CN110186996B - Online measurement device for photoelectric efficiency curve of gas phase component of smoldering side stream smoke of cigarette - Google Patents

Abstract

The invention discloses an on-line measuring device for photoelectric efficiency curve of gas phase component of smoldering side stream smoke of cigarettes, which is characterized in that: the non-combustion end of the cigarette is inserted into a cigarette socket of a stepping cigarette injector capable of controlling the movement direction and speed of the cigarette, the combustion end extends into the inner center of the thick end part of the fish tail cover, the outlet of the thin end part of the fish tail cover is sequentially connected with the flowmeter and the diaphragm vacuum pump through the flue gas flow tube through the Cambridge filter holder, the flue gas flow tube between the Cambridge filter holder and the flowmeter is communicated with one port of a flue gas transmission quartz capillary tube penetrating through the tube wall, and the other port of the flue gas transmission quartz capillary tube penetrates through the cavity wall of the photoionization flight time mass spectrometer to enter the vacuum ultraviolet ionization region. The invention has simple structure and is suitable for on-line measurement of the photoionization efficiency curve of the gas phase component of the smoldering side stream smoke of the cigarettes, thereby realizing the on-line identification function of isomers in the cigarettes.

Description

Online measurement of photoionization efficiency curve of gas phase components of cigarette smoldering side stream smoke device

Technical field

The invention belongs to the technical field of chemical composition analysis of cigarette smoke, and specifically relates to an online measurement device for the photoionization efficiency curve of the gas phase components of the smoldering side-flow smoke of cigarettes, thereby achieving the same-differentiation analysis of the gas-phase components of the smoldering side-flow smoke of cigarettes. The function of online identification of constructs.

Background technique

The combustion of cigarettes usually includes two ways: smoking and smoldering. Smoldering refers to the burning of cigarettes when they are smoked, and smoldering refers to the natural burning of cigarettes between puffs. Due to the different combustion methods of cigarette smoking and smoldering, two forms of cigarette smoke are produced, namely mainstream smoke and side flow smoke. The smoke that is sucked out from the filter end of the cigarette during smoking is called mainstream smoke; the smoke that is released from the burning end between puffs and diffuses through the cigarette paper and directly enters the environment is called side flow smoke, of which the former is the side stream of the cigarette. The main source of flue gas. Research shows that fresh cigarette mainstream smoke and side stream smoke are both high-concentration and highly active aerosols. In particular, the gas phase substances accounting for more than 90% by weight are active in nature, and the internal material composition changes rapidly. Therefore, in order to obtain nascent smoke information, conduct in-depth research on the release characteristics of smoke during cigarette combustion, and scientifically evaluate the quality, style characteristics and harmfulness of cigarette smoke, people use infrared spectroscopy methods and soft ionization mass spectrometry methods to analyze fresh cigarettes. A lot of research work has been carried out on online and real-time analysis of flue gas gas phase components.

Infrared spectroscopy is a fast and non-destructive analysis method. At present, this method has been widely used in the online analysis of gas phase components of cigarette mainstream and side stream smoke. However, infrared spectroscopy performs qualitative and quantitative analysis of components based on the specific absorption wavelength of compounds. Therefore, for complex flue gas systems, due to overlap and interference between spectral peaks, this method can only analyze a small number of components in the flue gas. Target substances are analyzed.

Vacuum ultraviolet photoionization time-of-flight mass spectrometry technology is an excellent, universal and fast detection method. It usually uses vacuum ultraviolet lamp, laser or synchrotron radiation as the ionization light source, and can perform soft ionization on organic compounds. Ionization almost only produces parent ions of the analyte without producing fragments, so this technology is very suitable for online and real-time research on complex mixtures. In recent years, Streibel et al. (Streibel T, Mitschke S, Adam T, et al. Time-resolved analysis of the emission of sidestream smoke (SSS) from cigarettes during smoking by photo ionisation/time-of-flight massspectrometry (PI-TOFMS): towards a better description of environmental tobacco smoke. Anal Bioanal Chem, 2013, 405(22):7071-7082.) For the first time, vacuum ultraviolet photoionization time-of-flight mass spectrometry using laser as the light source was used to analyze the chemical composition of cigarette sidestream smoke online. This type of technology has the advantages of fast response, high sensitivity, and is suitable for multi-component detection. However, since the photon energy generated by lasers and vacuum UV lamps is usually fixed, the flight time of laser vacuum UV photoionization sources and vacuum UV lamp ionization sources Mass spectrometry technology often can only provide photoionization mass spectra at a fixed photon energy, and isomers cannot be distinguished based on mass spectra alone. Although isomers have the same molecular weight, their physical and chemical properties are different, and even their sensory characteristics and harmfulness are also significantly different. Therefore, it is of great significance to identify and analyze isomers in cigarette smoke during online and real-time analysis.

Synchrotron radiation vacuum ultraviolet photoionization time-of-flight mass spectrometry technology can not only measure the photoionization mass spectrum of the substance to be measured at a fixed photon energy, but also utilize the characteristics of synchrotron radiation vacuum ultraviolet light with continuously tunable wavelength. Samples with stable flow are sampled and measured to obtain photoionization efficiency curves of chemical components with different mass numbers, thereby enabling qualitative identification and quantitative comparison of isomers in the substance to be tested. For example, Wang Chenghui and others (Wang Chenghui, Hu Yonghua, Wang Jian, et al. Calculation of ionization energy of chemical components of cigarette smoke and its application in qualitative analysis. Tobacco Science and Technology, 2011, 293(12):26-33.) have used A self-made manual cigarette smoke sampling syringe combined with synchrotron radiation photoionization time-of-flight mass spectrometry was used to online measure the photoionization efficiency curve of the gas phase chemical components of mainstream cigarette smoke, and the ionization energy of the material molecules was obtained based on the "inflection point" on the curve. The identification of isomers in the gas phase of cigarette smoke has been achieved. Pan et al. (Pan Y, Hu Y H, Wang J, et al. Online characterization of isomeric/isobaric components in the gas phase of mainstream cigarette smoke by tunablesynchrotron radiation vacuum ultraviolet photoionization time-of-flight massspectrometry and photoionization efficiency curve simulation. AnalyticalChemistry, 2013,85(24):11993-12001.) Using the same experimental device as above, combined with the simulation of photoionization efficiency curve, a relatively comprehensive identification of isomers in the gas phase of mainstream cigarette smoke was conducted. In the patent application with application number 201720575482.2, the applicant disclosed a measuring device for the photoionization efficiency curve of the gas phase components of mainstream cigarette smoke, which can realize online measurement of mainstream cigarette smoke under different puff numbers under standard cigarette smoking conditions. Photoionization efficiency curve of gas phase components. However, due to the different generation methods of cigarette mainstream smoke and side-stream smoke, the above devices are not suitable for online measurement of the photoionization efficiency curve of the gas phase components of cigarette side-stream smoke. In addition, the offline analysis device for cigarette side-flow smoke widely used in the tobacco industry and the above-mentioned online analysis device reported by Streibel et al. generally insert the filter end of the cigarette into a fixed cigarette holder in the smoking machine and Insert the combustion end into the fishtail hood, and use a vacuum pump to suck the side flow flue gas. When the smoking machine periodically smokes cigarettes, side-flow smoke will be generated periodically and cannot provide a stable smoke injection flow. Even when the smoking machine does not smoke and allows the cigarette to smolder naturally, as the cigarette burns, the length of the cigarette gradually becomes shorter, and the cigarette burning cone gradually approaches the fishtail cover, which will cause more smoke. The gas is adsorbed on the side wall of the fishtail cover; on the other hand, due to the different air flow rates in different parts of the fishtail cover, the combustion state of the cigarette combustion cone will be different, which will also affect the stability of the side flow smoke injection flow. sex. Therefore, this type of analysis device is not suitable for online measurement of the photoionization efficiency curve of cigarette sidestream smoke, and there are currently no reports on measurement methods and devices for the photoionization efficiency curve of cigarette sidestream smoke components.

Contents of the invention

In order to avoid the shortcomings of the above-mentioned prior art, the present invention provides a method with simple results, convenient operation and stable smoke injection flow, which can realize online measurement of the photoionization efficiency curve of the gas phase components of the smoldering side flow smoke of cigarettes. The device provides a good technical means for tobacco science and technology personnel to online analyze the isomers in the gas phase components of cigarette side stream smoke.

The present invention solves the technical problems by adopting the following technical solutions:

The invention is a device for measuring the photoionization efficiency curve of the gas phase components of smoldering side-flow smoke of cigarettes. It is characterized by: a stepping cigarette sampler, a fishtail cover, a photoionization time-of-flight mass spectrometer and a smoke transmission quartz capillary. ;

The stepper cigarette sampler includes: a controller, a servo motor, a conveyor belt, a cigarette slide rail, a "Π" type push rod and an infrared probe; the controller is connected to the servo motor and the infrared probe through wires. The probes are connected; one end of the conveyor belt is loaded on the rotating shaft of the servo motor, and the other end is loaded on the driven shaft. One end of the "Π"-shaped push rod is connected to the conveyor belt through a slider fixed on the conveyor belt. The conveyor belt is connected, and the other end is connected to a cigarette socket placed in the cigarette slide rail and into which cigarettes can be inserted;

The fishtail cover is a "convex" glass cylinder, which is composed of a thick end part and a thin end part; central vertical lines are arranged on the pipe wall of the thick end part of the fishtail cover, which are perpendicular to each other and on the same plane. There are two round holes inside, one of which is the round hole for inserting cigarettes, and the other round hole is the infrared detection round hole on the same side as the infrared probe; the outlet of the thin end part of the fishtail cover passes through the Cambridge filter The holder is connected to the flow meter and diaphragm vacuum pump in sequence through the flue gas flow pipe;

The photoionization time-of-flight mass spectrometer is provided with a synchrotron radiation vacuum ultraviolet light inlet and a vacuum ultraviolet photoionization zone internally, and an upper vacuum exhaust port and a lower vacuum exhaust port are externally provided;

One port of the flue gas transmission quartz capillary is connected to the flue gas flow tube between the Cambridge filter holder and the flow meter, and the other port passes through the cavity wall of the photoionization time-of-flight mass spectrometer. Enter the vacuum ultraviolet photoionization zone.

The present invention is also characterized by an online measuring device for photoionization efficiency curve of smoldering side-flow smoke gas phase components in that: the running direction and running speed of the rotating shaft of the servo motor can be set and controlled by the controller, and When the cigarette is burning, the running speed of the rotating shaft can also be automatically controlled by the infrared probe and the controller.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

1. According to the generation method of smoldering side-flow smoke of cigarettes, the present invention uses a stepping cigarette sampler to transport the cigarettes to be tested, and places the cigarettes to be tested in the cigarette slide rails, so that when the cigarettes move, There will be no left or right offset. At the same time, infrared probes are used to monitor the front and rear positions of the cigarette combustion cone, ensuring that the combustion cone burns at the center of the fishtail cover when the cigarette is smoldering, maximizing the stable smoke injection during mass spectrometry injection. The supply of flow can better realize online and real-time measurement of the photoionization efficiency curve of the gas phase components of the smoldering side stream smoke of cigarettes.

2. The invention has a simple structure and is easy to operate. It is not only suitable for online measurement of the photoionization efficiency curve of the gas phase components of the smoldering side flow smoke of special research cigarettes, but can also conveniently measure the gas phase components of the smoldering side flow smoke of ordinary cigarettes. Photoionization efficiency curve.

Description of the drawings

Figure 1 is a schematic structural diagram of the present invention;

Figure 2 is a side structural schematic diagram of the servo motor and the rotating shaft of the present invention;

Numbers in the picture: 1 step cigarette sampler, 2 controller, 3 servo motor, 4 cigarette slide rail, 5 cigarette socket, 6 cigarettes, 7 cigarette insertion round hole, 8 infrared detection round hole, 9 Infrared probe, 10 driven shaft, 11 conveyor belt, 12 fish tail cover, 13 slider, 14 "Π" type push rod, 15 rotating shaft, 16 Cambridge filter holder, 17 flue gas flow tube, 18 flow meter, 19 diaphragm vacuum pump, 20 flue gas transmission quartz capillary, 21 photoionization time-of-flight mass spectrometer, 22 vacuum ultraviolet photoionization zone, 23 synchrotron radiation vacuum ultraviolet light introduction port, 24 upper vacuum exhaust port, 25 lower vacuum exhaust port.

Figure 3 is the photoionization efficiency curve of several representative smoke components with mass numbers of 54, 78, 92 and 106 respectively in the smoldering side stream smoke gas phase of the cigarette in Example 1.

Figure 4 is the photoionization efficiency curve of several representative smoke components with mass numbers of 54, 78, 92 and 106 respectively in the smoldering side stream smoke gas phase of the cigarette in Example 2.

Detailed ways

The present invention will be further described below through specific embodiments and in conjunction with the accompanying drawings.

As shown in Figures 1 and 2, each component of the device includes: a stepper cigarette injector 1, a fishtail cover 12, a photoionization time-of-flight mass spectrometer 21 and a flue gas transmission quartz capillary 20.

The stepper cigarette sampler 1 is composed of a controller 2, a servo motor 3, a conveyor belt 11, a cigarette slide 4, a "Π"-shaped push rod 14 and an infrared probe 9 and other components. Among them: the controller 1 is connected to the servo motor 3 and the infrared probe 9 respectively through wires; one end of the conveyor belt 11 is loaded on the rotating shaft 15 of the servo motor 3, and the other end is loaded on the driven shaft 10; "Π" type push rod 14 One end is connected to the conveyor belt 11 through the slider 13 fixed on the conveyor belt 11, and the other end is connected to the cigarette socket 5 placed in the cigarette slide rail 4 and into which the cigarette 6 can be inserted.

The fishtail cover 12 is a "convex" glass cylinder, which is composed of a thick end part and a thin end part; the pipe wall of the thick end part of the fishtail cover 12 is provided with central vertical lines that are perpendicular to each other and in the same plane. 2 round holes, one of which is the round hole 7 for cigarette insertion, and the other round hole is the infrared detection round hole 8 on the same side as the infrared probe 9; the outlet of the thin end part of the fishtail cover 12 is clamped by the Cambridge filter The device 16 is connected to the flow meter 18 and the diaphragm vacuum pump 19 in sequence through the flue gas flow pipe 17.

The photoionization time-of-flight mass spectrometer 21 is provided with a synchrotron radiation vacuum ultraviolet light inlet 23 and a vacuum ultraviolet photoionization region 22 inside, and an upper vacuum exhaust port 24 and a lower vacuum exhaust port 25 are provided outside.

One port of the flue gas transmission quartz capillary 20 is connected to the flue gas flow tube 17 between the Cambridge filter holder 16 and the flow meter 18, and the other port passes through the cavity wall of the photoionization time-of-flight mass spectrometer 21 and enters the vacuum ultraviolet in the photoionization zone 22.

In the specific implementation, the settings of the controller 2 include four modes, namely: forward mode of constant speed operation, reverse mode of constant speed operation, infrared detection mode and stop operation mode. When the forward mode of constant speed operation or the reverse mode of constant speed operation is started, the rotating shaft 15 of the servo motor 3 rotates forward or reverse, thereby moving the cigarette socket 5 and the cigarette through the conveyor belt 11 and the "Π" type push rod 14 6 moves forward or reverse at a certain set rate; when the infrared detection mode is started, the cigarette socket 5 and the cigarette cigarette 6 only move in the direction of the fishtail cover 12, and the movement speed is combined by the infrared probe 9 and the controller 2 Automatic control; when the stop mode is started, the cigarette socket 5 and the cigarette 6 stop moving.

The infrared probe 9 is mounted on a base that can be adjusted up and down and rotated horizontally; the flue gas transmission quartz capillary 20 is located partially between the flue gas flow tube 17 and the cavity wall of the vacuum ultraviolet photoionization zone 22 of the photoionization time-of-flight mass spectrometer 21 There is an electric heating jacket, and the heating temperature is set and controlled by a dedicated temperature controller, and there is a gap between the flue gas transmission quartz capillary 20 and the flue gas flow tube 17 and the photoionization zone 22 cavity wall of the photoionization time-of-flight mass spectrometer 21. It can be connected or fixed in any way that does not leak air; the thin end part of the fishtail cover 12 and the Cambridge filter disc holder 16 can also be connected or fixed in any way that does not leak air.

The photoionization time-of-flight mass spectrometer 21 used in the present invention is an instrument jointly developed by Anhui China Tobacco Industry Co., Ltd. and the National Synchrotron Radiation Laboratory of the University of Science and Technology of China. Its mass resolution is better than 2000, and its light source can use a vacuum ultraviolet lamp. , can also make synchrotron radiation of vacuum ultraviolet light. When synchrotron radiation vacuum ultraviolet light is used as the ionization light source, the measurement method can adopt two modes, one is the detection mode of fixed photon energy, and the other is the detection mode of continuously scanning photon energy. In the present invention, synchrotron radiation vacuum ultraviolet light is used as the ionization light source, and a detection mode of continuous scanning photon energy is adopted.

Before the experiment, turn on the working power of the photoionization time-of-flight mass spectrometer 21, set its energy scan step, the measurement time of each mass spectrum and the photon energy scan range; install the Cambridge filter in the Cambridge filter holder 16 ; Turn on the diaphragm vacuum pump 19; set the working flow of the flow meter 18; set the heating temperature of the flue gas transmission quartz capillary 20; then, rotate and adjust the direction of the fishtail cover 12 so that the cigarette is inserted into the round hole 7 and faces the cigarette slide. Rail 4, and make the infrared detection round hole 8 face the infrared probe 9. At the same time, adjust the position of the infrared probe 9 so that the infrared light emitting hole, the center of the infrared detection round hole 8 and the thick end part of the fishtail cover 12 are in the same straight line. superior. When the vacuum degree of the photoionization time-of-flight mass spectrometer 21 meets the requirements and the heating temperature of the flue gas transmission quartz capillary 20 reaches the set temperature and stabilizes, the sample test can be performed.

During the experiment, first turn on the working power of the controller 2, set the movement rate of the cigarette socket 5, and start the reverse mode of constant speed operation. At this time, the cigarette socket 5 will move in the opposite direction of the fishtail cover 12. When the movement reaches the appropriate After reaching the position, start the stop operation mode and insert the cigarette 6 to be tested into the cigarette socket 5; then start the forward mode of constant speed operation. At this time, the cigarette socket 5 will drive the cigarette 6 towards the fishtail cover 12. Movement, when the front end of the cigarette 6 passes through the cigarette insertion hole 7 and exceeds the center of the thick end part of the fishtail cover 12 by 4-5mm, the stop operation mode is started again, and the cigarette 6 stops moving; then electronic ignition is used The device ignites the cigarette 6 upward from the inside of the port of the thick end part of the fishtail cover 12, and starts the infrared detection mode of the controller 2. When the cigarette 6 starts to move, the photoionization time-of-flight mass spectrometer 21 is started to pair the cigarette. Gas is measured.

After the measurement is completed, a series of photoionization mass spectra under different photon energies can be obtained, and then the peak areas of different mass spectrum peaks in each mass spectrum are integrated, and the integrated value of the same mass spectrum peak area is plotted against the photon energy. The photoionization efficiency spectral curves of different mass number smoke components in the smoldering side stream smoke gas phase of cigarettes can be obtained.

Example 1

A special research cigarette with a length of 15cm, a circumference of 24.2mm and no filter was used as the research object; the inner diameter and length of the smoke transmission quartz capillary were set to 100μm and 25cm respectively, and its heating temperature was set to 200 ℃; the working flow rate of the flow meter is set to 2000mL/min; the energy scanning step of the photoionization time-of-flight mass spectrometer is set to 4 Angstroms, the measurement time of each mass spectrum is set to 10 seconds, and the photon energy scanning range is set to It is set at 8.0~10.6eV. After the measurement is completed, using the photon energy value as the abscissa and the ion intensity value as the ordinate, the photoionization efficiency curves of flue gas components with different mass numbers can be obtained.

The photoionization efficiency curves of several representative smoke components with mass numbers of 54, 78, 92 and 106 in the vapor phase of the smoldering side-stream smoke of cigarettes are shown in Figure 3.

Example 2

Basically the same as Example 1, the difference is that a conventional cigarette with a cigarette length of 84mm, a tipping paper length of 32mm, and a circumference of 24.2mm is selected as the research object; The three energy ranges of 8.0-8.7eV, 8.7-9.6eV and 9.6-10.6eV are measured separately, that is, the first cigarette is measured in the energy range of 8.0-8.7eV, and then the second cigarette is measured in the energy range of 8.7-9.6eV. cigarette, and finally the third cigarette was measured in the energy range of 9.6-10.6eV. After the measurement, integrate the photon energy of each scanning energy segment and the corresponding mass spectrum peak ion intensity into the same document, and plot the photon energy value as the abscissa and the ion intensity value as the ordinate to obtain different mass charges. Photoionization efficiency curve of specific flue gas components in the photon energy range of 8.0 to 10.6eV.

The photoionization efficiency curves of several representative smoke components with mass numbers of 54, 78, 92 and 106 in the vapor phase of cigarette smoldering sidestream smoke are shown in Figure 4.

Therefore, the present invention provides an online measurement device for the photoionization efficiency curve of the gas phase components of the smoldering side-flow smoke of cigarettes, which can effectively realize online measurement of the photoionization efficiency curves of the gas-phase components of the smoldering side-flow smoke of different types of cigarettes. , thus providing an effective technical method and means for tobacco scientists to scientifically identify and analyze the isomers in the gas phase components of cigarette smoldering side-stream smoke.

Claims (2)

1. An on-line measuring device for photoelectric efficiency curve of gas phase component of smoldering side stream smoke of cigarette is characterized in that: a step cigarette injector (1), a fish tail cover (12), a photoionization flight time mass spectrometer (21) and a flue gas transmission quartz capillary tube (20) are arranged;

the step cigarette injector (1) comprises: the device comprises a controller (2), a servo motor (3), a conveyor belt (11), a cigarette slide rail (4), a pi-shaped push rod (14) and an infrared probe (9); the controller (2) is respectively connected with the servo motor (3) and the infrared probe (9) through leads; one end of the conveyor belt (11) is loaded on a rotating shaft (15) of the servo motor (3), and the other end of the conveyor belt is loaded on a driven shaft (10); one end of the pi-shaped push rod (14) is connected with the conveyor belt (11) through a sliding block (13) fixed on the conveyor belt (11), and the other end of the pi-shaped push rod is connected with a cigarette socket (5) which is arranged in the cigarette sliding rail (4) and can be inserted into a cigarette (6);

the fish tail cover (12) is a 'convex' glass cylinder and consists of a thick end part and a thin end part; 2 circular holes with center vertical lines perpendicular to each other and in the same plane are formed in the pipe wall of the thick end part of the fish tail cover (12), wherein one circular hole is a cigarette inserting circular hole (7), and the other circular hole is an infrared detection circular hole (8) on the same side as the infrared probe (9); the outlet of the thin end part of the fish tail cover (12) is sequentially connected with a flowmeter (18) and a diaphragm vacuum pump (19) through a Cambridge filter disc holder (16) and a flue gas circulation pipe (17);

the photoelectric ionization time-of-flight mass spectrometer (21) is internally provided with a synchrotron radiation vacuum ultraviolet light introduction port (23) and a vacuum ultraviolet light ionization region (22), and is externally provided with an upper vacuum extraction port (24) and a lower vacuum extraction port (25);

one port of the flue gas transmission quartz capillary tube (20) is communicated with a flue gas flow tube (17) between the Cambridge filter holder (16) and the flowmeter (18), and the other port passes through the cavity wall of the photoionization time-of-flight mass spectrometer (21) and enters a vacuum ultraviolet ionization region (22).

2. The on-line measurement device for the photoelectric efficiency curve of the gas phase component of the smoldering side stream smoke of the cigarette according to claim 1, which is characterized in that: the running direction and the running speed of the rotating shaft (15) of the servo motor (3) can be set and controlled by the controller (2), and the running speed of the rotating shaft (15) can be automatically controlled by the combination of the infrared probe (9) and the controller (2) when the cigarette (6) burns.