title: Chemical speciation of chromium(III) and (VI) using phosphonium cation impregnated polyurethane foams prior to their spectrometric determination.
abstract: Fast and selective sorptions of Cr(VI) species from aqueous media onto tetraphenylphosphonium bromide (TPP(+) · Br(-)) physically immobilized polyurethane foams (PUFs) sorbent were achieved. Based on the Scatchard model of binding sites of the PUFs and Langmuir and Dubinin-Radushkevich (D-R) adsorption models of Cr(VI) retention onto TPP(+) · Br(-) immobilized PUFs, a dual retention mechanism involving absorption related to "weak-base anion ion exchange" and an added component for "surface adsorption" was proposed. Thus, the TPP(+) · Br(-) loaded PUFs were successfully packed in column mode for preconcentration of trace and ultra trace concentrations of Cr(VI) as halochromates [CrO(3)C](-)(aq) from aqueous HCl media. The retained [CrOCl(3)](-)(aq) species were recovered with NaOH (1.0 mol L(-1)) and analyzed by flame atomic absorption spectrometry. Cr(III) species after oxidation to Cr(VI) with H(2)O(2) in aqueous KOH (1.0 mol L(-1)) were also retained and could be recovered by the proposed method. The limits of detection (LOD) and quantification (LOQ) of Cr(VI) were 0.04 and 0.13 µg L(-1), respectively. The chemical speciation of Cr(III, VI) species in various water samples at trace and ultra trace levels were carried out by TPP(+) · Br(-) loaded PUFs packed column. The enhancement factor and sensitivity factor of [CrO(3)C](-)(aq) sorption were 80.0 and 30.0, respectively.
authors: Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia. malsaeed@kau.edu.sa
authors: M S
authors: MS
authors: El-Shahawi
authors: A S
authors: AS
authors: Bashammakh
authors: M
authors: M
authors: Abdelmageed
mesh_terms: D053000:Analytic Sample Preparation Methods / Q000379:methods*; D002845:Chromatography; D002857:Chromium / Q000032:analysis* / Q000737:chemistry* / Q000302:isolation & purification; D009861:Onium Compounds / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*; D013057:Spectrum Analysis; D014865:Waste Disposal, Fluid
chemical_list: D009861:Onium Compounds; D009943:Organophosphorus Compounds; D011140:Polyurethanes; D002857:Chromium; C013289:tetraphenylphosphonium