Preconcentration of toxic elements in artificial saliva extract of different smokeless tobacco products by dual-cloud point extraction

Smokeless tobacco (SLT) has been associated with oral cancer. In present study, the total and artificial saliva extracted toxic elements (TEs), arsenic (As), cadmium (Cd), nickel (Ni) and lead (Pb) were estimated in SLT products (gutkha, green and brown snuff). Dual-cloud point extraction has been used for the preconcentration of As, Cd, Ni and Pb in artificial saliva extract, using complexing reagent, ammonium pyrrolidinedithiocarbamate. The dual-cloud point extraction procedure was based on forming complexes of elemental ions with complexing reagent and subsequent entrapping of the complexes in nonionic surfactant. Then the surfactant rich phase containing the complexes was treated with nitric acid, and detected ions were back extracted again into aqueous phase at the second cloud point extraction stage, and finally determined by electrothermal atomic absorption spectrometry. The validity of methodology was tested by simultaneously analyzing certified reference material and spike recovery test. The experimental enhancement factors of As, Cd, Ni and Pb were found to be 52, 58, 48 and 44, respectively. The concentration of As, Cd, Ni and Pb in artificial saliva extracts corresponds to 18-24, 45-75, 30-55, and 20-30%, respectively, of the total contents of TE in different types of SLT products (gutkha, brown and green snuff). It was estimated that 10 g intake of SLT products (gutkha, brown and green snuff) could contribute 2.2-13, 21-69, 3.4-48 and 10-75% of the provisional maximum tolerable daily intake of As, Cd, Ni and Pb, respectively for adults ~ 60 kg.