A cascade impactor 30 for measuring particle size distribution of an aerosol containing nicotine. The cascade impactor has an induction port 32 for receiving an inhaler 31 and at least one sample collection stage 33 having a nozzle assembly and collection means. Where the collection means is coated with isopropyl alcohol. Optionally, the cascade impactor features at least five or seven collection stages. Optionally, the cascade impactor is a Next Generation Impactor, an Andersen Cascade Impactor, a Multi-stage Liquid Impinger, a Marple-Miller Cascade Impactor or a Twin Impinger. Optionally, the cascade impactor has a micro-orifice collector. Optionally, the isopropyl alcohol is present in an amount no greater than 5 mL or 3 mL in each of the sample collection stages that are coated with alcohol. Optionally, at least one or seven of the sample collection stages are coated with glycerine, silicone oil Tween 80 or a mixture thereof. Optionally, the sample collection stages are removed from the cascade impactor a
