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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Separation Science and Technology

  • Publisher: Taylor and Francis
  • FAD Code: SSCT
  • CODEN: SSTEDS
  • ISSN: 0149-6395
  • Abbreviation: Sep. Sci. Technol.
  • DOI Prefix: 10.1080/0149639
  • Language: English
  • Comments: Fulltext from 1966 V1

Citations 6

"Determination Of Copper, Iron, Nickel, And Zinc In Ethanol Fuel By Flame Atomic Absorption Spectrometry Using On‐Line Preconcentration System"
Sep. Sci. Technol. 2005 Volume 40, Issue 12 Pages 2555-2565
Leonardo S. G. Teixeira, Marcos de A. Bezerra, Valfredo A. Lemos, Hilda C. dos Santos, Djane S. de Jesus, Antônio C. S. Costa

Abstract: In this work, an on-line system for pre-concentration and determination of copper, iron, nickel, and zinc at µg L-;1 level by flame atomic absorption spectrometry (FAAS) has been developed. Amberlite XAD-4 functionalized with 3,4-dihydroxybenzoic acid packed in a minicolumn was used as metal sorbent. The retained metals can be quickly eluted from sorbent material, with the eluent stream consisting of hydrochloric acid solution, directly to the nebulizer burner system of the FAAS. Analytical parameters were evaluated and the results demonstrated that all studied metals can be determined, using borate buffer to adjust the sample pH at 8.0. The results showed that the proposed method is simple and rapid. The limits of detection were estimated as 2.3, 5.0, 7.8, and 0.1 µg L-;1 for copper, iron, nickel, and zinc, respectively, using a pre-concentration time of 60 s and a sample flow rate of 5.5 mL min-;1. Enrichment factors of 22, 15, 12, and 54 and coefficients of variations of 3.5, 4.4, 4.4, and 3.2% were obtained in the determination of copper, iron, nickel, and zinc, respectively. The system presented an analytical throughput of 10 samples per hour and was successfully applied in the determination of metals in ethanol fuel.

"Synthesis And Application Of A New Functionalized Resin In On‐Line Preconcentration Of Lead"
Sep. Sci. Technol. 2005 Volume 40, Issue 7 Pages 1401-1411
Valfredo Azevedo Lemos, Juracir Silva Santos, Luana Sena Nunes

Abstract: An on-line system for pre-concentration and determination of lead at µg L-1 level is proposed. Amberlite XAD-2 functionalized with 2-(2'-benzothiazolylazo)-p-cresol (BTAC-XAD) packed in a minicolumn was used as sorbent. Chemical and hydrodynamic variables were evaluated and the results demonstrated that lead can be determined using sample pH at 7.0-7.5, elution with 0.050 mol L-1 HCl and a sample flow rate of 6.0 mL min-1. Enrichment factors of 19, 43, and 60 were achieved by using the time-based technique with pre-concentration periods of 60, 120, and 180 s, respectively. Detection limit (3s) was 1.7 µg L-1 when used pre-concentration time of 180 s. This procedure was applied to lead determination in natural water samples. Accuracy of procedure was confirmed by lead determination in certified reference materials.
Lead Environmental Spectrophotometry Resin Amberlite BTAC Preconcentration Optimization Reference material

"Synthesis Of α-Nitroso-β-Naphthol Modified Amberlite XAD-2 Resin And Its Application In On-Line Solid Phase Extraction System For Cobalt Preconcentration"
Sep. Sci. Technol. 2004 Volume 39, Issue 14 Pages 3317-3330
Valfredo Azevedo Lemos, Juracir Silva Santos, Patrãcia Xavier Baliza

Abstract: In this work, an on-line system for pre-concentration and determination of cobalt at µg l -;1 level is proposed. Amberlite XAD-2 functionalized with α-nitroso-β-naphthol (NN-XAD) packed in a minicolumn was used as sorbent. Cobalt (II) ions were sorbed in the minicolumn, from which it could be eluted by hydrochloric acid solution. This eluate reacted with Nitroso Salt R and the absorbance of the complex was read at 510 nm in a spectrophotometer. Signals were measured as peak height by using instrument software. Achieved sampling rate was 45 samples per hour. Analytical parameters were evaluated and the results demonstrated that cobalt can be determined, with sample pH in the range of 7.0-8.5, pre-concentration time of 60 s with a sample flow rate of 5.0 mL min -;1. The detection limit (3 s) was 6.0 µg l -;1 and the precision (assessed as the relative standard deviation) reached values of 6.1 to 1.9% in cobalt solutions of 10 to 300 µg l -;1 concentration, respectively. The proposed procedure was applied in natural waters. Recoveries of spike additions (10, 25, or 50 µg l -;1) to natural water samples were quantitative (92-106%).

"8-Hydroxyquinoline-5-sulfonic Acid (HQS) Impregnated On Lewatit MP 600 For Cadmium Complexation: Implication Of Solvent Impregnated Resins For Water Remediation"
Sep. Sci. Technol. 2003 Volume 38, Issue 1 Pages 149-163
Ying Wang, Chengyong Wang, Abraham Warshawsky, Brian Berkowitz

Abstract: The impregnation of 8-hydroxyquinoline-5-sulfonic acid (HQS) onto an anionic strong base resin Lewatit MP 600 is described. The procedure was carried out by mixing HQS with Lewatit MP 600 in water, instead of in organic solvents generally used in solvent impregnated resins (SIRs). The maximum impregnation is 0.95 mmol of HQS/g of Lewatit MP 600. The HQS-impregnated resin was used in a flow injection system incorporating a mini-column for cadmium chelation. Measured cadmium breakthrough curves were used to study the influence of various impregnated HQS, the influent concentration of cadmium, and the packed HQS-Lewatit MP 600, on cadmium binding. By increasing the impregnated HQS from 0.098 to 0.830 mmol/g of Lewatit MP 600, column capacity increased from 11.29 to 52.57 mmol Cd/L of HQS-Lewatit MP 600. Increasing the influent concentration of Cd reduced the column capacity due to a concurrent increase of competing anion (ClO4-). This in turn reduced the stability of cadmium complex in the resin phase. Varying the amounts of HQS-Lewatit MP 600 packed in a mini-column caused variations in Cd binding. A 450 mg quantity of 0.95 mmol HQS/g of Lewatit MP 600 can remove cadmium from an initial value of 1 ppm to 30 ppb (detection limit of our instrument). Cadmium and partially impregnated HQS can be eluted by 2 mol/L HNO3 and the resin can be regenerated to impregnate HQS for further cadmium complexation.

"A Rapid Method For The Extraction And Separation Of Uranium From Thorium And Other Accompanying Elements Using Octadecyl Silica Membrane Disks Modified By Tri-n-octyl Phosphine Oxide"
Sep. Sci. Technol. 2000 Volume 35, Issue 7 Pages 1011-1019
MOJTABA SHAMSIPUR, YADOLLAH YAMINI, PARVIZ ASHTARI, ALI REZA KHANCHI, MOHAMMAD GHANNADI-MARAGEH

Abstract: A simple method for rapid and selective separation of uranyl ion from Th4+ and other accompanying elements by using octadecyl silica membrane disks modified with tri-n-octyl phosphine oxide (TOPO) in the presence of 0.5 M HNO3 is presented. The influences of type and concentration of acid, nature of ligands, flow rates, and nature of stripping agents have been investigated. Maximum capacity of the membrane disks modified by 50 mg TOPO was found to be 938 µg of uranium. The method was applied to the recovery of uranyl ion from two different soil samples.
Preconcentration

"Continuous Free-flow Electrophoresis In An Alternating Two-dimensional Electric Field"
Sep. Sci. Technol. 1991 Volume 26, Issue 7 Pages 947-959
Joseph L. Shmidt; Huk Y. Cheh

Abstract: The charged solute moves in three directions, flowing continuously downwards with the main buffer and migrating electrophoretically in two other perpendicular directions. Particles are fractionated in proportion to the squares of their electrophoretic mobilities. The method is expected to show good resolution for the separation of peptides, proteins and organelles.
Electrophoresis Buffer