DETERMINATION OF TRACE-ELEMENTS IN AR GRADE ALKALI SALTS AFTER PRECONCENTRATION BY COLUMN SOLID-PHASE EXTRACTION ON TIO2 (ANATASE)

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 absor ption spectrometry (AAS). Multi-element preconcentration was achieved from NaCl, KCl, KNO3, NaNO3, CH3COONa, NaHCO3 and Na2CO3 solutions, wh ereas the sorption of trace elements from phosphates and sulfates is n ot 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 an d subsequent AAS are established. A method of determination of trace e lements in different salts is proposed. It is characterized by precisi on, reproducibility and a high preconcentration factor. The solid-phas e 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.