Trace-metal distribution of cigarette ashes as marker of tobacco brands

The trace-metal distribution of cigarette ashes offers a potential interest from the point of view of forensics and criminology dealing with the determination and classification of tobacco brands. There is a vast bibliography related to the determination of different metals in tobacco leaves. Nevertheless, none of them are directly linked to this matter. Therefore, in this work we present a methodology to assess the viability of discriminating between different tobacco brands by analysing the ashes after smoking. This methodology encompasses the data analysis by atomic techniques (inductively coupled plasma) and further data analysis by principal component analysis and partial least squares-discriminant analysis. The metal distribution (Zn, B, Mn, Fe, Mg, Cu, Ti, Al, Sr, Ca, Ba, Na, Li, and K) of cigarette ashes of different tobacco brands was determined in 149 samples obtained from local stores, representing the most common brands of cigarettes readily available to consumers in Spain. Further analysis of the data with PCA denoted significant differences between different brands of tobacco in their metallic content. In that sense, blond tobaccos were found to contain different patterns in metallic content than black tobaccos. Intrinsic differences were found between different brands, being possible to study the relationship between each brand and its metallic concentration and compare this relationship with other brands. Moreover the possibility of developing classification models to be able to discriminate between different brands was also introduced.