CN101382516A - Method for measuring non-protein nitrogen content in tobacco - Google Patents
Method for measuring non-protein nitrogen content in tobacco Download PDFInfo
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- CN101382516A CN101382516A CNA2008101475869A CN200810147586A CN101382516A CN 101382516 A CN101382516 A CN 101382516A CN A2008101475869 A CNA2008101475869 A CN A2008101475869A CN 200810147586 A CN200810147586 A CN 200810147586A CN 101382516 A CN101382516 A CN 101382516A
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Abstract
The invention discloses a measuring method of non-protein nitrogen content in tobaccos, which comprises the following steps: a) the tobaccos are weighted; b) the weighted tobaccos are put into plenty of acid solution or copper-bath so as to carry out heating until the protein is completely dissolved; c) the mixture is filtered and the acid solution or copper-bath in step b) is utilized to wash the filtrate; d) filter liquor is combined and constant volume is obtained; e) the filter liquor is taken for digestive treatment to obtain a constant volume; f) the filter liquor after volume limiting is removed, then NaOH solution is added, and a first equilibrium potential value is measured; g) NH4<plus> solution is added, and a second equilibrium potential value is measured; and finally, the non-protein nitrogen content in tobaccos is measured by combining the first equilibrium potential value and the second equilibrium potential value. The measuring method provided by the invention is a simple, convenient and efficient method for measuring the non-protein nitrogen content in tobaccos.
Description
Technical field
The present invention relates to the assay method that one-tenth is grouped in the tobacco, relate in particular to the assay method of non-protein nitrogen content in the tobacco.
Background technology
The content of each composition in the tobacco has determined the quality of tobacco, for example the tar of hybrid cigarette and nicotine ratio is 11:1, and fire-cured tobacco type is 13～14:1 mostly, thus hybrid cigarette compare biggest advantage with fire-cured tobacco type cigarette be exactly that perfume quantity foot and tar content are low.Contain protein in the tobacco, protein can make the flue gas bitter taste increase after burning, produces acid and excitement, therefore protein has harmful effect to cigarette odor-absorbing, if but protein content is low excessively, flue gas will seem flat so, and jealous and fragrance also can variation.In addition, protein hydrolyzable in modulated process is an amino acid, and the fragrance of amino acid content and flue gas and richness have tangible positive correlation.
Though it is less that the total amount of protein changes in the alcoholization process of tobacco, other compositions in the tobacco but can change along with the alcoholization process, thereby also cause the variation of protein content in the tobacco.Correspondingly,, all need grasp Protein content in the tobacco, measure Protein content in the tobacco in each stage for the research and development and the production of tobacco industry, very important to understanding quality of tobacco.
At present, tobacco business can carry out with reference to the tobacco business standard YC/T 166-2003 of the People's Republic of China (PRC) the detection method of protein, the test philosophy of the method also is to adopt usually both at home and abroad, its principle is, with the protein nitrogen in the acid precipitation tobacco samples such as acetate, by with nitrogenous thing of nonprotein nitrogen and Separation of Proteins, wash-out, then protein is disappeared together with other sediments and boil, protein nitrogen is converted into ammonium sulfate under the concentrated sulphuric acid and catalyst action, the highly basic distillation discharges ammonia, receive with the standard acid solution, back titration is at last by calculating Protein content in the tobacco.This method is to measure the content of protein nitrogen in the tobacco in essence, thereby by calculating Protein content.In the method mensuration process, sediment is disappeared boil after, also need to collect again the ammonia that discharges by the highly basic distillation, receive and back titration with the standard acid solution, need and will repeatedly sample be shifted, the error that human factor causes in the process of the test is bigger.
Summary of the invention
Technical matters to be solved by this invention be to provide one grow tobacco in the assay method of non-protein nitrogen content, the method for testing step is few, need not collect operations such as gas and titration again, measurement result is accurate, error is little.
In order to solve above technical matters, the invention provides following technical scheme:
One grow tobacco in the assay method of non-protein nitrogen content, comprise the steps:
A) take by weighing tobacco;
B) tobacco that takes by weighing is put into the acid or the copper-bath of capacity, be heated to protein and solidify fully;
C) filter and wash and leach thing with acid described in the step b) or copper-bath;
D) merging filtrate and constant volume;
E) get filtrate and carry out digestion process, constant volume;
F) pipette the filtrate that obtains behind the constant volume, add NaOH solution, measure the first equilibrium potential value;
G) add NH
4 +Solution is measured the second equilibrium potential value; Calculate non-protein nitrogen content in the tobacco in conjunction with the first equilibrium potential value and the second equilibrium potential value.
The assay method of non-protein nitrogen content in the tobacco hereto, what step a) and step b) were finished is the fixed nitrogen process; Step c) and step d) are that isolated by filtration is rejected the precipitation that protein solidifies formation; Step e) is the digestion process to filtrate; Step f) and step g) are adding NaOH solution and NH for measuring postdigestive filtrate
4 +Equilibrium potential value behind the standard solution, the difference in conjunction with two equilibrium potential values that record can calculate non-protein nitrogen content in the tobacco like this.
For whole assay method, in brief, at first handle Protein in Tobacco is rejected with the form of precipitation by fixed nitrogen, utilize the nitrogen content in the ammonia gas-sensing electrode method mensuration filtrate then, by calculating the content that can obtain nonprotein nitrogen in the tobacco.
By measuring non-protein nitrogen content in the tobacco, and again by measuring content of total nitrogen in the tobacco, can be easy to calculate, Protein content in the tobacco, the assay method step is few, need not carry out filter residue again shifts, collect operations such as gas and titration, and in the method for existing direct mensuration protein nitrogen, need carry out suction filtration handles and filter residue is transferred in the digestion vessel, after protein nitrogen is converted into ammonium sulfate, also need to utilize the highly basic distillation to discharge ammonia, receive with the standard acid solution, back titration, these operation experiments be more complicated and exist than big-difference because of experimenter's difference all.As can be seen, assay method step provided by the invention is few, need not collect operations such as gas and titration again, and measurement result is accurate, error is little.
Below to carrying out detailed argumentation and introduction in each step, and provide some preferred or can substitute technical schemes.
Step a) takes by weighing tobacco
Before address, this step is a step of fixed nitrogen process.In the present invention, the fixed nitrogen process refers to the process of Protein in Tobacco and acid reaction generation precipitation.The fixed nitrogen process is also referred to as the process of nitrogen curing etc.Definite says, this step is a weighing step, for simplicity, so this weighing step is defined as a step of fixed nitrogen process.
The weighing step is one of basic operation in the analytical test process.Because the proportion of tobacco leaf is smaller, so sky equality weighing equipment that weighing is used selects for use the high electronic balance of degree of accuracy or optical electrobalance relatively good, the general need of degree of accuracy are with being accurate to 0.001g (gram) or the higher testing tool of degree of accuracy.
Before carrying out this operation steps, also need to measure the moisture in the tobacco usually, what generally adopt is Oven Method.Also can and place dry environment stand-by with the tobacco sample oven dry.
Step b) is put into the acid or the copper-bath of capacity with the tobacco that takes by weighing, and is heated to protein and solidifies fully
This step is the step that the fixed nitrogen reaction takes place, and in this step, Protein in Tobacco and acid or copper sulphate reaction generate precipitation.Described acid needs certain concentration, and its essence is that certain pH is arranged.For different types of acid, also be different to the requirement of the mass percent concentration of acid, can select according to the acid of needs in the reality test.Acid stronger organic acid is generally selected in the acid that participates in reaction for use, and the most frequently used is acetate.Also can be acetate, propionic acid, malonic acid, trichloroacetic acid etc., perhaps their combination.Wherein acetate is the most frequently used, and when selecting acetate for use, the concentration of acetate preferably uses 0.4%～0.6%; Trichloroacetic acid is also comparatively commonly used, and when selecting trichloroacetic acid for use, the concentration of trichloroacetic acid preferably uses 0.8%～2.0%.The invention is not restricted to only use organic acid, also can use other solvent such as copper sulphate etc., if can with Protein in Tobacco generation sex change, it is heavy poly-to condense, thereby can get final product by filtering separate with nonprotein nitrogen.
When adopting acetate to carry out the fixed nitrogen reaction of protein, the concentration of acetate can select 0.4%～0.6% for use, the temperature of reaction is chosen as the boiling temperature of selected acetic acid solution, for the acetate of selecting 0.4%～0.6% for use, need to keep the acetate boiling more than 15 minutes, so that the generation fully of fixed nitrogen reaction.
Step c) is filtered and is leached thing with acid described in the step b) or copper-bath flushing
Step c) is that isolated by filtration is rejected the key step that protein solidifies the precipitation that forms.This step simple to operate adopts filter operation commonly used to get final product, and both can select common filtration for use, also can select the filtered version of suction filtration for use.This also is one of advantage of the present invention, in the process of directly measuring protein nitrogen, a filter process is arranged also in the prior art, but preferably adopt the form of suction filtration, then no this item requirement among the present invention, because the object of mensuration of the present invention is a filtrate, so, the form of employing suction filtration or common filtration can, moreover exist filtrate to shift the problem of difficulty when adopting suction filtration, so the filtration in this step is preferably used common filtered version, normal pressure filtration just.
Filter and leach thing with acid described in the step b) or copper-bath flushing, can so that filter paper or precipitate in residual nonprotein nitrogen enter filtrate, help improving accuracy of test.It is pointed out that the acid of using in this step or copper-bath are just consistent with the material described in the step b), do not represent must be with step b) in the acid of using or copper-bath concentration too.For example, if what use in the step b) is that concentration is 0.5% acetate, so can working concentration in the step c) be 0.7% acetate.It is pointed out that preferred mode is, the acid of using in the acid of using in the step c) or the concentration of copper-bath and the step b) or the concentration of copper-bath are more or less the same, as far as possible the acid or the copper-bath of working concentration unanimity.
Step d) merging filtrate and constant volume
As previously mentioned, this step is that isolated by filtration rejecting protein solidifies one of step of the precipitation that forms, also can think a step of preparing for next step operation.The filtrate of coming from step c) does not have a volume numerical value accurately, can't provide definite computing formula in follow-up computation process, so need constant volume yet.
Constant volume is a mode of operation commonly used in the chemical experiment, is about to the liquid of uncertain volume, adds certain amount of fluid, makes it have definite volume.The liquid of constant volume is solution if desired, and what then add usually is solvent.
Because the filtrate of coming from step c) has higher temperature, so preferably treat after the filtrate cooling constant volume again, in order to avoid influence the accuracy of constant volume.
Step e) is got filtrate and is carried out digestion process, constant volume
Step e) is the digestion process to filtrate.Digestion process refers to, and the organic nitrogen-containing material is under the effect of oxygenants such as the concentrated sulphuric acid, and through the heat-flash digest and decompose, nitrogen wherein is converted into the process of ammonia.Oxygenant is generally selected strong oxidizer for use.Described strong oxidizer can be selected from the concentrated sulphuric acid, concentrated hydrochloric acid, the concentrated sulphuric acid/hydrogen peroxide potpourri or concentrated hydrochloric acid/hydrogen peroxide potpourri etc.Because the volatility of hydrochloric acid is very strong, so, so must seal pressurization and reacting, prevent volatilization, otherwise the temperature of digestion is very limited, and then influences the effect that digests if use hydrochloric acid as oxygenant.Strong oxidizer is not selected nitric acid for use, and this is that reacting afterwards can be influential to test result owing to contain the nitrogen element in the nitric acid.
In this process, can also add catalyzer, accelerate the carrying out of digestion reaction.Catalyzer can be selected mercury and compound, selenium and compound thereof, copper and compound thereof, and perhaps their combination is concrete as mercury, mercury oxide, selenium, cupric oxide, copper sulphate etc., preferably uses mercury oxide.
Except oxygenant and catalyzer, in digestion reaction, can also add flux.With the concentrated sulphuric acid is example, and the effect of flux is can be so that the elevation of boiling point of the concentrated sulphuric acid, thus can raise the digestion temperature, thus can improve the effect of digestion, reduce digestion time.Flux has glazier's salt, salicylic acid etc.The better effects if of glazier's salt can be so that the elevation of boiling point to 350 of the concentrated sulphuric acid ℃ even higher, and salicylic effect is then weaker a little, and salicylic acid can be so that more than the elevation of boiling point to 340 of the concentrated sulphuric acid ℃.The boiling point of water-free sulfuric acid is 338 ℃.Because generally contain a spot of water in the employed sulfuric acid, so the heating of digestion process generally is divided into two stages, the phase one is to be heated to 100 ℃～150 ℃, makes that the moisture in the sulfuric acid fully is evaporated, and avoids reducing the boiling point of sulfuric acid.If the boiling point of sulfuric acid reduces, part of sulfuric acid will be evaporated in digestion process so, and then causes the loss of ammonia.Flux can be selected glazier's salt, sodium sulphate, salicylic acid or their combination.Preferred a kind of use wherein, and more preferably glazier's salt.
When sulfuric acid and flux use together, often also need to add catalyzer, at this moment, can be heated to sulfuric acid near boiling, and keep can finishing digestion process more than 0.5 hour; Under such reaction conditions, also can keep more than 1 hour, but the time is unsuitable oversize.The inventor points out that the digestion reaction time under this reaction conditions was advisable with 0.5～2.5 hour.
Because the temperature of digestion reaction is very high, can therefore after digestion is finished, need wait a mement more than 300 ℃ usually, treat to carry out next step operation again after filtrate is cooled off a little, also can add low amounts of water and prevent to cool off back ammonium sulfate and form crystal and be difficult for dissolving.
F) pipette the filtrate that obtains behind the constant volume, add NaOH solution, measure the first equilibrium potential value
Step f) and step g) are adding NaOH solution and NH for measuring postdigestive filtrate
4 +The step of the equilibrium potential value behind the standard solution, the difference in conjunction with two equilibrium potential values that record can calculate non-protein nitrogen content in the tobacco like this.
This step measurements be the first equilibrium potential value.
G) add NH
4 +Solution is measured the second equilibrium potential value; Calculate non-protein nitrogen content in the tobacco in conjunction with the first equilibrium potential value and the second equilibrium potential value.
This step measurements be the second equilibrium potential value.In conjunction with the first equilibrium potential value and the second equilibrium potential value, can obtain the content of nonprotein nitrogen in the tobacco by specific computing formula.
More than the details in each step of the present invention is illustrated, wherein also narrated some and improved and preferred scheme.
The assay method of non-protein nitrogen content in the tobacco of the present invention, can measure the non-protein nitrogen content in the tobacco rapidly and accurately, on the other hand, the nitrogen content in the method mensuration tobacco of measuring total nitrogen can be utilized, therefore Protein in Tobacco nitrogen content and Protein content can be drawn by calculating.Because the daily monitoring project that is determined as each tobacco enterprise of total nitrogen content in the tobacco is so as long as the detection that utilizes assay method of the present invention to finish non-protein nitrogen content in the tobacco can obtain Protein content in the tobacco.
The present invention passes through to measure non-protein nitrogen content in the tobacco, and again in conjunction with content of total nitrogen in the tobacco, can be easy to calculate Protein content in the tobacco, and the assay method step is few, need not carry out filter residue again and shift, collects operations such as gas and titration; And in the method for existing direct mensuration protein nitrogen, the method among The People's Republic of China's tobacco business standard YC-T 166-2003 for example, need carry out suction filtration handles and filter residue is transferred in the digestion vessel, after protein nitrogen is converted into ammonium sulfate, also need to utilize the highly basic distillation to discharge ammonia, receive with the standard acid solution, back titration, these operation experiments are more complicated and exist than big-difference because of experimenter's difference all.As can be seen, assay method provided by the invention has reduced artificial operate miss, not the content of directly measuring protein nitrogen in the tobacco, but utilize the ammonia gas-sensing electrode method to measure the content that nitrogen in the filtrate is filtered in tobacco digestion back, avoided the carrying out of follow-up complex steps, therefore having reduced artificial operate miss, is the method for non-protein nitrogen content in a kind of mensuration tobacco of simple and effective.
Embodiment
For further understanding the present invention, above-mentioned technical scheme is further elaborated and illustrates below in conjunction with concrete embodiment.
The concrete condition of the reagent of using in following examples sees Table 1, to reagent have specified otherwise except.
Table 1
In the table 1, the AR representative is analyzed pure.
Concrete assay method is:
1) extracts tobacco sample according to the standard GB/T19616-2004 of the People's Republic of China (PRC), tobacco sample is prepared the offal sample, measure moisture in the offal according to the tobacco business standard YC/T31-1996 of the People's Republic of China (PRC);
2) take by weighing about 2g offal, take by weighing precision and be accurate to 0.0001g, placing 100mL (milliliter) concentration is 0.5% acetic acid solution, and heating keeps boiling 15 minutes, filters with no nitrogen qualitative filter paper rapidly, and is that 0.5% acetic acid solution washes sediment with concentration.Merging filtrate, to be cooled after the room temperature constant volume to 200mL.The concentration of described acetic acid solution refers to mass concentration, i.e. mass percent.
3) accurately pipette 10mL filtrate in the 75mL digest tube with transfer pipet, and add 0.1g mercury oxide, 1.0g glazier's salt, 5mL sulfuric acid.Digest tube placed on the digester digest, the digester running parameter is: 100 ℃ keep 1h (hour), 370 ℃ keep 1h.Cold slightly after the digestion, add low amounts of water, cool to room temperature, water are settled to the 75mL scale mark, shake up.Need to prove that the digestion running parameter is 370 ℃ and does not represent the temperature of filtrate also to be 370 ℃.Set instrument parameter being 370 ℃ mainly is in order to keep the filtrate boiling in the digest tube.The mensuration of this temperature also can be other temperature, as long as can guarantee that the carrying out of digestion reaction is just passable.
4) with transfer pipet removing step 3) the digestive juice 10mL that obtains places the 100mL beaker, and beaker is put on the magnetic stirrer, puts into magnetic stirrer in the beaker and mixes son.Accurately add concentration value in 0.1～1.0moL/L scope, precision reaches NaOH solution 10～50mL of 0.01moL/L.Insert ammonia gas-sensing electrode under the situation of electromagnetic agitation, the potential value that reads is the first equilibrium potential value, is designated as E
1Accurately add concentration value again in 0.01～0.5moL/L scope, precision reaches the NH of 0.001moL/L
4 +Standard solution 10～100mL, the potential value that reads under electromagnetic agitation are the second equilibrium potential value, are designated as E
2
In this step, the amount and the NH of the NaOH solution of adding
4 +The amount of standard solution is to do suitable adjustment according to actual test case, and total principle is to make the measurement result error reduce.NH for example
4 +Standard solution can also select practical 1.00 * 10
-2The NH of mol/L
4 +Standard solution.In the process of measuring, E
1And E
2If difference range at 20～50mV (millivolt), the error of measurement result is less, more preferably, E
1And E
2Difference range be 20～50mV.
5) calculate the content of nonprotein nitrogen in the tobacco according to following formula:
In the formula, each alphabetical implication is:
C
S---standard ammonium chloride solution concentration (mol/L)
V
S---standard ammonium chloride solution volume (mL)
V
X---original solution volume (mL)
ΔE＝E
2-E
1(mV)
W---sample quality (g)
6) measure the total nitrogen content of tobacco according to the described method of the tobacco business standard YC/T161-2002 of the People's Republic of China (PRC).
7) calculate Protein content in the tobacco.Computing formula is:
6.25×(t-c)，
Wherein, t represents the measured total nitrogen content of step 6),
C represents the content of the nonprotein nitrogen of measuring in the step 5).
To 16 tobacco samples, each tobacco sample carry out 3 times the test, the non-protein nitrogen content of the tobacco sample of gained the results are shown in Table 2, protein content the results are shown in Table 3.
Table 2 non-protein nitrogen content (mass percent) testing result
Table 3 protein content (mass percent) testing result
In each test, as making a report on data, and the inventor finds that the typical curve related coefficient of testing is all greater than 0.999 at every turn with the mean value of two parallel sample testing results.
Can see that from table 2 data the coefficient of variation of other data is all less than 5% except that a sample.And show more that from the data of table 3 this method repeatability is better, and the coefficient of variation is less than 3%, and the overwhelming majority is all less than 2.4, usually all less than 2.Therefore, meet the requirement of analyzing and testing.
The contrast embodiment
According to the assay method of People's Republic of China (PRC) tobacco business standard YC/T166-2003 tobacco and tobacco product total protein content, above-mentioned 16 tobacco samples are carried out the mensuration of total protein content.What obtain the results are shown in Table 4.Table 4 is the comparison sheet of measured protein content of the present invention and the protein content that utilizes the industry standard assay method to draw.
Table 4
| Sample number into spectrum | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| The inventive method measured value | 7.49 | 11.78 | 9.96 | 8.25 | 10.36 | 9.14 | 10.37 | 9.71 |
| The industry standard measured value | 6.95 | 11.15 | 9.78 | 9.12 | 9.57 | 10.17 | 10.26 | 9.18 |
| Relative deviation, % | 3.72 | 2.73 | 1.10 | 5.01 | 3.96 | 5.35 | 0.55 | 2.82 |
Table 4 (continuing)
| Sample number into spectrum | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
| The inventive method measured value | 10.56 | 9.34 | 10.86 | 10.02 | 4.72 | 6.18 | 6.83 | 8.83 |
| The industry standard measured value | 10.61 | 8.91 | 10.63 | 9.14 | 5.19 | 5.97 | 7.24 | 7.97 |
| Relative deviation, % | 0.25 | 2.36 | 1.36 | 4.58 | 4.71 | 1.73 | 2.94 | 5.12 |
As can be seen from Table 4, the inventive method data measured with utilizing industry standard of utilizing of each sample contrast, and the relative deviation of every pair of data is all less than 6%.Utilizing 16 measured data of the inventive method as one group, utilizing 16 measured data of industry standard as one group, adopt the t check in the mathematical statistics method that these two groups of data are analyzed, obtaining the t value is 1.082, less than the value of tabling look-up t (0.1,15), t (0.1,15)=1.753.In 90% fiducial interval, two groups of data do not have evident difference as can be seen, therefore reach a conclusion: can adopt assay method provided by the present invention to replace original classical detection method.
More than technical scheme provided by the present invention is described in detail.Used specific embodiment in this instructions principle of the present invention and embodiment have been set forth, for one of ordinary skill in the art, according to the thought of the present invention part that may in implementation process, can change in specific embodiments and applications.Therefore, the content of this instructions record should not be construed as limitation of the present invention.
Claims (10)
1, one grow tobacco in the assay method of non-protein nitrogen content, comprise the steps:
A) take by weighing tobacco;
B) tobacco that takes by weighing is put into the acid or the copper-bath of capacity, be heated to protein and solidify fully;
C) filter and wash and leach thing with acid described in the step b) or copper-bath;
D) merging filtrate and constant volume;
E) get filtrate and carry out digestion process, constant volume;
F) pipette the filtrate that obtains behind the constant volume, add Na0H solution, measure the first equilibrium potential value;
G) add NH
4 +Solution is measured the second equilibrium potential value; Calculate non-protein nitrogen content in the tobacco in conjunction with the first equilibrium potential value and the second equilibrium potential value.
2, assay method according to claim 1 is characterized in that, the acid described in the step b) is organic acid.
3, assay method according to claim 2 is characterized in that, organic acid described in the step b) is an acetate, and concentration is 0.4%～0.6%.
4, assay method according to claim 3 is characterized in that, is heated to protein described in the step b) and solidifies and to be entirely, and is heated to the acetate boiling and keeps more than 15 minutes.
5, assay method according to claim 1 is characterized in that, digestive pharmaceutical comprises catalyzer and oxidizing substance in the step e) digestion process.
6, assay method according to claim 5 is characterized in that, described catalyzer is selected from mercury and compound, selenium and compound thereof, copper and compound thereof, perhaps their combination.
7, assay method according to claim 5 is characterized in that, described oxidizing substance is a sulfuric acid, and described digestive pharmaceutical also comprises flux, and described digestion process is: be heated to boiling, and keep more than 0.5 hour.
8, assay method according to claim 7 is characterized in that, described flux is selected from salicylic acid, glazier's salt or their combination.
9, assay method according to claim 1 is characterized in that, the difference of the described first equilibrium potential value and the second equilibrium potential value is 20～50mV.
10, assay method according to claim 9 is characterized in that, the difference of the described first equilibrium potential value and the second equilibrium potential value is 30～40mV.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565425A (en) * | 2011-12-30 | 2012-07-11 | 广东中烟工业有限责任公司 | Method for measuring protein nitrogen content in tobaccos |
| CN111505097A (en) * | 2020-06-12 | 2020-08-07 | 上海烟草集团有限责任公司 | Electrochemical method for measuring nicotine content in tobacco and tobacco related products |
-
2008
- 2008-09-03 CN CNA2008101475869A patent/CN101382516A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102565425A (en) * | 2011-12-30 | 2012-07-11 | 广东中烟工业有限责任公司 | Method for measuring protein nitrogen content in tobaccos |
| CN111505097A (en) * | 2020-06-12 | 2020-08-07 | 上海烟草集团有限责任公司 | Electrochemical method for measuring nicotine content in tobacco and tobacco related products |
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