University of North Florida
Browse the Citations
-OR-

Contact Info

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

View Stuart Chalk's profile on LinkedIn

Particulates

Classification: Environmental -> air -> particulates

Citations 8

"Sequential Injection Analysis Of Nitrites And Nitrates"
Anal. Chim. Acta 1995 Volume 315, Issue 3 Pages 321-330
M. T. Oms, A. Cerdà and V. Cerdà*

Abstract: A sequential injection system for the analysis of nitrate and nitrite is described. The sample and reagents are aspirated and mixed by flow reversal while being propelled to a reaction coil or to the detector. The determination of nitrite is based on the Griess-llosvay reaction. Nitrate is previously reduced by hydrazine in alkaline medium and analyzed as nitrite. The sequencing and overlap of the stacked zones are key parameters that have been studied together with concentrations of reagents, influence of temperature and potential interfering ions. Under the final optimal conditions up to 400 µM Of nitrite and nitrate can be analyzed, the detection limits being 0.07 ppm and 0.2 ppm respectively. The method has been tested with prepared standard samples, atmospheric aerosol filter extracts and wastewater samples. (14 references)
Nitrate Nitrite Sequential injection Interferences Flow reversal

"Application Of Hydride-generation Atomic Absorption Spectrometry To The Determination Of Lead Collected On Air Filters And Sphagnum Moss"
Analyst 1993 Volume 118, Issue 11 Pages 1433-1439
Helen M. F. Tavares, M. Teresa S. D. Vasconcelos, Adélio A. S. C. Machado and Paulo A. P. Silva

Abstract: Air was sampled through cellulose filters at 1.2 m3/cm2/day, and the filter was treated with concentrated HNO3 at 70-80°C for 10 min. The resulting solution was diluted with water and mixed with ammonium peroxydisulfate to give a final solution containing 6% peroxydisulfate and 0.75% HNO3. Dry moss was mixed with 0.01 M HNO3 and the mixture was purged with air for 20 min. After filtration, the solution was diluted with water and mixed with reagents to give final concentration of 0.75% HNO3, 6% ammonium peroxydisulfate and 2% sodium citrate. Sample solution was pumped at 6 ml/min into a continuous-flow hydride generator where Pb was reduced to plumbane by 7% NaBH4 (3 ml/min). A 200 ml/min flow of N2 was introduced into the gas-liquid separator to transport the hydride to the atomizer of the spectrometer. Analysis was carried out using an air-acetylene flame, with a delay time of 70 s and measurement at 217 nm. The calibration graph was linear up to 40 ng/ml and there was no interference from 60 ng/ml of Ni, 30 ng/ml of Cu and 1 µg/ml of Fe, Mn and Zn. The RSD decreased with increasing Pb concentration from 7% for 3 ng/ml to 1% for 20-40 ng/ml.
Lead Spectrophotometry Interferences

"Atomic Spectrometry Update: Clinical And Biological Materials, Foods And Beverages"
J. Anal. At. Spectrom. 1991 Volume 6, Issue 3 Pages 69R-107R
Simon Branch, Helen M. Crews, David J. Halls and Andrew Taylor

Abstract: This Update contains reviews on recent developments in the application of atomic spectrometry to the analysis of clinical and biological materials and of foods and beverages. These two reviews cover the references 90/1159-90/4166 and 91/1-91/825 which are listed fully as Atomic Spectrometry Update References in Volumes 5 and 6 of JAAS, respectively. A list of references to published papers in abbreviated form appears at the end of this Update. The Tables, in an improved format, summarise the methods and studies covered in these reviews. Last year's Update (J. Anal. Atomic Spectrom., 1990, 5, 75R) covered developments in the preceding year.
Fluorescence Mass spectrometry Spectrophotometry Voltammetry Clinical analysis Review Supercritical fluid Reference material Principal component analysis

"Micro-analytical Concept For Multicomponent Analysis Of Airborne Particulate Matter"
Fresenius J. Anal. Chem. 1991 Volume 340, Issue 9 Pages 525-533
Wolfgang Frenzel

Abstract: Atmospheric particulate matter, collected on membrane filters, was subjected to aqueous extraction (200 µL of ethanol, 2.8 mL of H2O) in an ultrasonic bath. A 50 µL portion of the extract was analyzed for NH4+ by a flow injection procedure with photometric detection (cf. Schulze et al., Anal. Chim. Acta., 1988, 214, 121), and for Cl-, NO3- and SO42- simultaneously by ion chromatography on a column (15 cm x 4.1 mm) of PRP-X 100 with 2 mM KH phthalate (pH 6.8) as mobile phase and conductivity detection. The remainder of the extract was subjected to concentrated HNO3 - HF - H2O2 digestion in a closed microwave system, before flame AAS and graphite furnace AAS determination of ten and six elements, respectively. A flow-chart of the microchemical procedure is presented. Results obtained from the analyzes of standard reference materials, an inter-laboratory comparison, and from alternative methods of accuracy control indicated that most components were determined with reasonable or good precision and accuracy by the described procedure.
Ammonium Spectrophotometry Sample preparation Sample preparation Column Filter Reference material

"Separation And Determination Of Trace Dinitropyrenes By Means Of Off-line Reduction-HPLC-chemiluminescence Detection. Application To Assessing Atmospheric Environment"
Anal. Sci. 1994 Volume 10, Issue 4 Pages 583-587
M. MAEDA, K. TSUKAGOSHI, M. MURATA, M. TAKAGI and T. YAMASHITA

Abstract: A FIA system using a bis(2,4,6-trichlorophenyl)oxalate (TCPO)-H2O2 chemiluminescence (CL) system was developed for the determination of trace PAH (details and schematic diagram given). Results obtained allowed the development of a HPLC-CL detection system. Suspended particulate matter in air was collected on a glass-fiber filter and the filter was extracted with CH2Cl2 for 15 min with sonication. The supernatant was filtered, the filtrate was evaporated to dryness under N2, the residue was dissolved in hexane and applied to a Sep-Pak silica cartridge. The cartridge was eluted (details given) and the fraction containing dinitropyrenes (DNP) was concentrated by rotary evaporation, dried under N2 and the residue dissolved in ethanol and mixed with 7% sodium hydrogen sulfide. After 24 h, benzene and 0.15 M NaOH were added with shaking for 15 min. The organic phase was analyzed by HPLC on an ODS column (25 cm x 4.6 mm i.d.) with acetonitrile/10 mM imidazole of pH 7.5 (1:1) as mobile phase and CL detection as above. A metal-free system was developed using a plastic-frame column and PTFE line. The detection limit was 0.025 pg for 1,8- and 1,6-DNP and 0.05 pg for 1,3-DNP.
Hydrocarbons, aromatic, polycyclic HPLC Chemiluminescence

"Simultaneous Determination Of Hydride And Non-hydride Forming Elements By Inductively Coupled Plasma Atomic-emission Spectrometry"
Anal. Proc. 1992 Volume 29, Issue 10 Pages 438-439
Zhang Li, Susan McIntosh and Walter Slavin

Abstract: Arsenic, Se, Sb, Bi, Cd, Cr, Cu, Fe, Mn, Ni and Pb were determined in the NIST environmental standard reference materials steel, coal fly ash, urban particulated and 1643b water by ICP-AES. A Perkin-Elmer FIAS-2000 flow injection system was used for hydride generation (experimental conditions tabulated). The sample solution was split into two streams, one being pumped directly to the nebulizer, the other mixed with HCl and NaBH4 solution in the mixing tubes of the chemifold. After separation, the hydride was swept into the spray chamber through a slightly modified cross-flow nebulizer cap. The hydride was then carried into the plasma together with sample aerosol. Recoveries of 20 µg L-1 of As, Sb and Se and 50 µg L-1 of non-hydride forming elements in river- and seawater standards were >80%.
Arsenic Selenium Antimony Bismuth Cadmium Chromium Copper Iron Manganese Nickel Lead Spectrophotometry Spectrophotometry Reference material FIAS-200 Nebulizer Volatile generation Volatile generation

"Analysis Of Atmospheric Ammonia And Particulate Ammonium By A Sensitive Fluorescence Method"
Environ. Sci. Technol. 1988 Volume 22, Issue 8 Pages 948-952
S. Rapsomanikis, M. Wake, A. M. N. Kitto, and Roy M. Harrison

Abstract: Atmospheric NH3 and particulate NH4+ were collected on H3PO4-impregnated Whatman 41 and PTFE filters, respectively, and the filters were extracted with water. The extracts were analyzed in a flow injection system by injecting the solution into the phthalaldehyde(I) eluent stream and measuring the fluorescence of the NH4+ - I moiety at 455 nm (excitation at 335 nm). Results correlated well with those obtained by the indophenol blue method; the detection limit was 204 ng m-3 for NH3 and 27 ng m-3 for NH4+. Air sampling with both filter packs and a denuder system was evaluated.
Ammonia Ammonium Fluorescence Method comparison

"Determination Of Aflatoxins In Dust And Urine By Liquid Chromatography/electrospray Ionization Tandem Mass Spectrometry"
Rapid Commun. Mass Spectrom. 1995 Volume 9, Issue 13 Pages 1234-1237
Anders Kussak, Carl-Axel Nilsson, Barbro Andersson, Jim Langridge

Abstract: A liquid chromatography/electrospray ionization tandem mass spectrometry method is described for the determination of aflatoxins B1, B2, G1 and G2. Samples of naturally contaminated airborne dust and spiked urine were cleaned up on immunoaffinity columns and analyzed by liquid chromatography using either mass spectrometry detection or post-column derivatization with bromine and fluorescence detection. With tandem mass spectrometry, detection limits (S/N = 3) calculated as amount ejected on column were: aflatoxin B1 4 pg, B2 4 pg, G1 5 pg, and G2 10 pg. (10 references)
Aflatoxin B1 Aflatoxin B2 Aflatoxin G1 Aflatoxin G2 HPLC Fluorescence Post-column derivatization Method comparison