the internal standard to prepare a test solution;

[0051] S20: detecting a hydrogen nuclear magnetic resonance spectrum of the solution to be tested, and obtaining the integrated area of ​​a characteristic peak of methylene hydrogen in the water-based gum sample to be tested and the integrated area of ​​a characteristic peak of benzyl hydrogen in the internal standard;

[0052] S30: Obtaining a correction factor for an internal standard; and

[0053] S40: Determine the content of vinyl alcohol groups in the water-based adhesive sample for the cigarette to be tested according to the integrated area of ​​the characteristic peak of methylene hydrogen in the water-based adhesive sample for the cigarette to be tested, the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard, the correction factor of the internal standard, and the content of the internal standard in the solution to be tested.

[0054] The present application uses the nuclear magnetic resonance method to obtain the integral area of ​​the characteristic peak of methylene hydrogen in the water-based glue sample to be tested and the integral area of ​​the characteristic peak of benzyl hydrogen in the internal standard, and combines the correction factor and the content of the internal standard to accurately obtain the content of vinyl alcohol groups in the water-based glue sample to be tested; the above method has at least the advantages of being fast and efficient, highly repeatable, and having a low detection limit.

[0055] At the same time, the peaks between 1.35PPM and 1.85PPM chemical shifts in the hydrogen nuclear magnetic resonance spectrum can be used to qualitatively determine whether the sample contains vinyl alcohol groups.

[0056] By mixing the sample to be tested with the internal standard and obtaining a correction factor between the internal standard and the vinyl alcohol group, the quantitative detection result can be made more real and accurate.

[0057] In some embodiments, before mixing the water-based adhesive sample, solvent and internal standard of the cigarette to be tested, the following steps are also included:

[0058] The water-based adhesive sample of the cigarette to be tested is dried and ground to prepare a powder sample.

[0059] In some specific examples, the drying method includes one or more of conventional oven drying, vacuum oven drying, and freeze drying. It should be noted that conventional oven drying is an oven drying method that does not require vacuum operation, as opposed to vacuum oven drying.

[0060] In some specific examples, the drying process is performed at a temperature of 90° C. to 110° C. and for a time of 0.5 h to 2 h.

[0061] As an example, the temperature of the drying treatment can be 90°C, 91°C, 92°C, 93°C, 94°C, 94°C, 96°C, 97°C, 98°C, 99°C, 100°C, 101°C, 102°C, 103°C, 104°C, 105°C, 106°C, 107°C, 108°C, 109°C, 110°C, or any value within the range formed by any two of the above point values; the time of the drying treatment can be 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, or any value within the range formed by any two of the above point values.

[0062] It can be understood that by performing the above-mentioned pretreatment on the water-based glue sample of the cigarette to be tested, the moisture in the sample can be effectively removed.

[0063] In some embodiments, the solvent comprises deuterated dimethyl sulfoxide.

[0064] It can be understood that the hydrogen atoms in deuterated dimethyl sulfoxide are replaced by deuterium. The nuclear magnetic resonance properties of deuterium are different from those of hydrogen. It will not produce the same signal as the sample hydrogen atoms in the hydrogen spectrum. Therefore, it can avoid the masking of the sample signal by the solvent hydrogen signal, making the sample hydrogen spectrum clearer and facilitating accurate analysis of the chemical shift and integrated area of ​​the hydrogen atoms in the sample.

[0065] In some embodiments, the internal standard comprises one or more of benzyl benzoate, styrene, 3-nitrostyrene, and 4-nitrostyrene.

[0066] In some examples, the internal standard includes benzyl benzoate. It is understood that benzyl benzoate contains benzyl hydrogen, which has a relatively unique and stable chemical shift, different from the chemical shift of hydrogen in common compounds. This makes it easy to identify in the spectrum and provides an accurate reference for the chemical shift of hydrogen in the sample, facilitating the location and analysis of other hydrogen signals.

[0067] In some embodiments, in S10, the step of mixing the water-based glue sample, the solvent and the internal standard for the cigarette to be tested further includes: ultrasonically dissolving the mixture of the water-based glue sample, the solvent and the internal standard.

[0068] Optionally, the ultrasonic dissolution time is 1 hour to 12 hours. As an example, the ultrasonic dissolution time can be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, or any value within the range formed by any two of the above point values.

[0069] In some embodiments, in S30, the step of obtaining the correction factor of the internal standard includes:

[0070] S31: mixing the n-hexane standard and the internal standard to prepare a mixed solution;

[0071] S32: detecting the H NMR spectrum of the mixed solution to obtain the integrated area of ​​the characteristic peak of methylene hydrogen in the n-hexane standard and the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard; and

[0072] S33: Obtain a correction factor based on the integrated area of ​​the characteristic peak of methylene hydrogen in the n-hexane standard and the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard.

[0073] In some specific examples, the molar numbers of the n-hexane standard and the internal standard in the mixed solution are the same.

[0074] In some embodiments, the correction factor = the integrated area of ​​the characteristic peak of methylene hydrogen in the n-hexane standard / the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard.

[0075] It is understood that the n-hexane standard contains vinyl alcohol groups and the content is known. By calculating the ratio of the integrated area of ​​the characteristic peak of methylene hydrogen in the n-hexane standard to the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard, the correction factor between the internal standard and the vinyl alcohol groups can be obtained.

[0076] In some embodiments, the correction factor is 1.0-1.2.

[0077] In some embodiments, the characteristic peaks of methylene hydrogen in the water-based gum sample for the cigarette to be tested include a 2# hydrogen characteristic peak, a 4# hydrogen characteristic peak, and a 5# hydrogen characteristic peak.

[0078] In some embodiments, the molar number M of the vinyl alcohol group in the water-based glue sample of the cigarette to be tested is used. 乙烯醇基 Calculate the content of vinyl alcohol groups in the water-based adhesive sample for the cigarette to be tested. The calculation formula is as follows:

[0079] M 乙烯醇基 =M 内标物 ×[(I2+I5) / 2-I4 / 3] / (A苄基氢 / 2)×correction factor;

[0080] Among them, M 内标物 is the molar number of the internal standard in the solution to be tested, I2 is the integrated area of ​​the characteristic peak of hydrogen #2, I5 is the integrated area of ​​the characteristic peak of hydrogen #5, I4 is the integrated area of ​​the characteristic peak of hydrogen #4, and A 苄基氢 is the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard.

[0081] In some embodiments, the concentration of the water-based glue sample for the cigarette to be tested in the test solution is 10 ppm to 10000 ppm.

[0082] As an example, the concentration of the water-based glue sample can be 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm, 1000ppm, 2000ppm, 3000ppm, 4000ppm, 5000ppm, 6000ppm, 7000ppm, 8000ppm, 9000ppm, 10000ppm, or any value within the range formed by any two of the above point values.

[0083] In some embodiments, the concentration of the internal standard in the test solution is 10 ppm to 10000 ppm.

[0084] As an example, the concentration of the internal standard can be 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm, 1000ppm, 2000ppm, 3000ppm, 4000ppm, 5000ppm, 6000ppm, 7000ppm, 8000ppm, 9000ppm, 10000ppm, or any value within the range formed by any two of the above point values.

[0085] In some embodiments, during the process of detecting the hydrogen nuclear magnetic resonance spectrum of the test solution, the frequency of the nuclear magnetic resonance is 300 MHz to 600 MHz.

[0086] As an example, the frequency of the nuclear magnetic resonance may be 300 MHz, 400 MHz, 500 MHz, 600 MHz, or any value within the range formed by any two of the above values.

[0087] In some embodiments, the delay time of the nuclear magnetic resonance is 2 s, the pulse sequence is zg30, and the number of scans is 32.

[0088] The method for detecting the vinyl alcohol content in water-based adhesive for cigarettes mentioned above has the advantages of simple operation, rapidity, high efficiency, good repeatability and low detection limit.

[0089] The present application will be further described below in conjunction with specific examples and comparative examples, but they should not be construed as limiting the scope of protection of the present application. The raw materials involved in the following specific examples, unless otherwise specified, can all be sourced from commercial sources, the instruments used, unless otherwise specified, can all be sourced from commercial sources, and the processes involved, unless otherwise specified, are all routinely selected by those skilled in the art.

[0090] Example 1 Testing of different water-based adhesive samples for cigarettes

[0091] Take the water-based adhesive samples A, B and C to be tested for cigarettes; process and test them according to the following steps respectively.

[0092] (1) Sample pretreatment: Stir the water-based adhesive sample to be tested evenly, weigh 1.0 g and place it on a glass slide. Dry it under vacuum at 100°C for 1 hour, then grind and mix it evenly to prepare a powder sample. Take 0.5 mg of the powder sample and place it in an NMR tube. Add 1 mL of deuterated dimethyl sulfoxide containing 1000 ppm of benzyl benzoate as an internal standard and sonicate for 3 hours to prepare the test solution.

[0093] (2) Obtaining the correction factor: 0.5 mmol of n-hexane (purity greater than 98%, J&K Technology Co., Ltd.) and 0.5 mmol of benzyl benzoate as internal standard were dissolved in 1 mL of deuterated dimethyl sulfoxide (Sigma-Aldrich), and nuclear magnetic resonance (NMR) tests were performed using a nuclear magnetic resonance spectrometer (Bruker 600 MHz, AVANCE NEO); the hydrogen spectra of n-hexane and benzyl benzoate were obtained respectively.

[0094] The liquid probe of the NMR spectrometer is 5 mm, the delay time is 2 s, the pulse sequence is zg30, and the number of scans is 32.

[0095] The benzyl hydrogen of the internal standard benzyl benzoate and the methylene hydrogen of n-hexane were integrated separately using integration software, and the correction factor was obtained by calculating the ratio of "methylene hydrogen area / 2" to "benzyl hydrogen area / 2". The average value of the two parallel measurements was used as the final measurement result. Specifically, the correction factor in this embodiment was 1.09.

[0096] (3) Perform nuclear magnetic resonance testing on the test solution prepared in step (1), and the test parameters are the same as those in step (2); use integration software to integrate the benzyl hydrogen of internal standard benzyl benzoate, methylene 2#, 4#, and 5# hydrogen in EVA (chemical shift is 1.35PPM~1.85PPM); obtain the integral area I2 of the characteristic peak of 2# hydrogen, the integral area I4 of the characteristic peak of 4# hydrogen, the integral area I5 of the characteristic peak of 5# hydrogen, and the integral area A of the characteristic peak of benzyl hydrogen in the internal standard. 苄基氢 .

[0097] The number of moles of vinyl alcohol groups in the water-based adhesive samples A, B and C to be tested is calculated according to the following formula (I): 乙烯醇基 , and further calculate the mass content of vinyl alcohol groups in the water-based glue sample for the cigarette to be tested.

[0098] M 乙烯醇基 =M 内标物 ×[(I2+I5) / 2-I4 / 3] / (A 苄基氢 / 2)×correction factor formula (I)

[0099] Finally, the calculation results of the mass content of vinyl alcohol groups in water-based adhesive samples A, B and C for cigarettes are shown in Table 1. Figure 1 This is the nuclear magnetic resonance spectrum of the water-based adhesive sample A for cigarettes; Figure 2 This is the NMR spectrum of the water-based adhesive sample B for cigarettes; Figure 3 This is the nuclear magnetic resonance spectrum of water-based glue sample C for cigarettes.

[0100] Table 1

[0101]

[0102] Example 2 Detection limit test

[0103] Referring to the steps described in Example 1, taking a 600 MHz nuclear magnetic resonance instrument as an example, a stepwise dilution method was adopted, and a signal-to-noise ratio of 3 was used as the method detection limit; the research showed that the detection limit of the detection method of the present application was 20 μg / mL.

[0104] Example 3 Repeatability test

[0105] Referring to the method described in Example 1, water-based adhesive samples for cigarettes with known vinyl alcohol concentrations were tested to examine the repeatability of the method. The results are shown in Table 2.

[0106] Table 2

[0107]

[0108] As can be seen from the table above, the relative standard deviation (RSD) of the results obtained by repeated testing a sample with a known concentration of 500 ppm using the detection method of the present application is only 4.93%, indicating that the above method has good detection repeatability.

[0109] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for detecting the content of vinyl alcohol groups in water-based adhesives for cigarettes, characterized in that: The steps include: Mixing the water-based adhesive sample of the cigarette to be tested, a solvent and an internal standard to prepare a test solution; Detecting the hydrogen nuclear magnetic resonance spectrum of the test solution to obtain the integrated area of ​​the characteristic peak of methylene hydrogen in the water-based gum sample for the test cigarette and the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard; obtaining a correction factor for the internal standard; and The content of vinyl alcohol groups in the water-based glue sample for the cigarette to be tested is determined based on the integrated area of ​​the methylene hydrogen characteristic peak in the water-based glue sample for the cigarette to be tested, the integrated area of ​​the benzyl hydrogen characteristic peak in the internal standard, the correction factor of the internal standard, and the content of the internal standard in the solution to be tested.

2. The method for detecting the content of vinyl alcohol groups in water-based adhesive for cigarettes according to claim 1, characterized in that: The step of obtaining the correction factor of the internal standard comprises: The n-hexane standard and the internal standard were mixed to prepare a mixed solution; Detecting the H NMR spectrum of the mixed solution to obtain the integrated area of ​​the characteristic peak of methylene hydrogen in the n-hexane standard and the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard; and The correction factor is obtained according to the integrated area of ​​the characteristic peak of methylene hydrogen in the n-hexane standard and the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard.

3. The method for detecting the content of vinyl alcohol groups in water-based adhesive for cigarettes according to claim 2, characterized in that: The correction factor is 1.0~1.

2.

4. The method for detecting the vinyl alcohol content in water-based adhesive for cigarettes according to any one of claims 1 to 3, characterized in that: The methylene hydrogen characteristic peaks in the water-based glue sample for the cigarette to be tested include a 2# hydrogen characteristic peak, a 4# hydrogen characteristic peak and a 5# hydrogen characteristic peak.

5. The method for detecting the vinyl alcohol content in water-based adhesive for cigarettes according to claim 4, characterized in that: According to the molar number M of vinyl alcohol groups in the water-based glue sample of the cigarette to be tested 乙烯醇基 The content of vinyl alcohol groups in the water-based adhesive sample to be tested is calculated using the following formula: M 乙烯醇基 =M 内标物 ×[(I2+I5) / 2-I4 / 3] / (A 苄基氢 / 2)×correction factor; Among them, M 内标物 is the molar number of the internal standard in the solution to be tested, I2 is the integrated area of ​​the characteristic peak of hydrogen #2, I5 is the integrated area of ​​the characteristic peak of hydrogen #5, I4 is the integrated area of ​​the characteristic peak of hydrogen #4, and A 苄基氢 is the integrated area of ​​the characteristic peak of benzyl hydrogen in the internal standard.

6. The method for detecting the vinyl alcohol content in water-based adhesive for cigarettes according to any one of claims 1 to 3 and 5, characterized in that: The concentration of the water-based adhesive sample for the cigarette to be tested in the test solution is 10ppm~10000ppm; and / or, The concentration of the internal standard in the test solution is 10 ppm to 10000 ppm.

7. The method for detecting the vinyl alcohol content in water-based adhesive for cigarettes according to any one of claims 1 to 3 and 5, characterized in that: The solvent includes deuterated dimethyl sulfoxide.

8. The method for detecting the vinyl alcohol content in water-based adhesive for cigarettes according to any one of claims 1 to 3 and 5, characterized in that: The internal standard comprises one or more of benzyl benzoate, styrene, 3-nitrostyrene and 4-nitrostyrene.

9. The method for detecting the vinyl alcohol content in water-based adhesive for cigarettes according to any one of claims 1 to 3 and 5, characterized in that: Before mixing the water-based adhesive sample, solvent and internal standard of the cigarette to be tested, the following steps are also included: The water-based adhesive sample for the cigarette to be tested is dried and ground to prepare a powder sample.

10. The method for detecting the vinyl alcohol content in water-based adhesive for cigarettes according to any one of claims 1 to 3 and 5, characterized in that: In the process of detecting the hydrogen nuclear magnetic resonance spectrum of the test solution, the frequency of the nuclear magnetic resonance is 300 MHz to 600 MHz.

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