Direct detection of lead in RTIL using DPASV on BDD film microcells and determination of concentration factor after extraction from aqueous samples

European Water Framework Directive and the Predicted Non Effect Concentrations for water organisms require determination of lead at very low concentrations: 1.2 μg/L. These low concentrations, generally in complex sample matrixes, have influence on the sensitivity and accuracy of the analytical method. Hence, prior to a determination, a clean-up and/or enrichment step is highly necessary. In this work, for the first time, the determination of Pb was performed using Differential Pulse Anodic Stripping Voltammetry (DPASV) on a Boron-Doped Diamond microcell directly in the room temperature ionic liquid (RTIL) extracting phase: Butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide which contained the complexing agent Trioctylphosphine oxide (TOPO). The calibration curves with and without TOPO are linear in the concentration range 0–4 μg/L of Pb, with a detection limit (DL) of 0.3 μg/L. The optimum conditions for higher concentration factor were determined: the aqueous phase should be a 0.1 M citrate buffer with pH 2. The obtained concentration factor was 5.0 ± 0.2 for lead in RTIL without chelating agent TOPO, and 9.0 ± 0.10 in IL with chelating agent TOPO.