CN113720937B

CN113720937B - Method for measuring content of cooling agent in electronic smoke sol

Info

Publication number: CN113720937B
Application number: CN202111005032.7A
Authority: CN
Inventors: 邹军; 邹阳; 刘梅森; 皮胜涛
Original assignee: Shenzhen Zinwi Biotech Co Ltd
Current assignee: Shenzhen Zinwi Biotech Co Ltd
Priority date: 2021-08-30
Filing date: 2021-08-30
Publication date: 2023-06-27
Anticipated expiration: 2041-08-30
Also published as: CN113720937A

Abstract

The application relates to the technical field of content determination of cooling agents, in particular to a method for determining the content of cooling agents in electronic smoke sol. The method for measuring the content of the cooling agent in the electronic smoke sol adopts a mode of combining a smoking machine and a filter disc to capture the cooling agent in the electronic smoke sol, then obtains an extraction solution through oscillation extraction, quantitatively analyzes the content of an object to be measured in the extraction solution by using gas chromatography and an internal standard method, and has higher sensitivity, accuracy and precision. The method for determining the content of the novel cooling agents such as WS-3, WS-23 and the like in the electronic smoke sol is established, the technical blank in the field is filled, and the method has guiding significance for making an industry standard determination method for the content of the cooling agents in the electronic smoke sol.

Description

Method for measuring content of cooling agent in electronic smoke sol

Technical Field

The application relates to the technical field of content determination of cooling agents, in particular to a method for determining the content of cooling agents in electronic smoke sol.

Background

The cooling agent is a general name of all chemical substances which can generate cooling effect and have weak drug properties, and has very wide application in foods such as chewing gum, beverage and the like, daily chemicals such as toothpaste, mouthwash, toilet water and the like. The cooling agent is added into the electronic cigarette oil, so that the electronic cigarette has cool taste during smoking. The most common cooling agent is menthol, but is not suitable for use in large amounts due to its strong smell and strong irritation to skin, mucosal tissue and eyes. Therefore, the novel cooling agents WS-3 (menthol amide) and WS-23 (2-isopropyl-N, 2, 3-trimethyl butyramide) are often added into the electronic cigarette tar, and the WS-3 and WS-23 can enable smokers to obtain mild, fresh, rich and durable cooling feeling.

However, the content of the cooling agent is too high, which may cause harm to human health, so that the content of the cooling agent in the electronic smoke sol inhaled by a human body needs to be controlled, and the quality control and risk assessment can be facilitated by measuring the content of the cooling agent in the electronic smoke sol. Regarding the determination of the content of the cooling agent, the content of the cooling agent in food and daily chemicals is mainly determined by gas chromatography-mass spectrometry at present in China. However, the components of the electronic cigarette oil are complex, and new substances may be generated in the heating and atomizing process, which causes great interference to the measurement of the content of the cooling agent in the electronic cigarette aerosol, and more accurate test data are difficult to obtain. The determination of the novel cooling agent in the electronic smoke sol is not reported in the literature at present, and no formal national standard exists in China for detecting the cooling agent in the electronic smoke sol and limiting the dosage of the cooling agent, so that the establishment of a proper method for determining the content of the novel cooling agent such as WS-3, WS-23 and the like in the electronic smoke sol becomes a very urgent problem in the current cooling agent research.

Disclosure of Invention

In order to determine the content of the cooling agent in the electronic smoke sol, the application provides a determination method of the content of the cooling agent in the electronic smoke sol.

The method for measuring the content of the cooling agent in the electronic smoke sol adopts the following technical scheme: the method for measuring the content of the cooling agent in the electronic smoke sol is characterized by comprising the following steps of:

and (3) flue gas collection: adding test tobacco tar into the electronic cigarette atomizer, arranging a filter disc between a smoking machine and the electronic cigarette atomizer, extracting electronic smoke sol generated by atomizing the tobacco tar by the electronic cigarette atomizer through the smoking machine, and capturing an object to be detected in the electronic smoke sol by using the filter disc;

preparing an internal standard solution: quinoline is used as an internal standard substance, and alcohol substances are used as solvents to prepare a quinoline standard solution;

extracting an object to be detected: placing a filter disc of the electronic smoke sol which is collected in a smoke collection way into a quinoline standard solution, oscillating to extract an object to be detected, and filtering the oscillated solution to obtain an extraction solution;

preparing a standard solution: preparing a series of standard solutions containing WS-23 and WS-3, wherein the concentration of quinoline in the series of standard solutions is the same as that of the quinoline standard solution, and the solvents of the series of standard solutions are the alcohols;

and (3) analysis and calculation: and detecting the series of standard solutions and the extracting solutions by using a gas chromatograph, and analyzing and calculating the content of the to-be-detected object in the electronic smoke sol.

Through the technical scheme, the electronic smoke sol enters the smoking machine through the electronic smoke atomizer, the filter disc on the filter is in contact with the electronic smoke sol, the filter disc can fully absorb the cooling agent in the electronic smoke sol, the cooling agent on the filter disc is extracted by using the quinoline standard solution, the extraction solution is obtained after filtration, and finally the gas chromatograph is used for detecting the extraction solution, and the content of an object to be detected in the extraction solution is analyzed and calculated by using an internal standard method; the signal peak of the internal standard quinoline is positioned between the signal peaks of WS-23 and WS-3, the chromatographic behavior of the quinoline and two substances to be detected is similar during detection and analysis, the influence of the split spectrum discrimination on the analysis is small, the signal peak of the quinoline and the two substances to be detected are obviously separated, the peak area is convenient to accurately calculate, and the accuracy of measurement is improved; the solubility of the quinoline and the object to be detected in the selected alcohol substances is good, the separation degree of the solvent peak of the selected alcohol substances, the peak of the object to be detected and the peak of the quinoline is good, and the influence on the analysis result is small; the ordinate of the standard curve manufactured by the internal standard method is the ratio of the peak area of the object to be detected to the peak area of the internal standard object, so that errors caused by the change of the operation conditions are eliminated to a certain extent during analysis, and the accuracy of the method is improved; the gas chromatography is used for analysis and detection, so that the method has high sensitivity and accuracy, high separation efficiency, high analysis speed and low cost.

Optionally, the smoking parameters of the smoking machine are set to: the suction capacity of each port is 55.0 mL+/-0.3 mL, the suction duration of each port is 3.0 s+/-0.1 s, and the suction interval time is 30.0 s+/-0.5 s; the aerosol from each 20 mouths of suction is captured on the same filter.

By adopting the technical scheme, the suction capacity is determined to be 55.0 mL/port, the suction duration is determined to be 3 s/port, and the suction frequency is determined to be 30 s+/-0.5 s, so that the actual condition of the smoker when sucking the electronic cigarette is convenient to simulate, the detection and cognition standards are unified, and the subsequent quality control and risk assessment are convenient.

Optionally, in the step of capturing the flue gas, the rough surface of the filter disc is used as an electronic flue gas sol contact surface.

By adopting the technical scheme, the rough surface of the filter disc contacts the electronic smoke sol, so that the contact area of the filter disc and the electronic smoke sol is increased, and the filter disc is favorable for capturing objects to be detected.

Optionally, the alcohol is selected from any one of methanol, ethanol and isopropanol.

By adopting the technical scheme, the solubility of the object to be detected and the quinoline in methanol, ethanol or isopropanol is good, the separation degree of the solvent peak from the object to be detected and the quinoline peak is good, and the influence on the analysis result is small.

Optionally, the oscillation rate in the extraction step of the object to be detected is 200-300r/min.

By adopting the technical scheme, the extraction effect is good when the oscillation rate is 200-300r/min, the oscillation rate is too low, and the extraction of the object to be detected is incomplete, so that the accuracy of the detection result can be influenced; the oscillation rate is too high, and the object to be detected is easily adsorbed on the inner wall of the container, so that the concentration of the object to be detected in the solution is reduced, and the accuracy of a detection result is affected.

Optionally, the oscillation time in the extraction step of the object to be detected is more than 30min.

By adopting the technical scheme, the incomplete extraction can be caused by the too short oscillation time, and when the oscillation time is 30min, substances on the filter disc can be completely extracted, so that the detection efficiency is improved.

Optionally, the shaken solution is filtered with an organic filter.

Through adopting above-mentioned technical scheme, the thing of awaiting measuring and quinoline can pass through organic filter membrane, and other small granule impurity can be filtered by organic filter membrane and get rid of, are favorable to protecting the chromatographic column, reduce the washing and the maintenance degree of difficulty of instrument, prolong the life of instrument.

Optionally, the split ratio of the gas chromatograph sample injection is 10:1-20:1.

By adopting the technical scheme, the object to be detected can reach the response value of the instrument, and is beneficial to protecting the chromatographic column; the split ratio is small, the content of a sample entering the chromatographic column is high, the chromatographic column is easy to overload, the separation efficiency is reduced, the peak tailing is deformed, the chromatographic column is difficult to clean, and the service life of the chromatographic column is seriously influenced; the split ratio is large, the content of the sample entering the chromatographic column is low, the response value of the instrument is not reached or is smaller, and the accuracy of the detection result is affected.

In summary, the present application has the following beneficial effects:

1. the method quantitatively analyzes the content of the object to be detected in the extraction solution by adopting the gas chromatography and an internal standard method, has higher accuracy and precision, has high separation efficiency, high analysis speed and low cost, eliminates errors caused by the change of the operation conditions to a certain extent, and improves the detection accuracy.

2. According to the method, the cooling agent in the electronic smoke sol is trapped in a mode of combining the smoking machine and the filter disc, so that the electronic smoke sol completely flows through the filter disc in a closed environment, objects to be detected can be fully trapped by the filter disc, pretreatment conditions are optimized, the trapping rate of the objects to be detected in the electronic smoke sol is improved, and the accuracy of a detection method is further improved; in addition, the method for extracting the object to be detected on the filter disc by using the oscillation extraction method is high in extraction efficiency and good in extraction effect.

3. The method for determining the content of the novel cooling agents such as WS-3, WS-23 and the like in the electronic smoke sol is established, the technical blank in the field is filled, and the method has guiding significance for making an industry standard determination method for the content of the cooling agents in the electronic smoke sol.

Drawings

FIG. 1 is a gas chromatogram of a standard solution having concentrations of WS-23 and WS-3 of 2 mg/L.

Fig. 2 is a gas chromatogram of an extraction solution of a tobacco tar a aerosol.

Detailed Description

The present application is described in further detail below with reference to the drawings and examples. The specific description is as follows: the following examples were conducted under conventional conditions or conditions recommended by the manufacturer, and the raw materials used in the following examples, except for the specific descriptions, were all commercially available, and the volume vessels used in the following examples were all washed with 10% ethanol and with deionized water, and then dried in the air.

Example 1

The method for measuring the content of the cooling agent in the electronic smoke sol comprises the following steps of:

and (3) flue gas collection: and preheating a smoking machine, and adding the test tobacco tar A into the electronic cigarette atomizer. After the atomization core is completely wetted by the tobacco tar A, the filter disc is arranged in the filter of the smoking machine, the rough surface of the filter disc is used as a smoke contact surface, the filter is connected with the electronic smoke atomizer, the filter is connected to the smoking machine after the smoking machine is preheated for 20min, and the to-be-detected objects in the electronic smoke sol are trapped.

Smoking parameter settings of the smoking machine: the suction curve is square wave, the suction capacity is 55.0 mL/port, the suction duration is 3 s/port, the suction frequency is 30s, the suction is divided into 5 series of suction, the number of times of each series of suction is 20, namely, aerosol of 20 ports is captured on the same filter sheet, the interval time of each series is 300s, the maximum flow is 18.5mL/s, the pressure difference is 50hPa, and the total capture of 100 ports of electronic smoke sol is realized.

Preparing an internal standard solution: accurately weighing 0.1g of quinoline standard substance in a 10mL volumetric flask, fixing the volume to the scale with isopropanol, and fully and uniformly mixing by a vortex mixer to obtain a quinoline standard solution with the concentration of 10000 mg/L; accurately transferring 10 mu L of quinoline standard solution with the concentration of 10000mg/L into a 10mL volumetric flask, fixing the volume to the scale by isopropanol, and fully shaking to prepare the quinoline standard solution with the concentration of 10 mg/L.

Extracting an object to be detected: the filter sheet after trapping the electron-fume sol was placed in a 100mL Erlenmeyer flask, and then 20mL of a 10mg/L quinoline standard solution was added, and then the 100mL Erlenmeyer flask was placed on a platform shaker and shaken at a rate of 250r/min for 30min. 2mL of the shaken solution was filtered through a 0.45 μm organic filter to obtain an extract solution.

Preparing a standard solution:

(1) Accurately weighing 0.1g of WS-23 standard substance in a 10mL volumetric flask, fixing the volume to the scale with isopropanol, and fully and uniformly mixing by a vortex mixer to prepare WS-23 standard solution with the concentration of 10000 mg/L. Accurately weighing 0.1g of WS-3 standard substance in a 10mL volumetric flask, fixing the volume to the scale with isopropanol, and fully and uniformly mixing by a vortex mixer to prepare WS-3 standard solution with the concentration of 10000 mg/L.

(2) Accurately transferring 0.1mL of each of WS-23 and WS-3 standard solutions with the concentration of 10000mg/L into a 10mL volumetric flask, adding 0.01mL of quinoline standard solution with the concentration of 10000mg/L, fixing the volume to a scale by isopropanol, and fully and uniformly mixing by a vortex mixer to obtain a mixed standard solution.

(3) Accurately transferring 0.2mL, 0.5mL, 1.0mL, 2.5mL and 5.0mL standard solutions to a 10mL volumetric flask, fixing the volume to the scale by using a 10mg/L quinoline standard solution, and fully and uniformly mixing by using a vortex mixer to prepare series standard solutions of which the concentrations of WS-23 and WS-3 are 2mg/L, 5mg/L, 10mg/L, 25mg/L and 50 mg/L.

And (3) analysis and calculation:

(1) Detection was performed using an Agilent8860 gas chromatograph, the detector being a hydrogen Flame Ionization Detector (FID).

Chromatographic conditions:

chromatographic column: DB-WAXUI with a size of 30m 0.25mm 0.25 μm;

heating program: the initial column temperature is 80 ℃, the column stays for 3min, the temperature is increased to 150 ℃ at 10 ℃/min, and the column stays for 2min; heating to 220 ℃ at 20 ℃/min, and keeping for 5min;

air flow rate: 400mL/min;

hydrogen flow rate: 30mL/min;

tail blow flow (N2): 25mL/min;

carrier gas flow (N2): 3mL/min;

sample inlet temperature: 245 ℃;

detector temperature: 250 ℃;

sample injection mode: the split ratio is 20:1;

sample injection amount: 1uL.

And (3) performing a blank experiment by using a quinoline standard solution, and detecting the quinoline standard solution and a series of standard solutions to obtain a gas chromatogram. As shown in FIG. 1, the signal peak of the quinoline is positioned between the signal peaks of WS-23 and WS-3, and the quinoline has similar chromatographic behavior with two coolants during analysis, and the influence of the split discrimination on the analysis is small, so that the measurement accuracy is improved. Retention time and peak area data of the test object and quinoline were read and recorded in table 1. The expected retention time for WS-23 was 11.379min, WS-3 was 15.454min, and quinoline was 12.670min.

TABLE 1

Data processing is carried out by using data analysis software matched with an Agilent8860 gas chromatograph, the detection results of the series of standard solutions are drawn into standard curves, and the obtained regression equation and the correlation coefficient R2 are shown in table 2. Wherein X is the concentration of an object to be detected, and the unit is mg/L; y is the ratio of the peak area of the object to be detected to the peak area of quinoline, and is dimensionless. As can be seen from Table 2, the regression equation correlation coefficients R2 of the two cooling agents are 0.9998 and 0.9999, respectively, and the concentration X of the analyte and the ratio Y of the peak area of the analyte to the peak area of the quinoline have excellent linear correlation.

TABLE 2

Project name	Regression equation	Correlation coefficient (R) ² )
			WS-23	Y＝0.0792X+0.0076	0.9998
WS-3	Y＝0.0887X-0.0044	0.9999

The extraction solution of tobacco tar A aerosol is detected to obtain a gas chromatogram, as shown in figure 2. As can be seen from fig. 2, the substance components in the electronic smoke sol are very complex, so that the measurement difficulty of the object to be measured is increased. The same method was used to detect the extraction solutions of aerosol of tobacco tar B and tobacco tar C. Retention time and peak area data of the test object and quinoline were read and recorded in table 3.

(2) Calculating to obtain the concentration CS of the object to be detected in the extracting solution by using a regression equation, and recording the concentration CS in the table 3;

(3) The content X of the test substance in the aerosol was calculated using the following formula and recorded in table 3:

x is the content of an object to be detected in the aerosol, and the unit is milligrams per hundred mouths (mg/100 mouths);

CS is the concentration of the analyte in the extraction solution in milligrams per liter (mg/L);

cblk is the concentration of the analyte in milligrams per liter (mg/L) in the blank;

v is the volume of the extraction solution in milliliters (mL);

d is dilution multiple of the extraction solution;

1000 is a unit conversion coefficient.

TABLE 3 Table 3

In the electronic cigarette industry, the content of substances in the electronic smoke sol is generally described by adopting the class of mg/50 mouth, mg/100 mouth or mg/200 mouth, so that in other embodiments, the pumping frequency can be set to be 50 or 200, and correspondingly, mg/50 mouth or mg/200 mouth is used as the unit of the content of the substances to be detected in the aerosol.

Example 2

Methodology evaluation test limit of detection: the detection limit of the object to be detected is determined by the signal to noise ratio (S/N) of more than or equal to 3, the detection limit of WS-23 is 0.5mg/L, and the detection limit of WS-3 is 0.3mg/L, which is favorable for the detection of two cooling agents with lower concentration.

Accuracy: one labeled sample was taken and repeated 10 times to obtain 10 results of parallel repeated experiments, which are recorded in table 4, and the Relative Standard Deviation (RSD) was calculated. As shown in Table 4, the method has a RSD of 1.20% for the quantitative analysis WS-23 and a RSD of 1.76% for the analysis WS-3, which meet the evaluation requirements, and thus has higher accuracy.

TABLE 4 Table 4

Accuracy: 5mg/L of standard solution was added to the extraction solution of the tobacco tar A aerosol, 10mg/L of standard solution was added to the extraction solution of the tobacco tar B aerosol, 30mg/L of standard solution was added to the extraction solution of the tobacco tar C aerosol, and the results were recorded in Table 5 in parallel.

TABLE 5

As can be seen from Table 5, the average recovery rates of WS-23 and WS-3 were 102.95% and 96.98%, respectively, which satisfy the recovery rate requirements, so that the method has higher accuracy for the measurement of the contents of WS-23 and WS-3.

The average recovery of WS-23 at low concentration was 98.60% closest to 100%, whereas the average recovery of WS-23 at medium and high concentrations was 105.25% and 105.00%, respectively, which are relatively far apart from 100%, so that the method is more suitable for measurement at lower WS-23 concentrations. Similarly, the average recovery of WS-3 at high concentrations was 100.15% closest to 100%, whereas the average recovery of WS-3 at low and medium concentrations was 97.55% and 93.24%, respectively, which were relatively far apart from 100%, so that the method was more suitable for the determination of higher WS-3 concentrations.

The present embodiment is merely illustrative of the present application and is not intended to be limiting, and those skilled in the art, after having read the present specification, may make modifications to the present embodiment without creative contribution as required, but is protected by patent laws within the scope of the claims of the present application.

Claims

1. The method for measuring the content of the cooling agent in the electronic smoke sol is characterized by comprising the following steps of:

the cooling agent is menthol amide and 2-isopropyl-N, 2, 3-trimethyl butyramide;

the alcohol substance is selected from any one of methanol, ethanol and isopropanol;

extracting an object to be detected: placing a filter disc of the electronic smoke sol which is collected in a smoke collection way into a quinoline standard solution, oscillating to extract an object to be detected, and filtering the oscillated solution by using an organic film to obtain an extraction solution; wherein the oscillation rate is 200-300r/min, and the oscillation time is more than 30 min;

and (3) analysis and calculation: detecting serial standard solutions and extracting solutions by using a gas chromatograph, wherein the detector is a hydrogen flame ionization detector, the temperature rise program is that the initial column temperature is 80 ℃, the temperature is kept for 3min, the temperature is increased to 150 ℃ at 10 ℃/min, the temperature is kept for 2min, the temperature is increased to 220 ℃ at 20 ℃/min, the temperature is kept for 5min, and the content of an object to be detected in the electronic smoke sol is analyzed and calculated;

the chromatographic column adopted is as follows: DB-WAX UI,30m 0.25mm 0.25um, polar column.

2. The method for determining the content of cooling agents in an electronic aerosol according to claim 1, wherein the smoking parameters of the smoking machine are set as follows: the suction capacity of each port is 55.0 mL+/-0.3 mL, the suction duration of each port is 3.0 s+/-0.1 s, and the suction interval time is 30.0 s+/-0.5 s; the aerosol from each 20 mouths of suction is captured on the same filter.

3. The method for determining the content of cooling agents in an electronic aerosol according to claim 1, wherein the step of trapping the fumes is characterized in that a rough surface of the filter is used as a contact surface of the electronic aerosol.

4. The method for determining the content of the cooling agent in the electronic smoke sol according to claim 1, wherein the split ratio of the gas chromatograph sample injection is 10:1-20:1.