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
Email: schalk@unf.edu
Website: @unf

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Journal of Environmental Science and Health

  • Publisher: Taylor and Francis
  • FAD Code: JESH
  • CODEN: JATEF9
  • ISSN: 1093-4529
  • Abbreviation: J. Environ. Sci. Heal.
  • DOI Prefix: 10.1081/ESE
  • Language: English
  • Comments: Fulltext from 2001 V36

Citations 5

"Determination Of Pb(II) With A Dithizone-modified Carbon Paste Electrode"
J. Environ. Sci. Heal. 2006 Volume 41, Issue 12 Pages 2735-2746
Ma Dolores Vázquez; Ma Luz Tascón; Luis Debán

Abstract: A dithizone (DTZ) modified carbon paste electrode was developed for the sensitive and selective determination of Pb(II) using differential pulse anodic stripping voltammetry as well in batch as in FIA system. The analysis procedure is based on an open circuit accumulation step in a stirred sample solution. This was followed by a medium exchange to a clean solution and subsequently by a proper anodic stripping. The analytical performance was evaluated with respect to the quantity of modifier in the paste, accumulation time, background electrolyte, Pb(II) concentration and other variables. When the accumulation time applied was 5 minutes, linear calibration graphs were obtained in the concentration range 1 x 10^-7-1 x 10^-5 M and 8 x 10^-8-5 x 1010-6 M for batch and Flow Injection Analysis (FIA), respectively. The detection limits found were 8.65 x 10^-8 M in batch and 4.45 x 10^-8 M in FIA. A convenient and rapid renewal of electrode surface allows the use of a single modified electrode surface in multiple analytical determinations. Several coexisting metals ions such as Cd(II), Hg(II), Cu(II) and Zn(II) had no interference on the determination of Pb(II). The proposed method was applied in the determination of lead in soils located in the vicinity of metallurgic transformation industry. The results obtained were in accordance to the ones supplied by Atomic Absorption Spectroscopy (AAS). Copyright © Taylor & Francis Group, LLC.

"Use Of Flow Injection And Sequential Injection Analysis Schemes For The Determination Of Trace-Level Concentrations Of Metals In Complex Matrices By ETAAS And ICPMS*"
J. Environ. Sci. Heal. 2005 Volume 40, Issue 8 Pages 1507-1524
Elo Harald Hansen

Abstract: Despite their excellent analytical chemical capacities for determination of low levels of metal species, electrothermal atomic absorption spectrometry and inductively coupled plasma mass spectrometry often require suitable pretreatment (separation and pre-concentration) of the sample material to facilitate the desired sensitivity and selectivity of measurement. Such pretreatment schemes are advantageously performed in flow injection (FI) or sequential injection (SI) manifolds, where all unit operations can be effected on-line and under enclosed and strictly controlled conditions. Various separation/pre-concentration procedures are feasible, such as liquid"liquid extraction (possibly including back extraction), (co)precipitation with collection in knotted coils, adsorption on hydrophilic or hydrophobic reactors, hydride generation, or the use of ion-exchange/chelating packed columns. After describing the particulars and characteristics of FI and SI, we present, via selected examples, various separation/pre-concentration FI/SI schemes for the determination of trace levels of metals, with particular emphasis on the use of the novel extension of FI/SI, that is, the so-called lab-on-valve concept.

"Speciation Of Arsenic Metabolite Intermediates In Human Urine By Ion-exchange Chromatography And Flow Injection Hydride Generation Atomic Absorption Spectrometry"
J. Environ. Sci. Heal. 2003 Volume 38, Issue 1 Pages 115-128
Mohammad Alauddin; Sarah T. Alauddin; Maya Bhattacharjee; Shamima Sultana; Dulaly Chowdhury; Hawa Bibi; Gholam H. Rabbani

Abstract: Biomethylation is considered as the principal metabolic and detoxification pathway for inorganic arsenic in human. The end products of methylation are less toxic and more readily excreted through urine. Therefore, speciation of metabolites in urine is essential to a better understanding of arsenic metabolism, health effects and detoxification ability of individuals exposed to arsenic through drinking water, food and environmental materials. Speciation of inorganic and methylated arsenic in urine is an analytical challenge and often requires expensive instrumentation. We have applied a relatively inexpensive technique for the separation and analysis of various arsenic species, such as, arsenite, arsenate, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in human urine. The technique is based on ion exchange chromatographic separation followed by flow injection hydride generation atomic absorption spectroscopy (FI-HG-AAS). The detection limit varies from 1.0 to 2.0 ?g/L for various species. The technique has been successfully applied to speciation of arsenic metabolite intermediates in urine samples collected from patients in Hajiganj, a serious arsenic affected area in Bangladesh. Arsenite (As(III)) was found to be the major component in the urine from these patients. Our findings from patients in Hajiganj, Bangladesh are presented in this paper. The technique permits us to carry out arsenic speciation in urine, essential for toxicological studies and possible nutritional intervention in combating arsenic poisoning in Bangladesh.

"Continuous-flow Photocatalytic Degradation Of Carbaryl In Aqueous-media"
J. Environ. Sci. Heal. 1993 Volume 28B, Issue 4 Pages 431-435
Peris-Cardells, E.; Terol, J.; Mauri, A. R.; de la Guardia, M.; Pramauro, E. (SFS)

Abstract: The photocatalytic degradation of carbaryl, present in aqueous solutions containing suspended TiO2 particles, has been studied in a continuous flow system, using a polytetrafluoroethylene photochemical reactor, equipped with an UV lamp. In order to optimize the process the effect of pH, catalyst and pesticide concentration, and irradiation time have been evaluated, working in the best conditions, the measured half-life of carbaryl was 26 seconds. More than 99% of carbaryl present in solutions containing 0.2 mg L-1 of pesticide decomposes after less than 1 minute irradiation.
Carbaryl Water Photochemistry Catalysis Optimization

"Low-cost Flow Injection Analysis For Cadmium Using 2-(2-Benzothiazolylazo)-4,5-dimethylphenol"
J. Environ. Sci. Heal. 1991 Volume 26, Issue 1 Pages 63-74
Kate Grudpan & Chusri Palsaludomsil

Abstract: 2-(2-benzothlazolylazo)-4,5-dlmethylphenol (BTDMP) has been applied as a new color reagent to flow Injection analysis (FIA) for cadmium. The low-cost FIA system used was made and assembled using low-cost and easily available materials. Optimum conditions for the FIA system were Investigated, such as analytical wavelength, a solvent as a carrier, alkalinity of the carrier, concentrations of reagents used, flow-rate and mixing coil length. Using the optimum conditions, a calibration curve was obtained for a linear range of 0-10 ppm Cd. Interferences of some metal ions (Zn, Cu, Co, Nl and Hg) were studied.
Cadmium Spectrophotometry Low cost Interferences Optimization