Characterisation of the mineral composition of tobacco products (cigar, shredded and rope)

Abstract

In this work, experimental design methodologies for the optimisation of analytical methods for the determination of inorganic constituents in tobacco products (cigar, shredded and rope) employing inductively coupled plasm optical emission spectrometry. Box-Behnken design was applied to optimise the digestion procedure of tobacco product samples using a closed digester block. The sample preparation was used dilute nitric acid, suitable for the concept of Green Chemistry. The operating conditions of spectrometer were optimised applying Doehlert design. The limits of quantification (LoQ) varied between 0.09 μg g−1 (Ba and Ti) and 116 μg g−1 (Na). The accuracy was confirmed by analysis of the certified reference materials (CRM) of oriental tobacco leaves (CTA-OTL-1), apple leaves (NIST 1515) and tomato leaves (CRM-Agro C1003a). The analytical method was applied for the determination of nineteen elements (Al, As, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Ni, P, S, Sr, Ti, V and Zn) in tobacco products samples (cigar, shredded and rope). The results showed that the mean concentrations of macroelements were higher in cigar samples, the exception being Na concentration, which was higher for rope tobacco. For all samples, K concentration was the highest observed, since it is the nutrient most readily absorbed by the plant. Regarding the microelements and trace elements, cigar samples had higher contents of the six metals (Zn > Ba > Ti > Ni > Co > Cd) than did shredded or rope tobacco. The shredded tobacco samples presented higher concentration of Fe and for rope tobacco, the higher concentrations were for Al > Mn > Cu. In addition, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to discriminate the different tobacco products thought elemental composition, being cigar tobacco showed differences in relation to shredded and rope tobacco samples.