On the Interaction Between Nicotine and Metal(II) Ions in Aqueous Solutions

A chemical investigation of the interaction mechanisms of nicotine with the metal(II) ions Pb2+, Fe2+, and Cu2+ is reported. The complex formation between nicotine and metal(II) has been investigated at 25.00 ± 0.02 ∘C, in constant ionic medium (as sodium perchlorate, or sodium chloride), by UV/Vis spectrophotometric and potentiometric methods. The experimental method consists of coulometric or volumetric titrations. The protolysis constants of nicotine have been determined under the same experimental conditions. The pH investigated spans between 3 and 10. By using the specific ion interaction theory the conditional constants of nicotine have been extrapolated at zero ionic strength. The results of the graphical and numerical methods adopted indicate, for all the systems investigated, the formation of a predominating Me(II)/nicotine mononuclear complexes.