GC-QTOF-MS (Gas Chromatography-Quadrature Time of Flight Mass Spectrometry)-based method for determining content of volatile benzene series in electronic cigarette and application

Abstract

The invention relates to a GC-QTOF-MS (Gas Chromatography-Quadrature Time of Flight Mass Spectrometry)-based method for determining the content of volatile benzene series in an electronic cigarette and application of the GC-QTOF-MS-based method. The determination method comprises the following steps: firstly, adding extract liquor into a to-be-detected sample containing the volatile benzene series for extraction, and then carrying out GC-QTOF-MS detection analysis, the volatile benzene series comprises any one or a combination of at least two of benzene, methylbenzene, ethylbenzene, p-xylene, m-xylene, o-xylene, cumene or styrene. The method comprises the following steps: capturing aerosol by using a Cambridge filter, establishing an extraction method for eight volatile benzene series in tobacco tar and aerosol, and carrying out qualitative and quantitative analysis on the eight volatile benzene series by using GC-QTOF-MS and an internal standard method. The method has the advantages of high sensitivity, low detection limit and the like, can meet simultaneous detection and analysis of electronic cigarette tobacco tar and aerosol samples with different concentrations, and can be used for actual supervision and safety evaluation of electronic cigarette products.

Description

Technical Field

[0001] The present invention relates to the technical field of physical and chemical index detection of electronic cigarettes, and particularly relates to a method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS and its application. Background Art

[0002] Electronic cigarettes, also known as nicotine delivery systems, are a type of consumer product designed to deliver nicotine to the lungs. They mainly consist of a battery, a heating and evaporation device, and a cartridge filled with e-liquid. The principle is to use an electric current to heat a heating wire to atomize the e-liquid, so that the nicotine-containing e-liquid aerosol is inhaled by the user, obtaining an experience similar to smoking cigarettes. Propylene glycol (PG), glycerol (VG), benzoic acid, flavorings, etc. in the e-liquid will produce benzene series during the heating process. Benzene series have been classified as strong carcinogens by the World Health Organization (WHO). Long-term exposure and inhalation of toxic and harmful gases or substances containing relatively high concentrations of benzene will cause symptoms such as headache, dizziness, insomnia, and memory decline, and lead to blood system diseases.

[0003] Currently, there are relatively few studies on benzene series in electronic cigarettes. Studies on 5 benzene series (benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene) in e-liquid of electronic cigarettes have been carried out, but there are few reports on the simultaneous quantitative analysis of multiple benzene series in e-liquid and aerosol. In addition, existing electronic cigarette products have relatively high requirements for raw materials and technology, and the content of a large number of regulatory components is relatively low. Existing methods for qualitative and quantitative analysis of benzene series have problems such as low sensitivity and high detection limits, and cannot meet the need for accurate detection of benzene series in electronic cigarettes in a low-concentration environment. In practical applications, it also cannot meet the actual needs of rapid and efficient detection of a large number of samples simultaneously. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS and its application. The method of the present invention can effectively detect 8 volatile benzene series, has a relatively low detection limit, high sensitivity of the analysis method, and low detection limit, and is suitable for the actual detection and analysis of samples with low-concentration content.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS. The determination method includes: first adding an extraction solution to a sample to be tested containing volatile benzene series for extraction, and then detecting it with a gas chromatography-triple quadrupole time-of-flight mass spectrometer (GC-QTOF-MS);

[0007] The volatile benzene series includes any one or a combination of at least two of benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, isopropylbenzene or styrene.

[0008] In the present invention, by extracting the sample to be tested, accurate detection results can be obtained. The operation is simple and fast, the detection time is short, meeting the actual needs of the new national standard for e-cigarette detection. This method has high sensitivity, with the lowest detection limit of 0.0001 μg / mL, and is better applicable to low-concentration samples, greatly improving the detection accuracy.

[0009] Preferably, the type of the sample to be tested includes e-cigarette oil and / or aerosol.

[0010] Preferably, the preparation method of the aerosol sample to be tested includes: collecting the aerosol with a filter after sucking the e-cigarette oil.

[0011] Preferably, the sucking volume is 50 - 60 mL, for example, it can be 50 mL, 55 mL or 60 mL, etc.

[0012] Preferably, the number of times of sucking for each sample is 15 - 20 times, for example, it can be 15 times or 20 times, etc.

[0013] Preferably, the duration of each sucking is 2 - 5 s, for example, it can be 2 s, 3 s, 4 s or 5 s, etc.

[0014] Preferably, the interval between each sucking is 20 - 40 s, for example, it can be 20 s, 25 s, 30 s, 35 s or 40 s, etc.

[0015] Preferably, the extraction includes: adding an extraction solution to the e-cigarette oil or the filter after collecting the aerosol, and performing vortex oscillation extraction.

[0016] In the present invention, the above method can effectively extract benzene series compounds in the aerosol and e-cigarette oil, filling the blank in this method, and the method is simple, improving the application scenario of this method.

[0017] Preferably, the mass of the e-cigarette oil is 0.5 - 1.5 g, for example, it can be 0.5 g, 1.0 g or 1.5 g, etc.

[0018] Preferably, the extraction solution includes any one or a combination of at least two of ethyl acetate, dichloromethane, cyclohexane or n-pentane; more preferably n-pentane.

[0019] In the present invention, by selecting n-pentane as the extraction agent, unexpected technical effects are obtained. Using only a single extraction agent can significantly improve the extraction effect, further reduce the detection limit, and thus improve the detection effect.

[0020] Preferably, the addition amount of the extraction solution is 10 - 20 mL, for example, it can be 10 mL, 15 mL, 20 mL, etc.

[0021] Preferably, the extraction solution further includes an internal standard.

[0022] Preferably, the internal standard includes toluene - d 8 。

[0023] In the present invention, the selected internal standard is toluene - d 8 , which can improve the accuracy of quantitative analysis of xylene isomers, better correct the loss or change of ethylbenzene and isopropylbenzene during the analysis process, and has a later retention time and is not easily affected by impurity peaks.

[0024] Preferably, the concentration of the internal standard in the extraction solution is 0.3 - 0.7 mg / mL, for example, it can be 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, or 0.7 mg / mL, etc.

[0025] Preferably, the speed of vortex - oscillation extraction is 2000 - 4000 r / min, and the time is 40 - 80 min. The 40 - 80 min can be, for example, 40 min, 50 min, 60 min, 70 min, or 80 min, etc.

[0026] Preferably, the detection method further includes the preparation of a standard solution and an internal standard solution.

[0027] Preferably, the concentration of the internal standard in the internal standard solution is 0.3 - 0.7 mg / mL, for example, it can be 0.3 mg / mL, 0.4 mg / mL, 0.5 mg / mL, 0.6 mg / mL, or 0.7 mg / mL, etc.

[0028] Preferably, the concentration range of volatile benzene series compounds in the standard solution is 0.0001 - 5 μg / mL, for example, it can be 0.0001 μg / mL, 0.0005 μg / mL, 0.001 μg / mL, 0.005 μg / mL, 0.01 μg / mL, 0.05 μg / mL, 0.1 μg / mL, 0.5 μg / mL, 1 μg / mL, 2 μg / mL, 3 μg / mL, 4 μg / mL, or 5 μg / mL, etc.

[0029] Preferably, the column temperature program for the GC-QTOF-MS detection is as follows: the initial column temperature is 30 - 50 °C for 1 - 5 min, then it is heated to 120 - 130 °C at a rate of 5 - 10 °C / min and held for 1 - 5 min, and then heated to 190 - 210 °C at a rate of 10 - 20 °C / min and held for 3 - 5 min. The 30 - 50 °C can be, for example, 30 °C, 35 °C, 40 °C, 45 °C or 50 °C, etc. The 1 - 5 min can be, for example, 1 min, 2 min, 3 min, 4 min or 5 min, etc. The 5 - 10 °C / min can be, for example, 5 °C / min or 10 °C / min, etc. The 120 - 130 °C can be, for example, 120 °C, 125 °C or 130 °C, etc. The 10 - 20 °C / min can be, for example, 10 °C / min, 15 °C / min or 20 °C / min, etc. The 190 - 210 °C can be, for example, 190 °C, 195 °C, 200 °C, 2050 °C or 210 °C, etc. The 3 - 5 min can be, for example, 3 min, 4 min or 5 min, etc.

[0030] Preferably, the split ratio for the GC-QTOF-MS detection is (15 - 25):1, and the (15 - 25) can be, for example, 15, 20 or 25, etc.

[0031] Preferably, the chromatographic column flow rate for the GC-QTOF-MS detection is 1.2 - 1.8 mL / min, and it can be, for example, 1.2 mL / min, 1.3 mL / min, 1.4 mL / min, 1.5 mL / min, 1.6 mL / min, 1.7 mL / min, or 1.8 mL / min, etc.

[0032] Preferably, the ion source temperature for the GC-QTOF-MS detection is 220 - 240 °C, and it can be, for example, 220 °C, 225 °C, 230 °C, 235 °C or 240 °C, etc.

[0033] Preferably, the purge flow rate for the GC-QTOF-MS detection is 1.2 - 1.8 mL / min, and it can be, for example, 1.2 mL / min, 1.3 mL / min, 1.4 mL / min, 1.5 mL / min, 1.6 mL / min, 1.7 mL / min, or 1.8 mL / min, etc.

[0034] Preferably, the acquisition mode for the GC-QTOF-MS detection is the Q3SCAN + SIM mode.

[0035] In the second aspect, the present invention provides an application of the method for determining the content of volatile benzene series in e-cigarettes based on GC-QTOF-MS according to the first aspect in detecting the volatile benzene series in e-cigarette oil and aerosol.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects:

[0037] (1) The present invention uses a Cambridge filter to aspirate and capture aerosols, which is faster and more efficient, and can also meet the needs of aerosol capture during the detection and analysis of other components, avoiding unnecessary waste during actual detection, analysis, and supervision. Subsequently, extraction is carried out with an extraction solution, which can better dissolve the aerosol components and ensure the accuracy of the experiment.

[0038] (2) The present invention has established a detection method for 8 volatile benzene series compounds in e-cigarette oil and aerosols, and has carried out actual detection and analysis of samples, providing technical support for the supervision and quality evaluation of e-cigarettes, providing technical reserves for the improvement of relevant detection standards, having a wider linear range and lower detection limits, and can meet the analysis of different e-cigarette samples. Description of the Drawings

[0039] Figure 1 : SIM chromatogram of 8 volatile benzene series compounds. Detailed Embodiments

[0040] The technical solution of the present invention will be further described below in conjunction with the drawings and through specific embodiments. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the patent protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0041] Sources of materials and instruments used in the following examples and test examples:

[0042] Standard solution of 8 benzene series compound mixtures: 1000 μg / mL, provided by the National Standard Substance Center;

[0043] Toluene-d 8 : 20 μg / mL, provided by the National Standard Substance Center;

[0044] Mass spectrometry grade n-pentane reagent, Beijing Merida Technology Co., Ltd.;

[0045] Cambridge filter: 44 mm, Whatman Company, UK;

[0046] Gas chromatography-mass spectrometry: GCMS-TQ8040 NX, Shimadzu Corporation, Japan;

[0047] E-cigarette smoking machine: Hefei Zhongwo Instrument Technology Co., Ltd.;

[0048] Vortex oscillator: Thermo Fisher Scientific, USA.

[0049] Example 1

[0050] This example establishes a detection method for 8 volatile benzene series compounds in e-cigarettes

[0051] (1) Preparation of standard samples

[0052] Precisely pipette 1.0 mL of the 8-component mixture standard sample solution with a concentration of 1000 μg / mL into a 100 mL volumetric flask, dilute it to the mark with methanol, and obtain a mixed standard sample solution with a concentration of 10 μg / mL. Then, perform serial dilution to obtain gradient concentration mixed standard sample solutions of 5, 2.5, 1, 0.5, 0.1, 0.01, and 0.0001 μg / mL. Add the internal standard toluene-d 8 with a concentration of 0.5 mg / L.

[0053] (2) Collection of aerosol

[0054] Place a Cambridge filter with a diameter of 44 mm in the collector, with the rough side of the filter facing the incoming smoke. Perform suction on the S1 e-liquid sample according to a suction volume of 55 mL, one puff every 30 s, each puff lasting for 3 s, and 20 puffs for each sample, to obtain the aerosol.

[0055] (3) Extraction

[0056] Take 1.0 g of the S1 e-cigarette e-liquid. First, add 1 mL of water to dissolve it in the e-liquid and the filter after collecting the aerosol, then add 15 mL of n-pentane respectively. Add the internal standard toluene-d 8 with a concentration of 0.5 mg / mL, vortex and oscillate for extraction at 3000 r / min for 60 min, and take the supernatant for injection analysis.

[0057] (4) Detection and analysis

[0058] The conditions for GC-QTOF-MS detection are as follows:

[0059] DA-WAX (30 m × 0.25 mm × 0.25 μm) chromatographic column, column temperature program: 40 °C (held for 3 min) → 10 °C / min → 130 °C (held for 3 min) → 20 °C / min → 200 °C (held for 5 min), transfer line temperature: 240 °C; chromatographic column flow rate: 1.5 mL / min; purge flow rate: 1.5 mL / min; split ratio: 20:1; chromatographic mass spectrometry interface temperature: 240 °C; ion source temperature: 230 °C; acquisition mode: Q3SCAN+SIM mode. The detection information of 8 volatile organic compounds and the internal standard is shown in Table 1.

[0060] Table 1

[0061] Number Compound Quantitative ion (m / z) Qualitative ion (m / z) 1 Benzene 78 51 2 Toluene 91 51 3 <![CDATA[Toluene-d 8 > 81 96 4 Ethylbenzene 91 106 5 p-Xylene 91 106 6 m-Xylene 91 106 7 Isopropylbenzene 105 120 8 o-Xylene 91 106 9 Styrene 78 104

[0062] Example 2

[0063] This example establishes a detection method for 8 volatile benzene series compounds in electronic cigarettes

[0064] (1) Preparation of standard products

[0065] Precisely pipette 1.0 mL of the 8-component mixture standard solution with a concentration of 1000 μg / mL into a 100 mL volumetric flask, dilute it to the mark with methanol, and obtain a mixed standard solution with a concentration of 10 μg / mL. Then, perform serial dilution to obtain gradient concentration mixed standard solutions of 5, 2.5, 1, 0.5, 0.1, 0.01, and 0.0001 μg / mL. Add the internal standard toluene-d 8 with a concentration of 0.5 mg / L.

[0066] (2) Collection of aerosol

[0067] Place a Cambridge filter with a diameter of 44 mm in the collector, with the rough side of the filter facing the incoming smoke. Aspirate the S1 e-liquid sample according to the following conditions: aspiration volume of 50 mL, one puff every 20 s, each puff lasting 5 s, and 15 puffs for each sample, to obtain the aerosol.

[0068] (3) Extraction

[0069] Take 0.5 g of the S1 e-liquid and the filter after collecting the aerosol. First, add 1 mL of water to each for dissolution, then add 20 mL of n-pentane to each, and add the internal standard toluene-d 8 with a concentration of 0.3 mg / mL. Vortex and oscillate for extraction at 4000 r / min for 40 min, and take the supernatant for injection analysis.

[0070] (4) Detection and analysis

[0071] The conditions for GC-QTOF-MS detection are as follows:

[0072] DA-WAX (30 m × 0.25 mm × 0.25 μm) chromatographic column, column temperature program: 38 °C (5 min) → 12 °C / min → 135 °C (5 min) → 22 °C / min → 205 °C (3 min), transfer line temperature: 240 °C; chromatographic column flow rate: 1.8 mL / min; purge flow rate: 1.2 mL / min; split ratio: 15:1; chromatographic mass spectrometry interface temperature: 240 °C; ion source temperature: 240 °C; acquisition mode: Q3SCAN+SIM mode. The detection information of 8 volatile organic compounds and the internal standard is shown in Table 2,

[0073] Table 2

[0074]

[0075]

[0076] Example 3

[0077] This example establishes a detection method for 8 volatile benzene series compounds in electronic cigarettes

[0078] (1) Preparation of standard products

[0079] Precisely pipette 1.0 mL of the 8-component mixture standard solution with a concentration of 1000 μg / mL into a 100 mL volumetric flask, dilute it to the mark with methanol to obtain a mixed standard solution with a concentration of 10 μg / mL, and then perform serial dilution to obtain gradient concentration mixed standard solutions with concentrations of 5, 2.5, 1, 0.5, 0.1, 0.01, and 0.0001 μg / mL. Add the internal standard toluene-d 8 The concentration is 0.5 mg / L.

[0080] (2) Collection of aerosol

[0081] Place a Cambridge filter with a diameter of 44 mm in the collector, with the rough side of the filter facing the incoming smoke. Aspirate the S1 e-liquid sample according to a suction volume of 60 mL, one puff every 30 s, each puff lasting 5 s, and 20 puffs for each sample, to obtain the aerosol.

[0082] (3) Extraction

[0083] Take 1.5 g of the S1 e-liquid. First, add 1 mL of water to dissolve it in the e-liquid and the filter after collecting the aerosol, then add 10 mL of n-pentane respectively, and add the internal standard toluene-d 8 The concentration is 0.7 mg / mL. Vortex and oscillate for extraction at 2000 r / min for 80 min, and take the supernatant for injection analysis.

[0084] (4) Detection and analysis

[0085] The conditions for GC-QTOF-MS detection are as follows:

[0086] DA-WAX (30 m×0.25 mm×0.25 μm) chromatographic column, column temperature program: 42 °C (1 min) → 8 °C / min → 125 °C (1 min) → 18 °C / min → 195 °C (8 min), transfer line temperature: 240 °C; column flow rate: 1.2 mL / min; purge flow rate: 1.8 mL / min; split ratio: 25:1; chromatographic mass spectrometry interface temperature: 240 °C; ion source temperature: 220 °C; acquisition mode: Q3SCAN+SIM mode. The detection information of 8 volatile organic compounds and the internal standard is shown in Table 3.

[0087] Table 3

[0088] Number Compound Quantitative ion (m / z) Qualitative ion (m / z) 1 Benzene 78 51 2 Toluene 91 51 3 <![CDATA[Toluene-d 8 > 81 96 4 Ethylbenzene 91 106 5 p-Xylene 91 106 6 m-Xylene 91 106 7 Isopropylbenzene 105 120 8 o-Xylene 91 106 9 Styrene 78 104

[0089] Example 4

[0090] This example establishes a detection method for 8 volatile benzene series compounds in electronic cigarettes

[0091] (1) Preparation of standard products

[0092] Precisely pipette 1.0 mL of the 8-component mixture standard solution with a concentration of 1000 μg / mL into a 100 mL volumetric flask, dilute it to the mark with methanol, and obtain a mixed standard solution with a concentration of 10 μg / mL. Then, perform serial dilution to obtain gradient concentration mixed standard solutions of 5, 2.5, 1, 0.5, 0.1, 0.01, and 0.0001 μg / mL. Add the internal standard toluene-d 8 with a concentration of 0.5 mg / L.

[0093] (2) Collection of aerosol

[0094] Place a Cambridge filter with a diameter of 44 mm in the collector, with the rough side of the filter facing the incoming smoke. Aspirate the S1 e-liquid sample according to the following parameters: aspiration volume of 55 mL, one puff every 20 s, each puff lasting 3 s, and 15 puffs for each sample, to obtain the aerosol.

[0095] (3) Extraction

[0096] Take 1.0 g of the S1 e-liquid and the filter after collecting the aerosol. First, dissolve each with 1 mL of water, then add 15 mL of methanol to each, and add the internal standard toluene-d 8 with a concentration of 0.5 mg / mL. Vortex and oscillate for extraction at 3000 r / min for 60 min, and take the supernatant for injection analysis.

[0097] (4) Detection and analysis

[0098] The conditions for GC-QTOF-MS detection are as follows:

[0099] DA-WAX (30 m × 0.25 mm × 0.25 μm) chromatographic column, column temperature program: 40 °C (held for 3 min) → 10 °C / min → 130 °C (held for 3 min) → 20 °C / min → 200 °C (held for 5 min), transfer line temperature: 240 °C; column flow rate: 1.5 mL / min; purge flow rate: 1.5 mL / min; split ratio: 20:1; chromatographic mass spectrometry interface temperature: 240 °C; ion source temperature: 230 °C; acquisition mode: Q3SCAN+SIM mode. The detection information of the 8 volatile organic compounds and the internal standard is shown in Table 4.

[0100] Table 4

[0101]

[0102]

[0103] The difference between this example and Example 1 lies only in that the extractant is methanol, and the rest are the same as in Example 1.

[0104] Example 5

[0105] This example is to establish a detection method for 8 volatile benzene series compounds in electronic cigarettes

[0106] (1) Preparation of standard products

[0107] Precisely pipette 1.0 mL of the 8-component mixture standard solution with a concentration of 1000 μg / mL into a 100 mL volumetric flask, dilute it to the mark with methanol, and obtain a mixed standard solution with a concentration of 10 μg / mL. Then, perform serial dilution to obtain gradient concentration mixed standard solutions with concentrations of 5, 2.5, 1, 0.5, 0.1, 0.01, and 0.0001 μg / mL. Add the internal standard substance toluene-d 8 The concentration is 0.5 mg / L.

[0108] (2) Collection of aerosol

[0109] Place a Cambridge filter with a diameter of 44 mm in the collector, with the rough side of the filter facing the incoming smoke. Aspirate the S1 e-liquid sample according to the aspiration volume of 50 mL, one puff every 30 s, each puff lasting for 3 s, and 20 puffs for each sample, to obtain the aerosol.

[0110] (3) Extraction

[0111] Take 1.0 g of the S1 e-liquid and the filter after collecting the aerosol, first add 1 mL of water to dissolve them respectively, then add 15 mL of ethanol respectively, add the internal standard substance toluene-d 8 The concentration is 0.5 mg / mL, vortex and oscillate for extraction at 3000 r / min for 60 min, and take the supernatant for injection analysis.

[0112] (4) Detection and analysis

[0113] The conditions for GC-QTOF-MS detection are as follows:

[0114] DA-WAX (30 m × 0.25 mm × 0.25 μm) chromatographic column, column temperature program: 40 °C (for 3 min) → 10 °C / min → 130 °C (for 3 min) → 20 °C / min → 200 °C (for 5 min), transfer line temperature: 240 °C; chromatographic column flow rate: 1.5 mL / min; purge flow rate: 1.5 mL / min; split ratio: 20:1; chromatographic mass spectrometry interface temperature: 240 °C; ion source temperature: 230 °C; acquisition mode: Q3SCAN+SIM mode. The detection information of 8 volatile organic compounds and the internal standard substance is shown in Table 5.

[0115] Table 5

[0116] Number Compound Quantitative ion (m / z) Qualitative ion (m / z) 1 Benzene 78 51 2 Toluene 91 51 3 <![CDATA[Toluene-d 8 > 81 96 4 Ethylbenzene 91 106 5 p-Xylene 91 106 6 m-Xylene 91 106 7 Isopropylbenzene 105 120 8 o-Xylene 91 106 9 Styrene 78 104

[0117] The difference between this example and Example 1 is only that the extractant is ethanol, and the rest are the same as those in Example 1.

[0118] Example 6

[0119] This example is to establish a detection method for 8 volatile benzene series compounds in electronic cigarettes

[0120] (1) Preparation of standard products

[0121] Precisely pipette 1.0 mL of the 8-component mixture standard solution with a concentration of 1000 μg / mL into a 100 mL volumetric flask, dilute it to the mark with methanol, and obtain a mixed standard solution with a concentration of 10 μg / mL. Then, perform serial dilution to obtain gradient concentration mixed standard solutions with concentrations of 5, 2.5, 1, 0.5, 0.1, 0.01, and 0.0001 μg / mL. Add the internal standard toluene-d 8 The concentration is 0.5 mg / L.

[0122] (2) Collection of aerosol

[0123] Place a Cambridge filter with a diameter of 44 mm in the collector, with the rough side of the filter facing the incoming smoke. Aspirate the S1 e-liquid sample according to a suction volume of 60 mL, one puff every 20 s, each puff lasting 3 s, and 15 puffs for each sample, to obtain the aerosol.

[0124] (3) Extraction

[0125] Take 1.0 g of the S1 e-liquid and the filter after collecting the aerosol, first add 1 mL of water to dissolve them separately, then add 15 mL of n-pentane separately, and add the internal standard toluene-d 8 The concentration is 0.5 mg / mL. Vortex and oscillate for extraction at 3000 r / min for 60 min, and take the supernatant for injection analysis.

[0126] (4) Detection and analysis

[0127] The conditions for GC-QTOF-MS detection are as follows:

[0128] DA-WAX (30 m × 0.25 mm × 0.25 μm) chromatographic column, column temperature program: 40 °C (held for 3 min) → 10 °C / min → 130 °C (held for 3 min) → 20 °C / min → 200 °C (held for 5 min), transfer line temperature: 240 °C; column flow rate: 1.5 mL / min; purge flow rate: 1.5 mL / min; split ratio: 20:1; chromatographic mass spectrometry interface temperature: 240 °C; ion source temperature: 230 °C; acquisition mode: Q3SCAN+SIM mode. The detection information of 8 volatile organic compounds and the internal standard is shown in Table 6.

[0129] Table 6

[0130]

[0131]

[0132] The difference from Example 1 is only that the addition amount of the extraction solution is 5 mL, and the rest are the same as those in Example 1.

[0133] Example 7

[0134] This example establishes a detection method for 8 volatile benzene series compounds in e-cigarettes

[0135] (1) Preparation of standard products

[0136] Precisely pipette 1.0 mL of the 8-component mixture standard product solution with a concentration of 1000 μg / mL into a 100 mL volumetric flask, dilute it to the scale with methanol, and obtain a mixed standard product solution with a concentration of 10 μg / mL. Then, perform serial dilution to obtain gradient concentration mixed standard product solutions with concentrations of 5, 2.5, 1, 0.5, 0.1, 0.01, and 0.0001 μg / mL. Add the internal standard substance toluene-d 8 The concentration is 0.5 mg / L.

[0137] (2) Collection of aerosol

[0138] Place a Cambridge filter with a diameter of 44 mm in the collector, with the rough side of the filter facing the incoming flue gas. Aspirate the S1 e-liquid sample according to a suction volume of 55 mL, one puff every 30 s, each puff lasting 5 s, and 15 puffs for each sample, to obtain the aerosol.

[0139] (3) Extraction

[0140] Take 1.0 g of the S1 e-cigarette e-liquid and the filter after collecting the aerosol, first add 1 mL of water to dissolve them respectively, then add 15 mL of n-pentane respectively, add the internal standard substance toluene-d 8 The concentration is 0.2 mg / mL, vortex and oscillate for extraction at 3000 r / min for 60 min, and take the supernatant for injection analysis.

[0141] (4) Detection and analysis

[0142] The conditions for GC-QTOF-MS detection are as follows:

[0143] DA-WAX (30m×0.25mm×0.25μm) chromatographic column, column temperature program: 40℃ (for 3min)→10℃ / min→130℃ (for 3min)→20℃ / min→200℃ (for 5min), transfer line temperature: 240℃; column flow rate: 1.5mL / min; purge flow rate: 1.5mL / min; split ratio: 20:1; chromatographic mass spectrometry interface temperature: 240℃; ion source temperature: 230℃; acquisition mode: Q3SCAN+SIM mode. The detection information of 8 volatile organic compounds and internal standards is shown in Table 7.

[0144] Table 7

[0145] Number Compound Quantitative ion (m / z) Qualitative ion (m / z) 1 Benzene 78 51 2 Toluene 91 51 3 <![CDATA[Toluene-d 8 > 81 96 4 Ethylbenzene 91 106 5 p-Xylene 91 106 6 m-Xylene 91 106 7 Isopropylbenzene 105 120 8 o-Xylene 91 106 9 Styrene 78 104

[0146] The only difference between the above method and Example 1 is that the concentration of the internal standard is 0.2 mg / mL, and the rest is consistent with Example 1.

[0147] Example 8

[0148] This example is to establish a detection method for 8 volatile benzene series in electronic cigarettes

[0149] (1) Preparation of standard samples

[0150] Accurately pipette 1.0 mL of 8 kinds of 1000 μg / mL mixed standard solutions into a 100 mL volumetric flask, dilute to volume with methanol to obtain a 10 μg / mL mixed standard solution, and then dilute to obtain gradient concentration mixed standard solutions of 5, 2.5, 1, 0.5, 0.1, 0.01 and 0.0001 μg / mL. Add the internal standard toluene-d 8 The concentration is 0.5mg / L.

[0151] (2) Aerosol capture

[0152] A Cambridge filter with a diameter of 44 mm was placed in the collector with the rough surface of the filter facing the incoming smoke. The S1 smoke oil sample was inhaled at a suction capacity of 55 mL, one puff every 20 seconds, each puff lasting 3 seconds, and 20 puffs per sample to obtain an aerosol.

[0153] (3) Extraction

[0154] Take 1.0g of S1 electronic cigarette oil and the filter after capturing aerosol, first add 1mL of water to dissolve, then add 15mL of n-pentane, and add internal standard toluene-d 8 The concentration was 0.5 mg / mL, and the extraction was carried out at 3000 r / min with vortex oscillation for 30 min. The supernatant was taken for sampling and analysis.

[0155] (4) Detection and analysis

[0156] The conditions for GC-QTOF-MS detection are as follows:

[0157] DA-WAX (30m×0.25mm×0.25μm) chromatographic column, column temperature program: 40°C (held for 3 min) → 10°C / min → 130°C (held for 3 min) → 20°C / min → 200°C (held for 5 min), transfer line temperature: 240°C; column flow rate: 1.5 mL / min; purge flow rate: 1.5 mL / min; split ratio: 20:1; chromatograph-mass spectrometry interface temperature: 240°C; ion source temperature: 230°C; acquisition mode: Q3SCAN+SIM mode. The detection information of 8 volatile organic compounds and internal standards is shown in Table 8.

[0158] Table 8

[0159]

[0160]

[0161] The difference from Example 1 is only that the vortex oscillation extraction time is 30 min, and the rest are the same as in Example 1.

[0162] Test Example 1

[0163] This test example conducts a system suitability test on this detection method

[0164] (1) Linear regression equation

[0165] The chromatograms of 8 volatile organic compounds in SIM mode are as Figure 1 shown

[0166] The detection information of 8 volatile organic compounds and internal standards in Example 1 is shown in Table 9. Taking the concentration ratio of the gradient concentration mixed standard solution as the abscissa and the peak area ratio as the ordinate to make a standard curve. The standard curves of each mixture are shown in Table 10. Select blank e-liquid and aerosol samples and add the target substances close to the low mass concentration (0.001 μg / mL), repeat the determination 11 times, calculate their standard deviation, and take 3 times the standard deviation as the detection limit (LOD) and 10 times the standard deviation as the quantification limit (LOQ).

[0167] Table 9

[0168] Number Compound Retention time (min) Quantitative ion (m / z) Qualitative ion (m / z) 1 Benzene 5.35 78 51 2 Toluene 7.15 91 51 3 <![CDATA[Toluene-d 8 > 7.17 81 96 4 Ethylbenzene 8.72 91 106 5 p-Xylene 8.84 91 106 6 m-Xylene 8.97 91 106 7 Isopropylbenzene 9.50 105 120 8 o-Xylene 9.72 91 106 9 Styrene 10.91 78 104

[0169] Table 10

[0170]

[0171] (2) Precision experiment

[0172] The mixed standard solution was continuously injected for analysis 6 times, and the RSD values of the peak areas of 8 volatile organic compounds were calculated, which were 3.46% (benzene), 1.98% (toluene), 3.10% (ethylbenzene), 3.25% (p-xylene), 3.55% (m-xylene), 2.13% (isopropylbenzene), 2.67% (o-xylene), and 2.64% (styrene), respectively. The results showed that the repeatability of this method met the requirements.

[0173] (3) Repeatability experiment

[0174] Six groups of S1 e-liquid and aerosol samples were prepared according to the method of Example 1, continuously injected for analysis, and the RSD values of the peak areas of 8 volatile benzene series compounds were calculated. The results of the repeatability experiment of the e-liquid samples are shown in Table 11, and the results of the repeatability experiment of the aerosol samples are shown in Table 12.

[0175] Table 11

[0176]

[0177]

[0178] Note: ND means below the detection limit.

[0179] Table 12

[0180] Compound 1 2 3 4 5 6 RSD Benzene 1216 1200 1204 1153 1126 1271 4.24％ Toluene ND ND ND ND ND ND - Ethylbenzene 3017 2943 2791 2992 3130 2952 3.73％ p-Xylene ND ND ND ND ND ND - m-Xylene ND ND ND ND ND ND - Isopropylbenzene ND ND ND ND ND ND - o-Xylene ND ND ND ND ND ND - Styrene ND ND ND ND ND ND -

[0181] Note: ND means below the detection limit.

[0182] (4) Stability test

[0183] E-liquid and aerosol samples were prepared according to the method of Example 1, and were injected for analysis at intervals of 0, 2, 4, 8, 12, and 24 h respectively. The RSD values of the peak areas of 8 volatile benzene series compounds were calculated. For the e-liquid samples, they were 4.66% (benzene) and 2.07% (ethylbenzene) respectively. For the aerosol samples, they were 3.67% (benzene) and 2.90% (ethylbenzene) respectively. The results showed that the stability of this method met the requirements.

[0184] Test Example 2

[0185] This test example is the spike recovery test

[0186] (1) E-liquid samples

[0187] Six 1-g blank e-liquid samples were weighed in parallel, added with a mixed standard solution at a concentration level of 1.0 μg / mL, extracted according to the extraction method of Example 1, and injected for analysis to investigate the spike recovery rate of the method. The results are shown in Table 13. The results showed that the spike recovery rates of 8 volatile benzene series compounds in the e-liquid were between 70.12% and 107.06%, and the RSD values were all less than 5%, indicating that the spike recovery rate of the method met the requirements.

[0188] Table 13

[0189]

[0190]

[0191] Note: ND means below the detection limit.

[0192] (2) Aerosol sample

[0193] Six blank Cambridge filter papers were taken, added with a mixed standard solution at a concentration level of 1.0 μg / mL, extracted according to the extraction method of Example 1, and analyzed by injection to investigate the spike recovery rate of the method. The results are shown in Table 14. The results show that the spike recovery rates of 8 volatile benzene series compounds in the aerosol are between 84.11% and 119.20%, and the RSD values are all less than 5%, indicating that the spike recovery rate of the method meets the requirements.

[0194] Table 14

[0195]

[0196]

[0197] Note: ND means below the detection limit.

[0198] Test Example 3

[0199] This test example analyzes the detection of the above-mentioned examples

[0200] According to the standard curve in this test example, the detection results of each example were obtained. The specific results are shown in Table 15.

[0201] Table 15

[0202] Group Benzene Toluene Ethylbenzene p-Xylene m-Xylene Isopropylbenzene o-Xylene Styrene Example 1 2.422 ND 0.713 ND ND ND ND ND Example 2 2.374 ND 0.699 ND ND ND ND ND Example 3 2.404 ND 0.712 ND ND ND ND ND Example 4 2.200 ND 0.591 ND ND ND ND ND Example 5 2.103 ND 0.503 ND ND ND ND ND Example 6 2.169 ND 0.507 ND ND ND ND ND Example 7 2.361 ND 0.695 ND ND ND ND ND Example 8 2.283 ND 0.710 ND ND ND ND ND

[0203] It can be seen from the results that:

[0204] 1. By comparing Example 1 with Examples 2 - 3, it can be seen that within the scope defined by the present invention, good detection effects are achieved.

[0205] 2. By comparing Example 1 with Examples 4 - 6, it can be seen that within the scope defined by the present invention, the extraction effect of the extractant n-pentane on 8 benzene series compounds is better than that of methanol and ethanol, and the amount of extractant used is small, but the extraction efficiency is relatively low.

[0206] 3. By comparing Example 1 with Example 7, it can be seen that within the scope defined by the present invention, the influence of the added internal standard concentration on the extraction efficiency is not significant.

[0207] 4. It can be seen from the comparison between Example 1 and Example 8 that within the scope defined by the present invention, the extraction time has a great influence on the extraction efficiency.

[0208] In summary, the present invention provides a method for detecting 8 volatile benzene series compounds in electronic cigarette oil and aerosol. Through methodological investigation and actual sample detection and analysis, it is proved that this method can meet the detection and analysis of both e-liquid samples and aerosol samples, and is simple and easy to operate.

[0209] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived within the technical scope disclosed by the present invention by those skilled in the art all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS, characterized in that: The determination method comprises: firstly adding an extraction liquid to a sample to be tested containing volatile benzene series to perform extraction, and then performing GC-QTOF-MS detection and analysis; The volatile benzene series substances include any one of benzene, toluene, ethylbenzene, p-xylene, m-xylene, o-xylene, isopropylbenzene or styrene, or a combination of at least two thereof.

2. The method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to claim 1, characterized in that: The types of samples to be tested include electronic cigarette oil and / or aerosol.

3. The method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to claim 2, characterized in that: The method for preparing the aerosol sample to be tested comprises: using a filter to capture the aerosol after inhaling the electronic cigarette oil; Preferably, the suction volume of the suction is 50-60 mL; Preferably, the number of suctions is 15-20 times; Preferably, each suction lasts for 2-5 seconds; Preferably, each suction interval is 20-40 seconds.

4. The method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to any one of claims 1 to 3, characterized in that: The extraction comprises: adding an extracting liquid to the electronic cigarette oil or the Cambridge filter after the aerosol is captured, and performing vortex oscillation extraction.

5. The method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to claim 4, characterized in that: The mass of the electronic cigarette oil is 0.5-1.5g; Preferably, the extract comprises any one of ethyl acetate, dichloromethane, cyclohexane or n-pentane, or a combination of at least two thereof; more preferably n-pentane; Preferably, the amount of the extract added is 10-20 mL; Preferably, the extract also includes an internal standard; Preferably, the internal standard comprises toluene-d8; Preferably, the concentration of the internal standard in the extract is 0.3-0.7 mg / mL; Preferably, the vortex oscillation extraction speed is 2000-4000r / min, and the time is 40-80min.

6. The method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to any one of claims 1 to 5, characterized in that: The detection method also includes the preparation of a standard solution and an internal standard solution.

7. The method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to claim 6, characterized in that: The concentration of the internal standard in the internal standard solution is 0.3-0.7 mg / mL; Preferably, the concentration range of volatile benzene series in the standard solution is 0.0001-5 μg / mL.

8. The method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to any one of claims 1 to 7, characterized in that: The column temperature program of the GC-QTOF-MS detection is as follows: the initial column temperature is 30-50°C for 1-5 min, then the temperature is increased to 120-130°C at 5-10°C / min and maintained for 1-5 min, then the temperature is increased to 190-210°C at 10-20°C / min and maintained for 3-5 min.

9. The method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to any one of claims 1 to 8, characterized in that: The split ratio of the GC-QTOF-MS detection is (15-25):1; Preferably, the chromatographic column flow rate detected by GC-QTOF-MS is 1.2-1.8 mL / min; Preferably, the ion source temperature of the GC-QTOF-MS detection is 220-240°C; Preferably, the purge flow rate of the GC-QTOF-MS detection is 1.2-1.8 mL / min; Preferably, the acquisition mode of the GC-QTOF-MS detection is Q3SCAN+SIM mode.

10. An application of the method for determining the content of volatile benzene series in electronic cigarettes based on GC-QTOF-MS according to any one of claims 1 to 9 in detecting volatile benzene series in electronic cigarette oil and aerosol.

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