Identification and determination of selenosulfate and selenocyanate in flue gas desulfurization waters.

In this work, 13 selenium species in flue gas desulfurization (FGD) waters from coal-fired power plants were separated and quantified using anion-exchange chromatography coupled to inductively coupled plasma mass spectrometry. For the first time, we identified both selenosulfate (SeSO(3)(2-)) and selenocyanate (SeCN(-)) in such waters, using retention time matching and confirmation by electrospray mass spectrometry. Besides selenite and selenate, selenosulfate was the most frequently occurring selenium species. It occurred in most samples and constituted a major fraction (up to 63%) of the total selenium concentration in waters obtained from plants employing inhibited oxidation scrubbers. Selenocyanate occurred in about half of the tested samples, but was only a minor species (up to 6% of the total selenium concentration). Nine additional Se-containing compounds were found in FGD waters, but they remain unidentified at this point.

Flow injection hydride generation electrothermal atomic absorption spectrometric determination of toxicologically relevant arsenic in urine.

Analytical procedure for the determination of toxicologically relevant arsenic (the sum of arsenite, arsenate, monomethylarsonate and dimethylarsinate) in urine by flow injection hydride generation and collection of generated inorganic and methylated hydrides on an integrated platform of a transverse-heated graphite atomizer for electrothermal atomic absorption spectrometric determination (ETAAS) is elaborated. Platforms are pre-treated with 2.7 micromol of zirconium and then with 0.10 micromol of iridium which serve both as an efficient hydride sequestration medium and permanent chemical modifier. Arsine, monomethylarsine and dimethylarsine are generated from diluted urine samples (10-25-fold) in the presence of 50 mmol L(-1) hydrochloric acid and 70 mmol L(-1)l-cysteine. Collection, pyrolysis and atomization temperatures are 450, 500, 2100 and 2150 degrees C, respectively. The characteristic mass, characteristic concentration and limit of detection (3sigma) are 39 pg, 0.078 microg L(-1) and 0.038 microg L(-1) As, respectively. The limits of detection in urine are ca. 0.4 and 1 microg L(-1) with 10- and 25-fold dilutions. The sample throughput rate is 25 h(-1). Applications to several urine CRMs are given.