Usage of Empore™ membrane in alcoholic media for copper(II) distribution studies

The sorption of copper(II) on a solid, iminodiacetic based, chelating material, the Empore™ membrane, in alcoholic solutions is considered. Determination of the acid–base properties, kinetic of metal sorption and complexing properties, in solutions with different percentages of ethanol, ranging from 0 to 40% is undertaken. The results are compared with those obtained using the classical iminodiacetic resin Chelex 100 in beads. No significant differences are found in the thermodynamic properties, but the kinetics of the metal sorption on the membrane is slower and a dependence of the process rate with the alcoholic content is observed. In the present investigation, the detection of copper(II) species both in alcoholic Italian distillate “grappa” and in its intermediate product (“flemma”), is carried out by the Resin Titration (RT) method using, as competitive reagent, the Empore™ membrane. To validate the procedure, synthetic solutions containing different percentages of ethanol are analysed.