Method for determining phenol compounds in electronic atomized liquid or aerosol of electronic atomized liquid and application of method

Abstract

The invention discloses a method for determining phenol compounds in electronic atomized liquid or aerosol thereof and application of the method, and belongs to the field of electronic atomized liquid analys.The method comprises the steps that a sample solution of the electronic atomized liquid or aerosol thereof is purified through a solid-phase extraction column, a silanization derivatization reagent is added into the purified solution for treatment, and then the sample solution is obtained; and carrying out gas chromatography-tandem mass spectrometry (GC-MS) analysis on the silanization derivative product, and detecting the phenol compounds. According to the method, phenol compounds are separated from main components, namely propylene glycol and glycerol matrixes, of the electronic atomized liquid through a solid-phase extraction method, interference on the phenol compounds is removed, N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA) achieves complete derivation on the seven phenol compounds, and the purity of the phenol compounds is improved. The content of the phenol compounds in the electronic atomized liquid and the aerosol can be accurately determined.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic atomization liquid analysis, and particularly relates to a method for determining phenolic compounds in electronic atomization liquid or its aerosol and its application. Background Art

[0002] Electronic cigarettes are a new type of nicotine delivery system, and the chemical components in their atomization liquid and aerosol are key monitoring indicators for regulatory agencies in various countries. Phenol, cresol (o-, m-, p-cresol), hydroquinone (o-, m-, p-hydroquinone), etc. belong to a class of harmful and potentially harmful components (HPHCs). They have pungent odors and can also cause strong irritation and carcinogenic effects on the skin and respiratory mucosa. These phenolic compounds are included in the list of 46 harmful components in tobacco by the Canadian government and are listed in the list of recommended regulated components by the "Tobacco Products Control Research Group" of the WHO.

[0003] Currently, the methods for determining phenolic compounds in electronic atomization liquid or its aerosol include high-performance liquid chromatography and ultra-high-performance liquid chromatography-tandem mass spectrometry, but neither can separate m-cresol and p-cresol, and their peak emergence times are exactly the same. The principle of the silylation derivatization reaction is to introduce silyl groups to replace active hydrogens into the molecule, change the polarity of the compound, and at the same time enhance the volatility and stability, which can achieve the separation of isomers.

[0004] Some researchers have used N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) to perform silylation treatment on the mainstream smoke of cigarettes. Although it can achieve the complete separation of various phenolic compounds, when the inventor uses the same method to perform silylation treatment on electronic atomization liquid and its aerosol, it is found that the interference is very large, and accurate quantification cannot be carried out. Moreover, the separation time of this method is nearly 30 minutes, which cannot meet the existing detection requirements.

[0005] For the determination of phenolic compounds in electronic atomization liquid or its aerosol, how to achieve the complete separation of various phenolic compounds is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] Purpose of the Invention

[0007] To overcome the above deficiencies, the purpose of the present invention is to provide a method for determining phenolic compounds in electronic atomization liquid or its aerosol and its application. The present invention realizes the separation of phenolic compounds from the main components of electronic atomization liquid, namely propylene glycol and glycerol matrix, by solid-phase extraction, removes the interference to phenolic compounds, enables N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) to completely derivatize 7 phenolic compounds, and can accurately determine the content of phenolic compounds in electronic atomization liquid and aerosol.

[0008] Solution

[0009] To achieve the object of the present invention, the technical solution adopted by the present invention is as follows:

[0010] In a first aspect, the present invention provides a method for determining phenolic compounds in an e-liquid or its aerosol. A sample solution of the e-liquid or its aerosol is purified through a solid-phase extraction column, a silylation derivatization reagent is added to the purified solution for treatment, and the silylation derivatization product is analyzed by gas chromatography-tandem mass spectrometry (GC-MS) to detect phenolic compounds.

[0011] Further, the solid-phase extraction column is an HLB Pro solid-phase extraction column or a PSD polystyrene divinylbenzene solid-phase extraction column;

[0012] Further, the solid-phase extraction column is activated before use. Optionally, the activation method includes sequentially activating with ethyl acetate, methanol, and water; optionally, the amounts of ethyl acetate, methanol, and water are 1-2 times the column volume;

[0013] Further, the purification of the solid-phase extraction column includes: loading and sampling the sample solution, rinsing, eluting, and collecting the eluate; optionally, water is used for rinsing; optionally, ethyl acetate is used for eluting.

[0014] Further, the silylation derivatization reagent includes N,O-bis(trimethylsilyl)trifluoroacetamide;

[0015] Optionally, the amount of the silylation derivatization reagent: 10-200 μL of the silylation derivatization reagent is added to each 1 mL of the purified solution; optionally, 15-100 μL of the silylation derivatization reagent is added to each 1 mL of the purified solution; optionally, 20-100 μL of the silylation derivatization reagent is added to each 1 mL of the purified solution; optionally, 20-50 μL of the silylation derivatization reagent is added to each 1 mL of the purified solution.

[0016] Further, the silylation derivatization conditions include:

[0017] The derivatization temperature is 30-70 °C, optionally 30-50 °C, optionally 50 °C;

[0018] and / or, the derivatization time is 10-60 min, optionally 10-30 min, optionally 30 min;

[0019] And / or, the dosage of the silylation derivatization reagent: 10 - 200 μL of the silylation derivatization reagent is added to every 1 mL of the purification solution; optionally, 15 - 100 μL of the silylation derivatization reagent is added to every 1 mL of the purification solution; optionally, 20 - 100 μL of the silylation derivatization reagent is added to every 1 mL of the purification solution; optionally, 20 - 50 μL of the silylation derivatization reagent is added to every 1 mL of the purification solution.

[0020] Further, the preparation of the electronic atomization liquid sample solution includes: adding 10 - 50 mL of water to every 1 g of the electronic atomization liquid, optionally 10 - 30 mL of water, optionally 10 - 20 mL of water.

[0021] Further, the preparation of the sample solution of the aerosol of the electronic atomization liquid includes: sucking with an electronic cigarette smoking machine, adding the sucked filter disc to water and shaking, optionally, the added amount of water is 10 - 50 mL, optionally 10 - 30 mL, optionally 10 - 20 mL;

[0022] Optionally, the sucking method includes: ISO sucking mode, sucking volume 55 mL, sucking time 3 s, interval time 27 s, sucking 100 puffs.

[0023] Further, the phenolic compounds include at least one of phenol, o - cresol, m - cresol, p - cresol, catechol, resorcinol, and hydroquinone.

[0024] Further, the chromatographic column used in gas chromatography - tandem mass spectrometry analysis is a (5% - phenyl) - methyl polysiloxane capillary column; and / or, the mass spectrometry ion source used in gas chromatography - tandem mass spectrometry analysis is an EI source, and the scanning mode is selected ion monitoring mode;

[0025] Optionally, the conditions of the chromatographic column include: the inlet temperature is 250 °C, the split ratio is 10:1, the carrier gas is helium, the temperature - rising program: hold at 80 °C for 1 min, raise the temperature to 200 °C at a rate of 10 °C / min, then raise the temperature to 250 °C at a rate of 30 °C / min, and hold for 8 min; optionally, the injection volume is 0.5 μL, and optionally, the constant flow rate of the carrier gas is 1.0 mL / min;

[0026] Optionally, the mass spectrometry conditions include: the transfer line temperature is 250 °C, the ion source temperature is 230 °C, and the monitoring time for each ion is 100 ms.

[0027] In the second aspect, a method for evaluating the safety of electronic cigarettes with respect to phenolic compounds is provided. The phenolic compounds in the electronic atomization liquid or its aerosol are detected by the method described in the first aspect, and whether the content of the phenolic compounds meets the safety index is evaluated.

[0028] In a third aspect, an analysis system for evaluating the safety of phenol compounds in electronic cigarettes is provided. The content of phenol compounds in the e-liquid or its aerosol is detected by the method described in the first aspect, and an evaluation result of whether the content of phenol compounds meets the safety index is output.

[0029] Advantageous Effects

[0030] In the present invention, phenol compounds are separated from the main components of e-liquid, propylene glycol and glycerol matrix, by solid-phase extraction method, removing the interference to phenol compounds, and achieving complete derivatization of phenol compounds, so as to accurately determine the content of phenol compounds in e-liquid and aerosol. In the present invention, N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) is used for silylation derivatization of 7 kinds of phenol compounds (phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol, hydroquinone), and complete separation can be achieved within 10 minutes, with fast analysis speed, good resolution, good peak shape, high response, high sensitivity and low detection limit. Description of the Drawings

[0031] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not constitute a limitation on the embodiments. The special word "exemplary" here means "serving as an example, an embodiment or an illustration". Any embodiment described as "exemplary" here does not have to be interpreted as superior to or better than other embodiments.

[0032] Figure 1 This is the total ion current chromatogram of the full scan of the phenol compound standard in Detection Example 1 of the present invention.

[0033] Figure 2 This is the standard curve graph of phenol of the present invention.

[0034] Figure 3 This is the standard curve graph of o-cresol of the present invention.

[0035] Figure 4 This is the standard curve graph of m-cresol of the present invention.

[0036] Figure 5 This is the standard curve graph of p-cresol of the present invention.

[0037] Figure 6 This is the standard curve graph of catechol of the present invention.

[0038] Figure 7 This is the standard curve graph of resorcinol of the present invention.

[0039] Figure 8 This is the standard curve graph of hydroquinone of the present invention.

[0040] Figure 9 This invention relates to the superposition comparison chart of the selected ion flow chromatograms of phenolic compounds and their standards in Detection Example 2. The blue line represents the chromatogram of the tobacco-flavored e-liquid after solid-phase extraction detected in Example 2; the black line represents the phenolic standard (2 ppm).

[0041] Figure 10 This invention relates to the superposition comparison chart of the selected ion flow chromatograms of phenolic compounds and their standards in Detection Example 3. The blue line represents the chromatogram of the tobacco-flavored e-liquid after solid-phase extraction detected in Example 3; the black line represents the phenolic standard (2 ppm).

[0042] Figure 11 This invention relates to the full-scan total ion flow chromatogram obtained by detecting phenolic compounds in Comparative Example 1.

[0043] Figure 12 This invention relates to the superposition comparison chart of the selected ion flow chromatograms of phenolic compounds obtained by detecting in Example 1 and Comparative Example 2. The blue line represents the chromatogram of the standard detected in Example 1; the black line represents the chromatogram of the standard detected in Comparative Example 2.

[0044] Figure 13 This invention relates to the full-scan total ion flow chromatogram obtained by detecting phenolic compounds in Comparative Example 3.

[0045] Figure 14 This invention relates to the superposition comparison chart of the selected ion flow chromatograms of phenolic compounds and their standards in Comparative Example 4. The blue line represents the chromatogram of the tobacco-flavored e-liquid after solid-phase extraction detected in Comparative Example 4; the black line represents the phenolic standard (2 ppm). Detailed Embodiments

[0046] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0047] In addition, to better illustrate the present invention, numerous specific details are given in the following detailed embodiments. Those skilled in the art should understand that the present invention can still be implemented without some specific details. In some embodiments, details of raw materials, components, methods, means, etc. well-known to those skilled in the art are not described in detail to highlight the gist of the present invention.

[0048] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or variations thereof such as "comprises" or "comprising" etc. will be understood to include the stated element or component, without excluding other elements or other components.

[0049] By first subjecting the e-liquid or its aerosol to solid-phase extraction purification and then performing silane derivatization with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), the present invention can achieve the complete separation of 7 phenolic compounds from the e-liquid or its aerosol, providing technical support for the safe use of e-cigarettes.

[0050] In the research of the present invention, it was found that propylene glycol and glycerol interfere with the separation of phenolic compounds, and it was found through research that solid-phase extraction purification can well avoid the interference.

[0051] The method for determining phenolic compounds in e-liquid and aerosol of the present invention specifically comprises the following steps:

[0052] (1) Preparation of e-liquid sample solution: Weigh the e-liquid sample into a 15 mL centrifuge tube, add water, shake for 10 - 20 min, and wait for purification;

[0053] (2) Preparation of aerosol sample solution of e-liquid: Connect the smoking device filled with e-liquid, the trap equipped with a Cambridge filter, and the e-cigarette smoking machine in sequence, aspirate the e-liquid sample according to the ISO aspiration mode, place the aspirated Cambridge filter in a 50 mL centrifuge tube, add water, shake for 10 - 20 min, and wait for purification; The aspiration mode can be an aspiration volume of 55 mL, an aspiration time of 3 s, and an interval time of 27 s;

[0054] (3) Solid-phase extraction purification: First, activate the solid-phase extraction column (preferably HLB Pro solid-phase extraction column), then load and sample the sample solution in (1) in the solid-phase extraction column, wash with water, vacuum dry, elute with the eluent, and collect the eluent for use; Among them, the solid-phase extraction column is activated with ethyl acetate, methanol, and water in sequence, and the eluent is ethyl acetate;

[0055] (4) Preparation of standard solution: Weigh a certain amount of phenolic compound standards (including phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol, hydroquinone) into a volumetric flask, add an organic solvent (such as ethyl acetate) to make up the volume, shake well, and prepare a series of phenolic compound standard solutions for use;

[0056] (5) Silanization Derivatization: Take 1 mL of the purified solution or 1 mL of the standard solution in a sample bottle, add a silanization derivatization reagent (such as N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). The reactive group for silanization derivatization is the trimethylsilyl group, and BSTFA contains two trimethylsilyl groups), and place it in a water bath atmosphere (30 - 70 °C) for a derivatization reaction for 10 - 60 min to obtain a silanized derivative product;

[0057] (6) Instrumental Analysis: The silanized derivative product is placed in a gas chromatography-tandem mass spectrometer, and the content of phenolic compounds is determined and analyzed by gas chromatography-tandem mass spectrometry. The chromatographic column conditions for gas chromatography-tandem mass spectrometry analysis are as follows: The chromatographic column is a (5%-phenyl)-methyl polysiloxane capillary column (HP-5MS UI), the inlet temperature is 250 °C, the injection volume is 0.5 μL, the split ratio is 10:1, the carrier gas is helium, the constant flow rate is 1.0 mL / min, and the temperature program is: hold at 80 °C for 1 min, increase the temperature at a rate of 10 °C / min to 200 °C, and then increase the temperature at a rate of 30 °C / min to 250 °C and hold for 8 min; The mass spectrometry conditions are: the transfer line temperature is 250 °C, the ion source is an EI source, the ion source temperature is 230 °C, the scanning mode is selected ion monitoring (SIM) mode, and the monitoring time for each ion is 100 ms.

[0058] In the following examples, the e-liquids used can be purchased from Dongguan Hongfu Biotechnology Co., Ltd., including e-liquids with flavors such as tobacco, mint, fruit, and coffee. They usually contain additives such as glycerin, propylene glycol, and flavors. The e-liquids used below all contain approximately 15% propylene glycol and 47% glycerin (by mass).

[0059] Example 1

[0060] The determination of phenolic compounds specifically includes the following steps.

[0061] (1) Preparation of Standard Solution: Weigh 100 mg of phenolic compound standards (including phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol, hydroquinone) in a 10 mL volumetric flask, add methanol and dissolve by ultrasonic, make up the volume, shake well, and prepare a standard stock solution of phenolic compounds with a concentration of 10 mg / mL; Pipette a certain amount of the standard stock solution and dilute it step by step, add dichloromethane to make up the volume, shake well, and prepare a standard solution of phenolic compounds with a linear range of 0.05 - 2 μg / mL for use;

[0062] (2) Silanization Derivatization: Take 1 mL of the phenol compound standard solution with a concentration of 2 μg / mL in step (1) into a sample bottle, add 20 μL of the silanization derivatization reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and place it in a 50 °C water bath atmosphere for a 30-minute derivatization reaction to obtain a silanized derivative product;

[0063] (3) Instrumental Analysis: Place the silanized derivative product in a gas chromatography-tandem mass spectrometer, and use gas chromatography-tandem mass spectrometry to determine and analyze the content of phenol compounds;

[0064] Among them, the chromatographic column conditions for gas chromatography-tandem mass spectrometry analysis are as follows: The chromatographic column is a (5%-phenyl)-methyl polysiloxane capillary column (HP-5MS UI), the inlet temperature is 250 °C, the injection volume is 0.5 μL, the split ratio is 10:1, the carrier gas is helium, the constant flow rate is 1.0 mL / min, and the temperature programming is as follows: Maintain at 80 °C for 1 minute, increase the temperature at a rate of 10 °C / min to 200 °C, then increase the temperature at a rate of 30 °C / min to 250 °C, and maintain for 8 minutes; The mass spectrometry conditions are as follows: The transfer line temperature is 250 °C, the ion source is an EI source, the ion source temperature is 230 °C, the scanning mode is full scan (SCAN) and selected ion monitoring (SIM) mode, and the monitoring time for each ion is 100 ms.

[0065] Example 2

[0066] Determination of phenol compounds in a tobacco-flavored e-liquid (purchased from Dongguan Hongfu Biotechnology Co., Ltd.), which specifically includes the following steps.

[0067] (1) Sample Solution Preparation: Weigh 1 g of the e-liquid sample into a 15 mL centrifuge tube, add 10 mL of water, and shake for 20 minutes for purification;

[0068] (2) Solid Phase Extraction Purification: First, activate the HLB Pro solid phase extraction column with ethyl acetate, methanol, and water with 1-2 column volumes in sequence, then load and inject the sample solution in step (1) into the HLB Pro solid phase extraction column, wash it with 1 column volume of water, vacuum dry it, elute it with 2 mL of ethyl acetate, collect the eluate for later use;

[0069] (3) Silanization Derivatization: Take 1 mL of the eluate in step (2) and 1 mL of the phenol compound standard solution with a concentration of 2 ppm into a sample bottle respectively, add 20 μL of the silanization derivatization reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and place it in a 50 °C water bath atmosphere for a 30-minute derivatization reaction to obtain a silanized derivative product;

[0070] (4) Instrumental analysis: The silylated derivative product is placed in a gas chromatography-tandem mass spectrometer, and gas chromatography-tandem mass spectrometry is used to determine and analyze the content of phenolic compounds;

[0071] Among them, the chromatographic column conditions for gas chromatography-tandem mass spectrometry analysis are as follows: The chromatographic column is a (5%-phenyl)-methyl polysiloxane capillary column (HP-5MS UI), the inlet temperature is 250 °C, the injection volume is 0.5 μL, the split ratio is 10:1, the carrier gas is helium, the constant flow rate is 1.0 mL / min, and the temperature programming is as follows: Keep at 80 °C for 1 min, increase the temperature at a rate of 10 °C / min to 200 °C, and then increase the temperature at a rate of 30 °C / min to 250 °C and keep for 8 min; The mass spectrometry conditions are as follows: The transfer line temperature is 250 °C, the ion source is an EI source, the ion source temperature is 230 °C, the scanning mode is selected ion monitoring (SIM) mode, and the monitoring time for each ion is 100 ms.

[0072] Example 3

[0073] Determination of phenolic compounds in the aerosol of a tobacco-flavored e-liquid specifically includes the following steps.

[0074] (1) Sample solution preparation: Connect the smoking device filled with e-liquid, the trap equipped with a Cambridge filter, and the e-cigarette smoking machine in sequence, and aspirate the e-liquid sample according to the ISO aspiration mode. The aspiration volume is 55 mL, the aspiration time is 3 s, the interval time is 27 s, and aspirate 100 puffs; Place the aspirated Cambridge filter in a 50 mL centrifuge tube, add 20 mL of water, and shake for 20 min for later use;

[0075] (2) Solid-phase extraction purification: First, activate the HLB Pro solid-phase extraction column with ethyl acetate, methanol, and water with a volume of 1-2 times the column volume in sequence, then load and inject the sample solution in step (1) into the HLB Pro solid-phase extraction column, wash it with 1 times the column volume of water, vacuum dry it, elute it with 2 mL of ethyl acetate, and collect the eluate for later use;

[0076] (3) Silylation derivation: Take 1 mL of the eluate in step (2) and 1 mL of a phenolic compound standard solution with a concentration of 2 ppm in a sample bottle respectively, add 20 μL of the silylation derivation reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and place it in a water bath atmosphere at 50 °C for a derivatization reaction for 30 min to obtain a silylated derivative product;

[0077] (4) Instrumental analysis: The silylated derivative product is placed in a gas chromatography-tandem mass spectrometer, and gas chromatography-tandem mass spectrometry is used to determine and analyze the content of phenolic compounds;

[0078] Among them, the chromatographic column conditions for gas chromatography-tandem mass spectrometry analysis are as follows: the chromatographic column is a (5%-phenyl)-methyl polysiloxane capillary column (HP-5MS UI), the inlet temperature is 250°C, the injection volume is 0.5 μL, the split ratio is 10:1, the carrier gas is helium, the constant flow rate is 1.0 mL / min, and the temperature programming is as follows: hold at 80°C for 1 min, increase the temperature at a rate of 10°C / min to 200°C, then increase the temperature at a rate of 30°C / min to 250°C, and hold for 8 min; the mass spectrometry conditions are as follows: the transfer line temperature is 250°C, the ion source is an EI source, the ion source temperature is 230°C, the scanning mode is selected ion monitoring (SIM) mode, and the monitoring time for each ion is 100 ms.

[0079] Example 4

[0080] Different from Example 1, different derivatization temperatures were used for derivatization to analyze the effect of different derivatization temperatures on the silylation derivatization efficiency of phenolic compounds. The specific steps are as follows.

[0081] (1) Silylation derivatization: Take 1 mL of a standard solution with a concentration of 2 μg / mL in a sample vial, add 100 μL of the silylation derivatization reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and place it in a water bath atmosphere for a derivatization reaction for 30 min to obtain a silylation derivatization product; among them, the water bath temperatures for the derivatization reaction include room temperature, 30°C, 40°C, 60°C, and 70°C.

[0082] (2) Instrumental analysis: The silylation derivatization product was placed in a gas chromatography-tandem mass spectrometer, and the content of phenolic compounds was determined and analyzed by gas chromatography-tandem mass spectrometry.

[0083] Among them, the chromatographic column conditions for gas chromatography-tandem mass spectrometry analysis are as follows: the chromatographic column is a (5%-phenyl)-methyl polysiloxane capillary column (HP-5MS UI), the inlet temperature is 250°C, the injection volume is 0.5 μL, the split ratio is 10:1, the carrier gas is helium, the constant flow rate is 1.0 mL / min, and the temperature programming is as follows: hold at 80°C for 1 min, increase the temperature at a rate of 10°C / min to 200°C, then increase the temperature at a rate of 30°C / min to 250°C, and hold for 8 min; the mass spectrometry conditions are as follows: the transfer line temperature is 250°C, the ion source is an EI source, the ion source temperature is 230°C, the scanning mode is selected ion monitoring (SIM) mode, and the monitoring time for each ion is 100 ms.

[0084] Example 5

[0085] Different from Example 1, different derivatization times were used for derivatization to analyze the effect of different derivatization times on the silylation derivatization efficiency of phenolic compounds. The specific steps are as follows.

[0086] (1) Silanization derivatization: Take 1 mL of a standard solution with a concentration of 2 μg / mL in a sample bottle, add 100 μL of the silanization derivatization reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and place it in a water bath atmosphere at 50 °C for derivatization reaction to obtain a silanized derivatized product; among them, the derivatization reaction time includes 10 min, 20 min, 40 min, 50 min, 60 min;

[0087] (2) Instrumental analysis: The silanized derivatized product is placed in a gas chromatography-tandem mass spectrometer, and the content of phenolic compounds is determined and analyzed by gas chromatography-tandem mass spectrometry;

[0088] Among them, the chromatographic column conditions for gas chromatography-tandem mass spectrometry analysis are as follows: The chromatographic column is a (5%-phenyl)-methylpolysiloxane capillary column (HP-5MS UI), the inlet temperature is 250 °C, the injection volume is 0.5 μL, the split ratio is 10:1, the carrier gas is helium, the constant flow rate is 1.0 mL / min, and the temperature programming is as follows: Hold at 80 °C for 1 min, increase the temperature at a rate of 10 °C / min to 200 °C, and then increase the temperature at a rate of 30 °C / min to 250 °C and hold for 8 min; The mass spectrometry conditions are as follows: The transfer line temperature is 250 °C, the ion source is an EI source, the ion source temperature is 230 °C, the scanning mode is selected ion monitoring (SIM) mode, and the monitoring time for each ion is 100 ms.

[0089] Example 6

[0090] The difference from Example 1 is that different dosages of the derivatizing agent are added for derivatization treatment to analyze the effect of different derivatizing agent dosages on the silanization derivatization efficiency of phenolic compounds, and the specific steps are as follows.

[0091] (1) Silanization derivatization: Take 1 mL of a standard solution with a concentration of 2 μg / mL in a sample bottle, add the silanization derivatization reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and place it in a water bath atmosphere at 50 °C for a derivatization reaction for 30 min to obtain a silanized derivatized product; among them, the dosage of the derivatizing agent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) includes 10 μL, 20 μL, 50 μL, 100 μL, 150 μL, 200 μL;

[0092] (2) Instrumental analysis: The silanized derivatized product is placed in a gas chromatography-tandem mass spectrometer, and the content of phenolic compounds is determined and analyzed by gas chromatography-tandem mass spectrometry;

[0093] Among them, the chromatographic column conditions for gas chromatography-tandem mass spectrometry analysis are as follows: the chromatographic column is a (5%-phenyl)-methyl polysiloxane capillary column (HP-5MS UI), the inlet temperature is 250 °C, the injection volume is 0.5 μL, the split ratio is 10:1, the carrier gas is helium, the constant flow rate is 1.0 mL / min, and the temperature programming is as follows: hold at 80 °C for 1 min, increase the temperature to 200 °C at a rate of 10 °C / min, then increase the temperature to 250 °C at a rate of 30 °C / min, and hold for 8 min; the mass spectrometry conditions are as follows: the transfer line temperature is 250 °C, the ion source is an EI source, the ion source temperature is 230 °C, the scanning mode is selected ion monitoring (SIM) mode, and the monitoring time for each ion is 100 ms.

[0094] Comparative Example 1

[0095] Compared with Example 1, the difference in Comparative Example 1 is that the phenolic compounds in Comparative Example 1 are not subjected to silylation derivatization reaction treatment.

[0096] Comparative Example 2

[0097] Compared with Example 1, the difference in Comparative Example 2 is that the silylation derivatization reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) in step (3) of Example 1 is replaced with N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA).

[0098] Comparative Example 3

[0099] Compared with Example 1, the difference in Comparative Example 3 is that the silylation derivatization reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) in step (2) of Example 1 is replaced with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA).

[0100] Comparative Example 4

[0101] Compared with Example 2, the difference in Comparative Example 4 is that the preparation of the sample solution by solid-phase extraction in steps (1) and (2) of Example 2 is replaced with direct extraction with ethyl acetate. The specific steps are as follows: (1) Weigh 1 g of the e-cigarette liquid sample into a 15 mL centrifuge tube, add 10 mL of ethyl acetate, shake for 20 min, and wait for derivatization.

[0102] Comparative Example 5

[0103] Compared with Example 2, the difference in Comparative Example 5 is that the HLB Pro solid-phase extraction column in step (2) of Example 2 is replaced with a Si silica solid-phase extraction column.

[0104] Comparative Example 6

[0105] Compared with Example 2, the difference in Comparative Example 6 is that the HLB Pro solid-phase extraction column in step (2) of Example 2 is replaced with a PSD polystyrene divinylbenzene solid-phase extraction column.

[0106] Test Example 1

[0107] The mass spectrometry analysis data of phenolic compounds in Example 1 are as Figure 1 shown in Table 1.

[0108] Table 1 Mass spectrometry analysis parameters of phenolic compounds in Example 1

[0109]

[0110]

[0111] As can be seen from Table 1, by using the method of the present application, 7 phenolic compounds in the standard solution can be completely separated within 10 min. Compared with 28 min of the prior art, the separation time is shortened by more than half, further meeting the requirements of rapid detection. From Figure 1 it can be seen that under the detection method of the present invention, the response values of 7 phenolic compounds are high and the peak shapes are good, which is beneficial to subsequent accurate quantification.

[0112] In order to investigate the sensitivity, detection limit and applicability of the detection method of the present invention, the corresponding linear ranges, linear correlation coefficients, detection limits (LOD), and quantification limits (LOQ) of 7 phenolic compounds are calculated from the detection data of Example 1 and recorded in Table 2. From the data in Table 2 and Figures 2 - 8 it can be seen that the linear correlation coefficients R 2 of 7 phenolic compounds all meet the requirement of >0.999, indicating that the linearity of 7 phenolic compounds is excellent in the range of 0.05 - 2 μg / mL. In addition, the detection limits of 7 phenolic compounds under the detection method of the present invention are between 0.0004 - 0.02 μg / g, which means the detection limits are between 0.4 - 20 ppb, and the quantification limits of 7 phenolic compounds are between 0.0014 - 0.01 μg / g. It can be seen that the method of the present invention has high sensitivity.

[0113] Test Example 2

[0114] In order to further verify the accuracy and reliability of the detection method of the present invention, an e-liquid with a tobacco flavor (purchased from Dongguan Hongfu Biotechnology Co., Ltd.) was selected, and the average value of 3 determinations in Example 2 was used as the background value of phenolic compounds. Then, a certain amount of phenolic compound standard solution was added to the e-liquid with a tobacco flavor, and it was measured in parallel 6 times according to the steps of Example 2, and the average recovery rate and precision (RSD) of 7 phenolic compounds were calculated and the results were recorded in Table 2.

[0115] Table 2 Investigation of relevant parameters of the methodology for phenolic compounds

[0116]

[0117]

[0118] Note: Regarding the detection limit (LOD) and quantification limit (LOQ), the signal-to-noise ratio S / N≥3 for each component in the detection limit solution and S / N≥10 for each component in the quantification limit solution were regarded as the acceptable standards. Recovery rate (%) = (measured value of spiked sample - measured value of unspiked sample) / theoretical spiked value * 100%, and relative standard deviation of precision RSD(%) = standard deviation of spiked recovery rate / average value of spiked recovery rate * 100%.

[0119] As can be seen from Table 2, the average recovery rates of the 7 phenolic compounds were in the range of 85% - 105%, and the RSD < 10%, indicating that the detection method of the present invention has high accuracy and reliability and all meet the requirements of the detection standards.

[0120] Figure 9 Figure is the superimposed comparison chart of the selected ion chromatograms of the phenolic compounds in the electronic atomization liquid in Example 2 and their standards. As can be seen from Figure 9 it that the phenolic compounds contained in the actual electronic atomization liquid all showed peaks at the corresponding retention times, with good peak shapes and no tailing. Other components of the atomization liquid did not interfere with them, indicating that the detection method of the present invention has strong anti-interference ability and is suitable for quantitative detection of phenolic compounds in actual electronic atomization liquids.

[0121] Table 3 records the contents of phenolic compounds in 10 flavors of electronic atomization liquids (purchased from Dongguan Hongfu Biotechnology Co., Ltd.), such as mint, fruit, and coffee, detected by the method of Example 2 of the present invention.

[0122] Table 3 Determination results of the contents of phenolic compounds in electronic atomization liquids

[0123]

[0124] Note: ND indicates not detected

[0125] As can be seen from Table 3, different contents of phenols were detected in all 10 flavors of electronic atomization liquids. o-Cresol, m-Cresol, p-Cresol, catechol, and hydroquinone were detected in some flavors, but resorcinol was not detected in all 10 flavors, indicating that the types and contents of phenolic compounds in electronic atomization liquids are closely related to the flavors of electronic atomization liquids.

[0126] Test Example 3

[0127] Figure 10To detect the overlay comparison chart of the selected ion flow chromatograms of the phenol compounds and their standards in Example 3, it can be seen from Figure 10 that phenol compounds can also be detected in the aerosol of the actual e-liquid. The phenol compounds all peak at the corresponding retention times, and the peak shapes are good without tailing. Other components in the aerosol do not interfere with them, indicating that the detection method of the present invention has strong anti-interference ability and is suitable for quantitative detection of phenol compounds in the actual e-liquid aerosol.

[0128] Table 4 records the contents of phenol compounds in the aerosols of 10 flavors of e-liquids (which can be purchased from Dongguan Hongfu Biotechnology Co., Ltd.), such as mint, fruit, tobacco, and coffee, detected by the method of Example 3 of the present invention.

[0129] Table 4 Determination Results of the Contents of Phenol Compounds in the Aerosols of E-Liquids

[0130]

[0131] Note: ND indicates not detected.

[0132] According to Table 4, phenols with different content levels are detected in the aerosols of 10 e-liquids with different flavors. o-Cresol, m-cresol, p-cresol, catechol, and hydroquinone are detected in some flavors. Resorcinol is not detected in the aerosols of the above 10 e-liquids, which is similar to the determination results of the corresponding flavored e-liquids. Catechol is not detected in some e-liquids but is detected in the aerosols of the e-liquids, indicating that phenol compounds may be generated during the use of e-liquids.

[0133] Test Example 4

[0134] Table 5 records the derivatization efficiency results of Examples 4-6. By comparing the response peak areas of the derivatives of 7 phenol compounds under different derivatization conditions (including derivatization temperature, derivatization time, and derivatizing agent dosage), the derivatization efficiency is calculated based on the derivatization condition with the largest response peak area. The largest response peak area of the derivatives of 7 phenol compounds at different derivatization temperatures is at 50 °C, the largest response peak area of the derivatives of 7 phenol compounds at different derivatization times is 30 min, and the largest response peak area of the derivatives of 7 phenol compounds at different derivatizing agent dosages is 20 μL.

[0135] Calculation method for the derivatization efficiency with the change of derivatization temperature: Derivatization efficiency = peak area of the silylation product at each temperature / peak area of the silylation product at 50 °C × 100%.

[0136] Calculation method of derivatization efficiency with respect to the change in derivatization time: Derivatization efficiency = Peak area of the silylated product at each reaction time / Peak area of the silylated product at 30 min × 100%.

[0137] Calculation method of derivatization efficiency with respect to the change in the amount of derivatizing agent: Derivatization efficiency = Peak area of the silylated product at each amount / Peak area of the silylated product at 20 μL × 100%.

[0138] Table 5 Influence of derivatization conditions on the derivatization efficiency of phenolic compounds in Examples 3 - 5

[0139]

[0140] It can be seen from the results in Table 5 that different derivatization temperatures have varying degrees of influence on the derivatization efficiency of phenolic compounds. Among them, when the temperature is in the range of 30 - 50 °C, the derivatization efficiency is greater than or close to 99%. When the derivatization temperature is 50 °C, the derivatization efficiency of phenolic compounds is the best. Different derivatization times have varying degrees of influence on the derivatization efficiency of phenolic compounds. When the derivatization time is in the range of 20 - 30 min, the derivatization efficiency is greater than or close to 99%. When the derivatization time is 30 min, the derivatization efficiency of phenolic compounds is the best. Different amounts of derivatizing agent also have varying degrees of influence on the derivatization efficiency of phenolic compounds. When 20 - 100 μL of derivatizing agent is added, the corresponding derivatization efficiency is greater than or close to 99%. When the amount of derivatizing agent is 20 μL, the derivatization efficiency of phenolic compounds is the best.

[0141] Test Example 5

[0142] Figure 11 is the total ion current chromatogram obtained by full scan detection of phenolic compounds in Comparative Example 1. As Figure 11 shown, the standard mixed solution containing 7 phenolic compounds was directly detected without derivatization reaction treatment. As a result, only 6 phenolic compounds showed peaks, that is, m - cresol and p - cresol were not successfully separated, and the peak shapes of the 6 phenolic compounds were tailing, with low response and low sensitivity.

[0143] Figure 12 is the superposition comparison chromatogram of selected ion current obtained by detecting phenolic compounds in Example 1 and Comparative Example 2. As Figure 12 shown, for phenolic compounds with the same concentration, the response obtained by silylation derivatization with N - methyl - N - (trimethylsilyl) trifluoroacetamide (MSTFA) is lower than that obtained by silylation derivatization with N,O - bis(trimethylsilyl) trifluoroacetamide (BSTFA). That is, BSTFA has higher reaction activity and better derivatization effect. It should be noted that the concentration of the standard solution used in Example 1 is 2 μg / mL, and it was found that the response values were the same during the comparison. In order to magnify the influence effect of different derivatizing agents, finally Figure 12The concentration used is 100 ppm.

[0144] Figure 13 It is the total ion current chromatogram of the full scan obtained by detecting the phenolic compounds in Comparative Example 3. As Figure 13 shown, after derivatizing the phenolic compounds with N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA), there are only 6 peaks for 7 phenolic compounds. There is an impurity peak between m-cresol and o / p-cresol. The peak emergence times of o-cresol and p-cresol are exactly the same, and the peak emergence times of the derivatives of phenolic compounds are slower than those derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA).

[0145] Figure 14 It is the superimposed comparison chromatogram of the selected ion current of the phenolic compounds in Comparative Example 4 and their standards. From Figure 14 it can be seen that when directly using ethyl acetate to extract the electronic atomization liquid of the sample, there are obvious peaks of propylene glycol and glycerol in the chromatogram, which affect the derivatization effect of the phenolic compounds. From Figure 9 it can be seen that after the same electronic atomization liquid of the sample is purified by solid-phase extraction to remove most of the main solvents glycerol and propylene glycol, the interference of the peaks of propylene glycol and glycerol in the chromatogram is greatly reduced, and the phenolic compounds can be fully derivatized. The corresponding response peaks of the derivatives of phenolic compounds are all higher than those in Comparative Example 4.

[0146] Test Example 6

[0147] Take 3 portions of the electronic atomization liquid with a tobacco flavor (available from Dongguan Hongfu Biotechnology Co., Ltd.). Take the average values of the 3 determinations in Example 2, Comparative Example 5, and Comparative Example 6 as the background values of the phenolic compounds; then take another 3 portions of the electronic atomization liquid with a tobacco flavor and add a certain amount of the standard solution of phenolic compounds respectively, and parallelly determine 6 times according to the steps of Example 2, Comparative Example 5, and Comparative Example 6. Finally, calculate the average recovery rates of the corresponding phenolic compounds and record them in Table 6. The purification effects of different solid-phase extraction columns on the electronic atomization liquid samples are reflected by the recovery rates of the corresponding phenolic compounds.

[0148] Table 6 Purification effects of different solid-phase extraction columns on electronic atomization liquids

[0149]

[0150] The results in Table 6 show that when using an Si silica gel solid-phase extraction column to purify the e-liquid, the recovery rate is significantly lower than that using an HLB Pro solid-phase extraction column. In particular, the recovery rates of resorcinol and hydroquinone are significantly low. After using a PSD polystyrene divinylbenzene solid-phase extraction column to purify the sample, the recovery rates of some phenol compounds are not much different from those after purification with an HLB Pro solid-phase extraction column and are between 85 - 105%, but the recovery rates of resorcinol and hydroquinone are significantly low. Therefore, choosing an HLB Pro solid-phase extraction column for solid-phase extraction and purification of the e-liquid can well separate phenol compounds from the e-liquid (propylene glycol / glycerol matrix), enabling the complete derivatization of phenol compounds.

[0151] In summary, the detection method of the present invention first uses solid-phase extraction to separate phenol compounds from the main components of the e-liquid, propylene glycol and glycerol matrix, removing the interference of the matrix on phenol compounds. Then, the separated phenol compounds are subjected to silicon derivatization treatment. Finally, the derivatized phenol compounds are analyzed under the gas chromatography-tandem mass spectrometry conditions screened in the present invention, which can quickly and accurately determine the content of phenol compounds in the e-liquid and aerosol. Among them, the method of N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) silylation derivatization combined with solid-phase extraction using an HLB Pro solid-phase extraction column can better separate and accurately quantify 7 phenol compounds (phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol, hydroquinone) in the e-liquid and aerosol from the main components of propylene glycol and glycerol matrix.

[0152] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining phenol compounds in electronic atomized liquid or its aerosol, characterized in that: The sample solution of the electronic atomization liquid or its aerosol is purified by a solid phase extraction column, a silanization derivatization reagent is added to the purified liquid for treatment, and the silanization derivatization product is analyzed by gas chromatography-tandem mass spectrometry GC-MS to detect phenol compounds.

2. The method according to claim 1, characterized in that The solid phase extraction column is an HLB Pro solid phase extraction column or a PSD polystyrene divinylbenzene solid phase extraction column; And / or, the solid phase extraction column is activated before use, and the activation method optionally comprises sequentially activating with ethyl acetate, methanol, and water; optionally, the amount of ethyl acetate, methanol, and water used is 1-2 times the volume of the column; And / or, the purification of the solid phase extraction column includes: loading the sample solution, rinsing, eluting, and collecting the eluate; optionally, water is used for rinsing; optionally, ethyl acetate is used for elution.

3. The method according to claim 1 or 2, characterized in that: Silylation derivatization reagents include N,O-bis(trimethylsilyl)trifluoroacetamide; Optionally, the amount of silanization derivatization reagent used: 10 to 200 μL of silanization derivatization reagent is added to every 1 mL of purification solution; optionally, 15 to 100 μL of silanization derivatization reagent is added to every 1 mL of purification solution; optionally, 20 to 100 μL of silanization derivatization reagent is added to every 1 mL of purification solution; optionally, 20 to 50 μL of silanization derivatization reagent is added to every 1 mL of purification solution.

4. The method according to any one of claims 1 to 3, characterized in that: Silylation derivatization conditions include: Derivatization temperature 30-70°C, optionally 30-50°C, optionally 50°C; and / or, the derivatization time is 10-60 min, optionally 10-30 min, optionally 30 min; And / or, the amount of silanization derivatization reagent: add 10 to 200 μL of silanization derivatization reagent to every 1 mL of purification solution; optionally, add 15 to 100 μL of silanization derivatization reagent to every 1 mL of purification solution; optionally, add 20 to 100 μL of silanization derivatization reagent to every 1 mL of purification solution; optionally, add 20 to 50 μL of silanization derivatization reagent to every 1 mL of purification solution.

5. The method according to any one of claims 1 to 4, characterized in that: The preparation of the electronic atomization liquid sample solution includes: adding 10 to 50 mL of water, optionally 10 to 30 mL of water, optionally 10 to 20 mL of water per 1 g of the electronic atomization liquid.

6. The method according to any one of claims 1 to 4, characterized in that: The preparation of the sample solution of the aerosol of the electronic atomization liquid includes: using an electronic cigarette smoking machine for suction, adding water to the filter after suction and shaking, optionally, the amount of water added is 10 to 50 mL, optionally 10 to 30 mL, optionally 10 to 20 mL.

7. The method according to any one of claims 1 to 6, characterized in that: The phenolic compound includes at least one of phenol, o-cresol, m-cresol, p-cresol, catechol, resorcinol and hydroquinone.

8. The method according to any one of claims 1 to 7, characterized in that: The chromatographic column used in the gas chromatography-tandem mass spectrometry analysis is a (5%-phenyl)-methylpolysiloxane capillary column; and / or, the mass spectrometry ion source used in the gas chromatography-tandem mass spectrometry analysis is an EI source, and the scanning mode is a selected ion monitoring mode; Optionally, the conditions of the chromatographic column include: the injection port temperature is 250°C, the split ratio is 10:1, the carrier gas is helium, the temperature program is: 80°C for 1 min, the temperature is increased to 200°C at a temperature increase rate of 10°C / min, and then increased to 250°C at a temperature increase rate of 30°C / min, and maintained for 8 min; the injection volume is optionally 0.5 μL, and the constant flow rate of the carrier gas is optionally 1.0 mL / min; Optionally, the mass spectrometry conditions include: a transmission line temperature of 250° C., an ion source temperature of 230° C., and a monitoring time of 100 ms for each ion.

9. An analytical method for evaluating the safety of phenolic compounds on electronic cigarettes, characterized in that: The method described in any one of claims 1 to 8 is used to detect phenol compounds in the electronic atomization liquid or its aerosol, and to evaluate whether the content of phenol compounds meets the safety indicators.

10. An analytical system for evaluating the safety of phenolic compounds on electronic cigarettes, characterized in that: Input the method described in any one of claims 1 to 8 to detect the content of phenol compounds in the electronic atomization liquid or its aerosol, and output an evaluation result of whether the content of phenol compounds meets the safety index.

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