Determination of trace elements in AR grade alkali salts after preconcentration by column solid-phase extraction on TiO2 (anatase)

Abstract

 Column solid-phase extraction using TiO₂ (anatase) as a solid sorbent was applied to preconcentrate traces of Cd, Co, Cu, Fe, Mn, Ni and Pb from AR grade alkali salts prior to their measurements by atomic absorption spectrometry (AAS). Multi-element preconcentration was achieved from NaCl, KCl, KNO₃, NaNO₃, CH₃COONa, NaHCO₃ and Na₂CO₃ solutions, whereas the sorption of trace elements from phosphates and sulfates is not quantitative. Optimal conditions (recoveries of the analytes >95%) for solid-phase co-extraction of the most common heavy metal ions are proposed. The conditions for quantitative and reproducible elution and subsequent AAS are established. A method of determination of trace elements in different salts is proposed. It is characterized by precision, reproducibility and a high preconcentration factor. The solid-phase extraction by TiO₂, combined with ETAAS allows the determination of 0.1 ng g^-1 Cd, 2 ng g^-1 Co, 1 ng g^-1 Cu and Ni, 0.5 ng g^-1 Mn and 0.4 ng g^-1 Pb.