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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Classification: Water -> high purity

Citations 6

"Continuous-flow Determination Of Low Concentrations Of Ammonium Ions Using A Gas Dialysis Concentrator And A Gas Electrode Detector System"
Analyst 1988 Volume 113, Issue 1 Pages 113-115
Hirokazu Hara, Atsushi Motoike and Satoshi Okazaki

Abstract: A gas-dialysis unit based on a micro-porous PTFE membrane (cf. Fraticelli and Meyerhoff, Anal. Chem., 1981, 53, 992) is described. The recipient buffer system is 0.01 M K H phthalate in which the diffused NH3 is converted into NH4+, which is detected by an NH3-selective electrode (Orion 95-12) after addition of NaOH. The concentration. factor is ~10 between 11°C and 29°C. The response is rectilinear for three decades up to 1000 µg L-1 with a limit of detection of 3 µg L-1 of N. The method is applied to purified and natural waters.
Ammonium Electrode Dialysis Heated reaction Preconcentration Teflon membrane

"Flow-analysis Method For The Determination Of Silicic Acid In Highly Purified Water By Gel-phase Absorptiometry With Molybdate And Malachite Green"
Analyst 1991 Volume 116, Issue 8 Pages 835-840
Kazuhisa Yoshimura and Ushio Hase

Abstract: The method described is based on the online concentration of ion association species formed between molybdosilicate and Malachite green on Sephadex LH-20 and direct detection of the species on the gel. The manifold used is described (with diagram). Malachite green solution is injected into the carrier stream and after 2 min, sample solution (containing 2 to 50 ng of Si) and molybdate solution are introduced simultaneously into the carrier stream. The absorbance is measured at 627 nm with use of a Sephadex LH-20 packed detection cell. The detection cell is washed with 2 M NaOH before introduction of the next sample. Silicic acid can be determined at muwg L-1 levels or lower in water with a sampling rate of 4 or 5 h-1.
Silicic acid Spectrophotometry Ion pair formation Sephadex Solid phase detection

"Membrane For Organic Solvent Sample Introduction Into Inductively Coupled Plasmas"
Spectrochim. Acta B 1989 Volume 44, Issue 10 Pages 1041-1048
Kenneth Bäckström and Anders Gustavsson, Pentti Hietala

Abstract: The membrane interface described by Gustavsson (Ibid., 1988, 43B, 917) was characterized and was applied in ICP-AES with on- or off-line continuous-flow extraction utilizing metal complexation. Detection limits were in the pg mL-1 range using organic solvents. Trace metal determinations in purified water samples yielded results of acceptable accuracy and precision.
Spectrophotometry Sample preparation Membrane Complexation Precision Extraction

"Simultaneous Determination Of Iron(III), Iron(II), Copper(II) And Zinc(II) In Water By Ion Chromatography With Post-column Derivatization"
Fenxi Ceshi Xuebao 1993 Volume 12, Issue 3 Pages 16-21
Wang Shengming

Abstract: Water was passed through a column of Dionex CS-2 with a mixed complexing agent solution of sulfosalicylic acid, tartaric acid and oxalic acid, and an eluent of protonated ethylenediammonium ion. The separated ions were treated with 4-(2-pyridylazo)resorcinol in a post-column reactor before spectrophotometric detection at 500 nm. The method was used to analyze environmental water and high-purity water.
Iron(2+) Iron(III) Copper(II) Zinc(II) HPIC Spectrophotometry Post-column derivatization

"Investigations On Flow Injection With Ion-selective Electrodes. 1. Rapid Determination Of Trace Sodium In High-purity Water"
Fenxi Huaxue 1989 Volume 17, Issue 12 Pages 1147-1149
Zou, A.;Wen, Y.

Abstract: The water sample (pH 12) flows to a Na+-selective electrode in a carrier stream of 0.3 M di-isopropylamine (2.7 mL min-1) in a flow injection manifold (diagram presented). A detection limit of 0.1 ng mL-1 is possible. The method is rapid, sensitive, accurate and convenient.
Sodium Electrode

"Determination Of Silica In Boiler Water"
LaborPraxis 1996 Volume 20, Issue 5 Pages 86-NA

Abstract: A Lambda FIA system is presented which meets the needs for an optimal detection limit and a practical sample throughput in the routine determination of silica in high-purity water. The system combines a sensitive double-beam spectrometer with an FIA module, an automatic sample feed and PC control. A 400 µL sample was used with a 50 nm flow cell and detection at 820 nm. The detection limit was 0.01 mg SiO2/l. The sample throughput was 60 samples/h; RSD was 3.5% at 0.02 mg SiO2/l.
Silica Spectrophotometry