Characterizing the Transport of Aluminum-, Silicon- and Titanium-Containing Particles and Nanoparticles in Mainstream Tobacco Smoke.

The most commonly observed forms of aluminum, silicon and titanium in tobacco products are aluminum silicates (e.g., kaolin), silica and titanium(IV) oxide. These compounds are neither water soluble nor volatile at cigarette combustion temperatures. Rather, they are transported in mainstream tobacco smoke as particles after being freed by combustion from the tobacco filler and can induce pulmonary inflammation when inhaled. Aluminum silicate particles are the most frequently observed particles in the pulmonary macrophages of smokers and have become known as 'smokers' inclusions'. A relatively new technique, single particle triple quadrupole inductively coupled plasma-mass spectrometry was used to analyze aluminum-, silicon- and titanium-containing particle deliveries in cigarette and little cigar mainstream tobacco smoke, and to collect information on solid inorganic particles. The mass concentration of aluminum-containing particles transmitted in mainstream smoke was low (0.89-0.56 ng/cigarette), which was not surprising because aluminum silicates are not volatile. Although the collective masses (ng/cigarette) of aluminum-, silicon- and titanium-containing particles under 100 nm diameter transported in mainstream smoke were low, an abundance of 'ultrafine' particles (particles < 100 nm or nanoparticles) was observed. Limitations of the particle background equivalent diameter (the smallest detectable particle size (MassHunter 4.5 Software) due to the environmentally ubiquitous silicon background restricted the determination of silica nanoparticles, but silica particles slightly below 200 nm diameter were consistently detected. Aluminum- and titanium-containing nanoparticles were observed in all cigarette and little cigar samples, with titanium(IV) oxide particle deliveries consistently fewer in number and smaller in diameter than the other two types of particles. The highest concentrations of aluminum-containing particles (as kaolin) were in the nanoparticle range with much lower concentrations extending to the larger particle sizes (>100 nm). The number and range of particle sizes determined in mainstream smoke is consistent with pulmonary deposition of aluminum silicates described by other researchers as contributing to the 'smokers' inclusions' observed in pulmonary macrophages.

Characterization of SPECTRUM Variable Nicotine Research Cigarettes.

OBJECTIVE: To provide researchers an extensive characterization of the SPECTRUM variable nicotine research cigarettes. METHODS: Data on cigarette physical properties, nicotine content, harmful and potentially harmful constituents in the tobacco filler was compiled. RESULTS: Data on physical properties, concentrations of menthol, nicotine and minor alkaloids, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, ammonia, and toxic metals in the filler tobacco for all available varieties of Spectrum research cigarettes are provided. The similarity in the chemistry and physical properties of SPECTRUM cigarettes to commercial cigarettes renders them acceptable for use in behavioral studies. Baseline information on harmful and potentially harmful constituents in research tobacco products, particularly constituent levels such as minor alkaloids that fall outside typical ranges reported for commercial, provide researchers with the opportunity to monitor smoking behavior and to identify biomarkers that will inform efforts to understand the role of nicotine in creating and sustaining addiction. CONCLUSIONS: Well characterized research cigarettes suitable for human consumption are an important tool in clinical studies for investigating the physiological impacts of cigarettes delivering various levels of nicotine, the impact of reduced nicotine cigarettes on nicotine addiction, and the relationship between nicotine dose and smoking behavior.