CN111189943B - Method for detecting glycerin permeation rate in tobacco flakes - Google Patents
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- CN111189943B CN111189943B CN202010147440.5A CN202010147440A CN111189943B CN 111189943 B CN111189943 B CN 111189943B CN 202010147440 A CN202010147440 A CN 202010147440A CN 111189943 B CN111189943 B CN 111189943B
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- G01—MEASURING; TESTING
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- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
Abstract
A method for detecting the glycerol permeation rate in tobacco flakes is characterized by detecting the content of glycerol in a gas phase evaporated on the surface of the tobacco flakes to represent the permeation rate, and the tobacco flakes arranged in a closed groove body are used for testing in an environment with constant temperature and humidity; on the tobacco flakeThe surface is coated with glycerol in an excessive way, the lower surface is exposed in a closed tank body provided with an air inlet and an air outlet, the air inlet of the closed tank body is communicated with test purge gas, the air outlet is directly introduced into each container containing low-temperature methanol solution through a pipeline, the time of the interval between the purge is fixed, the content of the glycerol in each methanol solution is detected by adopting gas chromatography, and finally the permeation rate hm of the glycerol in the sample is calculated to obtain
/（t e * A × h). The invention has the advantages that: the penetration test device is simple, the penetration rate of the glycerin liquid in the tobacco flakes is detected and obtained through a quantitative method, and the method can provide an evaluation method for the glycerin adding mode in the tobacco flakes or the tobacco sheets and the processing technology of tobacco materials.
Description
Technical Field
The invention relates to the field of production of heating non-combustion tobacco products, in particular to a method for detecting the penetration rate of glycerin in tobacco flakes.
Background
In recent years, heating non-burning cigarettes has received a great deal of attention in the consumer market. The main smoke agent of the heating non-combustion cigarette is glycerin, and the addition of the glycerin can remarkably promote nicotine in tobacco and products and realize effective release at lower temperature. But the addition of glycerin to the tobacco flakes is very slow, mainly due to the very low permeation rate of glycerin liquid in the tobacco flakes. All of the options for process conditions and pathways in the addition of the smoke producing agent to the tobacco sheet are critical to increasing the rate of penetration of the glycerin liquid into the tobacco material. In order to evaluate the processing quality of tobacco raw materials and tobacco sheets used for heating non-combustion tobacco products, the permeation rate of glycerin in the tobacco sheets is an important guiding index, and has important influence on the selection and determination of subsequent processes. However, currently, there are few reports on the detection method of the permeation rate of glycerin in tobacco and tobacco sheets.
Disclosure of Invention
The present invention is based on the above background and the state of the art and provides a method for detecting the permeation rate of glycerol in tobacco flakes.
The invention is based on the working mechanism that the evaporation rate of glycerin on the surface of the tobacco material is far greater than the permeation rate of glycerin in the tobacco material, and the permeation rate is characterized by detecting the content of glycerin in the gas phase evaporated on the surface of the tobacco material.
The purpose of the invention is realized by the following technical scheme:
a method for detecting the glycerol permeation rate in tobacco flakes is characterized by detecting the content of glycerol in a gas phase evaporated on the surface of the tobacco flakes to represent the permeation rate, and the tobacco flakes arranged in a closed groove body are used for testing in an environment with constant temperature and humidity; the upper surface of the tobacco flake is coated with glycerol in an excessive way, the lower surface of the tobacco flake is exposed in a closed groove body provided with an air inlet and an air outlet, the air inlet of the closed groove body is communicated with test purge air, the air outlet is directly introduced into each container containing low-temperature methanol solution through a pipeline, the time interval of the purge is fixed, the glycerol content in each methanol solution is detected by adopting gas chromatography, the glycerol quality detected in each time is recorded
The quality of the glycerol obtained by detection is measured according to the time sequence
Drawing with the time t to obtain a purged glycerol concentration change curve, wherein the mass concentration no-increase point is the mass concentration reaching the balance
The corresponding time point is the time t for reaching the equilibrium e . Finally, the permeation rate hm =of the glycerol in the sample is obtained through calculation
/（t e * A h), where a is the penetration area and h is the tobacco sheet thickness.
The method comprises the following specific steps:
1) The device for detecting the tobacco flake glycerol permeation rate is built (established), and comprises a cavity with controllable temperature and humidity and a purging and permeation test assembly arranged in the cavity, wherein the test assembly comprises a permeation purging groove for placing a tobacco flake sample, a tabletting sealing frame and a sealing frame cover plate which are arranged on the purging groove, the permeation purging groove is provided with a corresponding air inlet and an air outlet, the air inlet is connected with test purging air, and the air outlet is communicated with a container filled with low-temperature methanol solution through a pipeline;
in the step, the shape of the permeation purging groove is rectangular, square, round, oval or irregular; the bottom surface of the sealing frame is provided with a wire mesh to prevent the tobacco flakes from being blown to deform when the blowing airflow is too large.
2) Selecting intact and unbroken tobacco flakes, measuring the thickness h of the tobacco flakes, cutting the tobacco flakes into small pieces slightly larger than the notch according to the size and the shape of the notch of the permeation purging groove to be used as samples, placing the samples in the purging groove and pressing the samples by using a tabletting sealing frame to prevent the air leakage of the upper and lower sealing contact surfaces of the samples, wherein the permeation area of the permeation groove is A;
3) Placing the blowing groove and the sample in a cavity with controllable temperature and humidity, setting the temperature and humidity and the flow of blowing gas, and ensuring that the temperature and humidity of the cavity environment and the temperature and humidity of blowing gas flow are the same until the sample is balanced; in the step, the set air humidity is adjustable within the range of 0 to 100 percent, the air temperature is adjustable within the range of 5 to 95 ℃, and the flow of the blowing gas on the permeation surface is adjustable within the range of 0 to 5000 ml/min.
4) After the balance is finished, excessively coating glycerol on the upper surface of the tobacco flakes, ensuring that the mass of the glycerol on the tobacco flakes is far larger than the saturated absorption amount of the glycerol on the tobacco flakes, and pressing a closed sealing frame by using a cover plate to isolate the environment of an external cavity;
5) Timing is started after the glycerol is added, the lower surface without the glycerol keeps a certain volume flow for purging, the glycerol on the upper surface of the tobacco flake slowly permeates through the tobacco flake to reach the lower surface of the tobacco flake, then the glycerol is evaporated and gasified on the lower surface of the tobacco flake, and the purging interval is fixed for a long time t o (purge interval duration t o Can be 1-2 min). The purge gas containing glycerol molecules is introduced into a low-temperature methanol liquid with proper mass (the temperature is between 15 ℃ below zero and 5 ℃). The methanol liquid completely absorbs the glycerol molecules in the air and reaches the set interval time t o Then, the next methanol absorption liquid is switched,
6) Absorbing methanol liquid with glycerol, detecting glycerol concentration in methanol liquid by gas chromatography, and calculating to obtain t according to dilution ratio of chromatography o Mass M of glycerol absorbed by the i-th methanol liquid in the interval t, i Repeating the step 5) and the step 6) for multiple times to obtain the fixed time length t o Lower ith methanol absorption average mass of glycerol
；
7) The quality of the glycerol obtained by collecting and detecting the glycerol is determined according to the time sequence
Plotting with the time t to obtain a purged glycerol concentration change curve, wherein the mass concentration non-increasing point is the mass concentration reaching the balance
The corresponding time point is the time t for reaching the equilibrium e Finally calculateObtaining the permeation rate hm =of the glycerol in the sample
/（t e *A*h）。
In the invention, the device for providing the constant-temperature and constant-humidity air source for the constant-temperature and constant-humidity cavity and the sweep gas can select a detection device for isothermal adsorption and desorption of moisture of slice tobacco or tobacco shred biomass, which is named as 'a detection device for isothermal adsorption and desorption of moisture' in patent number 201510307227.5 filed by the applicant and granted by the applicant, and can provide a stable air source under a certain temperature and humidity state through the device.
The tobacco flakes are sheet-shaped materials and comprise tobacco sheets and cured tobacco leaves.
The invention has the advantages that: the penetration test device is simple, the penetration rate of the glycerin liquid in the tobacco sheet is detected and obtained through a quantitative method, and the method can provide an evaluation method for the glycerin adding mode in the tobacco and the tobacco sheet and the processing technology of tobacco materials.
Drawings
Fig. 1 is a schematic view of a glycerol permeation test apparatus and permeation components.
FIG. 2 is a top view of the permeate purge tank of FIG. 1;
FIG. 3 is a top view of the platen sealing frame of FIG. 1;
in FIGS. 1-3: 1. a temperature and humidity gas generator; 2. a temperature and humidity controllable cavity; 3. a permeation purging tank, a 3-1 purging tank air inlet and a 3-2 purging tank air outlet; 4. a tablet pressing sealing frame; 5. sealing the frame cover plate; 6. a sample; 7. a gas flow meter; 8. air holes; 9. methanol absorption liquid; 10. and (4) cooling the pool.
FIG. 4 shows the results of measurement of glycerol concentration in glycerol purge gas. Purge gas stream temperature T =60 ℃ and humidity RH =10%.
Detailed Description
The invention is further described below with reference to the accompanying drawings (examples):
the working mechanism of the invention is that the evaporation rate of glycerin on the surface of the tobacco flake is far greater than the permeation rate of glycerin in the tobacco flake, and the content of glycerin in the gas phase evaporated on the surface of the tobacco flake is detected.
The technical scheme of the invention is as follows:
a method for detecting the glycerol permeation rate in tobacco flakes is characterized by detecting the content of glycerol in a gas phase evaporated on the surface of the tobacco flakes to represent the permeation rate, and the tobacco flakes arranged in a closed groove body are used for testing in an environment with constant temperature and humidity; the upper surface of the tobacco flake is coated with glycerol in an excessive way, the lower surface of the tobacco flake is exposed in a closed groove body provided with an air inlet and an air outlet, the air inlet of the closed groove body is communicated with test purge air, the air outlet is directly introduced into each container containing low-temperature methanol solution through a pipeline, the time interval of the purge is fixed, the glycerol content in each methanol solution is detected by adopting gas chromatography, the glycerol quality detected in each time is recorded
The quality of the glycerol obtained by detection is measured according to the time sequence
Drawing with the time t to obtain a purged glycerol concentration change curve, wherein the mass concentration no-increase point is the mass concentration reaching the balance
The corresponding time point is the time t for reaching the equilibrium e . Finally, the penetration rate hm =of the glycerol in the sample is obtained through calculation
/（t e * A x h), wherein a is the penetration area and h is the tobacco sheet thickness.
The technical scheme of the invention is explained by combining the following steps with the attached drawings:
1. a device for detecting the glycerin permeation rate of tobacco flakes is constructed,
as shown in fig. 1-3: the device mainly comprises the following main components, a temperature and humidity gas generator 1; a temperature and humidity controllable cavity 2; a permeation purging tank 3; a tabletting sealing frame 4; a sealing frame cover plate 5; sample 6; a gas flow meter 7; an air hole 8; methanol absorption liquid 9; the pool 10 is cooled. The temperature and humidity gas generator 1 comprises two paths of gas, wherein the temperature and humidity chamber 2 is provided with constant-temperature and constant-humidity gas, and the sample purging gas is provided. The controllable temperature and humidity cavity 2 mainly keeps the environment that the permeation purging component is fixed, and the whole component water bath is used for heat preservation, so that the temperature is kept and wall condensation is avoided. The permeation purging groove 3 is mainly a gas passage box and comprises a gas inlet 3-1 and a gas outlet 3-2, and the upper layer comprises an open sample placing groove surface for flatly laying samples. The groove surface plan view (see fig. 2) is square. The tabletting sealing frame 4 is an annular frame matched with the size and shape according to the shape of the groove surface and used for fixing and sealing a sample, and the annular frame has a certain height, so that a certain amount of glycerin can be conveniently added without overflowing. The sample pressure surface is fixed with a wire mesh in parallel, so that the deformation of the sample purged by the atmospheric flow is prevented. The sealing frame cover plate 5 is a flat cover surface and is used for isolating the outside air after glycerin is added. The above components can be sealed with an upper high temperature resistant glue. In the figure 6, a prepared tobacco flake sample is shown. The flow controller 7 and the air hole 8 provide set constant temperature and humidity air flow and flow rate. The methanol absorption liquid 9 is used for capturing the glycerol, and the gas in the methanol absorption liquid can be sufficiently exchanged with the methanol by using a foam generator before entering the gas absorption liquid so as to adsorb and condense the glycerol. The cooling tank 10 provides low temperature to keep the methanol absorption liquid at low temperature and reduce volatilization.
2. Selecting intact and undamaged tobacco sheets, and measuring the thickness h of the tobacco sheets to be 0.09mm by using a thickness meter. According to the size and shape of the cavity of the permeation purging groove (the permeation area A of the permeation groove is 2cm x 2cm, and a small piece slightly larger than the shape and the area of the cavity is cut to be used as a sample.
3. And placing the purging groove and the sample in a sample cavity, setting the temperature and humidity and the gas flow, and ensuring that the environment of the sample cavity is the same as the temperature and humidity of the purging gas flow until the sample is balanced. In the example, the temperature T =60 ℃, the humidity RH =10% and the flow rate of the purge gas is 4000ml/min.
4. After the balance is finished, coating a certain mass of glycerin liquid on the upper surface of the tobacco flakes. And ensures that the mass of glycerin on the flakes is much greater than the saturated uptake of glycerin by the flakes (i.e., over-coating). After the glycerol coating is finished, the upper glycerol adding layer is sealed by the cover plate to isolate the external cavity environment.
5. And starting timing after the glycerol is added, and purging the lower surface without the glycerol at a certain volume flow. The glycerin on the upper surface of the tobacco sheet slowly permeates through the tobacco sheet to reach the lower surface of the tobacco sheet, and then the glycerin is evaporated and gasified on the lower surface of the tobacco sheet, so that the glycerin molecules evaporated near the lower surface of the tobacco sheet are completely carried away by air. Fixed purge interval duration t o For 1min, introducing a purging gas containing glycerol molecules into a low-temperature methanol liquid with proper mass, wherein the methanol liquid completely absorbs the glycerol molecules in the air. Reaching the set interval time t o After 1min, the next methanol absorption solution was switched.
6. The methanol liquid absorbed with the glycerol, and the concentration of the glycerol in the methanol liquid was measured by gas chromatography. T is calculated according to the dilution ratio of the chromatographic configuration o I.e. the mass M of the i-th glycerol absorbed by the methanol liquid in the 1min interval t, i . Repeating the step 5 and the step 6 for multiple times to obtain a fixed time length t o I.e. the average mass of glycerol absorbed by the i-th methanol at 1min
。
7. The quality of the glycerol obtained by collecting and detecting the glycerol is determined according to the time sequence
Plotting the time t to obtain a sweep glycerol mass curve (see FIG. 4), where the point of no mass increase is the osmotic mass at equilibrium
The result under the example conditions was 0.045mg, which corresponds to the time t at which equilibrium is reached e It was 55min. Finally, the permeation rate hm =of the glycerol in the sample is obtained through calculation
/（t e *A*h）。
Claims (6)
1. A method for detecting the glycerol penetration rate in tobacco flakes is characterized by comprising the following steps: the permeation rate of the tobacco sheet is characterized by detecting the content of glycerin in a gas phase evaporated from the surface of the tobacco sheet, and the tobacco sheet arranged in a closed groove body is used for testing in an environment with constant temperature and humidity; the method comprises the steps of coating excessive glycerol on the upper surface of a tobacco sheet, exposing the lower surface of the tobacco sheet to a closed groove body provided with an air inlet and an air outlet, communicating the air inlet of the closed groove body with test purge air, directly introducing the air outlet into each container containing low-temperature methanol solution through a pipeline, fixing purge interval duration, detecting the glycerol content in each methanol solution by adopting gas chromatography, and recording the glycerol quality detected in each duration
The quality of the glycerol obtained by detection is measured according to the time sequence
Drawing with the time t to obtain a purged glycerol concentration change curve, wherein the mass concentration no-increase point is the mass concentration reaching the balance
The corresponding time point is the time t for reaching the equilibrium e Finally, the permeation rate hm =of the glycerol in the sample is calculated
/（t e * A x h), wherein a is the penetration area and h is the tobacco sheet thickness; the method comprises the following specific steps:
1) The device for detecting the tobacco flake glycerol permeation rate is built and comprises a cavity with controllable temperature and humidity and a purging permeation test assembly arranged in the cavity, wherein the test assembly comprises a permeation purging groove for placing a tobacco flake sample, a tabletting sealing frame and a sealing frame cover plate which are arranged on the purging groove, the permeation purging groove is provided with a corresponding air inlet and an air outlet, the air inlet is connected with a test purging gas, and the air outlet is communicated with a container filled with a low-temperature methanol solution through a pipeline;
2) Selecting intact and undamaged tobacco flakes, measuring the thickness h of the tobacco flakes, cutting the tobacco flakes into small pieces slightly larger than the notch according to the size and the shape of the notch of the permeation purging groove to be used as samples, placing the samples in the purging groove and pressing the samples by using a sealing frame to prevent the air leakage of the upper and lower sealing contact surfaces of the samples, wherein the permeation area of the permeation groove is A;
3) Placing the blowing groove and the sample in a cavity with controllable temperature and humidity, setting the temperature and humidity and the flow of blowing gas, and ensuring that the temperature and humidity of the cavity environment and the temperature and humidity of blowing gas flow are the same until the sample is balanced;
4) After the balance is finished, excessively coating glycerin on the upper surface of the tobacco flake, ensuring that the mass of the glycerin on the tobacco flake is far larger than the saturated absorption amount of the tobacco flake to the glycerin, and pressing the sealed frame by using a cover plate to isolate the external cavity environment;
5) Timing is started after the glycerol is added, the lower surface without the glycerol keeps a certain volume flow for purging, the glycerol on the upper surface of the tobacco flake slowly permeates through the tobacco flake to reach the lower surface of the tobacco flake, then the glycerol is evaporated and gasified on the lower surface of the tobacco flake, and the purging interval is fixed for a long time t o Introducing a purging gas containing glycerol molecules into a low-temperature methanol liquid with proper mass and temperature of-15-5 ℃, wherein the methanol liquid completely absorbs the glycerol molecules in the air until a set interval time t is reached o Then, the next methanol absorption liquid is switched,
6) Absorbing methanol liquid with glycerol, detecting glycerol concentration in methanol liquid by gas chromatography, and calculating to obtain t according to dilution ratio of chromatography o Mass M of glycerol absorbed by the i-th methanol liquid in the interval t, i Repeating the step 5) and the step 6) for multiple times to obtain the fixed time length t o Lower ith methanol absorption average mass of glycerol
；
7) The quality of the glycerol obtained by collecting and detecting the glycerol is determined according to the time sequence
Drawing with the time t to obtain a purged glycerol concentration change curve, wherein the mass concentration without increasing point is the mass concentration reaching the equilibrium
The corresponding time point is the time t for reaching the equilibrium e Finally, the permeation rate hm =of the glycerol in the sample is calculated
/（t e *A*h）。
2. The method of detecting the rate of penetration of glycerin into a tobacco sheet according to claim 1, wherein: in the step 3), the set air humidity is adjustable within the range of 0-100%, the air temperature is adjustable within the range of 5-95 ℃, and the flow rate of the blowing gas of the infiltration surface is adjustable within the range of 0-5000 ml/min.
3. The method of detecting the rate of penetration of glycerin into a tobacco sheet according to claim 1, wherein: the shape of the permeation purging groove in the step 1) is rectangular, square, circular, oval or irregular.
4. The method for detecting the permeation rate of glycerin in tobacco flakes according to claim 1, characterized in that: the bottom surface of the tabletting sealing frame in the step 1) is provided with a wire mesh to prevent the tobacco flakes from being blown to deform when the blowing airflow is too large.
5. The method of detecting the rate of penetration of glycerin into a tobacco sheet according to claim 1, wherein: purge interval duration t in step 5) o Is 1-2min.
6. The method of detecting the rate of penetration of glycerin into a tobacco sheet according to claim 1, wherein: the tobacco flakes are tobacco flakes or baked tobacco leaves.
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| JPH01307635A (en) * | 1988-06-03 | 1989-12-12 | Hamamatsu Photonics Kk | Method of evaluating material transmission performance of thin film for testing |
| DE102013002724B3 (en) * | 2013-02-12 | 2014-07-03 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Method and device for determining the permeation rate of barrier materials |
| CN103575630B (en) * | 2013-10-23 | 2016-04-27 | 中国广州分析测试中心 | A kind of Simultaneously test combination gas respectively forms the assay method of the membrane permeability of gas |
| CN103698431B (en) * | 2013-12-27 | 2015-09-09 | 云南烟草科学研究院 | The assay method of glycerine, 1,2-PD in a kind of cigarette, electronic cigarette and low temperature cigarette |
| CN103760090A (en) * | 2014-02-13 | 2014-04-30 | 云南烟草科学研究院 | Determination method for penetrability of reconstituted tobacco base stock solution through paper-making process |
| CN106644886A (en) * | 2016-12-28 | 2017-05-10 | 中国石油天然气集团公司 | Method for testing seepage performance of thermoplastic plastic mixed gas and test device thereof |
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| CN110726648B (en) * | 2019-10-25 | 2022-04-29 | 中国烟草总公司郑州烟草研究院 | Method for characterizing diffusion rate of glycerol solution system in tobacco sheet |
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