University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Citations 4

"Determination Of Cadmium In Environmental Samples By Hydride Generation With In Situ Concentration And Atomic Absorption Detection"
Analyst 1997 Volume 122, Issue 4 Pages 331-336
Henryk Matusiewicz, Mariusz Kopras and Ralph E. Sturgeon

Abstract: A continuous-flow AAS system for Cd determination is described. A Cd solution acidified with HCl was mixed with 1 µg/ml Co and 0.5% thiourea (and also with 0.01 M didodecyldimethyl-ammonium bromide for reaction with KBH4) and diluted to 1 mL with water. The resulting solution was aspirated at a flow rate of 1 ml/min into a continuous-flow system and merged with a stream of either 2% NaBH4 or 4% KBH4 at a flow rate of 1 ml/min. The mixture was passed through a reaction cell/gas-liquid separator maintained at 50°C and the volatile Cd species evolved were carried by an Ar stream on to the inner wall of a GF for in situ pre-concentration at 200°C. Cd analysis was by ET AAS with atomization at 1800°C for 3 s; detection was at at 228.8 nm. The detection limit was 10 ng/l Cd with KBH4 as reagent. RSD were 10^-14% (n = 10). The method was applied to several environmental and biological CRM. The results obtained agreed with the certified values.
Cadmium Spectrophotometry Heated reaction Volatile generation Reference material Phase separator Preconcentration Volatile generation

"Determination Of Mercury In Filtered Seawater By Flow Injection With Online Oxidation And Atomic Fluorescence Spectrometric Detection"
J. Anal. At. Spectrom. 1996 Volume 11, Issue 7 Pages 511-514
Martin J. Bloxham, Steve J. Hill and Paul J. Worsfold

Abstract: A flow injection (FI) atomic fluorescence method incorporating an online bromide-bromate oxidation step to determine mercury in filtered seawater samples at the ng L-1 level is described. A heated reaction coil was incorporated in the FI manifold to increase the conversion of organic mercury into inorganic mercury(II) chloride from 50 to approaching 100%. Detection limits (3s) for mercury(II) chloride and methylmercury chloride were 25 and 23 ng L-1 Hg, respectively. The FI manifold could also be used to determine the total mercury concentration in biological materials and was validated by analyzing the CRM TORT-1 Lobster Hepatopancreas. Good agreement with the certified (330±60 µg l-1) value was achieved (353±64 pg l-1). The analysis of coastal water samples from Sutton Harbour, Plymouth, showed that mercury levels ranged from 24±5 to 54±10 ng l-1.
Mercury(II) Fluorescence Reference material

"Determination Of Organomercury In Biological Reference Materials By Inductively Coupled Plasma Mass Spectrometry Using Flow Injection Analysis"
Anal. Chem. 1988 Volume 60, Issue 23 Pages 2587-2590
Diane Beauchemin, K. W. M. Siu, and S. S. Berman

Abstract: Samples of DORM-1 dogfish muscle and TORT-1 lobster hepatopancreas were acidified with HCl and extracted with toluene, and the organomercury compounds were back-extracted into aqueous cysteine acetate solution. Extracts were analyzed by isotope-dilution ICP-MS with use of a flow injection technique and a 100 µL sample loop in order to overcome interference caused by the presence of 4% of Na in the extracts. Results were compared with those obtained by GC - ECD. Methylmercury is the only significant organomercury compound present in DORM-1.
Ethylmercury Methylmercury ion Phenylmercury Clinical analysis Mass spectrometry Mass spectrometry Method comparison Reference material Interferences Speciation

"Determination Of Arsenic And Selenium By Hydride Generation Atomic Absorption Spectrometry Using A Gas-liquid Separator And A Dehydration Trap"
Microchem. J. 1996 Volume 53, Issue 1 Pages 18-25
Hisatake Narasaki and Jun-Yan Cao

Abstract: Biological material (0.25 g) was allowed to stand overnight in 3 mL concentrated HNO3, 0.5 mL concentrated H2SO4 and 1 mL 60% HClO4 were added and the mixture was digested under low heat until the fumes of HClO4 subsided. The digests, including siliceous residues, were transferred to a Pt dish with water and evaporated to 2 mL. The residues were dissolved with 5 mL 46% HF, 1 mL 9 M H2SO4 was added and the solution was concentrated to 2 mL. The pH was adjusted to 3.5 with 1 M NH3 and applied to a SPE column (35 cm x 10 mm i.d.) packed with 10 cm Chelex 100 chelating ion-exchange resin and the column was washed with 2 x 10 mL water. For the analysis of As; the column effluents were diluted to 100 mL with water and a 10 mL portion was mixed with 5 mL 6 M HCl. Portions of both acid solutions were introduced into the flow injection hydride generation system (schematic shown) and mixed with a stream of 2% sodium tetrahydroborate(III) solution in a Pyrex mixing coil (16 cm x 2 mm i.d.). The hydride generated was collected in a gas-liquid separator, dehydrated in a dehydration trap and swept into an electrically heated furnace with a carrier stream of N2 (2.5 l/min) by manipulating electromagnetic relays and timers (operating details given). The atomized As and Se species were detected at 193.7 and 196 nm, respectively, by AAS. The detection limits were 0.6 and 1 ng/ml, respectively. Tolerance levels to 10 foreign ions are listed. The method was applied to the analysis of five NIST Standard Reference materials (listed). Results agreed well with certified values.
Arsenic Selenium Spectrophotometry Reference material Chelex