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 Monitoring

  • Publisher: Royal Society of Chemistry
  • FAD Code: JEVM
  • CODEN: JEMOFW
  • ISSN: 1464-0325
  • Abbreviation: J. Environ. Monit.
  • DOI Prefix: 10.1039
  • Language: English
  • Comments: Fulltext from 1999 V1

Citations 30

"A Near Real-time System For Continuously Monitoring Airborne Subtilisin-type Enzymes In The Industrial Atmosphere"
J. Environ. Monit. 2007 Volume 9, Issue 1 Pages 33-43
Frederick J. Rowell, David Sykes, Lynsey Grieveson, Brenden Theaker, Latha Sundar and Robert H. Cumming

Abstract: We describe the development and validation of a portable system comprising an air sampler coupled to an automated flow injection analysis device. The system is able to monitor airborne concentrations of subtilisin-type enzymes in the workplace atmosphere on a continuous basis. Sampling is in two stages: using a sampling head that is designed to mimic human respiration at approximately 1 m s-1 at a sampling rate of 600 l min-1. In the second stage, the captured particles are deposited by impaction from the air stream onto the inner surface of a cyclone that is continuously washed with a jet of buffer solution. Deposited particles are then washed into a reservoir from which samples are taken every 5-6 min and injected automatically into a continuous flow injection analysis system. Proteolytic enzyme in the sample passes through a bioreactor maintained at about 40°C. This contains a cellulose solid phase matrix on which is covalently immobilized Texas Red-labelled gelatin as substrate. The passing enzyme partially digests the substrate releasing fluorophore that is detected down stream in a flow cell coupled to a fluorimeter. The system is calibrated using enzyme standards and the intensity of the resulting peaks from the ex-air samples is converted to airborne concentrations using a mathematical model programmed into a PC. The system has a limit of detection of 4.8 ng m-3 and a dynamic range of 5-60 ng m-3. The within assay precision (RSD) is 6.3-9.6% over this range. The within batch precision is 20.3% at 20 ng m-3 and the corresponding between batch value is 19.5%. The system has been run for periods up to 8 h in the laboratory and for up to 4 h at a factory site and the values obtained compared with time-averaged values obtained from a conventional Galley sampler and in-house analysis when reasonable agreement of the results was observed. The stability of the system over 21 days of continuous use with standards injected periodically was studied. Linearity was observed for all the standard plots throughout. At the end of 21 days, after a total exposure equivalent to 2395 ng mL-1 of Savinase, the signal due to the 5.0 ng mL-1 standard was still easily detectable. © The Royal Society of Chemistry.

"Development Of A Simple Extraction Cell With Bi-directional Continuous Flow Coupled On-line To ICP-MS For Assessment Of Elemental Associations In Solid Samples"
J. Environ. Monit. 2006 Volume 8, Issue 12 Pages 1248-1254
Janya Buanuam, Kasipa Tiptanasup, Juwadee Shiowatana, Manuel Miró and Elo Harald Hansen

Abstract: A continuous-flow system comprising a novel, custom-built extraction module and hyphenated with inductively coupled plasma-mass spectrometric (ICP-MS) detection is proposed for assessing metal mobilities and geochemical associations in soil compartments as based on using the three step BCR (now the Measurements and Testing Program of the European Commission) sequential extraction scheme. Employing a peristaltic pump as liquid driver, alternate directional flows of the extractants are used to overcome compression of the solid particles within the extraction unit to ensure a steady partitioning flow rate and thus to maintain constant operationally defined extraction conditions. The proposed flow set-up is proven to allow for trouble-free handling of soil samples up to 1 g and flow rates ≤10 mL min-1. The miniaturized extraction system was coupled to ICP-MS through a flow injection interface in order to discretely introduce appropriate extract volumes to the detector at a given time and with a given dilution factor. The proposed hyphenated method demonstrates excellent performance for on-line monitoring of major and trace elements (Ca, Mn, Fe, Ni, Pb, Zn and Cd) released when applying the various extracting reagents as addressed in the BCR scheme, that is, 0.11 M CH 3COOH, 0.1 NH2OH.HCl and 30% water 2, even when a well recognized matrix-sensitive detector, such as ICP-MS, is used. As a result of the enhanced temporal resolution of the ongoing extraction, insights into the breaking down of phases and into the kinetics of the metal release are obtained. With the simultaneous multielement detection capability of ICP-MS, the dynamic fractionation system presents itself as an efficient front-end for evaluation of actual elemental association by interelement comparison of metals leached concurrently during the extraction time. Thus, the intimate elemental association between Cd and Zn in contaminated soils could be assessed.

"Formaldehyde Determination In Seawater. Preliminary Application To Coastal Samples At Terra Nova Bay (Antarctica)"
J. Environ. Monit. 2005 Volume 7, Issue 12 Pages 1299-1304
O. Largiuni, S. Becagli, M. Innocenti, A. M. Stortini, R. Traversi and R. Udisti

Abstract: A sensitive spectrofluorimetric-FIA (flow injection analysis) method for formaldehyde (HCHO) determination was improved with the aim of analyzing seawater samples. The fluorescence emission versus HCHO concentration shows a linear pattern from sub ?g L-1 to about 1000 ?g L-1. The reproducibility at 15 ppb level is about 2%. Interferences from other aldehydes were checked; only glyoxal shows a significative interference, but only when its concentration is about 6000 times higher than that of formaldehyde. Superficial (microlayer, just sub-pack or sea-ice free sea surface) and deep (along the water column, sub-pack or in sea-ice free areas) seawater samples were collected near the coast at Terra Nova Bay (Ross Sea, Antarctica) during the 1998/1999 and 2001/2002 Italian Antarctic Expedition. We report here the preliminary results of the spectrofluorimetric-FIA determination of the HCHO content. The mean seawater superficial formaldehyde concentration was 15 ?g L-1; the concentration along the water column ranged between 4.5 to over 40 ?g L-1 (20 ?g L-1 mean concentration), usually with a maximum value for the 30 m depth, corresponding to a fluorescence maximum. The sampling was repeated 7 times in the austral summer in order to evaluate seasonal changes in the formaldehyde concentration/seawater depth profiles. The results show changes in the formaldehyde concentration at different depths. © The Royal Society of Chemistry 2005.

"Flow-injection Analysis With Fluorescence Detection For The Determination Of Trace Levels Of Ammonium In Seawater"
J. Environ. Monit. 2005 Volume 7, Issue 1 Pages 37-42
Roslyn J. Watson, Edward C. V. Butler, Lesley A. Clementson and Kate M. Berry

Abstract: A method using flow-injection, gas-diffusion, derivatization and then fluorescent detection has been established for ammonium ion determination in seawater. The fluorescent derivative formed by reacting ortho-phthaldialdehyde (OPA) and sulfite with ammonia gives high sensitivity while removing potential interferences. This is required to measure the low concentrations of ammonium often seen in the open ocean. The experimental conditions (flow-rate, reagent concentrations, membrane configurations, etc.) were manipulated to improve performance. For a sample throughput of 30 samples h-1, the limit of detection was 7 nM, the coefficient of variation was 5.7% at 800 nM, and the calibration curve was linear to at least 4 ?mol L-1. Interferences were minimised by a gaseous diffusion step. Volatile small molecular-weight amines as interferents were discriminated against by this method. They neither passed through the membrane as efficiently as ammonia, nor reacted as readily with OPA when sulfite was the reductant. Contamination by ammonia from laboratory and shipboard sources complicates application of the method to natural waters, especially measurement of low concentrations (< 100 nM) in open-ocean waters. Steps to overcome contamination are described in detail. Some results are presented for ammonium determination in Southern Ocean and Huon Estuary (Tasmania) waters.

"Measurement Of Chemical Oxygen Demand (COD) In Natural Water Samples By Flow Injection Ozonation Chemiluminescence (FI-CL) Technique"
J. Environ. Monit. 2004 Volume 6, Issue 8 Pages 673-678
Baohui Jin, Ying He, Jincan Shen, Zhixia Zhuang, Xiaoru Wang and Frank S. C. Lee

Abstract: COD determination based on ozone oxidation of α-naphthol combined with UV radiation (UV-O3) has been studied in the present work. Utilizing the phenomenon that luminol can be oxidized by the dissolved ozone to produce luminescence, we have established a new method of utilizing aqueous chemiluminescence to determine COD. The kinetics and mechanism of the ozonation reaction of α-naphthol have been investigated in order to gain a better understanding of the general applicability and limitation of the technique. Real world samples were analyzed and the results show that the relative error of COD-FI-CL measurement for water samples was <10%. Compared with the results of the conventional potassium permanganate method, the COD values of the FI-CL method are consistently higher (0-20% relative). The higher COD values suggest that the ozone-UV system is a more effective oxidation technique.

"Evaluation Of A Novel Passive Sampling Technique For Monitoring Volcanogenic Hydrogen Sulfide"
J. Environ. Monit. 2004 Volume 6, Issue 7 Pages 630-635
Claire J. Horwell, Andrew G. Allen, Tamsin A. Mather and John E. Patterson

Abstract: A novel, low-cost passive sampling procedure for monitoring of volcanogenic hydrogen sulfide is reported. The technique is based on absorption of H 2S onto treated sections of photographic paper, which are housed in plastic film canisters during exposure. The H2S reacts with silver halide in the photographic paper, causing a color-change reaction from white, through brown, to black, depending on concentration of atmospheric H 2S. The sampler is sensitive to <<30 ppb to ~1000 ppb of H 2S. Here we present results from a series of optimization and quantification experiments. An active sampling procedure for rapid H 2S measurement is also reported, based on absorption of H 2S onto Whatman No. 41 cellulose filters treated with silver nitrate, and was shown to be quantitative using a single filter at flow rates <1.0 L min-1 for collection of <200 µg of sulfide (as H2S). Determination of sulfide collected on the substrates was performed using a rapid flow-injection technique based on the fluorescence quenching of fluorescein mercuric acetate (FMA) by sulfide. This was optimized at a FMA concentration of 8 mg L-1, at which 100% quenching was obtained at a solution sulfide concentration of 3 mg L-1.

"On-site Simultaneous Determination Of Anions And Cations In Drainage Water Using A Flow Injection-capillary Electrophoresis System With Contactless Conductivity Detection"
J. Environ. Monit. 2004 Volume 6, Issue 3 Pages 169-174
Pavel Kub&aacute;, Miriam Reinhardt, Beat M&uuml;ller and Peter C. Hauser

Abstract: Drainage water diverted from a farm pasture, which was heavily loaded with manure, was monitored during a rain event. Concurrent anion and cation determinations at intervals of 10 min could be achieved with a new capillary electrophoresis system employing dual injection at opposite ends of the separation capillary. The flow injection approach enabled automation of the sampling process. Interruption of the separation voltage was not necessary. Contactless conductivity detection with an electrolyte solution optimized for the purpose allowed the facile simultaneous detection of the inorganic ions Cl-, NO3-, SO42-, HPO42-, NO2-, NH4+, K+, Ca2+, Na+ and Mg 2+ and the acquisition of temporal concentration profiles of these species. The detection limits achieved were between 20 and 200 ?g l -1 for all ions and the repeatability of peak areas and peak heights was better than 1%. The quantitative results were verified by analyzing individual samples later in the laboratory with photometry and ion chromatography and the average deviations were found to be between 4 and 12%. This contribution presents a further step in the development of capillary electrophoresis towards a fully automated, low maintenance field method.

"Analysis Of River Water Samples Utilising A Prototype Industrial Sensing System For Phosphorus Based On Micro-system Technology"
J. Environ. Monit. 2002 Volume 4, Issue 5 Pages 767-771
Michaela Bowden, Margaret Sequiera, Jens Peter Krog, Peter Gravesen and Dermot Diamond

Abstract: The application of a phosphorus monitoring device based on microsystems technology (MST) to the analysis of river water is presented. An alternative to the standard molybdenum blue method known as the yellow vanadomolybdophosphoric acid method has been very effectively implemented. The method is simple, a reagent and sample are mixed in a 1: 1 ratio forming a yellow complex that absorbs strongly below 400 nm in the UV spectrum. The kinetics of the reaction are rapid and sample turnaround is typically 3 min at room temperature. Therefore a very uncomplicated microfluidic design can be adopted. The working wavelength was chosen as 380 nm to coincide with the peak output of a UV-LED narrow bandwidth light source recently developed by Nichia. The limit of detection for the yellow method in the microfluidic system is 0.2 ppm with a dynamic linear range from 0 50 ppm. The method was applied to a measurement of phosphorus in a local river at specific sampling points along its course.

"Speciation Of Arsenic In Plants By HPLC-HG-AFS: Extraction Optimisation On CRM Materials And Application To Cultivated Samples"
J. Environ. Monit. 2002 Volume 4, Issue 4 Pages 596-602
Yusuf Bohari, Gabriella Lobos, Hugo Pinochet, Florence Pannier, Annette Astruc and Martine Potin-Gautier

Abstract: A recently developed method for the determination of arsenic species (arsenite, arsenate, monomethylarsonate, MMAA, and dimethylarsinate, DMAA) has been applied to the study of arsenic speciation in plants. This method uses ion-exchange liquid chromatography coupled on-line to atomic fluorescence spectrometry through continuous hydride generation. Various extraction procedures have been studied in detail using three plant certified reference materials. None of the procedures tested revealed fully satisfying results with all kinds of plant samples; microwave assisted extraction with 0.3 mol L-1 orthophosphoric acid was found to be the most convenient for dealing with terrestrial plants. Species stability appears good. This method was applied to real world cultivated plant parts. Arsenate appears to predominate in soils, roots and leaves; unidentified species (probably arsenosugars) play an important role (60%) in rice fruits. Carrot was found to be the most contaminated edible plant part, containing 1 mg kg-1 essentially as arsenate species. MMAA was detected in all soils and some plant parts especially shallots at low levels, whereas DMAA was found only in one soil sample and in hot pepper leaves. Arsenite is a minor component of all soils; it is also present in some plant parts at low levels. However, no evident relationships were found between As speciation in the various plant parts and much more detailed studies will be necessary to elucidate As behavior in plants.

"On-line Solid Phase Extraction With Polyurethane Foam: Trace Level Spectrophotometric Determination Of Iron In Natural Waters And Biological Materials"
J. Environ. Monit. 2002 Volume 4, Issue 4 Pages 522-527
Ricardo J. Cassella

Abstract: This paper reports the development of a simple and accurate on-line procedure for pre-concentration and determination of dissolved iron in waters and biological materials using unloaded polyether-type polyurethane foam as solid extractor. In the developed flow injection system, the analyte was pre-concentrated from acidic aqueous medium as iron-thiocyanate complex with post-elution with ascorbic acid solution and spectrophotometric measurement with 1,10-phenanthroline as colorimetric reagent. In order to improve the performance of the system several chemical and flow variables were investigated as well as the effect caused by the presence of possible interferents. The method was validated by the analysis of two certified reference materials. Application of the methodology was carried out by the determination of dissolved iron content in eight natural water samples with different characteristics. The results were compared with those obtained by electrothermal atomic absorption spectrometry (ETAAS) and no statistical difference was observed. The detection limit was 0.75 µg L-1 and the RSD was 1.2% for 2 min pre-concentration time. At this condition, a productivity of 20 samples h-1 was achieved. Increasing the pre-concentration time up to 3 min, a detection limit of 0.45 µg L-1, an RSD of 1.5% and an analytical throughput of 15 h-1 were verified.

"Application Of Cryofocusing Hydride Generation And Atomic Fluorescence Detection For Dissolved Mercury Species Determination In Natural Water Samples"
J. Environ. Monit. 2002 Volume 4, Issue 4 Pages 517-521
T. Stoichev, R. C. Rodriguez Martin-Doimeadios, D. Amouroux, N. Molenat and O. F. X. Donard

Abstract: The concentration levels of mercury (Hg) species in natural water samples are usually low. Consequently, accurate analysis with low detection limits is still a major problem. In this work, a method was applied for the simultaneous direct determination of dissolved mercury species in water samples by on-line hydride generation (HG), cryogenic trapping (CT), gas chromatography (GC) and detection by atomic fluorescence spectrometry (AFS). The suitability of the method for real samples with different organic matter and chloride contents was evaluated by recovery experiments in synthetic and natural spiked water samples. The HG method was compared with other current available methods for mercury analysis with respect to the different fraction of mercury analyzed, i.e. reactive, reducible or total. HG derivatization and SnCl2 reduction (with and without previous oxidation with BrCl) were applied to synthetic and natural (spiked and non-spiked) water samples. The influence of chloride and dissolved organic matter concentrations was studied. The results suggest that the HG procedure is suitable for the simultaneous determination of Hg2+ and MeHg+ in surface water samples. Inorganic mercury analyzed by HG (i.e. reducible) is close to the total inorganic mercury.
Speciation

"Current Strategies In Nitrite Detection And Their Application To Field Analysis"
J. Environ. Monit. 2002 Volume 4, Issue 3 Pages 465-471
Jodi Dutt and James Davis

Abstract: The various analytical protocols that have been developed to aid the measurement of nitrite within environmental samples have been critically appraised and their applicability to field measurement assessed. The present communication presents a perspective on current techniques and technologies encompassing spectroscopic, electrochemical and chromatographic methodologies and highlights, those that are liable to emerge in the near future. Commercial devices have been included and where appropriate the advantages and limitations posed by their operation within field contexts have been described.

"Turbidimetric Determination Of Chloride In Different Types Of Water Using A Single Sequential Injection Analysis System"
J. Environ. Monit. 2002 Volume 4, Issue 3 Pages 458-461
Raquel B. R. Mesquita, S&iacute;lvia M. V. Fernandes and Ant&oacute;nio O. S. S. Rangel

Abstract: A sequential injection analysis system for the turbidimetric determination of chloride in different types of water is proposed. The determination is based on the reaction of chloride with silver ions and the subsequent measurement of the turbidity caused by silver chloride precipitation. In this method, the use of toxic reagents, such as mercury thiocyanate, commonly employed in most spectrophotometric techniques for chloride determination, is avoided. The main feature of the developed system is the use of a single configuration to carry out the determination over a wide concentration range (2-400 mg L-1) by changing only the aspirated sample volume. This characteristic allows the determination of chloride in ground, surface and wastewaters using the same manifold. In addition, a considerable saving of precipitating reagent is achieved due to non-continuous consumption. The results obtained with the developed system were statistically indistinguishable from those of the potentiometric titration reference method. Relative standard deviations for ten consecutive injections were lower than 3.7%, with a sampling frequency of between 55 and 57 determinations per hour.

"Speciation Of Nickel In Airborne Particulate Matter By Means Of Sequential Extraction In A Micro Flow System And Determination By Graphite Furnace Atomic Absorption Spectrometry And Inductively Coupled Plasma Mass Spectrometry"
J. Environ. Monit. 2001 Volume 3, Issue 6 Pages 681-687
Lars F&uuml;chtjohann, Norbert Jakubowski, Dieter Gladtke, Dieter Klockow and Jos&eacute; A. C. Broekaert

Abstract: A four-stage sequential extraction procedure for the speciation of nickel has been applied to ambient aerosol samples. The determination of the soluble, sulfidic, metallic and oxidic Ni fractions in particulate matter was carried out by graphite furnace (electrothermal) atomic absorption spectrometry (ETAAS)-and inductively coupled plasma mass spectrometry (ICP-MS). An EDTA solution, a mixture of diammonium citrate and hydrogen peroxide, -and a KCuCl3 solution were used as leaching agents for the determination of the soluble, sulfidic and metallic species; respectively, and nitric acid was used for the determination of oxidic compounds after microwave digestion of particulate matter sampled on filters. A new micro-scale filter holder placed in a closed flow injection analysis (FIA) system for use in nickel speciation by means of sequential extraction, and the results of the optimization of the extraction conditions are described. The temperature program for ETAAS was optimized for all extraction solutions with the aid of temperature curves. Pyrolysis temperatures of 900, 600 and 1000°C were found to be Optimum for EDTA, hydrogen peroxide plus ammonium citrate and KCuCl3-containing solutions, respectively. Airborne dust was sampled on filters at two locations near to a metallurgical plant in Dortmund, Germany. Concentrations in the low ng m(-3) range down to the detections limits (0.1-0.3 ng m(-3)) and various nickel species were found to be present in the collected dust. The mean fractions of total nickel (sampling period of one month) were found to contain 36±20% of soluble, 6±4% of sulfidic, 11±15% of metallic and 48±18% of oxidic nickel.

"Measuring The CO2 Flux At The Air/water Interface In Lakes Using Flow Injection Analysis"
J. Environ. Monit. 2001 Volume 3, Issue 3 Pages 317-321
F. V. Almeida, J. R. Guimar&atilde;es and W. F. Jardim

Abstract: The carbon dioxide flux at the air/water interface in lakes was calculated after the determination of H2CO3* (free CO2) and atmospheric CO2 using flow injection analysis (FIA) coupled to a conductometric detector. The method is based on the diffusion of CO2 through a hydrophobic membrane into a flow of deionized water, generating a gradient of conductivity proportional to the concentration of CO2 in the sample. Using one experimental set-up, the speciation of the inorganic carbon (H2CO3* and dissolved inorganic carbon) was accomplished by simply adjusting the sample pH. The determination of CO2 in the atmosphere was carried out by direct injection of the gaseous samples. The FIA apparatus was taken into the field and CO2 fluxes were evaluated in several Brazilian lakes. In these lakes, representing different eutrophic stages, the CO2 flux varied from -242 (invasive) up to 3227 (evasive) µmol CO2 m-2 h-1.

"The Application Of ICP-SMS, GF-AAS And HG-AFS To The Analysis Of Water And Sediment Samples From A Temperate Stratified Estuary"
J. Environ. Monit. 2001 Volume 3, Issue 1 Pages 113-120
Ashley T. Townsend, Jeanette O Sullivan, Alison M. Featherstone, Edward C. V. Butler and Denis J. Mackey

Abstract: Three atomic spectrometry techniques, namely sector field inductively coupled plasma mass spectroscopy, graphite furnace atomic absorption spectrometry and hydride generation atomic fluorescence spectroscopy (ICP-SMS, GF-AAS and HG-AFS, respectively), housed at separate independent laboratories, were used to analyze water and sediment samples collected from the Huon River Estuary, SE Tasmania (Australia) in the Austral spring 1998. A dithiocarbamate-chelation/back-extraction technique was used to separate and pre-concentrate Co, Ni, Cu, Zn, Cd and Pb from eight collected water samples prior to analysis by ICP-SMS and GF-MS. A number of other elements in the waters were analyzed directly (Mn, Fe and Zn by GF-AAS; As by HG-AFS), or following sample dilution (1 + 19; V, Mn, Fe, As, Mo, Ba and U by ICP-SMS). Where: possible, previously corroborated GF-AAS and HG-AFS techniques were used to verify obtained ICP-SMS results. From the analysis of four reference waters (SLEW-1 and -2, SLRS-3 and NASS-5), good agreement, to within±10-20%, was typically found between certified (or information only values) and measured results (irrespective of analytical technique). Exceptions included Zn (and sometimes Fe) that could not be quantified by ICP-SMS due to elevated blank signals, and As which was found to lie below ICP-SMS detection limits. For Huon Estuary water samples, inter-method agreement was within±10-20% (for those elements amenable to analysis by more than one technique). Nitric acid extracts of two certified reference materials (Buffalo River Sediment and BCSS-1) and six Huon Estuary sediments were analyzed by ICP-SMS (for Al, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd and Pb) and HG-AFS (for As). Results from the certified reference materials indicated extraction efficiencies of 60 70% (for most elements). A close correlation between ICP-SMS and HG-AFS was obtained for leachable As in the sediments. In terms of potential inorganic contaminants, the Huon Estuary was found to be a relatively clean water system. The elemental concentrations measured in water and sediment samples from this region were found to lie within current Australian guidelines for estuaries. In general, no one analytical technique was able to accurately determine all elements in all samples from this relatively pristine estuarine environment, A combination of all three analytical techniques was necessary for the successful analysis of the elements considered in this study.

"Speciation Of Arsenic Using Solid Phase Extraction Cartridges"
J. Environ. Monit. 2001 Volume 3, Issue 1 Pages 81-85
Serife Yal&ccedil;in and X. Chris Le

Abstract: Various solid phase extraction (SPE) cartridges were investigated for speciation of arsenite [As(III)], arsenate [As(v)], monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). Cartridges containing different types of sorbent materials were tested for arsenic retention and elution characteristics. Alumina cartridges were found to completely retain all thr four target arsenic species, and are suitable for removal and pre-concentration purposes. For speciation analysis, different arsenic species were separated on the basis of their selective retention on and elution from specific cartridges. DMA was retained on a resin-based strong cation exchange cartridge and eluted with 1.0 M HCl. MMA and As(v) were both retained on a silica-based strong anion exchange cartridge and sequentially eluted with 60 mM acetic acid (for MMA) and 1.0 M HCl [for As(v)]. As(III) was not retained on either cartridge and remained in solution. Arsenic species in solution and those eluted from the cartridges were subsequently quantified by using flow injection with hydride generation atomic fluorescence spectrometry (FI-HGAFS) and hydride generation atomic absorption spectrometry (FI-HGAAS). A detection limit of 0.05 µg L-1 arsenic in water sample was achieved using HGAFS. An application of the method was demonstrated at a drinking water treatment facility. As(III) and As(v) species were determined in water at various stages of treatment. The method is suitable for routine determination of trace levels of arsenic in drinking water to comply with more stringent environmental regulations.

"Determination Of Germanium In Urine And Its Usefulness For Biomonitoring Of Inhalation Exposure To Inorganic Germanium In The Occupational Setting"
J. Environ. Monit. 2001 Volume 3, Issue 1 Pages 67-73
Harry A. Roels and Jean-Pierre Buchet

Abstract: The present study aimed to assess whether urinary germanium concentration can be used as a biomarker of inhalation exposure to airborne dust from metallic germanium (Ge) or GeO2 in the occupational setting. A novel hydride generation-based method coupled with flow injection graphite furnace atomic absorption spectrometry (HG/FI-GFAAS) was developed for the determination of urinary germanium. Tt was found that urinary germanium concentration could be reliably determined by a standard additions method after thorough digestion of the urine and careful pH adjustment of the digest. The limit of detection (LOD) in urine for the HG/FI-GFAAS method was 0.25 µg Ge L-1. In Belgian control male subjects, the urinary germanium concentration was below this LOD. In 75 workers currently exposed to inorganic germanium compounds, respirable and inhalable concentrations of germanium in the aerosols were measured on Monday and Friday at the job sites using personal air samplers. Spot-urine samples were collected on the same days before and after the well; shift. The germanium concentrations of respirable dust correlated very well with those of inhalable dust and represented 20% of the inhalable fraction. Workers exposed to metallic Ge dust were on average ten times less exposed to germanium than those whose exposure involved GeO2 (3.4 versus 33.8 µg Ge m(-3)). This difference was reflected in the urinary germanium concentrations (3.4 versus 23.4 µg Ge g-1 creatinine). Regression analysis showed that the concentration of germanium in the inhalable fraction explained 42% of the post-shift urinary germanium concentration either on Monday or on Friday, whereas in a subgroup of 52 workers mainly exposed to metallic germanium dust 57% (r=0.76) of the Monday post-shift urinary germanium was explained. Urinary elimination kinetics were studied in seven workers exposed to airborne dust of either metallic Ge or GeO2. The urinary elimination rate of germanium was characterized by half-times ranging from 8.2 to 18.1 h (on average 12 h 46 min). The present study did not allow discrimination between the germanium species to which the workers were exposed, but it showed fast urinary elimination kinetics for inhalation exposure to dust of metallic Ge and GeO2. It pointed out that urine samples taken at the end of the work shift call be used for biological monitoring of inorganic germanium exposure in the occupational setting.

"Monitoring The Species Of Arsenic, Chromium And Nickel In Milled Coal, Bottom Ash And Fly Ash From A Pulverized Coal-fired Power Plant In Western Canada"
J. Environ. Monit. 2001 Volume 3, Issue 1 Pages 1-6
Fariborz Goodarzi and Frank E. Huggins

Abstract: The concentration of As, Cr and Ni and their speciation (As3+:5+, Cr3+:6+ and Ni0:2+) in milled coal, bottom ash and ash collected by electrostatic precipitator (ESP). From a coal fire-power plant in western Canada were determined using HGAAS, ICP-AES and XANES. The chemical Fractionation of these elements was also determined by a sequential leaching procedure, using deionized water, NH(4)OAC and HCl as extracting agents. The leachate was analyzed by ICP-AES. Arsenic in the milled coal is mostly associated with organic matter, and 67% of this arsenic is removed by ammonium acetate. This element is totally removed from milled coal after extraction with HCl. Arsenic occurs in both the As3+ and the As5+ oxidation states in the milled coal, while virtually all (> 90%) of the arsenic in bottom ash and fly ash appears to be in the less toxic arsenate (As5+) form. Both Ni and Cr in the milled coal are extracted by HCl, indicating that water can mobilize Ni and Cr in an acidic environment. The chromium is leached by water from fly ash as a result of the high pH of the water, which is induced during the leaching. Ammonium acetate removes Ni from bottom ash through an ion exchange process. Chromium in milled coal is present entirely as Cr3+, which is an essential human trace nutrient. The Cr speciation in bottom ash is a more accentuated version of the milled coal and consists mostly of the Cr3+ species. Chromium in fly ash is mostly Cr3+, with significant contamination by stainless-steel from the installation itself.
Speciation

"Field Cryofocussing Hydride Generation Applied To The Simultaneous Multi-elemental Determination Of Alkyl-metal(loid) Species In Natural Waters Using ICP-MS Detection"
J. Environ. Monit. 2000 Volume 2, Issue 6 Pages 603-612
C. M. Tseng, D. Amouroux, I. D. Brindle and O. F. X. Donard

Abstract: Two hydride generation manifold systems, utilizing flow injection and cryotrapping techniques for alkyl-metal(loid) speciation analysis in natural waters, are described in this paper. They provide shipboard capacity for simultaneous derivatization of analytes with NaBH4 and cryotrapping of the generated products in a field packed column at -196°C. The first system is a large-volume hydride generator, using a reagent-injection flow technique as a flow batch type, that has been fully optimized and applied to the simultaneous detection of alkylated species in estuarine waters. The technique permits the analysis of a large volume sample (0.5-11) at a sampling rate of 3 h-1. The second is an online continuous flow hydride generator. A sampling rate of 3-12 h-1 can be achieved with samples of 0.1-0.5 l. In addition, shipboard operation eliminates major problems related to sample pretreatment, transport and storage. Ultra-trace multi-element determination is finally performed in the laboratory by cryogenic GC hyphenated with ICP-MS. Routine detection limits of 0.5-10 pg (as metal) for 0.5 l water samples were achieved for the selected alkyl-metal(loid) species of arsenic, germanium, mercury and tin. Concentrations of various species, obtained from water samples taken from the Rhine estuary, are also presented. These species include alkylated arsenic compounds, other than methyl derivatives, that have been tentatively identified and are reported here for the first time.
Interferences

"Shipboard Techniques Based On Flow Injection Analysis For Measuring Dissolved Fe, Mn And Al In Seawater"
J. Environ. Monit. 2000 Volume 2, Issue 5 Pages 496-502
Jeroen T. M. de Jong, Marie Boye, V&eacute;ronique F. Schoemann, Rob F. Nolting and Hein J. W. de Baar

Abstract: An overview is presented of sampling techniques and flow injection analysis (FIA) methods for low concentrations of Fe, Mn and Al in filtered seawater. On the basis of sampling procedures, filtration techniques, accuracy, blanks, detection limits, intercalibration results and oceanographic consistency, the feasibility of these FIA methods was evaluated. It was found that these metals could be measured on board with a minimum risk of contamination and with good accuracy even at low subnanomolar levels (< 0.5 nM). Results for reference seawater were in the case of Fe-FIA and Mn-FIA in excellent agreement with the certified values. Data from samples analyzed by Fe-FIA and by cathodic stripping voltametry (CSV) compared well, as did Mn-FIA and GFAAS. All three methods gave results that were mostly in good agreement with data from the same ocean regions published by other research groups. Two different types of surface water sampling were also tested and compared, namely conventional hand filling of a sample bottle from a rubber dinghy away from the ship, and underway pumping of seawater using a tow fish. The latter method gave the best results. Also, conventional membrane filtration and cartridge filtration for large volume filtration were compared using Fe and Al data from water column samples. Good agreement was found for both filter types, although for defining dissolved metal species the latter filter type was preferred.
Preconcentration

"Trace Level Determination Of Perchlorate In Water Matrices And Human Urine Using ESI-FAIMS-MS"
J. Environ. Monit. 2000 Volume 2, Issue 5 Pages 393-397
Barbara Ells, David A. Barnett, Randy W. Purves and Roger Guevremont

Abstract: High-field asymmetric waveform ion mobility spectrometry (FAIMS) separates perchlorate from interfering isobaric ions of bisulfate and dihydrogenphosphate in the gas-phase. The use of a new FAIMS prototype and waveform generator, along with the use of a mixed carrier gas, in this electrospray ionisation (ESI)-FAIMS-mass spectrometry (MS) study gave a detection limit for perchlorate in a relatively clean matrix of tap water of 0.050 ppb. Flow injection analysis (FIA) of dilutions of fortified waste water, a fortified river water certified reference material (CRM; SLRS-4, National Research Council of Canada), and a fortified human urine Standard Reference Material (SRM; 2381, National Institute of Standards and Technology) gave detection limits of 0.37 ppb, 0.50 ppb, and 4.8 ppb, respectively, in the undiluted matrices.

"Chemical Availability Of Mercury In Stream Sediments From The Almaden Area, Spain"
J. Environ. Monit. 2000 Volume 2, Issue 4 Pages 360-366
R. C. Rodr&iacute;guez Mart&iacute;n-Doimeadios, J. C. Wasserman, L. F. Garc&iacute;a Bermejo, D. Amouroux, J. J. Berzas Nevado and O. F. X. Donard

Abstract: The chemical speciation, fractionation and availability of mercury in sediments from a cinnabar mining area (Almaden, Spain) was studied with different extraction and analytical procedures, in order to determine the degree to which the ecosystem is harmed by this pollutant. Three total extraction procedures, a sequential extraction and the speciation of organo-mercury compounds were performed in nine sediment samples. In the study area, although concentrations of mercury can be extremely high (up to 1000 mg kg-1), no organo-mercury compounds were detected (< 2 µg kg-1) and the availability of this element seems restricted. One of the methods for total extraction presented considerably lower recovery in Almadens sediments, yet the results were controlled with certified reference materials. This disagreement was attributed to the fact that the mercury is in a refractory form. Sequential extraction was able to show that most of the mercury is associated with sulfides (probably as metacinnabar) or in the residual refractory phase (probably as red cinnabar).

"Accuracy And Traceability In Environmental Monitoring - Pitfalls In Methylmercury Determinations As A Case Study"
J. Environ. Monit. 2000 Volume 2, Issue 4 Pages 292-299
Ph. Quevauviller

Abstract: The concepts of accuracy and traceability as applied to environmental analysis are still prone to misunderstandings. While accuracy refers to the closeness of analytical values to true values (trueness) and among various repetitions (precision), the term traceability implies a link of data obtained to established references through an unbroken chain of comparisons all with stated uncertainties. These misunderstandings, possibly occurring among the analytical community, may have consequences on environmental data interpretation. Recent discussions in the field of environmental speciation analysis illustrated that accuracy and traceability issues are still not firmly established within the environmental chemistry community. This paper discusses this issue, taking methylmercury as a case study.

"Comparison Study Of Five Analytical Methods For The Fractionation And Subsequent Determination Of Aluminum In Natural Water Samples"
J. Environ. Monit. 2000 Volume 2, Issue 2 Pages 171-181
Torild Wickstr&oslash;m, Nicholas Clarke, Kirsti Derome, John Derome and Eirin R&oslash;geberg

Abstract: Five methods for aluminum fractionation used in different laboratories in Norway and Finland were compared using six control, 75 soil water and 10 lake water samples. Different fractionation principles [cation exchange, formation of the Pyrocatechol Violet (PCV) or quinolin-8-ol (oxine) complex], types of cation exchanger [Amberlite (Na/H) or Bond Elut (H)], reaction time (from 2.3 s), flow systems (flow injection analysis or segmented flow) and determination principles (molecular absorption spectrometry or ICP-AES) were tested. Determination of the labile fraction was strongly dependent on the method used and the largest differences were observed between the ICP-AES method with cation exchange (Bond Elut H form) and the quickly reacting method (oxine, 2.3 s). Different flow systems, both using cation exchange and determination of the PCV complex but with different reaction times and an extra acidification step, resulted in large differences in the reactive and non-labile fractions determined. However, the determination of the labile fraction gave similar results with both these methods. The two different types of cation exchanger used (with and without pH buffering and with different counter ions) in the ICP-AES methods resulted in differences, mainly because of a smaller non-labile fraction in the non-buffered system. The two flow injection systems (oxine and PCV complexation) showed common trends, which may be connected with the short reaction times used. Comparison with theoretical equilibrium calculations using the model ALCHEMI suggested that the best correlation for the determination of the labile fraction were obtained with the ICP-AES method with an Amberlite column.
Speciation pH

"Methodologies For Determination Of Antimony In Terrestrial Environmental Samples"
J. Environ. Monit. 2000 Volume 2, Issue 2 Pages 97-109
Martin J. Nash, John E. Maskall and Steve J. Hill

Abstract: Methodologies for the environmental analysis of total antimony and aqueous chemical speciation are critically reviewed, including preparation techniques for aqueous and solid matrices and the determination of solid state partitioning and recommendations are given for future research directions. Concentrations of total antimony commonly present in aqueous and solid environmental samples are readily determined using present day analytical techniques. This has resulted primarily from technological advances in microwave digestion for solid matrices and the development of plasma based analyte detection systems. ICP-AES and ICP-MS techniques are both utilised for the environmental analysis of total antimony concentrations. However, ICP-MS is increasingly favoured as a result of reduced spectral interferences and the potential for analyte detection in the pg mL-1 range. Determination of aqueous antimony speciation presents a number of complex analytical challenges and highly selective separation and identification techniques are required prior to detection. The majority of published techniques including common applications of hydride generation are insufficiently selective for the determination of intrinsic chemical speciation and often only oxidation state data are obtained. The recent in-line applications of HPLC-ICP-MS offer the potential for highly selective separations of aqueous antimony species and determination of detailed chemical speciation data. However, considerable development work is required to optimise chromatographic separations and identify uncharacterized species resident in environmental systems. Analytical techniques to aid the determination of antimonys associations with solid environmental matrices include the application of chemical extraction procedures and leaching experiments. To date, this area of analytical research has received little attention and further studies are required to elucidate this aspect of antimonys environmental chemistry.

"Aquatic Humus From An Unpolluted Brazilian Dark-brown Stream: General Characterization And Size Fractionation Of Bound Heavy Metals"
J. Environ. Monit. 2000 Volume 2, Issue 1 Pages 39-44
Julio C. Rocha, Jeosadaque J. de Sene, Ademir dos Santos, Ilda A. S. Toscano and Luiz Fabr&iacute;cio Zara

Abstract: The main pool of dissolved organic carbon in tropical aquatic environments, notably in dark-colored streams, is concentrated in humic substances (HS). Aquatic HS are large organic molecules formed by micro-biotic degradation of biopolymers and polymerization of smaller organic molecules. From an environmental point of view, the study of metal-humic interactions is often aimed at predicting the effect of aquatic HS on the bioavailability of heavy metal ions in the environment. In the present work the aquatic humic substances (HS) isolated from a dark-brown stream (located in an environmental protection area near Cubatao city in Sao Paulo-State, Brazil) by means of the collector XAD-8 were investigated. FTIR studies showed that the carboxylic carbons are probably the most important binding sites for Hg(II) ions within humic molecules. C-13-NMR and H-1-NMR studies of aquatic HS showed the presence of constituents with a high degree of aromaticity (40% of carbons) and small substitution. A special five-stage tangential-flow ultrafiltration device (UF) was used for size fractionation of the aquatic HS under study and for their metal species in the molecular size range 1-100 kDa (six fractions). The fractionation patterns showed that metal traces remaining in aquatic HS after their XAD-8 isolation have different distributions. Generally, the major percentage of traces of Mn, Cd and Ni (determined by ICP-AES) was preferably complexed by molecules with relatively high molecular size. Cu was bound by fractions with low molecular size and Co showed no preferential binding site in the various humic fractions. Moreover, the species formed between aquatic HS and Hg(II), prepared by spiking (determined by CVAAS), appeared to be concentrated in the relatively high molecular size fraction F-1 (> 100 kDa).

"Continuous Flow Methods For Evaluating The Response Of A Copper Ion Selective Electrode To Total And Free Copper In Seawater"
J. Environ. Monit. 1999 Volume 1, Issue 5 Pages 483-487
Ruth S. Eriksen, Denis J. Mackey, Peter Alexander, Roland De Marco and Xue Dong Wang

Abstract: This work describes the development of an instrument for measuring free and total copper in seawater by continuous flow analysis (CFA) with an Orion copper(II) ion selective electrode (CuISE). Sample analysis times are reduced considerably by using an extrapolation technique based on the fitting of an empirical mathematical expression to the electrode time-response curve enabling a prediction of the final equilibrium potential. CuISE measurements in seawater samples containing nanomolar levels of total copper can be very time consuming, and this predictive approach significantly reduces sample analysis time, and improves sample throughput. The time taken to measure pCu in seawater to a precision of±0.1, using conventional potentiometry, varies considerably depending on the condition of the electrode membrane but can be reduced by a factor of 3-6 (typically from 60 to 10 min) by using the extrapolation technique in conjunction with CFA. Details are given of the protocols used for preconditioning the CuISE. The system can be used as a portable instrument for field measurements or for shipboard measurements of free copper in seawater. Extrapolated equilibrium potentials are within±0.5 mV of true steady state values.
Extrapolation method Membrane

"Biomonitoring Of Antimony In Environmental Matrices From Terrestrial And Limnic Ecosystems"
J. Environ. Monit. 1999 Volume 1, Issue 5 Pages 477-481
Michael Krachler, Mechthild Burow and Hendrik Emons

Abstract: Elder and poplar leaves from various sampling sites were studied with respect to their antimony content. Moreover, a retrospective determination of Sb was performed in representative limnic and terrestrial samples of the Federal Enviromnental Specimen Bank of Germany which have been collected over 14 years. The analytical procedure is based on an open vessel acid digestion of freeze-dried biological samples and the subsequent quantification of Sb in the digests by flow injection hydride generation atomic absorption spectrometry. Strict quality control schemes were applied to the entire procedure to guarantee accurate and precise results. No long-term changes of the Sb concentrations were found in spruce shoots or poplar leaves from different sampling sites. However, spruce shoots from a semi-natural region showed concentrations of Sb (similar to 22 ng g-1; range: 17-29 ng g-1) that were approximately four times lower than in corresponding samples from an urban-industrialized area. The analysis of virgin and washed elder leaves revealed that approximately 20-30% of the Sb is present on the leaf surface. Sb levels in elder leaves ranged from 5.2±0.3 ng g-1 in samples from Argentina to 589±30 ng g-1 in leaves collected directly beside a motorway in Germany. Similarly, poplar leaves from Argentina and Chile showed about 4 ng Sb g-1 whereas 150 ng Sb g-1 was found in poplar leaves from Germany. The lowest concentrations of Sb were determined in digests of pigeon eggs (similar to 2 ng g-1), bream liver (similar to 4 ng g-1) and deer liver (similar to 6 ng g-1). A similar pattern of Sb concentrations in spruce shoots, leaves or liver samples from an industrialized area and an agrarian ecosystem in Germany was established. Concentrations of Sb in elder leaves were closely associated with car traffic, giving maximum concentrations of 589 ng g-1 directly beside a motorway, 207 ng g-1 50 m from the motorway and 153 ng g-1 in a dose residential area.
Speciation

"Validation Of A Diffusive Sampler For NO2"
J. Environ. Monit. 1999 Volume 1, Issue 4 Pages 349-352
Annika Hagenbj&ouml;rk-Gustafsson, Roger Lindahl, Jan-Olof Levin and Doris Karlsson

Abstract: A diffusive sampler for NO2, Willems badge, was validated in laboratory experiments and held tests. The collecting reagent for NO2 in the sampler is triethanolamine, and the analysis is based on a modified colorimetric method, the Saltzman method. The analysis was performed by a flow injection analysis (FIA) technique. The sampling rate for the sampler was determined to be 40.0 mL min-1. There was no effect of NO2 concentration or relative humidity on sampling rate, and the influence of sampling time was found to be small. The detection limit was 4 µg m(-3) for a 24 h sample. The capacity is high enough to allow sampling of 150 µg m(-3) for 7 days, which is twice the recommended Swedish short-term (24 h) guideline value as a 98-percentile over 6 months. In held tests, the sampler performed well, even at wind speeds higher than 2 m s-1, and at low temperatures. The overall uncertainty of the method was 24%. The sensitivity and capacity of the method also make it suitable for personal sampling for 2-8 h in working environments.