ICP-OES Determination of Titanium (IV) in Marine and Wastewater Samples after Preconcentration onto Unloaded and Reagent Immobilized Polyurethane Foams Packed Columns

Abstract

A novel method that utilizes untreated and polyurethane foam (PUF) physically immobilized with the reagent 4-(2-pyridylazo) resorcinol (PAR) or 2, 3, 5-triphenyl-2H-tetrazolium chloride (TZ + Cl-) as solid phase extractor packed column has been developed for preconcentration and subsequent determination of titanium(IV) ions in marine and wastewater samples. The method is based on retention of the titanium(IV) traces present in aqueous media at pH 3-4 onto the reagent treated PUF packed column, followed by recovery with HNO 3 (2.0 mol dm-3) and subsequent ICP-OES determination. The uptake of titanium species onto the unloaded-and reagent impregnated PUF was fast and followed a first-order rate equation. Titanium sorption onto PUF followed Langmuir, Freundlich and Dubinin-Radushkevich (D-R) type isotherm models. Thus, a dual-mode sorption mechanism involving absorption related to "weak-base anion exchange" and an added component for "surface adsorption" seems a more likely retention model. PAR-immobilized PUF packed column has been applied successfully for complete collection of titanium(IV) species in fresh and wastewater samples at low level of titanium (<0.5 ng Ti mL-1) at pH 3-4. The retained titanium species were then recovered (97-101%) from the packed column with HNO 3 and determined by ICP-OES. The proposed PUF packed column method was further applied for analysis of picomolar concentrations of dissolved Ti species in marine water.

An extraction-chromogenic system for vanadium(IV,V) based on 2,3-dihydroxynaphtahlene

“…We selected TTC for the present study since it is the simplest commercially available tetrazolium salt. Moreover, TTC has many applications based on ion-association [17][18][19][20][21][22] and oxidation-reduction [23][24][25]. Molecular parameters of TTC and some compounds containing its cation TT + are given in the literature [26,27].…”