University of North Florida
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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

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Beatriz S. Fernandez Band

Abbrev:
Fernandez Band, B.S.
Other Names:
Beatriz S. Fernández Band, B. S. F. Band
Address:
Department of Chemistry and Engineering Chemistry, Universidad Nacional del Sur, Av. Alem 1253, 8000, Bahía Blanca, Argentina
Phone:
+54-291-459-5100
Fax:
+54-291-459-5160

Citations 11

"A Sensitive Spectrophotometric Method For Lead Determination By Flow Injection Analysis With On-line Preconcentration"
Talanta 2004 Volume 63, Issue 2 Pages 405-409
María S. Di Nezio, Miriam E. Palomeque and Beatriz S. Fernández Band

Abstract: A new flow injection (FI) system for the determination of Pb(II) at trace level with a pre-concentration step and spectrophotometric detection is proposed. It is based on pre-concentration of lead ions on chitosan and dithizone-lead complex formation in aqueous medium (pH 9). The chemicals and FIA variables influencing the performance of the system were optimized and applied to the determination of lead in natural, well, and drinking water samples. It is a simple, highly sensitive, and low cost alternative methodology. The method provided a linear rage between 25 and 250 µg l-1, a detection limit of 5.0 ng mL-1 and a sample throughput of 15 h-1. The obtained results of spiked samples are in good agreement between the proposed method and ICP-AES.

"Fluorimetric Determination Of Fluoride In A Flow Assembly Integrated On-line To An Open/closed FIA System To Remove Interference By Solid Phase Extraction"
Talanta 2002 Volume 58, Issue 5 Pages 849-853
M. Garrido, A. G. Lista, M. Palomeque and B. S. Fernández Band

Abstract: A simple flow injection fluorimetric method for fluoride determination is proposed. The method is based on the enhanced fluorescence of quercitin-Zr(IV) complex when fluoride ion is present in the sample. An open/closed FIA manifold with a mini-column of Dowex 50W X8 resin was used to remove the most important interference (aluminum). The two FIA assemblies were integrated on-line to automate the pretreatment of the water sample and fluoride determination. The calibration graph was linear over the range 0.1-3.0 µg mL-1 of fluoride with a correlation coefficient of 0.999 and LOD 0.06 µg mL-1. The relative standard deviation was 2.5% and the sample throughput was 52 h-1 without pretreatment and 10 h-1 with pretreatment of the sample. The method was applied to the determination of fluoride in water samples. (C) 2002 Elsevier Science B.V. All rights reserved.
Solid phase extraction

"Flow Injection Fluorimetric Determination Of Mercury(II) With Calcein"
Talanta 1999 Volume 50, Issue 4 Pages 881-885
A. G. Lista, M. E. Palomeque and B. S. Fernández Band

Abstract: A flow injection spectrofluorimetric method for the determination of Hg(II) is described. The method is based on the complex that is formed between Hg(II) and calcein at pH 11-12. This reagent was not used before for determining Hg(II). The excitation wavelength is 324 nm and the emission wavelength is 522 nm. The calibration graph shows a linear range between 7.7 and 128 µg L-1 (relative standard deviation 2.0%), the sampling rate was 90 h-1. The effect of several interferents has been examined. Trace mercury in natural waters were determined satisfactorily using a modified manifold, which has an EDTA stream in order to minimize the calcium and magnesium interference.

"Automated Flow-injection Method For Cadmium Determination With Pre-concentration And Reagent Preparation On-line"
Quim. Nova 2005 Volume 28, Issue 1 Pages 145-148
María S. Di Nezio; Miriam E. Palomeque; Beatriz S. Fernández Band

Abstract: The spectrophotometric determination of Cd(II) using a flow injection system provided with a solid-phase reactor for cadmium pre-concentration and on-line reagent preparation, is described. It is based on the formation of a dithizone-Cd complex in basic medium. The calibration curve is linear between 6 and 300 ?g L-1 Cd(II), with a detection limit of 5.4 ?g L -1, an RSD of 3.7% (10 replicates in duplicate) and a sample frequency of 11.4 h-1. The proposed method was satisfactorily applied to the determination of Cd(II) in surface, well and drinking waters.

"Simultaneous Determination Of Levodopa And Benserazide By Stopped-flow Injection Analysis And Three-way Multivariate Calibration Of Kinetic-spectrophotometric Data"
J. Pharm. Biomed. Anal. 2004 Volume 36, Issue 3 Pages 541-547
Marcelo Pistonesi, María E. Centurión, Beatriz S. Fernández Band, Patricia C. Damiani and Alejandro C. Olivieri

Abstract: The simultaneous determination of levodopa and benserazide in pharmaceutical formulations is described, based on the application of multidimensional partial least-squares regression to the kinetic-spectrophotometric data provided by diode-array detection within a stopped-flow injection method where analytes react with periodate. Flow injection parameters were adequately optimized. Accurate analysis is performed with no sample pre-treatment steps, and with minimum experimental effort. Satisfactory recovery results were obtained on a number of synthetic and commercial samples, in the latter case including the comparison with liquid chromatography measurements.

"Flow Injection Biamperometric Determination Of Captopril"
J. Pharm. Biomed. Anal. 2002 Volume 30, Issue 3 Pages 547-552
Miriam E. Palomeque and Beatriz S. Fernández Band

Abstract: An automated method to determine captopril (1-[(2S)-3-mercapto-2-methylpropionyl]-L-proline) is proposed. A flow injection manifold based on the indirect biamperometric detection of the captopril by using Fe(III)/Fe(II) as an indicating redox system and a Z-shaped flow-cell configuration, was developed. The calibration curve is linear over the range 0.03-3.6 µg mL-1 of captopril. The relative standard deviation for the determination of 0.76 µg mL-1 of captopril is 0.97% (n = 12) and the sample throughput is 69 h-1. This method was applied to the determination of captopril to commercially available pharmaceutical preparations. Copyright 2002 Elsevier Science B.V. [Journal Article; In English; England]

"A Fast Fluorimetric Flow Injection Method To Determine Ibuprofen"
J. Braz. Chem. Soc. 2006 Volume 17, Issue 7 Pages 1428-1431
Adriana G. Lista; Miriam E. Palomeque; Beatriz S. Fernández Band*

Abstract: The native fluorescence of ibuprofen was enhanced when a host-guest complex of the analyte with ? cyclodextrin (?-CD) was formed. So, based on this fact, a flow injection method to determine ibuprofen in different pharmaceutical preparations with fluorescence detection (?em 287 nm, ?exc 223 nm) was developed. The calibration curve was linear over the range 6.00 -60.0 mg L-1 of ibuprofen and the detection limit (LOD) for S/N=3 was 4.5 mg L-1. The relative standard deviation was 1.2% and the sample throughput 240 h-1. The method was validated by comparing the proposed and the official method to commercial preparation samples. © 2006 Sociedade Brasileira de Qui?mica.

"Inline Concentration On Chitosan And The Use Of 2,2 -dipyridyl-2-pyridylhydrazone For The Flow Injection Spectrophotometric Determination Of Lead"
Anal. Sci. 1999 Volume 15, Issue 9 Pages 847-850
Adriana G. Lista And Beatriz S. Fernández Band

Abstract: A flow injection system with spectrophotometric detection involving the inline concentration was developed for lead determination in natural water samples. Lead concentration was carried out in a mini-column packed with novel stuff chitosan, and sorption occurred at pH=6 -9. The amount of lead flowing through the chitosan was controlled by time, the CTAB surfactant was passed through a mini-column and a 0.2 M NaOH stream was used as the eluent. The eluted lead merged with 2,2-dipyridyl-2-pyridylhydrazone (DPPH) reagent synthesised in the authors lab and with a berate solution; complex formation took place at pH 11 -12 inside a following reactor and monitoring was carried out at 468 nm. The detection limit was 0.13 µg L-1 and, the sample throughput was 25 h-1. The accuracy was assessed by running spiked river-water samples.
Preconcentration Chitosan

"Cloud-point Extraction/preconcentration On-line Flow Injection Method For Mercury Determination"
Anal. Chim. Acta 2004 Volume 502, Issue 2 Pages 173-177
M. Garrido, M. S. Di Nezio, A. G. Lista, M. Palomeque and B. S. Fernández Band

Abstract: A cloud-point extraction/pre-concentration (CPE/P) step is incorporated on-line into a flow injection system which is used to determine low levels of Hg(II) added to natural water samples. The analyte is complexed with dithizone. A solid reagent column (SRC) is used to prepare the reagent on-line by using 5% (v/v) Triton X-100 solution as solvent. The CPE/P is carried out by using the non-ionic surfactant Triton X-100. After obtaining the cloud-point on-line, the surfactant-rich phase containing the complex is collected in a mini column packed with cotton wool. Then, a hot water stream is passed through the column to elute the complex and the absorbance is measured at 500 nm.All the flow and chemical variables are optimized and the enhancement factor for the system is estimated. The calibration is linear over the range 0.05-0.5 µg mL-1, the RSD is 4.8%, the limit of detection (signal:noise = 3) is 0.014 µg mL-1 and the sample throughput is 30 h-1. An open/closed system is used to eliminate the interference of iron(III).

"Determination Of Vanadium(V) By A Kinetic Stopped-flow FIA Method With Spectrophotometric Detection"
Anal. Chim. Acta 1998 Volume 366, Issue 1-3 Pages 287-293
M. E. Palomeque, A. G. Lista and B. S. Fernández Band*

Abstract: Two automated methods to determine V5+ in water are described. A continuous-flow system based on the classical reaction for V5+ determination with 3,3'dimethylnaphtidine in acid medium using a stopped-flow technique and spectrophotometric detection was developed (Method A). It was possible to increase reaction kinetics to obtain a higher sample throughput (34/h), lower detection limits (0.2 mg/L), and high sensitivity. To determine still a lower V5+ concentrations, a pre-concentration step was introduced in the above system (Method B). This manifold has a lower detection limits (0.032 µg/mL) and high sensitivity (4 times greater than Method A). Both methods showed a good reproducibility (relative standard deviation for Method A = 1.9% and for Method B = 2.3%).
Vanadium(V) Water Spectrophotometry Stopped-flow Kinetic Method comparison

"Evaluation Of Complex Spectral-pH Three-way Arrays By Modified Bilinear Least-squares: Determination Of Four Different Dyes In Interfering Systems"
Analyst 2005 Volume 130, Issue 9 Pages 1291-1298
Nilda R. Marsili, Adriana Lista, Beatriz S. Fernandez Band, Héctor C. Goicoechea and Alejandro C. Olivieri

Abstract: This article reports on the first application of a modified version of the bilinear least-squares model to absorbance-pH second-order data recorded for complex samples. The latter are composed of fruit drink powders, where four different analytes and additional background components occur. The analytes are the common juice colorants tartrazine, yellow sunset, allura red and indigo carmine. The data have been measured after generating a double pH gradient within a flow injection system. The selected chemometric methodology adequately exploits the second-order advantage, needed to take into account the background interferents present in real samples. Due to severe spectral overlapping between the acid and basic forms of each of the colorants in the working pH range, other second-order multivariate calibration methods such as parallel factor analysis and multivariate curve resolution-alternating least-squares could not be successfully applied to the presently studied samples. Recoveries of 94.8, 104.7, 109.3 and 105.3% were obtained for yellow sunset, indigo carmine, allura red and tartrazine respectively in the real test samples. © The Royal Society of Chemistry 2005.