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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Electrode

Classification: Electrode -> membrane -> crown ether

Citations 3

"Flow Injection Potentiometry By Poly(vinyl Chloride)-membrane Electrodes With Substituted Azacrown Ionophores For The Determination Of Lead(II) And Mercury(II) Ions"
Anal. Chim. Acta 1998 Volume 372, Issue 3 Pages 387-398

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Xinhao Yang, D. Brynn Hibbert* and Peter W. Alexander

Abstract: A flow cell with a poly(vinyl chloride) (PVC) neutral-ionophore liq.-membrane ion-selective electrode was developed for flow injection potentiometry (FIP). The flow system was optimized and five substituted azacrown ethers: 7,16-dithenoyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTODC), 7,16-di-(2-thiopheneacetyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTAODC), 7,16-dithenyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (DTDC), 1,10-dioxa-4,7,13,16-tetraazacyclooctadecane (TC) and 4,7,13,16-tetrathenoyl-1,10-dioxa-4,7,13,16-tetraazacyclooctadecane (TTOTC) synthesized and studied as the ionophores in Pb2+ (DTAODC, TTOTC) and Hg2+ (DTDC, DTODC, TC, TTOTC) selective electrodes. The short contact times between analyte and ionophore in FIP allow the measurement of a strongly complexing ion such as Hg2+ that sats. the electrodes in batch anal., or in continuous-flow anal. that comes to a steady state. For the mercury-selective electrodes with ionophores with amide functional groups (TTOTC and DTODC) a carrier of 10 mM potassium nitrate increases the speed of response and recovery to baseline. The linear calibration range for a DTAODC lead-selective electrode was pPb = 2.0 to 5.0 with a slope of 32.5 mV decade-1 and for a TTOTC mercury-selective electrode, pHg = 3.0 to 5.5 with a slope of 28.4 mV decade-1. Highly reproducible measurements were obtained (relative standard deviation <2%) at a flow rate of 3.0 mL min-1 giving a typical throughput of 40 samples h-1 for Pb2+ and 30 samples h-1 for Hg2+.
Lead(2+) Mercury(II) Optimization Apparatus Detector

"The Application Of Various Immobilized Crown Ether Platinum-modified Electrodes As Potentiometric And Amperometric Detectors For Flow Injection Analyses Of Catechol And Catecholamines"
Electroanalysis 1995 Volume 7, Issue 5 Pages 420-424

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Suzanne K. Lunstord, Yi-Long Ma, Ahmed Galal, Cynthia Striley, Hans Zimmer, Harry B. Mark Jr.

Abstract: The crown ethers were polymerized onto a 2 mm diameter Pt disc electrode. The monomer solution comprised 0.025 M crown ether and 0.20 M tetrabutylammoniumtetrafluoriborate as supporting electrolyte in acetonitrile. Amperometric measurements were performed with a BAS model MF-1021 flow cell. Static potentiometric and potentiometric FIA measurements were performed with the polymer-modified electrode PTFE block incorporated into a standard BAS thin-layer flow cell with a Ag/AgCl electrode as second electrode. Measurements were performed with an Orion model 601A ionanalyzer. The potentiometric FIA response of all the crown ethers was linear over the range 10 mM to 10 µM. The lowest detection limits were 0.5 µmM for the potentiometric FIA with minimum interference from ascorbic acid, uric acid and acetaminophen. Detection limits for amperometric FIA was 5 µmM but there was significant interference from ascorbic acid, uric acid and acetaminophen.
Catechol, derivatives Catecholamine, derivatives Crown ether Complexation Interferences

"The Electrochemistry Of Neurotransmitters At Conducting Organic Polymer Electrodes Electrocatalysis And Analytical Applications"
Bioelectrochem. Bioenerg. 1995 Volume 38, Issue 2 Pages 229-245

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Harry B. Mark, Jr., N. Attaa, Y. L. Ma, K. L. Petticrew, H. Zimmer, Y. Shia, S. K. Lunsford, J. F. Rubinson and Ahmed Galal

Abstract: The electrooxidation of catechols, catecholamines and NADH at conventional electrode materials is generally characterized by high degrees of irreversibility as well as strong adsorption and, hence, fouling by reactants and/or products of the reactions. On the contrary, the rates of the electron transfer are highly catalyzed by the use of conducting polymer films, such as poly(3-methylthiophene), polyphenylene, polyanaline and polypyrrole, as described here. Furthermore, the usual fouling problems are eliminated. Even interference from electroinactive large proteins, such as haemoglobin, and other surfactants are substantially reduced. Also, electron spectroscopy for chemical analysis, energy-dispersive analysis of X-rays, theoretical diffusion coefficient calculations, metal ion coordination, solution diffusion analyzes of cyclic voltammograms etc. show that the electron transfer occurs at the polymer-solution interface and not at the inert electrode substrate surface after diffusion through the polymer matrix or through pores. The analytical application of these polymer electrodes as amperometric detectors for flow injection analysis and high performance liquid chromatography are given. In addition, selective potentiometric electrodes for catecholamines based on conducting polymer films of crown ethers, such as binaphthyl-20-crown-6, dibenzo-18-crown-6, etc., have been developed and characterized. These potentiometric detectors significantly decrease the usual interferences of ascorbic acid, uric acid and acetaminophen found in amperometric detection. (60 References)
Catecholamines Interferences Catalysis Diffusion coefficients Crown ether