Field

The present disclosure relates to aerosol provision cartridges and systems such as nicotine provision systems (e.g. e-cigarettes) comprising coated metallic components. The present disclosure also relates to the use of coated metallic components to stabilise and/or improve the aerosol.

Background

Aerosol provision systems such as e-cigarettes generally contain, amongst other parts, an aerosol provision cartridge which comprises a reservoir of a source liquid, typically including nicotine, from which an aerosol is generated, e.g. through vaporisation or other means. The aerosol provision cartridge may also comprise an aerosol generating

component, such as a heater, which is fluidly connected to the source liquid contained in the reservoir. When a user inhales on the device, the aerosol generating component is activated to vaporise an amount of the source liquid. More particularly, such devices are usually provided with one or more air inlet holes located away from a mouthpiece of the system. When a user sucks on the mouthpiece, air is drawn in through the inlet holes and past the aerosol generating component. There is a flow path connecting between the aerosol generating component and an opening in the mouthpiece so that air drawn past the aerosol generating component continues along the flow path to the mouthpiece opening, carrying some of the aerosol produced from the aerosol generating component with it. The aerosol- carrying air exits the aerosol provision system through the mouthpiece opening for inhalation by the user.

Typical aerosol generating components comprise a heater. The source liquid is generally arranged within the system such that it can access the aerosol generating component. For example, it may be that the aerosol generating component is a wire which is heated during use of the device. As a result of the contact between the source liquid and the wire, when the wire is hearted during use the source liquid is vaporised and

subsequently condenses into an aerosol which is then inhaled by the user. The means by which the source liquid can contact the wire may vary. It is not uncommon for the source liquid to be stored in a wadding or other type of holding matrix. This wadding or matrix can either itself directly contact the heating wire or, alternatively, it may be that a further "wick" is in contact with both the wadding and the heating wire. This wick serves to draw the source liquid from the wadding to the heating wire during use.

Other types of systems do not employ wadding to hold the source liquid. Instead, in these systems the source liquid is held freely in a tank or other storage region and is directly fed to the heating wire (which may itself include a wicking core to assist in holding the source liquid in proximity to the wire). Typically, the aerosol generating component is contained within an aerosol generating region. In some instances, this aerosol generating region is a chamber. The primary characteristics of such a region are that it should provide sufficient space to house the aerosol generating component, as well as to allow for the desired degree of airflow past the aerosol generating component and on to the mouthpiece outlet. Whilst it is desired that substantially all of the vapour that is generated in the aerosol generating region is entrained in the airflow travelling past the aerosol generating component, this does not always occur. For example, in some instances vapour produced in the aerosol generating region can condense and remain within that region. In other words, not all of the vapour produced is entrained in the through-flowing airflow. The result of this is that condensate can accumulate within the aerosol generating region. As a result of the aerosol generating region being provided with an inlet to allow for the ingress of air so as to allow for formation of the aerosol, the aerosol generating region is typically not liquid impermeable - in other words, the aerosol generating region is generally not sealed and as a result any condensate which has accumulated in the aerosol generating region may migrate to other parts of the aerosol provision cartridge. Depending on the composition of the liquid source, this may or may not present certain issues. For example, if the condensate produced from the aerosol generating component contains compounds that are reactive with other components of the aerosol provision cartridge outside of the aerosol generating region, it may be that the acceptability of the aerosol delivered to the user deteriorates over time as a result of the reaction products from the condensate reacting with the other components within the cartridge becoming entrained in the airflow through the device and thus into the resulting aerosol.

Therefore, it would be desirable to provide an aerosol provision cartridge which is able to provide a consistently acceptable aerosol to a user.

Summary

In a first aspect there is provided an aerosol provision cartridge for use with an aerosol provision system, said cartridge comprising:

a liquid storage region in fluid communication with an aerosol generating region; and one or more metallic components, located substantially outside of the aerosol generating region and liquid storage region, wherein at least one of the said metallic components has a coating comprising silver and/or gold.

In a further aspect there is provided an aerosol provision cartridge for use with an aerosol provision system, said cartridge comprising:

a liquid storage region comprising a source liquid, said source liquid comprising nicotine and at least one acid; an aerosol generating region in fluid communication with the liquid storage region; and

one or more metallic components, located substantially outside of the aerosol generating region and liquid storage region, wherein at least one of the said metallic components has a coating comprising silver and/or gold.

In a further aspect there is provided an aerosol provision cartridge for use with an aerosol provision system, said cartridge comprising:

a liquid storage region in fluid communication with an aerosol generating region; said aerosol generating region configured to be substantially liquid-free; and one or more metallic components, located substantially outside of the aerosol generating region and liquid storage region, wherein at least one of the said metallic components has a coating comprising silver and/or gold.

It has surprisingly been found that aerosols produced from cartridges and systems of the present invention are more acceptable to consumers.

In a further aspect there is provided the use of a metallic component having a coating comprising gold and/or silver in an aerosol provision cartridge to stabilise and/or improve the acceptability of the aerosol to a user.

In a further aspect there is provided a method of preventing the deterioration of the sensorial attributes of an aerosol produced from an aerosol provision cartridge comprising utilising in the construction of the cartridge a metallic component having a coating comprising gold and/or silver.

In a further aspect there is provided an aerosol provision system comprising an aerosol provision cartridge as defined herein, and an aerosol provision device comprising a power source and an input means.

The approach described herein is not restricted to specific embodiments such as set out below, but includes and contemplates any appropriate combinations of features presented herein. For example, an electronic aerosol provision system may be provided in accordance with the approach described herein which includes any one or more of the various features described below as appropriate.

Brief Description of the Drawings Various embodiments will now be described in detail by way of example only with reference to the following drawings:

Figure 1 is a schematic (exploded) diagram of an aerosol provision system such as an e-cigarette in accordance with some embodiments;

Figure 2 is a schematic diagram of a main body portion of the e-cigarette of Figure 1 in accordance with some embodiments;

Figure 3 is a schematic diagram of an aerosol source portion of the e-cigarette of Figure 1 in accordance with some embodiments;

Figure 4 is a schematic diagram showing certain aspects of one end of the main body portion of the e-cigarette of Figure 1 in accordance with some embodiments;

Figures 5A to 5E are schematic diagrams of components of an aerosol provision system in accordance with some other embodiments;

Figure 6 is an exploded, schematic diagram showing various components of an aerosol provision system in accordance with some other embodiments; and

Figure 7 provides a graph showing user preference levels for aerosols produced from different aerosol provision cartridges.

Detailed Description

Aspects and features of certain examples and embodiments are discussed / described herein. Some aspects and features of certain examples and embodiments may be implemented conventionally and these are not discussed / described in detail in the interests of brevity. It will thus be appreciated that aspects and features of apparatus and methods discussed herein which are not described in detail may be implemented in accordance with any conventional techniques for implementing such aspects and features.

As described above, the present disclosure relates to an aerosol provision cartridge which may form part of an aerosol provision system, such as an e-cigarette. Throughout the following description the term "e-cigarette" is sometimes used; however, this term may be used interchangeably with aerosol (vapour) provision system, or vapour provision device. Further, term "aerosol provision cartridge" may also be referred to as cartomiser, clearomiser or tank, as such terms are common in the field of aerosol provision systems such as e- cigarettes.

Figure 1 is a schematic diagram of an aerosol / vapour provision system such as an e-cigarette 10 in accordance with some embodiments (not to scale). The e-cigarette has a generally cylindrical shape, extending along a longitudinal axis indicated by dashed line LA, and comprises two main components, namely a body 20 and a cartomiser 30. The cartomiser includes an internal chamber containing a liquid storage region comprising a source liquid from which an aerosol is to be generated, and an aerosol generating component. The cartomiser 30 further includes a mouthpiece 35 having an opening through which a user may inhale the aerosol produced by the aerosol generating component. In this regard, reference to an "aerosol generating component" refers to a component which generates an aerosol either directly or indirectly. For example, where the aerosol generating component is a heater, source liquid may be evaporated and subsequently condense to form an aerosol.

The liquid storage region for the source liquid may comprise a foam matrix or any other structure, such as a wadding, within a housing for retaining the source liquid until such time that it is required to be delivered to the aerosol generating component. Alternatively, the liquid storage region may simply be a reservoir which an amount of "free liquid" contained therein. The liquid storage region may be "closed" or "open". In other words, where the liquid storage region is "closed", the user is not able to re-fill the liquid storage region with liquid once it has been depleted without dismantling or otherwise breaking the device in a manner which is not envisaged by the manufacturer. Where the liquid storage region is "open" it is configured to be re-filled by the user. This "open" configuration can generally be achieved by using a mouthpiece or other component that seals the liquid storage region, but which can be removed (via a screw thread etc.) such that access to the liquid storage region is provided.

The aerosol generating component includes a heater for vaporising the source liquid to form the aerosol. The aerosol generating component may further include a wick or similar facility to transport a small amount of the source liquid from the storage region to a heating location on or adjacent the heater.

The body 20 includes a re-chargeable cell or battery to provide power for the e- cigarette 10 and a circuit board for generally controlling the e-cigarette. In use, when the heater receives power from the battery, as controlled by the circuit board, the heater vaporises the source liquid at the heating location to generate the aerosol, and this is then inhaled by a user through the opening in the mouthpiece. The aerosol is carried to the mouthpiece along an air channel that connects the aerosol generating region to the mouthpiece opening as a user inhales on the mouthpiece.

In this particular example, the body 20 and cartomiser 30 are detachable from one another by separating in a direction parallel to the longitudinal axis LA, as shown in Figure 1 , but are joined together when the device 10 is in use by a connection, indicated schematically in Figure 1 as 25A and 25B, to provide mechanical and electrical connectivity between the body 20 and the cartomiser 30. The electrical connector on the body 20 that is used to connect to the cartomiser also serves as a socket for connecting a charging device (not shown) when the body is detached from the cartomiser 30. The other end of the charging device can be plugged into an external power supply, for example a USB socket, to charge or to re-charge the cell / battery in the body of the e-cigarette. In other implementations, a cable may be provided for direct connection between the electrical connector on the body and the external power supply.

In connection with this, in order to allow for connection with the body 20 (both mechanically and electrically) the cartomiser 30 generally contains one or more metallic components. For example, these components may be screw thread rings, electrodes, or intermediate supporting members (all not shown). When assembled, such metallic components allow for the cartomiser 30 to be connected to the body 20 in a manner which supports the aerosol generating component in the aerosol generating region, allows for the provision of electrical current to the aerosol generating component, and allows for airflow to travel into the aerosol generating region so that it may collect the vapour/aerosol produced therein and deliver it to the user.

The e-cigarette 10 is provided with one or more holes (not shown in Figure 1) for air inlet. These holes connect to an air running passage through above mentioned metallic components of the e-cigarette 10 to the mouthpiece 35. The air passage includes a region around the aerosol generating region and a section comprising an air channel connecting from the aerosol generating region to the opening in the mouthpiece.

When a user inhales through the mouthpiece 35, air is drawn into this air passage through the one or more air inlet holes, which are suitably located on the outside of the e- cigarette. This airflow (or the resulting change in pressure) is detected by a pressure sensor (as an example of an input means) that in turn activates the aerosol generating component (heater in this case) to vaporise a portion of the source liquid to generate the aerosol. The airflow passes through the air passage, and combines with the aerosol in the region around the aerosol generating region, and the resulting aerosol then travels along the air channel connecting from the aerosol generating region to the mouthpiece 35 to be inhaled by a user. The cartomiser 30 may be detached from the body 20 and disposed of when the supply of source liquid is exhausted (and replaced with another cartomiser if so desired). Alternatively, the cartomiser maybe refillable.

It will be appreciated the e-cigarette 10 shown in Figure 1 is presented by way of example, and various other implementations can be adopted. For example, in some embodiments, the cartomiser 30 is provided as two separable components, namely a cartridge comprising the liquid storage region and mouthpiece (which can be replaced when the liquid from the reservoir is exhausted), and a vaporiser / aerosol generating component comprising a heater (which is generally retained). In some embodiments, the aerosol generating component may itself be replaceable. As another example, the charging facility may connect to an additional or alternative power source, such as a car cigarette lighter socket. Figure 2 is a schematic (simplified) diagram of the body 20 of the e-cigarette of Figure 1. Figure 2 can generally be regarded as a cross-section in a plane through the longitudinal axis LA of the e-cigarette. Note that various components and details of the body, e.g. such as wiring and more complex shaping, have been omitted from Figure 2 for reasons of clarity.

As shown in Figure 2, the body 20 includes a battery or cell 210 for powering the e- cigarette 10, as well as a chip, such as an application specific integrated circuit (ASIC) or microcontroller for controlling the e-cigarette 10. The ASIC may be positioned alongside or at one end of the battery 210. The ASIC is attached to a sensor unit 215 to detect an inhalation on mouthpiece 35 (or alternatively the sensor unit 215 may be provided on the ASIC itself). In response to such a detection, the ASIC provides power from the battery or cell 210 to the heater in the cartomiser to vaporise source liquid and introduce an aerosol into the airflow which is inhaled by a user. It should be noted that the precise positioning of the

ASIC/sensor within the body 20 is not strictly limited.

The body further includes a cap 225 to seal and protect the far (distal) end of the e- cigarette. There is an air inlet hole provided in or adjacent to the cap 225 to allow air to enter the body and flow past the sensor unit 215 when a user inhales on the mouthpiece 35. This airflow therefore allows the sensor unit 2 5 to detect the user inhalation and so activate the aerosol generating component of the e-cigarette.

At the opposite end of the body 20 from the cap 225 is the connector 25B for joining the body 20 to the cartomiser 30. The connector 25B provides mechanical and electrical connectivity between the body 20 and the cartomiser 30. The connector 25B includes a body connector 240, which is metallic (silver-plated in some embodiments) to serve as one terminal for electrical connection (positive or negative) to the cartomiser 30. The connector 25B further includes an electrical contact 250 to provide a second terminal for electrical connection to the cartomiser 30 of opposite polarity to the first terminal, namely body connector 240. The electrical contact 250 is mounted on a coil spring 255. When the body 20 is attached to the cartomiser 30, the connector 25A on the cartomiser pushes against the electrical contact 250 in such a manner as to compress the coil spring in an axial direction, i.e. in a direction parallel to (co-aligned with) the longitudinal axis LA. In view of the resilient nature of the spring 255, this compression biases the spring 255 to expand, which has the effect of pushing the electrical contact 250 firmly against connector 25A, thereby helping to ensure good electrical connectivity between the body 20 and the cartomiser 30. The body connector 240 and the electrical contact 250 are separated by a trestle 260, which is made of a non-conductor (such as plastic) to provide good insulation between the two electrical terminals. The trestle 260 is shaped to assist with the mutual mechanical engagement of connectors 25A and 25B. It may be that when the sensor 215 is located at the opposite end of the body 20 relative to the cap 225, the body includes one or more air inlet holes provided in or adjacent to connector 25B to allow air to enter the body and flow past the sensor unit 215 when a user inhales on the mouthpiece 35.

Figure 3 is a schematic diagram of the cartomiser 30 of the e-cigarette of Figure 1 in accordance with some embodiments. Figure 3 can generally be regarded as a cross-section in a plane through the longitudinal axis LA of the e-cigarette. Note that various components and details of the body, e.g. such as wiring and more complex shaping, have been omitted from Figure 3 for reasons of clarity.

The cartomiser 30 includes an air passage 355 extending along the central

(longitudinal) axis of the cartomiser 30 from the mouthpiece 35 to the connector 25A for joining the cartomiser to the body 20.

A liquid storage region 360 is provided around the air passage 335. This storage region 360 may be implemented, for example, by providing cotton or foam soaked in source liquid. Alternatively, it may be a simple reservoir which contains the source liquid in a free state, i.e. not held within a wadding, matrix or the like. The cartomiser also includes a heater 365 for heating liquid from the storage region 360 to generate an aerosol to flow through air passage 355 and out through an opening in the mouthpiece 35 in response to a user inhaling on the e-cigarette 10. The heater is powered through lines 366 and 367, which are in turn connected to opposing polarities (positive and negative, or vice versa) of the battery 210 via connector 25A (the details of the wiring between the power lines 366 and 367 and connector 25A are omitted from Figure 3).

The connector 25A includes an inner electrode 375, which may be made of a metal suitable for conducting electrical current. When the cartomiser 30 is connected to the body 20, the inner electrode 375 contacts the electrical contact 250 of the body 20 to provide a first electrical path between the cartomiser and the body. In particular, as the connectors

25A and 25B are engaged, the inner electrode 375 pushes against the electrical contact 250 so as to compress the coil spring 255, thereby helping to ensure good electrical contact between the inner electrode 375 and the electrical contact 250.

The inner electrode 375 is surrounded by an insulating ring 372, which may be made of plastic, rubber, silicone, or any other suitable material. The insulating ring is surrounded by the cartomiser connector 370, which may be made of a suitable metal which is able to conduct electricity. When the cartomiser 30 is connected to the body 20, the cartomiser connector 370 contacts the body connector 240 of the body 20 to provide a second electrical path between the cartomiser and the body. In other words, the inner electrode 375 and the cartomiser connector 370 serve as positive and negative terminals (or vice versa) for supplying power from the battery 210 in the body to the heater 365 in the cartomiser via supply lines 366 and 367 as appropriate. In one embodiment, the connector 25A is a metallic component having a coating comprising silver and/or gold. In one embodiment, the inner electrode 375 is a metallic component having a coating comprising silver and/or gold. In one embodiment, the cartomiser connector 370 is a metallic component having a coating comprising silver and/or gold. In one embodiment, one or more of the connector 25A, the inner electrode 375, and the cartomizer connector 370 are metallic components having a coating comprising silver and/or gold.

In one embodiment, one, two, three, four, five, six, or every metallic component of the aerosol provision cartridge which is upstream of the aerosol generating chamber (relative to the airflow entering said chamber) and which is outside of the liquid storage region and aerosol generating region has a coating comprising gold and/or silver.

In one embodiment, every metallic component of the aerosol provision cartridge which is upstream of the aerosol generating chamber (relative to the airflow entering said chamber) and which is outside of the liquid storage region and aerosol generating region has a coating comprising gold and/or silver.

In one embodiment, every metallic component of the aerosol provision cartridge outside of the liquid storage region and aerosol generating region has a coating comprising gold and/or silver.

In one embodiment, it may be desirable to ensure that any metallic components that are in contact with airflow through the device are coated with a coating comprising gold and/or silver. In one embodiment, the surface of one or more of metallic components of the aerosol provision cartridge which is in contact with the airflow through the device is coated with a coating comprising gold and/or silver.

The cartomiser connector 370 is provided with two lugs or tabs 380A, 380B, which extend in opposite directions away from the longitudinal axis of the e-cigarette. These tabs are used to provide a bayonet fitting in conjunction with the body connector 240 for connecting the cartomiser 30 to the body 20. This bayonet fitting provides a secure and robust connection between the cartomiser 30 and the body 20, so that the cartomiser and body are held in a fixed position relative to one another, without wobble or flexing, and the likelihood of any accidental disconnection is very small. At the same time, the bayonet fitting provides simple and rapid connection and disconnection by an insertion followed by a rotation for connection, and a rotation (in the reverse direction) followed by withdrawal for disconnection. It will be appreciated that other embodiments may use a different form of connection between the body 20 and the cartomiser 30, such as a snap fit or a screw connection.

Figure 4 is a schematic diagram of certain details of the connector 25B at the end of the body 20 in accordance with some embodiments (but omitting for clarity most of the internal structure of the connector as shown in Figure 2, such as trestle 260). In particular, Figure 4 shows the external housing 201 of the body 20, which generally has the form of a cylindrical tube. This external housing 201 may comprise, for example, an inner tube of metal with an outer covering of paper or similar.

The body connector 240 extends from this external housing 201 of the body 20. The body connector as shown in Figure 4 comprises two main portions, a shaft portion 241 in the shape of a hollow cylindrical tube, which is sized to fit just inside the external housing 201 of the body 20, and a lip portion 242 which is directed in a radially outward direction, away from the main longitudinal axis (LA) of the e-cigarette. Surrounding the shaft portion 241 of the body connector 240, where the shaft portion does not overlap with the external housing 201 , is a collar or sleeve 290, which is again in a shape of a cylindrical tube. The collar 290 is retained between the lip portion 242 of the body connector 240 and the external housing 201 of the body, which together prevent movement of the collar 290 in an axial direction (i.e. parallel to axis LA). However, collar 290 is free to rotate around the shaft portion 241 (and hence also axis LA).

As mentioned above, the cap 225 is provided with an air inlet hole to allow air to flow past sensor 215 when a user inhales on the mouthpiece 35. However, the majority of air that enters the device when a user inhales flows through collar 290 and body connector 240 as indicated by the two arrows in Figure 4.

Figures 5A to 5E schematically represent in perspective view some aspects of part an aerosol provision/provision cartridge 500 according to some other embodiments. In particular, Figure 5A schematically represents a first component comprising a liquid storage region component 502 and Figure 5B schematically represents a second component 510 comprising part of a housing for the aerosol provision cartridge 500. These two components of the aerosol provision cartridge 500 are shown separately in Figures 5A and 5B for ease of representation, whereas in normal use these two components are assembled together as schematically represented in Figure 5C. In the assembled state for this particular design of aerosol provision system, the liquid storage region component 502 is fitted inside the housing component 510. It will be appreciated the aerosol provision cartridge 500 will be configured to be connected to an aerosol provision device (similar to the body 20 of the e- cigarette 10 described above) in order to form an aerosol provision system. Such an aerosol provision device typically comprises a power source and an input means (such as a pressure sensor or button) such that when the input means is activated by the user power is supplied from the power source to the aerosol generating component in the aerosol provision cartridge. Such other features of the aerosol provision system may be provided in accordance with conventional techniques. More generally, it will be appreciated that aspects and features of aerosol provision systems described herein may be implemented in accordance with any established techniques apart from where modified in accordance with the embodiments described herein.

The liquid storage region component 502 comprises a liquid storage body 506 defining a liquid storage region. The liquid storage region comprises a source liquid from which an aerosol is to be generated. The base of the liquid storage component is open and cooperates with membrane 601 and optionally also liquid distributing component 602. Thus, it will be appreciated that both membrane 601 and component 602 may be dimensioned to be received within the opening of the liquid storage component 502, and they may further form an interference fit with the inner wall of the liquid storage component 502.

The membrane 601 is positioned between the liquid storage region and an aerosol generating region of the system (not shown in Figure 5). The membrane 601 allows for the source liquid contained in the liquid storage region to be fluidly communicated to the aerosol generating region of the system.

In this regard, the presence of the membrane typically results in a reduced "flow" of liquid compared to the "direct flow" that is seen in other systems of the prior art. The particular construction of the membrane need not be particularly limited, provided that it allows for the source liquid contained within the liquid store to be transferred to the aerosol generating region. It is also generally preferred if the membrane has a degree of heat resistance. In one embodiment, the membrane is formed from a porous material. In one embodiment, the membrane is formed from a porous ceramic material. In one embodiment, the membrane is formed from ceramic fibres. In this regard, ceramic fibres are known to be heat resistant and yet also provide a degree of porosity owing to their structure. Ceramic fibres may also be known as "high-temperature insulation wool" (HTIW). High-temperature insulation wool is an accumulation of fibres of different lengths and diameters, produced synthetically from mineral raw materials. The raw mineral materials are typically melted and then processed into fibres which are then formed into the final material. Different types of HTIW may be available, such as alkaline earth silicate wool, alumina silicate wool, and poly- silicate wool. Alumino silicate wool, also known as "refractory ceramic fibre" (RCF), are amorphous fibres produced by melting a combination of Al ₂ 0 ₃ and Si0 ₂ , usually in a weight ratio of about 50:50. In one embodiment, the membrane is formed from an alumina silicate wool. In one embodiment, the alumina silicate wool has a Al ₂ 0 ₃ content of from 48 to 54% and a Si0 ₂ content of from 46 to 52%. Other raw materials, such as Fe ₂ 0 ₃ may also be present in minor amounts. The skilled person is aware of the various considerations for producing high temperature insulation wool. In this regard, a suitable high temperature insulation wool may be obtained from Zibo Dingrong High-Temperature Materials Co., Ltd, Zibo City, Shandong Province, China. The dimensions of the membrane itself are not particularly limited. Typically, the thickness of the membrane may be in the range 0.1 mm to 2 mm. In one embodiment, the thickness of the membrane may be in the range 0.1 to 1 mm. In one embodiment, the thickness of the membrane may be in the range 0.5 to 1.5 mm. In one embodiment, the thickness of the membrane may be in the range 0.5 to 1 mm.

The shape of the membrane may not be particularly limited. Typically, the

membrane has a shape which conforms to the general cross-sectional shape of the liquid storage region. For example, as shown in Figure 5D, the membrane has a shape which corresponds to the cross-sectional profile of the liquid storage region of liquid storage component 502. Such a shape helps to ensure that an interference/friction fit can be established with the inner walls of the liquid storage component. The membrane is generally planar.

However, it may in some circumstances be non-planar where such a configuration is necessary. For example, it may be that the membrane is tubular with the source liquid being stored in a storage region radially outward of the membrane, with the aerosol generating region, including aerosol generating component, being disposed radially inwardly of the tubular membrane.

In some embodiments, at the interface between the aerosol generating region and the liquid storage region, there may be a membrane support (not shown). This membrane support is generally rigid and serves to support the membrane from its underside (the side projecting towards the aerosol generating region). The membrane support is typically metal, and in some cases is produced from stainless steel. The grade of stainless steel used for the membrane support is not particularly limited, and it may be selected from 304L, 316L etc. The membrane support typically spans the liquid provision region of the membrane. In other words, where the membrane is generally circular, the membrane support spans substantially the entire diameter of the membrane. In this regard, the membrane support is typically Ί" shaped in that it has a central linear section capped by two substantially linear bars formed at substantially right angles to the central linear section.

The aerosol generating region comprises an aerosol generating component, such as a heater. In some embodiments, the heater takes the form of a wire 701 , which may also be coiled. The coiled wire may have a wick 801 running through the longitudinal axis formed by the turns of the coil. This wick may then contact the membrane at point "C" shown for example in Figure 6 so as to draw liquid from the membrane onto or near the wire.

As discussed above, a liquid distribution component 602 may optionally be present in the system between the membrane and the liquid storage region. The liquid distribution component 602 may have the function of providing more controlled wetting of the

membrane. Thus, the component 602 has one or more through holes 603 which allow for the source liquid to flow from the liquid storage region onto the membrane. The membrane and the liquid distribution component may generally be disposed such that their central point is in-line with the central longitudinal axis of the system. In this regard, such a configuration (showing the membrane only) is shown in Figure 6. The general configuration of the liquid distribution component 602 (if present) may be similar to that of the membrane. Thus it may have a corresponding cross-sectional profile and be generally planar.

The reservoir body 506 is generally in the form of a circular cylinder with a flat face 508 running longitudinally along one side. The reservoir body 506 may be formed in accordance with conventional techniques, for example comprising a moulded plastics material.

The housing component 510 is generally tubular and circularly symmetric. The housing component 510 comprises a main housing component 512 and a mouthpiece component 514. These may be formed separately or integrally. The main housing

component 512 and mouthpiece component 514 may be formed in accordance with conventional techniques, for example comprising extruded aluminium or moulded plastic. The main housing component 512 comprises a generally cylindrical tube having an interior dimension conforming to the exterior dimension of the liquid storage component 502. Thus the liquid storage component 502 can be received within the housing component 510 in a close-fitting arrangement, as schematically represented in Figure 5C. It will be appreciated the housing component 510 will in general extend further than represented in Figure 5C so as to generally enclose the aerosol generator 504. The mouthpiece component 514 of the housing component 5 0 is contoured to provide a transition from the shape of the main housing component to a shape which is economically suited to be received by a user's lips during use. The mouthpiece component 514 includes an opening 516 at the end through which a user may inhale aerosol generated by the aerosol source.

As can be seen from the schematic representation in Figure 5C, when the liquid storage component 502 is inserted into the housing component 510, the provision of the flat surface 508 creates a spacing between the outside wall of the reservoir body 506 and the inside wall of the housing component 510. This region where the first component 502 and the second component 510 of the aerosol provision system 500 are spaced apart thereby defines part of an air channel 520 connecting from the vicinity of the aerosol generator 504 to the opening 516. Other parts of the air channel are defined by the interior of the housing 510 that does not surround the liquid storage component 502 adjacent to the mouthpiece 514 and the interior surface of the mouthpiece 514. In general there may be further structural elements of the aerosol provision system in these regions to define the air channel 520. For example, flow restrictors and / or baffles and / or switchbacks may be provided to govern the airflow in accordance with conventional techniques. As discussed briefly above, Figure 6 shows an exploded view of the aerosol provision system 500 and also indicates the presence of a heating wire 701 as the aerosol generating component, and a wick 801 that extends through the wire (which in this configuration is coiled). The wire and wick sit in a housing of the aerosol generating region (not shown). The wire is electrically connected through (optionally via/through the housing of the aerosol generating region) to a power source in the body 20 of the system. As will be apparent from Figure 6, source liquid is stored with the liquid storage region formed within the liquid storage component 502. The membrane 601 then separates the liquid storage region (and thus the source liquid) from the aerosol generating region containing the wire 701 and the wick 80 . The membrane 601 serves as a barrier to the "free flow" of source liquid into the aerosol generating region. However, the membrane 601 is configured to fluidly communicate the liquid storage region with the aerosol generating region. In other words, the source liquid is able to travel across the membrane 601 from one side to the other. Wick 801 is typically in contact with the underside of the membrane 601 and thus serves to draw the source liquid that has travelled across the membrane 601 towards the heating wire. The wick itself can be made of any suitable material known in the art which has a high degree of heat resistance and is capable of transporting a liquid, e.g. through capillary action. In one embodiment, the wick 801 is secured to the underside of the membrane. This may be achieved through the use of an adhesive, or through physical means (such as a clamp etc.). Such an arrangement ensures good contact with the underside of the membrane. Points "C" shown in Figure 6 illustrate points of contact between the wick 801 and the underside of the membrane.

The aerosol provision system 500 may also comprise components that correspond substantially to those described earlier with respect to e-cigarette 10. In this regard, aerosol provision system 500 may additionally comprise a screw component and an inner electrode. In one embodiment, the screw component is a metallic component having a coating comprising silver and/or gold. In one embodiment, the inner electrode is a metallic component having a coating comprising silver and/or gold. In one embodiment, both the screw component and the inner electrode are metallic components independently having a coating comprising gold and/or silver.

In one embodiment, the screw component is located outside of the aerosol generating region. In one embodiment, the inner electrode is located outside of the aerosol generating region.

In one embodiment, one, two, three, four, five, six, or every metallic component of the aerosol provision cartridge which is upstream of the aerosol generating chamber (relative to the airflow entering said chamber) and which is outside of the liquid storage region and aerosol generating region has a coating comprising gold and/or silver. In one embodiment, every metallic component of the aerosol provision cartridge which is upstream of the aerosol generating chamber (relative to the airflow entering said chamber) and which is outside of the liquid storage region and aerosol generating region has a coating comprising gold and/or silver.

In one embodiment, every metallic component of the aerosol provision cartridge outside of the liquid storage region and aerosol generating region has a coating comprising gold and/or silver.

The coated metallic components referred to herein generally have a coating comprising gold and/or silver. In the context of the present invention, a "coating" refers to a outer layer of coating material that may extend over the entire surface of the base metallic component. Alternatively, the coating may not extend over the entire surface of the base metallic component, and instead be limited to discrete areas. Although the term "coating" is used in the present invention, the term "plating" is deemed to be equivalent.

Coating such components has surprisingly led to aerosols that are more acceptable to users. This is explained with further reference to the examples below. Generally, the coating used to coat the metallic components referred to herein comprise at least one of gold and/or silver. In one embodiment, the metallic components referred to herein have a coating comprising at least gold. In one embodiment, the metallic components referred to herein have a coating comprising at least silver. In one embodiment, the metallic components referred to herein have a coating comprising a gold alloy. In one embodiment, the coating comprises gold in an amount of about 99 %w/w, with reference to the weight of the coating. In one embodiment, the coating comprises gold in an amount of greater than 99 %w/w, with reference to the weight of the coating. In one embodiment, the coating comprises gold in an amount of about 99.7 %w/w, with reference to the weight of the coating. In one

embodiment, the coating comprises gold in an amount of about 99.9 %w/w, with reference to the weight of the coating. Suitable gold containing coatings (also referred to as platings) are defined under standards such as Mil-G-45204, ASTM B488 or AMS 2422. Suitable silver containing coatings (also referred to as platings) are defined under standards such as QQ-S- 365, ASTM B700, AMS 2410, AMS 2411 and AMS 2412.

The thickness of the coating on the metallic components must be such that the base metal of the metallic component is not exposed. In one embodiment, the coating on the metallic component(s) is at least 0.001 mm thick. In one embodiment, the coating on the metallic component(s) is at least 0.002 mm thick. In one embodiment, the coating on the metallic component(s) is at least 0.003 mm thick. In one embodiment, the coating on the metallic component(s) is at least 0.004 mm thick. In one embodiment, the coating on the metallic component(s) is at least 0.005 mm thick. In one embodiment, the coating on the metallic component(s) is from 0.001 mm to about 0.005 mm thick. In one embodiment, the coating on the metallic component(s) is from 0.001 mm to about 0.004 mm thick. In one embodiment, the coating on the metallic component(s) is from 0.001 mm to about 0.003 mm thick. In one embodiment, the coating on the metallic component(s) is from 0.001 mm to about 0.002 mm thick. In one embodiment, the coating on the metallic component(s) is from 0.002 mm to about 0.005 mm thick. In one embodiment, the coating on the metallic component(s) is from 0.003 mm to about 0.005 mm thick. In one embodiment, the coating on the metallic component(s) is from 0.004 mm to about 0.005 mm thick. In one embodiment, the coating on the metallic component(s) is about 0.004 mm thick.

The metallic components of the invention are typically brass or stainless steel. In one embodiment, the coated metallic components are brass, coated with a coating comprising gold and/or silver.

In one embodiment, the source liquid comprises nicotine and benzoic acid, and the metallic components are brass, coated with a coating comprising gold.

The general operating principles of the aerosol provision system 500 schematically represented in Figures 5A to 5E and Figure 6 may be similar to those described above for the aerosol provision system represented in Figures 1 to 4. Thus, in use, a user sucks on the mouthpiece 514, which leads to air being drawn into the interior of the aerosol provision system 500 through inlet openings in the aerosol provision system (not shown in the figures). A controller of the aerosol provision system is configured to detect the inlet of air, for example based on a change in pressure, and activate the aerosol generating component in response thereto. Thus, an aerosol of the source liquid is generated. As air is drawn through the aerosol provision system it carries some of the aerosol through the air channel 520 to the opening 516 in the mouthpiece 514. In this regard, the housing of the aerosol generating region generally has a cross-section that conforms to the cross-section of housing component 510. This allows any aerosol formed in the aerosol generating region to access channel 520.

In some embodiments, the source liquid comprises nicotine, a carrier and one or more acids. The carrier of the source liquid may be any suitable solvent such that the source liquid can be vaporised for use. In one aspect the solvent is selected from glycerol, propylene glycol (PG) and mixtures thereof. In one aspect the solvent is at least glycerol. In one aspect the solvent consists essentially of glycerol. In one aspect the solvent consists of glycerol. In one aspect the solvent is at least propylene glycol. In one aspect the solvent consists essentially of propylene glycol. In one aspect the solvent consists of propylene glycol. In one aspect the solvent is at least a mixture of propylene glycol and glycerol. In one aspect the solvent consists essentially of a mixture of propylene glycol and glycerol. In one aspect the solvent consists of a mixture of propylene glycol and glycerol. The carrier of the source liquid may be present in any suitable amount. In one aspect the carrier is present in an amount of 1 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 5 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 10 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 20 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 30 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 40 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 50 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 60 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 70 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 80 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 90 to 98 wt% based on the source liquid. In one aspect the carrier is present in an amount of 1 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 5 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 10 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 20 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 30 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 40 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 50 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 60 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 70 to 90 wt% based on the source liquid. In one aspect the carrier is present in an amount of 80 to 90 wt% based on the source liquid.

In one aspect the source liquid further comprises water. The water may be present in any suitable amount. In one aspect water is present in an amount of 1 to 50 wt% based on the source liquid. In one aspect water is present in an amount of 5 to 50 wt% based on the source liquid. In one aspect water is present in an amount of 10 to 50 wt% based on the source liquid. In one aspect water is present in an amount of 20 to 50 wt% based on the source liquid. In one aspect water is present in an amount of 1 to 40 wt% based on the source liquid. In one aspect water is present in an amount of 5 to 40 wt% based on the source liquid. In one aspect water is present in an amount of 10 to 40 wt% based on the source liquid. In one aspect water is present in an amount of 20 to 40 wt% based on the source liquid. In one aspect water is present in an amount of 1 to 30 wt% based on the source liquid. In one aspect water is present in an amount of 5 to 30 wt% based on the source liquid. In one aspect water is present in an amount of 10 to 30 wt% based on the source liquid. In one aspect water is present in an amount of 20 to 30 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is from 1 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 5 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 10 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 20 to 98 wt% based on the source liquid, in one aspect the combined amount of carrier and water in the source liquid is 30 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 40 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 50 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 60 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 70 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 80 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 90 to 98 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 1 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 5 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 10 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 20 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 30 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 40 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 50 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 60 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 70 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 80 to 90 wt% based on the source liquid. In one aspect the combined amount of carrier and water in the source liquid is 90 to 90 wt% based on the source liquid.

The source liquid comprises an acid, such as an organic acid. In one aspect the organic acid is a carboxylic acid. The carboxylic acid may be any suitable carboxylic acid. In one aspect the organic acid is a mono-carboxylic acid. In one aspect the organic acid is selected from the group consisting of acetic acid, lactic acid, benzoic acid, levulinic acid, formic acid, citric acid, pyruvic acid, succinic acid, tartaric acid, oleic acid, sorbic acid, propionic acid, phenylacetic acid, and mixtures thereof. In one embodiment, the source liquid comprises benzoic acid. In one embodiment, the source liquid comprises levulinic acid.

In one embodiment, the total content of acid present in the source liquid is no greater than 1 mole equivalents based on the nicotine. In one embodiment, the total content of acid present in the source liquid is no greater than 0.9 mole equivalents based on the nicotine. In one embodiment, the total content of acid present in the source liquid is no greater than 0.8 mole equivalents based on the nicotine. In one embodiment, the total content of acid present in the source liquid is no greater than 0.7 mole equivalents based on the nicotine. In one embodiment, the total content of acid present in the source liquid is no greater than 0.6 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is no greater than 0.55 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is no greater than 0.5 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is no greater than 0.45 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is no greater than 0.4 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is no greater than 0.35 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is no greater than 0.3 mole equivalents based on the nicotine.

In one aspect the total content of acid present in the source liquid is from 0.1 to 0.6 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is from 0.1 to 0.5 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is from 0.2 to 0.6 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is from 0.1 to 0.4 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is from 0.3 to 0.6 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is from 0.2 to 0.5 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is from 0.3 to 0.5 mole equivalents based on the nicotine. In one aspect the total content of acid present in the source liquid is from 0.2 to 0.4 mole equivalents based on the nicotine.

Nicotine may be provided at any suitable amount depending on the desired dosage when inhaled by the user. In one aspect nicotine is present in an amount of no greater than 6 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.4 to 6 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.8 to 6 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1 to 6 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1.8 to 6 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.4 to 5 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.8 to 5 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1 to 5 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1.8 to 5 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of no greater than 4 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.4 to 4 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.8 to 4 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1 to 4 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1.8 to 4 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of no greater than 3 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.4 to 3 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.8 to 3 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1 to 3 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1.8 to 3 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of no greater than 1.8 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.4 to 1.8 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.5 to 1.8 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.8 to 1.8 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 1 to 1.8 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of less than 1.8 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.4 to less than .8 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.5 to less than 1.8 wt% based on the total weight of the source liquid. In one aspect nicotine is present in an amount of from 0.8 to less than 1.8 wt% based on the total weight of the source liquid, In one aspect nicotine is present in an amount of from 1 to less than 1.8 wt% based on the total weight of the source liquid.

The source liquid may comprise a number of other components such as flavourings. The amounts of these components can generally be varied depending on the desired profile of the source liquid. In some embodiments, the flavourings are dissolved in propylene glycol and so the "flavouring" component may be understood as a combination of the PG and the active flavouring compounds. Typical flavouring components may include menthol, and other active compounds providing other sensory flavours such as cherry, smokey etc. The acid is typically present in the source liquid as a source of protons with which to protonate the nicotine present in the source liquid. In this regard, nicotine generally exists as a free base in which neither of its nitrogen atoms are "protonated". The inclusion of an acid in the source liquid provides a source of protons which can protonate the nicotine.

In a further aspect, there is provided an aerosol provision cartridge for use with an aerosol provision system, said cartridge comprising:

a liquid storage region in fluid communication with an aerosol generating region; said aerosol generating region configured to be substantially liquid-free; and one or more metallic components, located substantially outside of the aerosol generating region and liquid storage region, wherein at least one of the said metallic components has a coating comprising silver and/or gold.

In this regard, the term an "said aerosol generating region configured to be substantially liquid-free" means that the aerosol generating region is a chamber which is substantially free of liquid during use. In other words, whilst small amounts of condensate may form in the aerosol generating region/chamber, it is intended that in normal use this part of the cartridge will not be a reservoir or store for liquid that is to be vaporized.

In one embodiment, there are no metallic components in the aerosol generating region/chamber, other than the aerosol generating component.

In a further aspect there is provided the use of a metallic component having a coating comprising gold and/or silver in an aerosol provision cartridge to stabilise and/or improve the acceptability of the aerosol to a user. In this regard, the metallic component having a coating comprising gold and/or silver is as defined with respect to the aerosol provision cartridge defined above.

In a further aspect there is provided a method of preventing the deterioration of the sensorial attributes of an aerosol produced from an aerosol provision cartridge comprising utilising in the construction of the cartridge a metallic component having a coating comprising gold and/or silver. In this regard, the metallic component having a coating comprising gold and/or silver is as defined with respect to the aerosol provision cartridge defined above.

In a further aspect there is provided an aerosol provision system comprising an aerosol provision cartridge as defined herein, and an aerosol provision device comprising a power source and an input means. The aerosol provision device may be as defined above with regard to, for example, the body 20 described with reference to the embodiment of Figures 1 to 4.

Thus, described above are examples of aerosol provision systems that can help ameliorate the issues discussed above with regard to the generation of degradation products. The following examples serve to illustrate the surprising benefits of the present system.

Examples

An assessment was made of an aerosol provision system comprising metallic components having various coatings. An aerosol provision system (ePen,

www.govype.com) was modified such that metallic components of the aerosol provision cartridge which were outside of the aerosol generating region/chamber and liquid storage region were coated with a range of coatings. The coatings assessed contained:

• Nickel (Example 1 )

• Tin (Example 2)

• Gold (Example 3)

• Silver (Example 4)

Multiple cartridges were prepared for each example and the liquid storage region of each aerosol provision cartridge was filled with a source liquid comprising nicotine, water, glycerol and an organic acid as set out in Table 1. Thus, for each experiment, Sample 1 contained no organic acid, whereas Samples 2 and 3 contained 0.3 molar equivalents and 0.75 molar equivalents of acid respectively, relative to the nicotine in the source liquid.

Table 1

Each sample was stored for 14 days at ambient temperature. Additionally, replicates where prepared and stored under "accelerated" conditions of elevated temperatures as follows:

• 1 week at 40°C;

• 3 weeks at 40°C; and

• 7 weeks at 40°C

Prior to user assessment of the aerosol, an analysis was carried out of the trace metals (if any) present in the aerosol. The samples comprising metallic components with nickel, gold and silver containing coatings did not lead to unacceptable levels of metals being identified in the aerosol. The samples comprising metallic components with tin containing components had unacceptable levels of metals in the aerosol and were not used in the user assessment of the aerosol.

For the user assessment, six users were asked to rate the aerosol in terms of preference on a scale of 1 to 4, a lower score indicating a higher preference. Their preferences were recorded and the average reference provided. As can be seen from Figure 7, aerosols produced from aerosol provision cartridges comprising a protonated formulation (a liquid source comprising nicotine and an acid) and metallic components outside of the aerosol generating region coated with coatings comprising nickel were generally less preferred compared to coatings comprising gold or silver. When the metallic components were coated with a coating comprising gold, the preference was greatest. Selecting specific components outside of the aerosol generating region and coating them with suitable coatings (comprising gold or silver) leads to more preferred aerosols. Without being bound in this regard, it is thought that this is the case because metallic components generally located outside of the aerosol generating region nevertheless may become exposed to source liquid. This exposure may then lead to reaction products being produced which, over time, will become entrained in the airflow through the device and become perceptible to the user. As a result of selectively coating such metallic components, the aerosol provided to the user can be stabilised and/or improved relative to systems without such selective coatings. In order to address various issues and advance the art, this disclosure shows by way of illustration various embodiments in which the claimed invention(s) may be practiced. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and to teach the claimed invention(s). It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limitations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope of the claims. Various embodiments may suitably comprise, consist of, or consist essentially of, various

combinations of the disclosed elements, components, features, parts, steps, means, etc. other than those specifically described herein, and it will thus be appreciated that features of the dependent claims may be combined with features of the independent claims in combinations other than those explicitly set out in the claims. The disclosure may include other inventions not presently claimed, but which may be claimed in future.