CN108375641B - Method for detecting benzo [ a ] pyrene in tobacco smoke - Google Patents

Abstract

The invention discloses a method for detecting benzo [ a ] pyrene in tobacco smoke, which comprises the following steps: (A) placing the tobacco sample and the glass fiber filter disc under constant temperature and humidity for balancing for 48 hours; (B) weighing not less than 3.0g of the tobacco leaf sample obtained in the step A, placing the tobacco leaf sample into a quartz tube, heating by using infrared rays, carrying out temperature rise program heating, introducing air into the quartz tube during heating to simulate the combustion process of the tobacco leaves, stopping infrared ray heating after a period of time, introducing nitrogen into the quartz tube at a certain direction to simulate the smoldering process of the tobacco leaves, trapping chemical components in smoke by using a glass fiber filter disc, and repeatedly carrying out the steps of simulating combustion and simulating smoldering for a plurality of times; (C) putting the glass fiber filter disc into a conical flask, adding an internal standard substance, and extracting with an organic solvent; (D) the extract was analyzed by GC-MS. The method has the advantages that the using amount of tobacco shreds can exceed that of tobacco leaf raw materials of 4 cigarettes, the operation is simple and convenient, the manual intervention is less, the working efficiency is greatly improved, and the accurate analysis of trace benzo [ a ] pyrene in the smoke of the tobacco leaves is ensured.

Description

Method for detecting benzo [ a ] pyrene in tobacco smoke

Technical Field

The invention belongs to the technical field of analytical chemistry, and particularly relates to a simple, efficient, accurate and sensitive method for detecting benzo [ a ] pyrene in tobacco smoke. Wherein gas chromatography-mass spectrometry is commonly abbreviated as GC-MS in the field of analytical chemistry.

Background

The domestic and foreign research shows that: the health effects of smoking mainly come from the chemicals released by the combustion of tobacco. Among harmful components in the particulate phase of cigarette smoke, benzo [ α ] pyrene has the highest carcinogenic activity. Therefore, the method has important significance for accurately measuring the content of benzo [ a ] pyrene in the smoke of the cigarette. The cigarette smoke benzo [ alpha ] pyrene content is very low, the general concentration is in ng/count order, and the smoke sample matrix is very complex, so that the quantitative analysis difficulty of benzo [ alpha ] pyrene in the cigarette smoke is higher. At present, for analysis of benzo [ a ] pyrene in smoke of tobacco raw materials, cigarettes need to be rolled, then the cigarettes are smoked by a smoking machine, and mainstream smoke of more than 4 cigarettes is captured and then analyzed. The cigarette is made by manual rolling and a cigarette making machine, the manual cigarette is poor in stability, a large amount of raw materials are consumed for making by the cigarette making machine, the smoking machine consumes time for smoking and trapping smoke, and a large amount of manpower and material resources are consumed for the whole operation.

In order to simplify the experimental operation process and improve the analysis accuracy, researchers simulate the cigarette burning and smoking process by thermal cracking and thermogravimetry, extract the obtained smoke components or directly analyze the smoke components by using instruments such as GC/MS and the like, so that the cigarette rolling and a large number of pretreatment processes are avoided, the analysis time is saved, and the analysis accuracy is improved. Although the heating speed in thermal cracking is high, the detection is released after the capture by a cold trap, an adsorption tube and the like, and the amount of a loaded sample is small, so that trace chemical components are difficult to detect; in addition, the existing thermal cracking instrument adopts heating wires for heating, heating is not uniform, heating waste heat cannot be rapidly cooled, and the thermal cracking process cannot truly simulate cigarette smoking (only can simulate the cigarette combustion heating process, but cannot simulate the cooling process). Although the thermogravimetric analyzer has large bearing capacity, the heating speed is too slow, generally less than 10 ℃/s, and the rapid heating in the cigarette smoking process cannot be simulated, so that the chemical components generated in the smoking process cannot be accurately analyzed. Therefore, a new method is needed to realize the rapid analysis of benzo [ a ] pyrene in the tobacco smoke.

Disclosure of Invention

The invention provides a method for detecting benzo [ a ] pyrene in tobacco flue gas, which adopts an infrared mirror reflection furnace device to simulate a cigarette smoking and burning process and a smoldering process, wherein in the simulated burning process, air is introduced, and tobacco shreds can be quickly heated to the highest temperature of 900 ℃ for smoking cigarettes, so that the cigarettes can be fully burned; and in the process of simulating smoldering, stopping infrared heating, and introducing nitrogen to quickly realize cooling. The obtained flue gas is collected by a glass fiber filter disc, extracted and analyzed by GC-MS. The method ensures that the using amount of the tobacco shreds can exceed that of tobacco leaf raw materials of 4 cigarettes, ensures the analysis content of trace benzo [ a ] pyrene in the smoke, has simple and convenient operation and less manual intervention, greatly improves the working efficiency and the analysis accuracy, can meet the rapid analysis of a large amount of tobacco leaf raw materials, and provides a new method for the rapid analysis of trace benzo [ a ] pyrene in the smoke of the tobacco leaves.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for detecting benzo [ a ] pyrene in tobacco smoke comprises sample preparation and analysis, and specifically comprises the following steps:

(A) sample treatment: the tobacco sample and the glass fiber filter sheet are placed under constant temperature and constant humidity to be balanced for 48 hours;

(B) simulating tobacco leaf suction: weighing not less than 3.0g of the tobacco leaf sample obtained in the step A, placing the tobacco leaf sample into a quartz tube, placing the quartz tube into an infrared mirror reflection furnace, connecting a catcher filled with a glass fiber filter disc to the other end of the infrared mirror reflection furnace, heating the quartz tube by using an infrared ray heating program, introducing air into the quartz tube during heating to simulate the combustion process of the tobacco leaves, stopping infrared ray heating after a period of time, introducing nitrogen into the quartz tube by changing the direction to simulate the smoldering process of the tobacco leaves, repeatedly performing the steps of heating and introducing air and stopping heating and introducing nitrogen for a plurality of times, and taking out the glass fiber filter disc after simulated suction is completed;

(C) organic solvent extraction: b, putting the filter disc obtained in the step B into a 50mL conical flask, adding 10mL-20mL of organic solvent containing deuterated benzo [ a ] pyrene (D12-BaP), performing ultrasonic extraction for 10-20min, and concentrating the extract liquid to 1mL under reduced pressure;

(D) GC-MS analysis: and D, enabling the extraction liquid containing the benzo [ a ] pyrene obtained in the step C to enter a gas chromatography system, and carrying out mass spectrum detection and quantification.

Preferably, the tobacco leaf sample and the glass fiber filter sheet in the step A are processed by balancing for 48 hours under the conditions of the temperature of 22 ℃ +/-2 ℃ and the relative humidity of 60 +/-5%.

Preferably, the mass of the tobacco leaf sample in the step B is 3.0 g-10.0 g.

Preferably, the programmed temperature conditions of the infrared specular reflection furnace in the step B are as follows: the temperature is raised to 40 ℃ after 2s in the simulated combustion process, raised to 900 ℃ after 4s in the simulated smoldering process, lowered to 40 ℃ after 4s in the simulated smoldering process, and lowered to the room temperature after 2 s.

Preferably, the air is introduced at a flow rate of 40-50sccm and the nitrogen is introduced at a flow rate of 40-50sccm in step B.

Preferably, the organic solvent in step C is one of cyclohexane, dichloromethane and acetone.

Preferably, the GC-MS conditions in step D are as follows:

gas chromatographic column: HP-5MS (30 m.times.0.25 mm.times.0.25 μm); carrier gas: helium with purity more than or equal to 99.999%; flow rate: 1 mL/min; the sample inlet temperature is 280 ℃;

temperature program of chromatographic column: the initial temperature is 150 ℃, the temperature is kept for 1min, the temperature is increased to 200 ℃ at the speed of 10 ℃/min, then the temperature is increased to 280 ℃ at the speed of 5 ℃/min, and the temperature is kept for 10 min;

mass spectrum conditions: an electron bombardment source; the ion source temperature is 230 ℃, the transmission line temperature is 280 ℃, the scanning mass range is 50-400 amu, and the scanning interval is 0.5 s.

Compared with the prior art, the invention has the beneficial effects that:

1. by adopting an infrared mirror reflection furnace device and an infrared heating mode, the tobacco shreds can be quickly heated to the highest burning and smoking temperature of 900 ℃, so that the quick heating process after the cigarettes are ignited and smoked is realistically simulated. After the infrared heating is stopped, the temperature reduction process can be quickly realized because the infrared heating has no thermal delay effect and nitrogen is introduced into the sample in the direction change, so that the smoldering process is vividly simulated. Wherein the smoldering combustion process refers to an anoxic combustion process of the cigarette without human smoking (i.e. without oxygen supply).

2. The using amount of the tobacco shreds can reach or even exceed that of tobacco leaf raw materials of 4 cigarettes (about 2.8g of tobacco shreds), all the tobacco shreds are operated at any time of simulated heating or smoldering, the content of chemical components in the smoke is guaranteed to be high enough, the method is particularly suitable for analyzing trace chemical components in the smoke, the absolute content of trace chemical components of benzo [ a ] pyrene is guaranteed due to large sample amount, and the method can be completed by one-time analysis. Compared with the prior art, the traditional smoking simulator can only smoke one cigarette at a time, the total amount of the cut tobacco is small, and only a small section of cut tobacco burnt at the end or in shade participates in the experiment at any moment, so that the absolute content of trace chemical components is too low, and the analysis result is inaccurate; to analyze accurately, the conventional smoking simulator has to smoke a plurality of cigarettes one by one to accumulate the trace chemical components, which takes too long time.

3. The method is simple and convenient to operate, does not need to carry out pretreatment, has less manual intervention, greatly improves the working efficiency and the analysis accuracy, and can meet the requirement of rapid analysis of a large amount of tobacco leaf raw materials.

Drawings

FIG. 1 is a schematic view of an infrared specular reflection furnace apparatus according to the present invention. Wherein the reference numerals have the following meanings: 1-a sample; 2-a quartz tube; 3-a control system; 4-glass fiber filter; 5-heating the inner wall of the infrared mirror reflection furnace.

FIG. 2 is a gas chromatogram of a tobacco leaf smoke sample in the method for detecting benzo [ a ] pyrene in tobacco leaf smoke of the invention.

Detailed Description

The present invention is further described with reference to the accompanying drawings, but the invention is not limited in any way, and any changes or substitutions that may be made on the basis of the claims are within the scope of the invention.

Example 1

A method for detecting benzo [ a ] pyrene in tobacco smoke comprises the following steps:

(A) sample treatment: the tobacco leaf sample and the glass fiber filter sheet are placed under constant temperature and humidity (the temperature is 22 +/-2 ℃ and the relative humidity is 60 +/-5%) to be balanced for 48 hours;

(B) simulating tobacco leaf suction: and B, weighing 3.5g of the tobacco leaf sample obtained in the step A, putting the tobacco leaf sample into a special quartz tube, putting the quartz tube into an infrared mirror reflection furnace, connecting a catcher filled with a glass fiber filter disc to the other end of the infrared mirror reflection furnace, and performing simulated suction by utilizing infrared heating. The programmed temperature conditions of the infrared mirror reflection furnace are as follows: heating to 40 ℃ for 2s, heating to 900 ℃ for 4s, cooling to 40 ℃ for 4s, and cooling to room temperature for 2 s. The combustion process and the smoldering process were alternately repeated 3 times. The programmed temperature rise process of the infrared mirror surface reflection furnace is provided with the following air program: air is continuously introduced at the flow rate of 50sccm in the temperature rising process, and nitrogen is continuously introduced at the flow rate of 50sccm in the temperature reducing process. After the simulated suction is finished, taking out the glass fiber filter disc;

(C) organic solvent extraction: placing the filter disc obtained in the step B into a 50mL conical flask, adding 1mL of 20 mu g/L deuterated benzo [ a ] pyrene (D12-Ba ] P) solution, accurately adding 19mL of cyclohexane, performing ultrasonic extraction for 10min, and concentrating the extract under reduced pressure to 1 mL;

(D) GC-MS analysis: and D, enabling the extraction liquid containing the benzo [ a ] pyrene obtained in the step C to enter a gas chromatography system, and carrying out mass spectrum detection and quantification. Gas chromatographic column: HP-5MS (30 m.times.0.25 mm.times.0.25 μm); carrier gas: helium with purity more than or equal to 99.999%; flow rate: 1 mL/min; the sample inlet temperature is 280 ℃; temperature program of chromatographic column: the initial temperature was 150 ℃ and held for 1min, ramped up to 200 ℃ at a rate of 10 ℃/min, ramped up to 280 ℃ at a rate of 5 ℃/min and held for 10 min. Mass spectrum conditions: an electron bombardment source; the ion source temperature is 230 ℃, the transmission line temperature is 280 ℃, the scanning mass range is 50-400 amu, and the scanning interval is 0.5 s.

For 3 flue-cured tobacco samples, the determination results of benzo [ a ] pyrene were 6.8, 8.6 and 10.2ng/g, respectively, and the recovery rates were 95.4%, 95.8% and 95.9%, respectively.

In contrast, the same tobacco leaves were rolled into cigarettes, 5 cigarettes (3.5g of tobacco) were smoked with a conventional smoking machine, the cigarette smoke and filter were collected, and analyzed by GC-MS after extraction, with benzo [ a ] pyrene assay results of 6.6, 8.7 and 10.4ng/g, and recovery rates of 95.1%, 95.4% and 95.6, respectively. The content obtained by the method is close to the content obtained by a simulated smoking machine, and the result of the method is consistent with the result of the method.

In contrast, in the same tobacco leaves, the benzo [ a ] pyrene was measured at 7.6, 9.8 and 11.8ng/g by thermal cracking analysis, and the recovery rates were 93.5%, 93.8% and 94.5%, respectively. Because benzo [ a ] pyrene is mainly produced in the combustion process, the thermal cracking method cannot simulate the smoldering process (the benzo [ a ] pyrene produced in the smoldering process is less), and the obtained content is obviously higher than that obtained by a simulated smoking machine, so that the simulation of the cigarette smoking condition by the method of the invention is more vivid.

Example 2

A method for detecting benzo [ a ] pyrene in tobacco smoke comprises the following steps:

(A) sample treatment: the tobacco leaf sample and the glass fiber filter sheet are placed under constant temperature and humidity (the temperature is 22 +/-2 ℃ and the relative humidity is 60 +/-5%) to be balanced for 48 hours;

(B) simulating tobacco leaf suction: and B, weighing 7.0g of the tobacco leaf sample obtained in the step A, putting the tobacco leaf sample into a special quartz tube, putting the quartz tube into an infrared mirror reflection furnace, connecting a catcher filled with a glass fiber filter disc to the other end of the infrared mirror reflection furnace, and performing simulated suction by utilizing infrared heating. The programmed temperature conditions of the infrared mirror reflection furnace are as follows: heating to 40 ℃ for 2s, heating to 900 ℃ for 4s, cooling to 40 ℃ for 4s, and cooling to room temperature for 2 s. The combustion process and the smoldering process were alternately repeated 3 times. The programmed temperature rise process of the infrared mirror surface reflection furnace is provided with the following air program: air is continuously introduced at the flow rate of 50sccm in the temperature rising process, and nitrogen is continuously introduced at the flow rate of 50sccm in the temperature reducing process. After the simulated suction is finished, taking out the glass fiber filter disc;

(C) organic solvent extraction: placing the filter disc obtained in the step B into a 50mL conical flask, adding 1mL of 20 mu g/L deuterated benzo [ a ] pyrene (D12-Ba ] P) solution, accurately adding 19mL of cyclohexane, performing ultrasonic extraction for 10min, and concentrating the extract under reduced pressure to 1 mL;

(D) GC-MS analysis: and D, enabling the extraction liquid containing the benzo [ a ] pyrene obtained in the step C to enter a gas chromatography system, and carrying out mass spectrum detection and quantification. Gas chromatographic column: HP-5MS (30 m.times.0.25 mm.times.0.25 μm); carrier gas: helium with purity more than or equal to 99.999%; flow rate: 1 mL/min; the sample inlet temperature is 280 ℃; temperature program of chromatographic column: the initial temperature was 150 ℃ and held for 1min, ramped up to 200 ℃ at a rate of 10 ℃/min, ramped up to 280 ℃ at a rate of 5 ℃/min and held for 10 min. Mass spectrum conditions: an electron bombardment source; the ion source temperature is 230 ℃, the transmission line temperature is 280 ℃, the scanning mass range is 50-400 amu, and the scanning interval is 0.5 s.

For 3 additional flue-cured tobacco samples, the benzo [ a ] pyrene measurements were 5.8, 9.4 and 11.5ng/g, respectively, with recoveries of 95.2%, 95.8% and 96.2%, respectively.

In contrast, the same tobacco leaves are rolled into cigarettes, 10 cigarettes (7.0g of cut tobacco) are smoked by a traditional smoking machine, cigarette smoke and filter tips are collected, after extraction, analysis is carried out by GC-MS, the determination results of benzo [ a ] pyrene are respectively 5.6, 9.6 and 11.2ng/g, and the recovery rates are respectively 94.9%, 95.2% and 95.8%. The content obtained by the method is close to the content obtained by a simulated smoking machine, and the result of the method is consistent with the result of the method.

In contrast, in the same tobacco leaves, analysis was performed by a thermal cracking method, and the determination results of benzo [ a ] pyrene were 6.5, 10.8 and 12.8ng/g, respectively, and the recovery rates were 92.7%, 93.4% and 93.8%, respectively. Because benzo [ a ] pyrene is mainly produced in the combustion process, the thermal cracking method cannot simulate the smoldering process (the benzo [ a ] pyrene produced in the smoldering process is less), and the obtained content is obviously higher than that obtained by a simulated smoking machine, so that the simulation of the cigarette smoking condition by the method of the invention is more vivid.

Test example 1

As in example 1, 1 of the flue-cured tobacco samples was selected, and the samples were subjected to parallel measurement 6 times (same batch processing) under the same conditions, and the relative standard deviation of the results of the 6 parallel measurements was calculated to obtain benzo [ a ] pyrene with RSD of 4.3% and recovery rate of 95.5%; in addition, samples are analyzed by the same procedure according to the traditional GB \ T21130-2007 method, the RSD of the benzo [ a ] pyrene is measured to be 4.6%, the recovery rate is 94.6%, and the result shows that the precision of the test result of the improved method can meet the detection requirement.

Claims (6)

1. A method for detecting benzo [ a ] pyrene in tobacco smoke is characterized by comprising sample preparation and analysis, and specifically comprises the steps of simulating cigarette smoking by using an infrared mirror reflection furnace, trapping smoke by using a glass fiber filter, extracting an organic solvent and carrying out GC-MS (gas chromatography-mass spectrometry), wherein the steps are as follows:

(A) sample treatment: the tobacco sample and the glass fiber filter sheet are placed under constant temperature and constant humidity to be balanced for 48 hours;

(B) simulating tobacco leaf suction: weighing not less than 3.0g of the tobacco leaf sample obtained in the step A, placing the tobacco leaf sample into a quartz tube, placing the quartz tube into an infrared mirror reflection furnace, connecting a catcher filled with a glass fiber filter disc to the other end of the infrared mirror reflection furnace, heating the quartz tube by using an infrared ray heating program, introducing air into the quartz tube during heating to simulate the combustion process of the tobacco leaves, stopping infrared ray heating after a period of time, introducing nitrogen into the quartz tube by changing the direction to simulate the smoldering process of the tobacco leaves, repeatedly performing the steps of heating and introducing air and stopping heating and introducing nitrogen for a plurality of times, and taking out the glass fiber filter disc after simulated suction is completed;

(C) organic solvent extraction: b, putting the filter disc obtained in the step B into a 50mL conical flask, adding 10mL-20mL of organic solvent containing deuterated benzo [ a ] pyrene D12-Ba P, performing ultrasonic extraction for 10-20min, and concentrating the extract liquid to 1mL under reduced pressure;

(D) GC-MS analysis: c, enabling the extraction liquid containing benzo [ a ] pyrene obtained in the step C to enter a gas chromatography system, and carrying out mass spectrum detection and quantification;

the temperature programming conditions of the infrared mirror reflection furnace in the step B are as follows: the temperature is raised to 40 ℃ after 2s in the simulated combustion process, raised to 900 ℃ after 4s in the simulated smoldering process, lowered to 40 ℃ after 4s in the simulated smoldering process, and lowered to the room temperature after 2 s.

2. The method according to claim 1, wherein the tobacco sample and the glass fiber filter of step a are equilibrated at a temperature of 22 ℃ ± 2 ℃ and a relative humidity of 60 ± 5% for 48 hours.

3. The method according to claim 1, wherein the mass of the tobacco leaf sample in step B is 3.0g to 10.0 g.

4. The method according to claim 1, wherein the air is introduced at a flow rate of 40 to 50sccm and the nitrogen is introduced at a flow rate of 40 to 50sccm in step B.

5. The method of claim 1, wherein the organic solvent in step C is one of cyclohexane, dichloromethane, and acetone.

6. The method according to claim 1, wherein the GC-MS conditions in step D are as follows:

gas chromatographic column: the HP-5MS specification is 30m multiplied by 0.25mm multiplied by 0.25 mu m; carrier gas: helium with purity more than or equal to 99.999%; flow rate: 1 mL/min; the sample inlet temperature is 280 ℃;

temperature program of chromatographic column: the initial temperature is 150 ℃, the temperature is kept for 1min, the temperature is increased to 200 ℃ at the speed of 10 ℃/min, then the temperature is increased to 280 ℃ at the speed of 5 ℃/min, and the temperature is kept for 10 min;

mass spectrum conditions: an electron bombardment source; the ion source temperature is 230 ℃, the transmission line temperature is 280 ℃, the scanning mass range is 50-400 amu, and the scanning interval is 0.5 s.

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