Preconcentration of Cr(III) and total Cr in waters for flame AAS in a flow-through electrochemical/sorption cell

Abstract

Chromium in water samples is determined by flame atomic absorption spectrometry (AAS) after the preconcentration of Cr(III) species on activated alumina at pH 7 in a flow system coupled on-line to the AAS instrument. The total Cr concentration is determined after the electrochemical reduction of chromate ions to Cr(III) which are preconcentrated together with the original Cr(III) species in the sample. Both the reduction and the sorption are carried out in a combined cell containing a porous electrode, a layer of the sorbent and the counter electrode in series. The porous electrode is made of glassy carbon particles coated with gold. Tap, river and synthetic sea water samples were analyzed with this method. The detection limits are 0.5 ng/ml and 250 ng/ml for 500 ml and 1 ml sample solution, respectively.

Flow-Through Chronopotentiometry in Waste Water Analysis

“…A separation of Cr species prior to the measurement is therefore inevitable either by means of a minicolumn (Cespon-Romero et al, 1996;Rao et al, 1998) or HPLC (Allen & Koropchak, 1993;Lintschinger et al, 1995;Andrle et al, 1997;Luo & Berndt, 1998). The procedure can be simplified by making use of a flow cell coupled in-line to a flame AAS instrument (Beinrohr et al, 1996), consisting of a porous electrode for oxidising Cr(III) to Cr(VI) and a sorbent for trapping Cr(VI). Cr(VI) is collected without electrolysis and on elution measured by AAS.…”

Atomic Absorption, Atomic Emission, and Flame Emission Spectrometry

“…Ma et al (339) investigated the influence of operating parameters on precision and sensitivity in FI-FAAS. Beinrohr et al (340) electrochemically reduced Cr species to Cr(III) and preconcentrated the analyte on activated alumina in a flow-through system for FAAS. There continues to be a proliferation of separation and preconcentration methods using FI-FAAS.…”

Highly Sensitive Detection of Heavy Metal Elements Using Laser-Induced Breakdown Spectroscopy Coupled with Chelating Resin Enrichment

“…At present, conventionally commercial analytical instruments such as inductively coupled plasma optical emission spectroscopy (ICP-OES) [4,5], inductively coupled plasma mass spectroscopy (ICP-MS) [6,7], atomic absorption spectroscopy (AAS) [8,9], X-ray fluorescence spectroscopy (XRF) [10], etc., are used for the analysis and detection of heavy metals in liquids. Although spectral analysis methods are able to provide high detection precision and excellent limits of detection (LODs), nonetheless, their preliminary sample processing steps are cumbersome and eventually spread secondary pollution.…”