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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Julian Alonso-Chamarro

Abbrev:
Alonso Chamarro, J.
Other Names:
Julián Alonso-Chamarro
Address:
Unitat de Química Analítica, Department de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona Spain
Phone:
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Fax:
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Email:

Citations 4

"Flow Injection System Based On The Sandwich Technique For Saving Expensive Reagents"
Clin. Chim. Acta 1991 Volume 203, Issue 1 Pages 67-76
Alberto N. Araujo, José L. F. C. Lima, Julián Alonso-Chamarro*, Jordi Bartrolí and Manel Poch

Abstract: We report the application of a sandwich technique in flow injection systems which afford low consumption of expensive reagents and two reagent recirculation systems. The potential applicability of the technique thus developed was assessed by determining glucose in serum samples by the enzymatic glucosidase/peroxidase method. It was possible to perform up to 450 determinations with the same amount of reagent used to perform 50 determinations by batch procedures. The sampling rate was 80 determinations per hour with a 0.9% relative standard deviation. Serum was subjected to flow injection analysis with mixing with phosphate buffer solution (pH 7.4) and 11 mM phenol - 0.8 mM 4-aminoantipyrine - peroxidase (900 iu l-1) - glucose oxidase (15,000 iu l-1) and detection at 520 nm. An eight-port injection valve (cf. Alonso et al., Anal. Chim. Acta, 1987, 199, 191) was used to reduce reagent consumption along with a recycling system for the enzyme reagent solution The within-batch coefficient of variation (n = 10) was 0.9%. The method was used to perform 450 determinations with the same amount of reagent used to perform 50 determinations by the batch procedure. The sampling rate was 80 determinations h-1. The results compared well with those obtained using a Hitachi 735 batch analyzer..
Glucose Serum Human Spectrophotometry Clinical analysis Buffer Calibration Low cost Sandwich technique Reagent consumption Enzyme

"Continuous Flow Analytical Microsystems Based On Low-temperature Co-fired Ceramic Technology. Integrated Potentiometric Detection Based On Solvent Polymeric Ion-selective Electrodes"
Anal. Chem. 2006 Volume 78, Issue 9 Pages 2985-2992
Nuria Ibanez-Garcia, Manel Bautista Mercader, Zaira Mendes da Rocha, Carlos Antonio Seabra, Mário Ricardo Góngora-Rubio, and Julián Alonso Chamarro

Abstract: In this paper, the low-temperature co-fired ceramics (LTCC) technology, which has been commonly used for electronic applications, is presented as a useful alternative to construct continuous flow analytical microsystems. This technology enables not only the fabrication of complex three-dimensional structures rapidly and at a realistic cost but also the integration of the elements needed to carry out a whole analytical process, such as pretreatment steps, mixers, and detection systems. In this work, a simple and general procedure for the integration of ion-selective electrodes based on liquid ion exchanger is proposed and illustrated by using ammonium- and nitrate-selective membranes. Additionally, a screen-printed reference electrode was easily incorporated into the microfluidic LTCC structure allowing a complete on-chip integration of the potentiometric detection. Analytical features of the proposed systems are presented. © 2006 American Chemical Society.

"Nitrate-ion Selective Electrode As Reference Electrode For Flow Injection Analysis"
Anal. Chim. Acta 1992 Volume 261, Issue 1-2 Pages 419-423
Julian Alonso-Chamarro*, Jordi Bartroli and Cecília Jimenez

Abstract: A system for pH measurement is described and illustrated; it incorporated a Si3N4 ISFET (Centro Nacional de Microelectronica, CSIC/UAB, Bellaterra) as sensor and a flow-through tubular electrode containing NO3- liquid ion exchanger (Orion), placed in a closed branch of the main channel, as reference. The carrier solution was 25 mM KNO3. Response was near-Nernstian between pH 1 and 13, and up to 0.1 M Na+ or -K+ did not interfere. The sampling rate was 120 h-1 and the coefficient of variation was 0.5% (n = 10) for repeated injection of buffers of different pH values. The development of a flow injection system for pH determination using pH ion-sensitive field-effect transistor in conjunction with a tubular flow-through nitrate ion-selective electrode (ISE) as a reference electrode is described. With this system, the linear working range extends from pH 1 to 13 with a sensitivity of 56 mV per pH unit and a relative standard deviation of 0.4%. A stable baseline and good response are obtained by placing the tubular ISE in a closed branch of the main channel.
pH Electrode Field effect transistor Interferences Linear dynamic range

"Sandwich Techniques In Flow Injection Analysis. 3. Simultaneous Determination Of Chromium(VI) In Two Concentration Ranges"
Anal. Chim. Acta 1992 Volume 261, Issue 1-2 Pages 219-223
J. Alonso-Chamarro*, J. Bartrolí and R. Barber

Abstract: A diagram is shown of the manifold, equipped with an eight-port switching valve, in which the sample is 'sandwiched' between two flows of 1,5-diphenylcarbazide (I) solution of different concentration. and absorbance measurements (at 540 nm) are made at the two sample - reagent interfaces; peak height is evaluated. Reagent 1 comprises 0.25 mM I and reagent 2 contains 1 mM I, each in 0.04 M H2SO4. By this means, two calibration ranges, from 0.02 to 1.0 and from 1 to 30 ppm (curvilinear) of Cr(VI), can be covered; the corresponding detection limits are 0.01 and 0.5 µg mL-1. Sample throughput is ~45 h-1 and the coefficient of variation is 1%. The method has been applied to the output from a pilot plant used to remove Cr(VI) from leather-factory waste water. A flow injection system based on the sandwich technique is proposed for the determination of Cr(VI). Two simultaneous working ranges of concentration. are achieved by appropriate selection of the reagent composition at the two reagent-sample interfaces. The optimized system allows the determination of Cr(VI) at levels up to 1 µg mL-1 with a detection limit of 0.01 µg mL-1 for one of the interfaces. For the other, determinations up to 30 µg mL-1 with a detection limit of 0.5 µg mL-1 are possible. The sample throughput achieved was about 45 h-1 with a relative standard deviation <1% in the middle of both ranges. The method was applied to determine Cr in water.
Chromium(VI) Industrial Spectrophotometry Sandwich technique Optimization Linear dynamic range