Chromium Speciation in Wastewater and Sewage by Solid-Phase Extraction Using a New Diphenylcarbazone-Incorporated Resin

A new procedure for the determination of chromium species in polluted environmental samples by flame atomic absorption spectrometry was developed in this work. A new material containing 1,5-diphenylcarbazone included in a polymeric matrix was prepared and employed as a solid-phase extraction material for selective separation of Cr(III) ions under dynamic conditions. Chromium(III) ions were retained on this sorbent with high efficiency and repeatability (95 %, RSD = 1 %) from solutions with pH 9.0. The quantitative recovery of analyte was obtained with 0.1 mol L-1 EDTA. The concentration of Cr(VI) ions was calculated from the difference between the concentration of total chromium and Cr(III) ions. The prepared sorbent exhibits good chemical and mechanical stability, sorption capacity and selectivity towards Cr(III) ions in the presence of Cu(II), Ni(II), Mn(II) and Ca(II) ions. The accuracy of the separation method was proved by analysis of reference material of wastewater RES 10.2. The developed procedure was applied for chromium speciation analysis in municipal sewage samples.