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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Milko Novic

Abbrev:
Novic, M.
Other Names:
Address:
National Institute of Chemistry, P.O. Box 3430, Hajdrihova 19, SI-1001, Ljubljana, Slovenia
Phone:
+386-1-476-0200
Fax:
+386-1-425-9244

Citations 5

"Ion-exchange-based Eluent-free Preconcentration Of Some Anions"
J. Chromatogr. A 2001 Volume 909, Issue 2 Pages 289-296
Milko Novic, Marjan Gucek, Janja Tursica, Yan Liu and Nebojsa Avdalovic

Abstract: Preconcentration procedures based on ion-exchange methods are often used to enhance the sensitivities of analytical techniques where the eluent used for eluting the pre-concentrated ions does not influence the subsequent analytical step. Until recently, only a limited use of ion-exchange-based sample pre-concentration procedures has been found in those analytical techniques where the eluent components strongly influence the separation procedure [e.g., capillary electrophoresis (CE)]. In this paper, we present a pre-concentration procedure based on (i) the pre-concentration of anions on an ion-exchange resin, (ii) the subsequent elution of analytes, and (iii) on-line removal of eluent components by chemical suppression using an appropriate suppressor device (either packed-bed suppressor column or micromembrane suppressor). The adjustment of the system parameters, combined with a computer-controlled, sensing/switching system, resulted in a minimal additional dilution of the eluted pre-concentrated anions. The efficiency of the proposed enrichment/matrix removal procedure was tested by using off-line CE analysis of collected pre-concentrated samples, reaching a LOD of 1 µg/l for a selected anion.

"Use Of Flow Injection Analysis Based On Iodometry For Automation Of Dissolved Oxygen (Winkler Method) And Chemical Oxygen Demand (dichromate Method) Determinations"
Fresenius J. Anal. Chem. 1988 Volume 332, Issue 7 Pages 750-755
M. Novic, B. Pihlar and M. Dular

Abstract: In the modified Winkler method, water (300 ml) was mixed with 1 mL of each of the precipitation solution and 1 mL of concentrated H2SO4 and, after 30 min, an aliquot was injected into a stream of water (0.56 mL min-1) and mixed with 0.4 M KI (0.56 mL min-1). After passing through a PTFE reaction tube (50 cm x 0.5 mm), the I3- in solution was determined amperometrically in a wall-jet cell at a vitreous-carbon electrode at -200 mV vs. Ag - AgCl. Dissolved O was determined by the standard-additions method with use of KIO3 as standard. Calibration graphs were rectilinear for up to 30 mg L-1 of dissolved O and the detection limit was 5 µg l-1. Results agreed with those obtained with a WTW OXI 91 oxymeter. The apparatus could also be modified for use in the determination of COD by oxidation of organic compounds with K2Cr2O7 in H2SO4 and reaction of the excess of K2Cr2O7 with KI producing I3- which was determined amperometrically as above.
Chemical oxygen demand Oxygen Environmental Amperometry Electrode Electrode Standard additions calibration

"Determination Of Optimal Conditions To Achieve Maximal Response At Maximal Repeatability In FIA-AMZ Experiment Through A Mathematical Modelling Approach"
Croat. Chem. Acta 2002 Volume 75, Issue 2 Pages 531-543
Milko Novic and Marjana Novic

Abstract: The determination of optimal experimental conditions in flow injection analysis asynchronous merging zone technique (FIA-AMZ) on the basis of a mathematical model is proposed. An improved commutator enabling reagent addition with minimal frontal dispersion is used for the simultaneous determination of two species, Fe2+ and Fe3+ ions. The mathematical model used to simulate the detector response is based on a bell-shaped function. The model is well suited for the fitting of symmetrical as well as for very asymmetrical detector responses, reflecting different dispersion of the sample plugs. The influence of the frontal dispersion of the reagent, asymmetrically added to the sample plug, is studied using the proposed model. A measure for an optimal ratio between the sensitivity and repeatability is described on the basis of the parameters obtained from the simulations of the experimental curves obtained for different dispersions.
Optimization

"Simultaneous Dermination Of Iron (II) And Iron(III) By Flow Injection Analysis. A Mathematical Simulation Of The Detector Response"
Anal. Chim. Acta 1997 Volume 348, Issue 1-3 Pages 101-112
Milko Novi, Marjana Novi*, Jure Zupan, Nadja Zafran and Boris Pihlar

Abstract: A mathematical model for the description of the detector signal obtained in flow injection asynchronous merging zone technique (FIA-AMZ) is proposed. FIA-AMZ is based on the separate injection of a sample and an appropriate reagent in such a way that both injected solutions are covered only partly. The resulted detector signal consists of two consecutive peaks whose heights are proportional to the concentration of the detectable component present in the sample and another component which becomes detectable after the reagent has been added. The detector signals (the concentration profiles of the analytes) are described by a modified Gauss curve, which proved to be better than a combination of Gauss-Lorentz curves. The conversion of undetectable to detectable form of the analyte is described by a sigmoidal function the slope of which corresponds to the frontal dispersion of the added reagent and to the reaction kinetics. The model is tested on the system for the simultaneous spectrophotometric determination Fe2+ and Fe3+. It is shown that fitting of the experimental curves with a model function enables the optimization of the experimental conditions at applied FIA manifold, and consequently the simultaneous determination of concentrations of Fe2+ and Fe3+ ions in a single measurement.
Iron(2+) Iron(III) Simulation Modeling Simultaneous analysis Speciation

"Determination Of The Separation Efficiency Of Semipermeable Membranes Using A Two Sample Loop-based Flow Injection System"
Anal. Chim. Acta 1991 Volume 251, Issue 1-2 Pages 261-267
M. Novi*, B. Pihlar

Abstract: A method for the determination of the transfer through a semipermeable membrane (microporous PTFE tape), based on a two sample loop flow-injection system, was developed. Investigated and reference samples were injected simultaneously and after the diffusion unit the acceptor stream was merged with the stream carrying the reference sample. Quantitative analysis of the fraction of permeated analyte was with only one injection, and as a measure of the fraction of analyte transferred the ratio of the two consecutive signal areas was used. The method was developed for the determination of the separation yield of HCN using an electrochemical detector. The accuracy of the method was verified by the fraction collection method. This simple procedure could be also applied to other separation devices (e.g., dialysis membranes, liquid-liquid extraction) and other measuring techniques (spectrophotometric, atomic absorption spectrometric, etc.).
Membrane