Puff-by-puff nicotine trapping system and puff-by-puff total nicotine and free nicotine content determination method

Abstract

The invention relates to the technical field of cigarette detection, and discloses a puff-by-puff nicotine trapping system and a puff-by-puff total nicotine and free nicotine content determination method. The system comprises a fishtail cover; the side-flow flue gas puff-by-puff trapping module comprises a particulate matter trapping module and a gas phase matter trapping module which are connected in series; the mainstream smoke puff-by-puff trapping module comprises a suction simulation unit; the inlet ends of the main stream smoke trapping gas paths are converged and connected to the common end of the three-way valve (2). According to the structure of the trapping system, particulate matters and gas-phase matters in main stream smoke and side stream smoke of cigarettes can be trapped at the same time, the content of puff-by-puff total nicotine and free nicotine in the trapped main stream smoke and side stream smoke can be measured, and comprehensive, dynamic and accurate analysis of the cigarette smoke can be realized.

Description

Technical Field

[0001] This invention relates to the field of cigarette testing technology, specifically to a puff-by-puff nicotine collection system. Furthermore, it relates to a method for determining the total nicotine and free nicotine content in cigarette smoke per puff. Background Technology

[0002] Mainstream cigarette smoke analysis is a crucial aspect of cigarette quality evaluation. Nicotine, a unique component of tobacco, significantly impacts cigarette safety and sensory quality. In tobacco and tobacco products, nicotine exists in both protonated and free forms, with the majority existing in the protonated form. Studies have shown that the strength of cigarette smoke, reflecting the physiological intensity of smoking, is related to the content of free nicotine in the smoke. Therefore, exploring pretreatment and measurement methods for different forms of nicotine in cigarette smoke is of paramount importance.

[0003] During cigarette smoking, the chemical composition of the mainstream and sidestream smoke changes with the length of the cigarette, meaning there are differences in the chemical composition of each puff. Domestic and international research on the puff-by-puff composition of cigarette smoke mainly focuses on the mainstream smoke. Ceschini et al. conducted puff-by-puff studies using a button-controlled single-puff smoking machine. Plunkett et al. used a dual infrared diode array laser system to simultaneously analyze and detect multiple gas-phase components in cigarette smoke puff by puff. Zhao Xiaodong et al. invented a puff-by-puff collection device for the Borgwaldt RM20H rotary smoking machine, achieving puff-by-puff collection of the mainstream cigarette smoke. However, the collection steps for each single-puff particulate phase in the puff-by-puff collection device are relatively cumbersome and complex.

[0004] In recent years, as people have become increasingly concerned about the health effects of smoking, their attention has extended beyond smokers to include environmental smoke, with sidestream cigarette smoke being used as a crucial indicator for predicting indoor air quality. Therefore, establishing a simple system for simultaneously capturing and measuring puff-by-puff nicotine and free nicotine in both mainstream and sidestream smoke is essential. This system can more accurately reflect the release of nicotine and free nicotine during smoking, providing guidance for cigarette formulation design, product maintenance, and quality control. Furthermore, it offers theoretical support for a proper understanding and evaluation of the impact of smoking on ambient air quality. While these methods have achieved significant results in smoke capture, they still lack the ability to simultaneously capture both mainstream and sidestream smoke in each puff, making it difficult to achieve comprehensive, dynamic, and accurate analysis of cigarette smoke. Therefore, developing a dedicated device capable of capturing all smoke in real time for each puff is crucial for achieving dynamic and accurate analysis of different types of cigarette smoke. Summary of the Invention

[0005] In view of the above-mentioned deficiencies or defects in the prior art, the present invention aims to provide a puff-by-puff nicotine capture system and a method for determining the content of total nicotine and free nicotine in each puff. The capture system is designed to simultaneously capture particulate matter and gaseous matter in the mainstream and sidestream smoke of cigarettes, and can measure the content of total nicotine and free nicotine in the captured mainstream and sidestream smoke, thereby enabling comprehensive, dynamic and accurate analysis of cigarette smoke.

[0006] To achieve the above objectives, a first aspect of the present invention provides a full flue gas capture system, comprising: Fishtail cover, used to guide and capture sideflow smoke; The side-flow flue gas collection module includes a particulate matter collection module and a gaseous matter collection module connected in series. The particulate matter collection module includes multiple parallel particulate matter collection gas paths, with the inlet ends of each gas path converging and connecting to the outlet of the fishtail hood, and the outlet ends of each gas path converging and connecting to the gaseous matter collection module. The particulate matter collection gas path includes a side-flow flue gas front-end control valve, a side-flow flue gas filter collector, and a side-flow flue gas rear-end control valve connected in series. The gaseous matter collection module includes a sampling pump and a side-flow flue gas collection bag connected in series. Mainstream flue gas capture modules include: The suction simulation unit includes a cigarette holder for fixing the cigarette, a suction power source for generating simulated suction power, and a three-way valve disposed between the cigarette holder and the suction power source; the three-way valve is configured to selectively connect the suction power source to the cigarette holder or the ambient atmosphere. Multiple parallel mainstream flue gas collection paths are connected to the common end of a three-way valve at their inlet ends. Each mainstream flue gas collection path includes a mainstream flue gas filter collector and a mainstream flue gas inlet-to-outlet switching control valve arranged sequentially. The common end of each mainstream flue gas inlet-to-outlet switching control valve is equipped with a suction power source, or the common ends of all mainstream flue gas inlet-to-outlet switching control valves are connected to the suction port of the suction power source. The switching end of each mainstream flue gas inlet-to-outlet switching control valve is connected to a mainstream flue gas inlet-to-outlet collection bag for storing flue gas through the inlet control valve of the mainstream flue gas inlet-to-outlet collection bag.

[0007] In some embodiments, along the direction of flue gas flow, a filter and a flow regulating valve are sequentially installed on the connecting pipeline between the gas phase capture module and the particulate phase capture module.

[0008] In some embodiments, the three-way valve is a three-way clamp valve.

[0009] The puff-by-puff nicotine collection system provided by this invention, through the configuration of a sidestream smoke collection module, a mainstream smoke collection module, and a fishtail hood, can simultaneously collect particulate matter and gaseous matter in both mainstream and sidestream cigarette smoke. It can also measure the total and free nicotine content in the collected mainstream and sidestream smoke, enabling comprehensive, dynamic, and precise analysis of cigarette smoke. Furthermore, the system offers flexible configuration, allowing for the selection of different experimental schemes, making it suitable not only for monitoring cigarette quality but also for scientific research on cigarette components.

[0010] A second aspect of this invention provides a method for determining the total nicotine and free nicotine content in cigarette smoke per puff, the method comprising the following steps: S10, Preparation steps: Set suction parameters and number of suction ports; S20, Synchronous puff-by-puff collection steps: Light the cigarette, start the suction power source (1) and sampling pump (44); For the Nth puff (N=1,2,3...): By opening the Nth side flow flue gas front-end control valve and the Nth side flow flue gas rear-end control valve, the side flow flue gas flows through the Nth side flow flue gas filter collector in sequence and is then transported by the sampling pump to the side flow flue gas collection bag. By controlling the Nth mainstream flue gas outlet switching control valve, the mainstream flue gas flows through the Nth mainstream flue gas filter collector in sequence and is then sucked in by the suction power source. Then, the valve is switched to connect to the mainstream flue gas outlet collection bag and the flue gas is pushed into the bag. S30, Measurement steps: After the collection is completed, the mainstream flue gas filter collector and the side flow flue gas filter collector corresponding to the N port are mixed with the extraction solvent to obtain the extract. The extract was subjected to GC / MS analysis to obtain the total nicotine content during the Nth puff. The extract and water were mixed and separated to obtain an aqueous phase and an organic phase. The organic phase was then analyzed by GC / MS to obtain the content of free nicotine during the Nth puff.

[0011] The method for determining the total nicotine and free nicotine content in cigarette smoke provided by this invention enables quantitative analysis of total nicotine and free nicotine in both mainstream and sidestream smoke, thereby achieving comprehensive, dynamic, and accurate analysis of cigarette smoke. This method is simple, rapid, and suitable for batch sample analysis, showing significant application prospects.

[0012] In some embodiments, the specific steps of storing flue gas in the sidestream flue gas capture bag and the mainstream flue gas capture bag in the synchronous capture step include: For mainstream flue gas capture bags: During suction, the control valves of the designated mainstream flue gas are switched one by one to connect the corresponding mainstream flue gas filter collector and the suction power source, and the flue gas is sucked into the suction power source. During exhaust, the main flue gas switching control valve is switched to connect the suction power source with the main flue gas collection bag, pushing the flue gas into the bag. For side-flow flue gas collection bags: During the suction cycle of the target inlet, the corresponding front-end control valve and rear-end control valve of the side flow flue gas are opened. Keep the sampling pump running continuously, and deliver the generated side flue gas to the side flue gas collection bag through the corresponding side flue gas filter collector; After the target side flow flue gas collection time is reached, the corresponding front-end and rear-end control valves for the side flow flue gas are closed.

[0013] In some embodiments, in step S20, after the Nth suction is completed, a purge suction is performed; wherein, before each purge suction, the three-way valve is switched to be connected to the ambient atmosphere to draw in air, and the purge suction gas is pushed into the mainstream flue gas collection bag.

[0014] In some embodiments, in step S30, GC / MS employs HP-INNOWAX columns.

[0015] In some embodiments, in step S30, the extraction solvent is selected from at least one of dichloromethane, isopropanol, tert-butyl methyl ether, and n-hexane.

[0016] In some embodiments, the extraction solvent is dichloromethane.

[0017] In some embodiments, in step S30, the water is neutral water; the preparation process of neutral water includes: boiling the water and then sealing it so that the temperature of the water is room temperature and the pH is 7±0.2.

[0018] In some embodiments, in step S30, the organic phase is dried before being determined by GC / MS.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of one embodiment of the nicotine collection system of the present invention; Figure 2 This is the extraction efficiency result of different extraction solvents for nicotine in Example 2 of the present invention; Figure 3 This is the total ion chromatogram of free nicotine in the side-flow flue gas in Embodiment 2 of the present invention.

[0021] Explanation of reference numerals in the attached figures 1. Suction syringe; 2. Three-way valve; 3. Fish tail cover; 4. Ashtray; 5. Cigarette holder; 6-11. Mainstream smoke filter trap; 18-23. Mainstream smoke switching control valve; 24-29. Sidestream smoke front-end control valve; 30-35. Sidestream smoke filter trap; 36-41. Sidestream smoke rear-end control valve; 42. Filter; 43. Flow regulating valve; 44. Sampling pump. Detailed Implementation

[0022] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0023] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the orientation in the assembled and used state. "Inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] The first aspect of this invention provides a puff-by-puff nicotine collection system, such as Figure 1 As shown, the puff-by-puff nicotine collection system includes a fishtail hood 3, a sideflow flue gas puff-by-puff collection module, and a mainstream flue gas puff-by-puff collection module.

[0026] Fishtail Cover 3 The fishtail cover 3 is manufactured according to the relevant provisions of standard YC / T 185-2004, and is used to guide the direction of the sideflow smoke of cigarettes and capture some particulate matter in the sideflow smoke. In one optional embodiment, the fishtail cover 3 includes an air inlet and an air outlet, with the air inlet being wider and the air outlet being narrower. In another optional embodiment, the fishtail cover 3 also includes a guide rail, which is installed perpendicular to the horizontal plane. The fishtail cover 3 is fixed on the slider of the guide rail and located directly above the cigarette, so that the fishtail cover can move in a direction perpendicular to the horizontal plane. The side wall of the fishtail cover 3 near the air inlet is provided with a notch for the cigarette to enter. When the cigarette is held in the cigarette holder 5, it can enter the fishtail cover 3 through the notch. The fishtail cover 3 is placed vertically with the air inlet facing downwards and the air outlet facing upwards. An ashtray 4 can be placed below the air inlet of the fishtail cover 3 to catch the ash that falls during cigarette combustion. Its area and shape should cover as much of the area where ash might fall as possible. A cigarette holder 5 is used to hold the cigarette to be tested.

[0027] Side-flow flue gas collection module The side-flow flue gas collection module includes a particulate matter collection module and a gaseous matter collection module connected in series. The particulate matter collection module includes multiple particulate matter collection gas paths connected in parallel. The inlet ends of each gas path are connected to the outlet of the fishtail hood 3, and the outlet ends of each gas path are connected to the gaseous matter collection module. The particulate matter collection gas path includes a side-flow flue gas front-end control valve, a side-flow flue gas filter collector, and a side-flow flue gas rear-end control valve connected in series. The gaseous matter collection module includes a sampling pump 44 and a side-flow flue gas collection bag connected in series.

[0028] Cambridge filters can be installed within the 30-35mm section of the sideflow flue gas filter trap to capture particulate matter in the sideflow flue gas. Different sizes of Cambridge filters can be used depending on the specific requirements, such as 44mm or 92mm.

[0029] The side-flow flue gas front-end control valves 24-29 can be normally closed electromagnetic clamp valves to avoid direct contact between the valve core and the flue gas, which would affect the collection of particulate matter and prevent blockage. The side-flow flue gas rear-end control valves 36-41 can be electromagnetic three-way valves to control the on / off of the collection path.

[0030] More preferably, along the direction of flue gas flow, a filter 42 and a flow regulating valve 43 are also sequentially installed on the connecting pipeline between the gas phase capture module and the particulate phase capture module.

[0031] The purpose of filter 42 is to purify the side-flow flue gas to protect downstream precision components. Although most of the particulate matter in the side-flow flue gas is effectively intercepted by the fishtail hood 3 and the side-flow flue gas filter traps 30-35, extremely small particles and liquid aerosols may still penetrate or circumvent the filter. If these substances are allowed to directly enter the subsequent gas path, they may contaminate, clog, or even damage the precision valve passage of the downstream flow control valve 43 and the internal gas chamber and diaphragm of the sampling pump 44, affecting their normal operating performance and service life. In addition, if gas phase composition analysis equipment such as gas bags or analyzers are connected downstream, these residual particulate matter will cause cross-contamination and interfere with the accuracy of the analysis results.

[0032] Therefore, setting up filter 42 is equivalent to adding a safety barrier, thereby ensuring the long-term stable operation of flow regulating valve 43 and sampling pump 44, and maintaining the integrity and reliability of the data of the entire device.

[0033] In one specific embodiment of the present invention, the filter 42 may be a micro-mist filter with a filtration capacity of 0.01μm to further filter the side-flow flue gas and protect the components in the downstream gas path.

[0034] The purpose of the flow control valve 43 is to achieve precise and stable control of the sampling flow rate of the side-stream flue gas. In analytical chemistry, any sampling and measurement must be performed under known, constant, and repeatable conditions. For the capture of side-stream flue gas, the sampling flow rate is a crucial parameter. The sampling pump 44 itself can provide suction power and allow for approximate flow rate setting, but its output flow rate may fluctuate due to factors such as load and voltage, and fine-tuning is difficult. This is precisely the function of the flow control valve 43. Based on the flow indicator of the sampling pump 44, the operator can precisely set and stabilize the sampling flow rate of the side-stream flue gas at a specific value required by standard methods, such as 3.0 L / min, by finely adjusting this valve. If the sampling flow rate fluctuates, even if the same mass of particulate matter is captured, the flue gas concentration it represents will be different, which will lead to the incomparability of experimental data between different batches or even different numbers of samples.

[0035] In one specific embodiment of the present invention, the sampling pump 44 is selected to be an adjustable diaphragm air pump. The sampling pump 44 also includes a pump controller and a real-time flow indicator. The pump controller is used to control the suction flow rate of the air pump, for example, the suction flow rate is adjustable in the range of 0~6 L / min, and the real-time flow indicator monitors the actual flow rate of the side-flow flue gas in the air pipe. By setting the suction flow rate of the diaphragm air pump to a value slightly higher than the predetermined suction flow rate by the pump controller, and then fine-tuning it by the real-time flow indicator and the multi-turn metering needle valve, the sampling flow rate of the side-flow flue gas can be adjusted to a fairly accurate value.

[0036] Mainstream flue gas capture module The mainstream smoke collection module includes: a suction simulation unit, comprising a cigarette holder 5 for fixing cigarettes, a suction power source 1 for generating simulated suction power, and a three-way valve 2 disposed between the cigarette holder 5 and the suction power source 1; the three-way valve 2 is configured to selectively connect the suction power source 1 to the cigarette holder 5 or the ambient atmosphere; multiple parallel mainstream smoke collection gas paths, the inlet ends of each gas path converging and connecting to the common end of the three-way valve 2; each mainstream smoke collection gas path includes a mainstream smoke filter collector and a mainstream smoke collection switching control valve arranged sequentially; the common end of each mainstream smoke collection switching control valve is equipped with the suction power source 1, or the common ends of all mainstream smoke collection switching control valves converge and connect to the suction port of the suction power source 1; the switching end of each mainstream smoke collection switching control valve is connected to a mainstream smoke collection gas bag for storing smoke through a mainstream smoke collection gas bag inlet control valve.

[0037] The three-way valve 2 includes three ports: port A, port B, and port C. Port A is connected to the outlet of the cigarette holder 5, port B is connected to the ambient atmosphere, and port C is connected to the inlet of the main exhaust pipe of the mainstream smoke.

[0038] The suction power source 1 includes a drive motor, a piston driven by the drive motor, and a cylinder housing the piston; the drive motor is electrically connected to a controller configured to control the drive motor so that the piston moves within the cylinder according to a predetermined suction program.

[0039] In a preferred embodiment of the present invention, the suction power source 1 may be a suction syringe. The suction syringe has a piston structure, and a stepper motor drives the piston to move within a circular glass tube, thereby simulating the inhalation of a cigarette by a person. The suction syringe also includes a controller for controlling the movement mode of the stepper motor. Those skilled in the art can easily understand that by changing the parameters of the controller, the suction mode, such as the suction duration, suction cycle, suction curve, etc., can be changed, and the purpose of calibration such as capacity can be achieved. Further details are omitted here.

[0040] The labyrinth ring and neoprene gasket installed inside the cigarette holder 5 wrap around the cigarette butt area, serving to seal and fix it in place.

[0041] The inlet ends of each mainstream flue gas collection path converge and connect to the common end of the three-way valve 2. Each mainstream flue gas collection path includes a mainstream flue gas filter collector 6-11 and mainstream flue gas inlet-to-outlet switching control valves 18-23 arranged sequentially. The common end of each mainstream flue gas inlet-to-outlet switching control valve 18-23 is equipped with a suction power source 1, or the common ends of all mainstream flue gas inlet-to-outlet switching control valves 18-23 converge and connect to the suction port of a suction power source 1. The switching ends of each mainstream flue gas inlet-to-outlet switching control valve 18-23 are connected to a mainstream flue gas inlet-to-outlet collection bag for storing flue gas through the inlet control valve of the mainstream flue gas inlet-to-outlet collection bag.

[0042] In some embodiments, the three-way valve 2 is an electromagnetic three-way clamp valve, with its normally closed end connected to the cigarette holder 3 and its normally open end connected to the atmospheric environment.

[0043] Cambridge filters can be installed in the mainstream flue gas filter traps 6-11 to capture particulate matter in the mainstream flue gas. The number of mainstream flue gas filter traps is the same as the number of individual suction ports. Their inlet ends are connected together in parallel and then connected to the common end of the three-way valve 2. Different specifications of Cambridge filters can be used depending on the actual situation, such as 44mm or 92mm filters.

[0044] The main flue gas switching control valve is a set of three-way valves used for switching flue gas from one outlet to another, and the number is the same as that of the main flue gas filter trap.

[0045] In some embodiments, the normally closed end of the mainstream flue gas switching control valve is connected in series with the outlet end of the mainstream flue gas filter trap, and their common end is connected together in parallel and then connected to the suction port of the suction power source.

[0046] The mainstream flue gas capture bag is used to store mainstream flue gas. The mainstream flue gas capture bag includes multiple openings, which are connected to the mainstream flue gas switching control valves, so that the mainstream flue gas in each mainstream flue gas capture path can be discharged into the bag.

[0047] A second aspect of this invention provides a method for determining the total nicotine and free nicotine content in cigarette smoke per puff, based on the puff-by-puff nicotine collection system described in the first aspect above. This method includes the following steps: S10, Preparation steps: Set suction parameters and number of suction ports; S20, Synchronous puff-by-puff collection steps: Light the cigarette, start the suction power source 1 and sampling pump 44; for the Nth puff (N=1,2,3...): By opening the Nth side flow flue gas front-end control valve and the Nth side flow flue gas rear-end control valve, the side flow flue gas flows through the Nth side flow flue gas filter collector in sequence and is then transported by the sampling pump 44 to the side flow flue gas collection bag. By controlling the Nth mainstream flue gas outlet switching control valve, the mainstream flue gas flows through the Nth mainstream flue gas filter collector in sequence and is then sucked in by the suction power source 1. Then, the valve is switched to connect to the mainstream flue gas outlet collection bag and the flue gas is pushed into the bag. S30, Measurement steps: After the collection is completed, the mainstream flue gas filter collector and the side flow flue gas filter collector corresponding to the N port are mixed with the extraction solvent to obtain the extract. The extract was subjected to GC / MS analysis to obtain the total nicotine content during the Nth puff. The extract and water were mixed and separated to obtain an aqueous phase and an organic phase. The organic phase was then subjected to GC / MS analysis to determine the content of free nicotine during the Nth puff.

[0048] In some embodiments, the suction parameters include temperature, relative humidity, suction capacity, suction duration, suction interval, and side-flow flue gas suction flow rate.

[0049] In some embodiments, the number of suction ports is 3-10, which can be adjusted according to the actual situation.

[0050] More preferably, in step S20, the specific steps of storing the flue gas in the sidestream flue gas capture bag and the mainstream flue gas capture bag in the synchronous capture step include: For mainstream flue gas capture bags: During suction, the specified mainstream flue gas switching control valve is controlled to connect the corresponding mainstream flue gas filter collector to the suction power source 1, and the flue gas is sucked into the suction power source 1. During exhaust, the main flue gas switching control valve is switched to connect the suction power source 1 with the main flue gas collection bag, pushing the flue gas into the bag. For side-flow flue gas collection bags: During the suction cycle of the target inlet, the corresponding front-end control valve and rear-end control valve of the side flow flue gas are opened. Keep the sampling pump 44 running continuously, and deliver the generated side flue gas to the side flue gas collection bag through the corresponding side flue gas filter collector; After the target side flow flue gas collection time is reached, the corresponding front-end and rear-end control valves for the side flow flue gas are closed.

[0051] More preferably, in step S20, after completing the Nth suction, a purge suction is performed; wherein, before each purge suction, the three-way valve 2 is switched to be connected to the ambient atmosphere to draw in air, and the purge suction gas is pushed into the mainstream flue gas collection bag.

[0052] In some embodiments, in step S30, the GC / MS can employ a column conventionally selected in the art, such as an HP-INNOWAX column or a DB-5 column. In one specific embodiment of the present invention, the GC / MS uses an HP-INNOWAX column, which provides better peak shape and higher detection accuracy.

[0053] In some embodiments, in step S30, the extraction solvent is selected from at least one of dichloromethane, isopropanol, tert-butyl methyl ether, and n-hexane. In one specific embodiment of the invention, the extraction solvent is dichloromethane.

[0054] In some embodiments, in step S30, the water is neutral water; the preparation process of neutral water includes: boiling the water and then sealing it so that the temperature of the water is room temperature and the pH is 7 ± 0.2. The pH can be adjusted using dilute acid or dilute alkali as a pH adjuster.

[0055] In some embodiments, in step S30, the organic phase is dried before GC / MS determination. Drying can be performed using conventional organic phase drying methods selected in the art. In one specific embodiment of the invention, anhydrous sodium sulfate can be used to dry the organic phase.

[0056] The present invention will be described in detail below through embodiments.

[0057] Unless otherwise specified, the raw materials used in the following examples are all commercially available products.

[0058] Example 1 A puff-by-puff nicotine collection system, see Figure 1 It includes a suction syringe 1, a three-way valve 2, a fishtail cover 3, an ashtray 4, a cigarette holder 5, a mainstream smoke filter trap 6~11, a mainstream smoke switching control valve 18~23, a side-flow smoke front-end control valve 24~29, a side-flow smoke filter trap 30~35, a side-flow smoke rear-end control valve 36~41, a filter 42, a flow regulating valve 43, and a sampling pump 44; The mainstream flue gas filter trap 6 and the port-to-port switching control valve 23 constitute the first port mainstream flue gas particulate matter collection path; The mainstream flue gas filter trap 7 and the port-to-port switching control valve 22 constitute the second mainstream flue gas particulate matter collection path; The mainstream flue gas filter trap 8 and the port-to-port switching control valve 21 constitute the mainstream flue gas particulate matter and collection path at the third port. The mainstream flue gas filter trap 9 and the port-to-port switching control valve 20 constitute the fourth port mainstream flue gas particulate matter collection path; The mainstream flue gas filter trap 10 and the port-to-port switching control valve 19 constitute the fifth port mainstream flue gas particulate matter collection path; The mainstream flue gas filter trap 11 and the port-to-port switching control valve 18 constitute the sixth port mainstream flue gas particulate matter collection path; The side-flow smoke front-end control valve 24~29, side-flow smoke filter collector 30~35, side-flow smoke rear-end control valve 36~41, filter 42, flow regulating valve 43, and sampling pump 44 constitute the cigarette side-flow smoke particulate matter collection section. The side-flow flue gas front-end control valve 24, the side-flow flue gas filter collector 30, and the side-flow flue gas rear-end control valve 36 constitute the first side-flow flue gas particulate matter collection path. The side-flow flue gas front-end control valve 25, the side-flow flue gas filter collector 31, and the side-flow flue gas rear-end control valve 37 constitute the second side-flow flue gas particulate matter collection path. The side-flow flue gas front-end control valve 26, the side-flow flue gas filter collector 32, and the side-flow flue gas rear-end control valve 38 constitute the third side-flow flue gas particulate matter collection path. The side-flow flue gas front-end control valve 27, the side-flow flue gas filter collector 33, and the side-flow flue gas rear-end control valve 39 constitute the fourth side-flow flue gas particulate matter collection path. The side-flow flue gas front-end control valve 28, the side-flow flue gas filter collector 34, and the side-flow flue gas rear-end control valve 40 constitute the fifth side-flow flue gas particulate matter collection path. The side-flow flue gas front-end control valve 29, the side-flow flue gas filter collector 35, and the side-flow flue gas rear-end control valve 41 constitute the sixth side-flow flue gas particulate matter collection path. Example 1 can capture up to 6 main and side stream flues one by one. Those skilled in the art can easily understand that to capture more than 6 smokes one by one, it can be achieved by adding parallel capture paths. The air inlet ends of the mainstream smoke filter traps 6~11 are connected in parallel, and then connected to the common end of the three-way valve 2 through an air pipe; the three-way valve 2 is an electromagnetic three-way clamp valve, whose normally closed end is connected to the cigarette holder 5, and its normally open end is connected to the atmospheric environment.

[0059] The side-flow flue gas front-end control valves 24-29 adopt normally closed electromagnetic clamp valves to avoid direct contact between the valve core and the flue gas, which would affect the collection of particulate matter and prevent blockage. The side-flow flue gas rear-end control valves 36-41 adopt electromagnetic three-way valves to control the on / off of the collection path. The labyrinth ring and neoprene gasket installed inside the cigarette holder 5 wrap around the cigarette butt area, serving to seal and fix it. The inlet ends of the side-flow flue gas front-end control valves 24~29 are connected together in parallel, and then connected to the upper air outlet of the fishtail cover through an air pipe; The material and dimensions of the fishtail cover 3 are processed in accordance with the relevant provisions in standard YC / T 185-2004, and are used to capture particulate matter in part of the side-flow flue gas; Filter 42 uses a micro-mist filter with a filtration capacity of 0.01μm to further filter the side-flow flue gas and protect the components in the downstream gas path; The flow regulating valve 43 is used to precisely control and regulate the suction flow rate of the side-flow flue gas, and is achieved by using a multi-turn metering needle valve; The sampling pump 44 provides the suction power for the side-flow flue gas and selects to use an adjustable diaphragm air pump. The sampling pump 44 also includes a pump controller and a real-time flow indicator. The pump controller is used to control the suction flow rate of the air pump. The suction flow rate is adjustable from 0 to 6 L / min. The real-time flow indicator monitors the actual flow rate of the side-flow flue gas in the air pipe.

[0060] Example 2 A method for determining the total nicotine and free nicotine content in cigarette smoke per puff, based on the puff-by-puff nicotine collection system provided in Example 1, the method comprising: S1. Capture of mainstream and sidestream flue gas: The cigarette samples were balanced according to the method of GB / T 16447—2004, and then screened for draw resistance and weight to prepare cigarette samples. After the aspiration syringe was calibrated, aspiration was performed in an environment with a temperature of 22±2℃ and a relative humidity of 60±5%. The aspiration volume was set to 35mL, the aspiration duration to 2 seconds, the aspiration interval to 60 seconds, the side flow flue gas aspiration flow rate to 3L / min, and the number of aspiration ports to 6. Open the side-flow smoke front control valve 24 and the side-flow smoke rear control valve 36, switch the direction of the three-way valve 2 to the cigarette holder 5, switch the direction of the port-to-port switching control valve 23 to the mainstream smoke filter trap 6, and keep the port-to-port switching control valves 18~22 isolated from the corresponding mainstream smoke filter trap. Install the fishtail cover 3, the main flow smoke filter trap and the side flow smoke filter trap, prepare the cigarette sample, light the cigarette, and at the same time start the suction syringe and sampling pump to collect the main flow and side flow smoke. Light the cigarette and start the suction syringe 1 to complete the first suction. When the suction syringe 1 is reset, switch the direction of the control valve 23 to the inlet control valve of the gas bag 12 to discharge the main smoke into the gas bag. Because the existence of dead volume is unavoidable due to factors such as air pipe connection and valve core, a certain number of cleaning suctions (volume) must be performed to ensure the collection effect in order to capture the mainstream flue gas more completely. After the first puff, immediately switch the three-way valve 2 to the ambient atmosphere and seal the end of the cigarette butt. Since the dead volume is calculated to be 90mL in this embodiment, three consecutive puffs are performed to clear the gas, and the inhaled gas is discharged into the gas bag. Calculations show that the volume from the fishtail cover body to the front control valve is about 300 mL. Therefore, it takes about 6 seconds to draw this part of the gas through the side flow flue gas filter trap. So, 6 seconds after the second suction starts, close the side flow flue gas front control valve 24 and the side flow flue gas rear control valve 36, open the side flow flue gas front control valve 25 and the side flow flue gas rear control valve 37, and keep the rest closed. This can effectively distinguish the side flow flue gas from one port to another. Based on the first full flue gas capture method described above, complete all 6 suction runs; S2. Methods for determining total nicotine and free nicotine in mainstream and sidestream flue gas: Pretreatment method: Place the collected Cambridge filters into a 50 mL Erlenmeyer flask, add 20 mL of dichloromethane extraction solution, accurately add 50 μL of 30 mg / mL n-heptadecane internal standard solution, and extract by shaking at 160 rpm for 30 min. Let stand for later use, take the extract, and determine the total nicotine by GC / MS; transfer 10 mL of the above extract, add 10 mL of neutral water, transfer to a centrifuge tube, vortex extract for 15 min, centrifuge at 8000 rpm for 5 min, and let stand for 5 min to separate the aqueous phase and dichloromethane phase; take the organic phase, dry it with anhydrous sodium sulfate, and determine the free nicotine by GC / MS; Preparation of neutral water: Boil ultrapure water, seal the container, and cool to room temperature. Before use, adjust the pH to 7.0 ± 0.2 using dilute acid or dilute alkali. Gas chromatography / GC / MS analysis conditions: Chromatographic column: HP INNOWAX column; Inlet temperature: 240℃; Split ratio: 40 1; Carrier gas: He, 99.999%; Flow rate: 1.0 mL / min; Temperature program: 100℃ for 1 min, increase to 240℃ at a rate of 10℃ / min, and hold at 240℃ for 5 min; Solvent delay: 3.5 min; Electron energy: 70 eV; Ion source temperature: 230℃; Quadrupole temperature: 150℃; Transfer line temperature: 240℃; Selected ion monitoring (SIM) was used for scanning. The NIST spectral library was used for spectral analysis, and the characteristic ions of the standard and target analytes were used for qualitative analysis. The characteristic ions and internal standard method were used for quantification. The selection of ions for quantitative and qualitative analysis is shown in Table 1.

[0061] Table 1. Quantitative and qualitative ion selection of nicotine and n-heptadecane

[0062] S2.1 Optimization of chromatographic conditions Comparative analysis of DB-5 column and HP INNOWAX column, preferred HP INNOWAX columns offer better peak shapes.

[0063] S2.2 Optimization of extraction conditions The results of total nicotine determination by different extractants were compared between extracts with and without sodium hydroxide (1 mL 1 mol / L). Figure 2 As shown. By Figure 2 It is known that direct extraction with dichloromethane and isopropanol is highly effective in extracting both free and protonated nicotine, followed by tert-butyl methyl ether. Hexane, however, has low extraction efficiency for protonated nicotine, requiring the addition of NaOH to convert it into free nicotine and improve extraction efficiency. Considering the accuracy of total nicotine determination and the convenience of subsequent free nicotine determination, direct single-stage extraction with dichloromethane is preferred. Figure 3 This is a chromatogram of total ion flow of free nicotine in the side-flow flue gas.

[0064] S2.3 Methodological evaluation: standard curve, limit of quantitation, and limit of detection. GC / MS analysis was performed on a series of nicotine standard working solutions of different concentrations. Quantification was achieved using the internal standard method. Regression analysis was performed with the peak area ratio of nicotine to internal standard as the ordinate and the concentration ratio of the response as the abscissa to obtain the linear regression equation and correlation coefficient of the nicotine working curve. Ten parallel determinations of the lowest concentration standard solution were conducted, and the standard deviation was calculated. The limit of detection (LOD) was calculated using a signal-to-noise ratio of 3 (S / N=3), and the limit of quantitation (LOQ) was calculated using S / N=10. The results are shown in Table 2. Table 2 shows that the nicotine working curve exhibits good linearity (the regression equation...). R 2 (All values ​​are greater than 0.997), indicating high method sensitivity, which can meet the requirements of quantitative analysis.

[0065] Table 2. Linear regression equation, correlation coefficient, limit of quantitation, and limit of detection.

[0066] S2.4, Recovery Rate and Precision Three different levels of standard solutions (low, medium, and high) were added to the Cambridge filters mentioned above, and spiked recovery experiments were conducted. The results are shown in Table 3. The results indicate that this method is stable and the total nicotine recovery rate is good, but the recovery rate of free nicotine is low. This is mainly because the free nicotine standard added to the filter is partially converted to a bound state under acidic conditions. The pH of the extraction system was determined to be 4.85.

[0067] Table 3. Linear regression equation, correlation coefficient, limit of quantitation, and limit of detection.

[0068] S2.5, Data Reproducibility The particulate matter from the third mainstream flue gas and the particulate matter from the sidestream flue gas were collected, and the total nicotine and free nicotine contents were determined. The experiment was repeated three times, and the RSD was less than 10%, indicating that the method has good repeatability.

[0069] S2.6, Actual Sample Measurement The total nicotine and free nicotine of control sample 0#, sample 1#, and sample 2# (all three samples are cigarette samples, the difference being the different mass fraction of potassium citrate in the cigarette paper) were determined according to the method described in Example 2. The results are shown in Tables 4, 5, and 6, respectively.

[0070] Table 4. Determination results of puff-by-puff nicotine and free nicotine in the mainstream and sidestream flue gas of control sample #0.

[0071] Table 5. Determination results of puff-by-puff nicotine and free nicotine in the mainstream and sidestream flue gas of control sample #1.

[0072] Table 6. Determination results of puff-by-puff nicotine and free nicotine in the mainstream and sidestream flue gas of control sample #2.

[0073] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0074] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0075] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A puff-by-puff nicotine collection system, characterized in that, include: Fishtail cover (3) is used to guide and capture side-flow flue gas; The side-flow flue gas collection module includes a particulate matter collection module and a gaseous matter collection module connected in series. The particulate matter collection module includes multiple particulate matter collection gas paths connected in parallel. The inlet ends of each gas path are connected to the outlet of the fishtail cover (3), and the outlet ends of each gas path are connected to the gaseous matter collection module. The particulate matter collection gas path includes a side-flow flue gas front-end control valve, a side-flow flue gas filter collector, and a side-flow flue gas rear-end control valve connected in series. The gaseous matter collection module includes a sampling pump (44) and a side-flow flue gas collection bag connected in series. Mainstream flue gas capture modules include: The suction simulation unit includes a cigarette holder (5) for fixing the cigarette, a suction power source (1) for generating simulated suction power, and a three-way valve (2) disposed between the cigarette holder (5) and the suction power source (1); the three-way valve (2) is configured to selectively connect the suction power source (1) to the cigarette holder (5) or the ambient atmosphere; Multiple parallel mainstream flue gas collection paths are connected to the common end of the three-way valve (2) at their inlet ends. Each mainstream flue gas collection path includes a mainstream flue gas filter collector and a mainstream flue gas port-to-port switching control valve arranged in sequence. The common end of each mainstream flue gas port-to-port switching control valve is equipped with a suction power source (1) or the common ends of all the mainstream flue gas port-to-port switching control valves are connected to the suction port of the suction power source (1). The switching end of each mainstream flue gas port-to-port switching control valve is connected to a mainstream flue gas port-to-port collection bag for storing flue gas through the inlet control valve of the mainstream flue gas port-to-port collection bag.

2. The puff-by-puff nicotine collection system according to claim 1, characterized in that, Along the direction of flue gas flow, a filter (42) and a flow regulating valve (43) are also sequentially installed on the connecting pipeline between the gas phase capture module and the particulate phase capture module.

3. The puff-by-puff nicotine collection system according to claim 1, characterized in that, The three-way valve (2) is a three-way clamp valve.

4. A method for determining the total nicotine and free nicotine content in cigarette smoke per puff, characterized in that, Based on the puff-by-puff nicotine collection system according to any one of claims 1-3, the determination method comprises the following steps: S10, Preparation steps: Set suction parameters and number of suction ports; S20, Synchronous puff-by-puff collection steps: Light the cigarette, start the suction power source (1) and sampling pump (44); For the Nth puff (N=1,2,3...): By opening the Nth side-flow flue gas front-end control valve and the Nth side-flow flue gas rear-end control valve, the side-flow flue gas flows through the Nth side-flow flue gas filter collector in sequence and is then transported by the sampling pump (44) to the side-flow flue gas collection bag. By controlling the Nth mainstream flue gas outlet switching control valve, the mainstream flue gas flows through the Nth mainstream flue gas filter collector in sequence and is then sucked in by the suction power source (1). Then, the valve is switched to connect to the mainstream flue gas outlet collection bag and the flue gas is pushed into the bag. S30, Measurement steps: After the collection is completed, the mainstream flue gas filter collector and the side flow flue gas filter collector corresponding to the N port are mixed with the extraction solvent to obtain the extract. The extract was subjected to GC / MS analysis to obtain the total nicotine content during the Nth puff. The extract was mixed with water and then separated into an aqueous phase and an organic phase. The organic phase was then subjected to GC / MS analysis to determine the content of free nicotine during the Nth puff.

5. The determination method according to claim 4, characterized in that, In step S20, the specific steps of storing flue gas in the sidestream flue gas capture bag and the mainstream flue gas capture bag in the synchronous capture step include: For the aforementioned mainstream flue gas collection bag: During suction, the specified mainstream flue gas switching control valve is controlled to connect the corresponding mainstream flue gas filter collector to the suction power source (1), and the flue gas is sucked into the suction power source (1). During exhaust, the mainstream flue gas switching control valve is switched to connect the suction power source (1) with the mainstream flue gas collection bag, and the flue gas is pushed into the bag. For the side-flow flue gas collection bag: During the suction cycle of the target inlet, the corresponding front-end control valve and rear-end control valve of the side flow flue gas are opened. Keep the sampling pump (44) running continuously, and transport the generated side flue gas through the corresponding side flue gas filter collector to the side flue gas collection bag; After the target side flow flue gas collection time is reached, the corresponding front-end and rear-end control valves for the side flow flue gas are closed.

6. The determination method according to claim 4, characterized in that, In step S20, after the Nth suction is completed, a purge suction is performed; before each purge suction, the three-way valve (2) is switched to be connected to the ambient atmosphere to draw in air, and the purge suction gas is pushed into the mainstream flue gas collection bag.

7. The determination method according to any one of claims 4-6, characterized in that, In step S30, the GC / MS uses HP-INNOWAX columns.

8. The determination method according to any one of claims 4-6, characterized in that, In step S30, the extraction solvent is selected from at least one of dichloromethane, isopropanol, tert-butyl methyl ether, and n-hexane, preferably dichloromethane.

9. The determination method according to any one of claims 4-6, characterized in that, In step S30, the water is neutral water; The preparation process of the neutral water includes: boiling the water and then sealing it so that the temperature of the water is room temperature and the pH is 7±0.

2.

10. The determination method according to any one of claims 4-6, characterized in that, In step S30, the organic phase is dried before being measured by GC / MS.

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