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

Waste

Classification: Waste -> nuclear

Citations 5

"The Proper Place Of Analytical Chemistry In Environmental Management"
Crit. Rev. Anal. Chem. 1999 Volume 29, Issue 2 Pages 155-162
Jirí Janata

Abstract: Obtaining new information through characterizaton (chemical analysis) has its costs associated with it. These costs must be justified. It is argued that the value of any analysis, new chemical sensor, or a new analytical procedure for environmental management task is ultimately determined by its rational use. A formal procedure for justification of chemical characterization is outlined.

"Continuous-flow Solvent Extraction System For The Determination Of Trace Amounts Of Uranium In Nuclear Waste Reprocessing Solutions"
Analyst 1988 Volume 113, Issue 3 Pages 463-469
Raja H. Atallah, Gary D. Christian and Steven D. Hartenstein

Abstract: A continuous-flow solvent-extraction system, which is interfaced to a spectrophotometer (Beckman DU-7), is described and illustrated. The synthetic sample (0.6 ml) is loaded via a four-way valve over 1 min and mixed with a salting-out solution of aqueous NH3 - Al(NO3)3 in a PTFE coil (80 cm x 0.8 mm); the solution converges with a stream of isobutyl methyl ketone and extraction occurs in a PTFE coil (3 m x 0.8 mm). The organic layer is separated by a PTFE membrane and mixed with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in ethanol - pyridine in a knotted PTFE tube (1 m x 0.5 mm). The absorbance is measured at 578 nm (e = 60,000). The calibration graph was rectilinear for 1 to 40 ppm of U and the detection limit was 0.2 ppm. Extraction and separation efficiencies were 80 and 90%, respectively. Alternatively the system is operated with 5-min loading of a 3 mL sample in which the sample is continuously pumped in a closed loop with a fixed volume of extractant. For this system a rectilinear calibration graph is obtained for 0.05 to 0.5 ppm and the enrichment factor is 4-fold. Interference from Zr is masked by F-.
Uranium Spectrophotometry Sample preparation Closed loop Interferences Solvent extraction Teflon membrane Knotted reactor

"Automated Analysis Of Radionuclides In Nuclear Waste: Rapid Determination Of Strontium-90 By Sequential Injection Analysis"
Anal. Chem. 1996 Volume 68, Issue 2 Pages 333-340
Jay W. Grate, Robert Strebin, Jiri Janata, Oleg Egorov, and Jaromir Ruzicka

Abstract: A 10 mL PTFE holding coil (HC; 20 cm) located prior to a multipoint valve (MPV) and a 50-100 µm Sr-Spec column (10 cm x 2.1 mm i.d.) was filled with water from a carrier stream. Portions (6 ml) of 8 M HNO3 reagent were subsequently drawn into the HC via the MPV and the Sr-Spec column was conditioned with 1 mL 8 M HNO3 drawn from the HC via the MPV. A 100 µL portions of strontium-90/yttrium-90, strontium-85 (yield tracer) and caesium-137 in 8 M HNO3 (preparation described) was drawn into the HC and the 'stack' of zones created in the HC was drawn through (0.5 ml/min) the column. Yttrium-90, caesium-137 and other radionuclides (present in waste samples) were displaced with 6 mL 8 M HNO3 and strontium-90 and strontium-85 subsequently displaced with 7.5 mL water. Eluates and liquid scintillation cocktail (1:2) were fed via a T-piece and a mixing coil to a liquid scintillation counter. Calibration graphs were linear up to ~25000 strontium-90 disintegrations/min. Results for aged waste samples (preparation described) were in excellent agreement with conventional analysis (procedures described).
Strontium-90 Scintillation counter Sequential injection Column

"Improved Method For The Determination Of Manganese In Nuclear Power Plant Waters"
J. Chromatogr. A 1993 Volume 640, Issue 1-2 Pages 371-378
Archava Siriraks and John Stillian, Dennis Bostic

Abstract: Manganese was determined in nuclear power plant water by ion chromatography in a Dionex DX-300 system with pre-concentration. on a MetPac CC-1 column, separation on an IonPac CS12 column with 10 mM HCl/8 mM H3PO4 as eluent (1 ml/min) and cation micro-membrane suppression and conductivity detection with post-column derivatization with 0.4 mM pyridylazoresorcinol/1 M dimethylethanolamine/0.3 M NaHCO3 and detection at 530 nm. The detection limit was 90 pg of Mn (1-3 pg/ml); no calibration ranges or RSD are given.
Manganese HPIC Preconcentration Post-column derivatization Metpac

"Isotopic And Ultratrace Analysis Of Uranium In Radioactive Waste Samples By Double-focusing Sector Field ICP-MS"
Schr. Forschungszent. Juelich, Reihe Energietech. 1998 Volume 2, Issue 1997 Pages 323-327
Kerl, W.;Becker, J.S.;Dietze, H.J.;Dannecker, W.

Abstract: To optimize the determination of U, ultrasonic nebulization for double-focused sector field ICP-MS was found to be the best nebulization method. With this method the detection limits for several actinide isotopes in highly pure water were determined A precision of <0.1% RDS was achieved for isotopic ratio determination in the ng/mL concentration. range, and the excellent agreement of isotopic ratios obtained by double-focusing sector field ICP-MS and α-spectrometry even for comparable small values of isotopic ratios down to 10^-6 demonstrated the capability of ICP-MS. To minimize the radioactive contamination in the instrument a microconcentric nebulizer in combination with an HPLC injection valve was suitable for flow injection analysis to reduce the sample volume to several µL.
Uranium Mass spectrometry Nebulizer Optimization