Chromium speciation by TXRF analysis

Abstract

Chromium (Cr) is an element which usually occurs in two different forms, Cr(III) and Cr(VI). As Cr(VI) is much more toxic than Cr(III), no complicated analytical methods with low detection limit are needed for chromium speciation. In the present work, a new method is presented for chromium speciation at low concentrations by selective membrane collection and total Reflection x‐ray fluorescence (TXRF) analysis. Various membranes were produced on the surface of quartz reflectors containing different complexing ligands in Nafion and poly vinyl chloride (PVC) matrices. The membranes were produced on the surface of quartz glass, while the reflectors were immersed in water solutions with low concentrations of chromium salts for many hours. When the equilibration stage was achieved, the reflectors were analyzed by TXRF. Completely selective membranes for Cr(III) and Cr(VI) were prepared with minimum detection limits lower than 0.6 ng.ml−1 (ppb) in drinking water. Copyright © 2009 John Wiley & Sons, Ltd.

Atomic spectrometry update–X-ray fluorescence spectrometry

“…When discussing chemical speciation, the conventional approach typically uses X-ray absorption near edge spectrometry (XANES) spectra around the K-or L-edge of the chemical element. In a publication by Kallithrakas-Kontos et al 110 an interesting simple approach was described in which selective membranes and TXRF were directly combined. In this arrangement the membrane was placed on the reflector surface and then immersed for many hours in aqueous solutions containing low concentrations of chromium salts.…”

Influence of smoking on the elemental composition of oral fluids: a TXRF approach

“…X‐ray fluorescence (XRF) in combination with synchrotron radiation (SRXRF) and total reflection analysis (TXRF) have proved to be a very useful tool to diagnosis via the elemental analysis12, 13 and even speciation of toxic elements 14. In this sense TXRF analysis could provide a fast and simple method of analysis of oral fluids, for diagnosis and evaluation.…”

3-Ethyl-4-(p-chlorobenzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one (EPHBAT) as precipitant for carrier element free coprecipitation and speciation of chromium(III) and chromium(VI)

“…The Cr(VI) is extremely toxic and may cause contact allergic dermatitis on the skin and may also be a trigger for many diseases [29,30]. Chromium(III) assisted different enzymatic reaction in human body such as regulate functioning glucose, lipid, and protein metabolism [29][30][31][32][33][34][35]. For the determination of chromium species, Cr(III) and Cr(VI), different separation-enrichment techniques including solvent extraction, membrane filtration, cloud point extraction, solid phase extraction and coprecipitation have been used [19][20][21][22][36][37][38][39].…”