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Selective Chelating Agents

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Chemical Sensors".

Deadline for manuscript submissions: closed (30 November 2012) | Viewed by 6832

Special Issue Editor

University of Pittsburgh at Greensburg, Faculty of Natural Sciences, 150 Finoli Drive, B-22 Smith Hall, Greensburg, PA 15601, USA
Interests: metal-ion chelation and speciation; strip and optical sensors; potentiometry and ion-selective electrodes; membranes; method calibration; determination of metals in environmental and biological samples; molecular and atomic absorption spectrometries; field analytical methodologies

Special Issue Information

Dear Colleagues,

Sensors based on potentiometric and spectrometric measurements of electrical and optical signals, respectively, have been utilized for detection of interesting analytes for the past 4–5 decades. Both types of sensors rely upon binding of an interesting analyte by a ligand (molecular or ionic) in a reversible or irreversible manner, accompanied by a measureable signal that is usually proportional to analyte concentration. A highly desirable characteristic of chelating ligands used in these sensors is selectivity for specific analytes, toward analyte detection and quantitation with minimal or no interferences. Currently, there are a plethora of analytical applications of potentiometric and optical sensors containing selective chelators, from food analysis, to industrial quality control, to biological, medical, and environmental analyses. The need for sensors incorporating selective chelators for detection and quantitation of analytes in a wide range of applications will continue for years to come.

This special issue of Sensors seeks to address the role of selective chelators in the design and implementation of potentiometric and optical sensors for chemical analysis, and the issues related to their use in sensors. Thus, we solicit review articles and original research papers on chelators for inorganic and organic anions and cations as well as neutral molecules, selectivity of chelators for specific cations, anions, and neutral molecules, utilization of photochromic and electrochromic molecules containing chelating functional groups toward photo- or electroreversible analyte sensing, and applications of selective chelating agents to the determination of a wide range of analytes. New analyte-specific chelators with high selectivity, new approaches to selective analyte chelation coupled with schemes for reversibility, and novel applications of selective chelators in sensors for detection and quantitation of analytes, are also considered.

Dr. Mark T. Stauffer
Guest Editor

Keywords

  • Chelation
  • Selectivity
  • Ligand receptors
  • Potentiometric and optical sensors
  • Reversible and irreversible binding
  • Inorganic anionic and cationic analytes
  • Organic anionic and cationic analytes
  • Neutral molecular analytes
  • Analytical applications

Published Papers (1 paper)

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Research

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Article
Evaluation of Complexation Ability Using a Sensor Electrode Chip Equipped with a Wireless Screening System
by Takaaki Isoda, Ikuko Urushibara, Hikaru Sato and Noriyoshi Yamauchi
Sensors 2012, 12(6), 8405-8425; https://doi.org/10.3390/s120608405 - 19 Jun 2012
Cited by 3 | Viewed by 6501
Abstract
We fabricated an electrode chip with a structure coated by an insulation layer that contains dispersed SiO2 adsorbent particles modified by an amino-group on a source-drain electrode. Voltage changes caused by chelate molecule adsorption onto electrode surfaces and by specific cation interactions [...] Read more.
We fabricated an electrode chip with a structure coated by an insulation layer that contains dispersed SiO2 adsorbent particles modified by an amino-group on a source-drain electrode. Voltage changes caused by chelate molecule adsorption onto electrode surfaces and by specific cation interactions were investigated. The detection of specific cations without the presence of chelate molecules on the free electrode was also examined. By comparing both sets of results the complexation ability of the studied chelate molecules onto the electrode was evaluated. Five pairs of source-drain electrodes (×8 arrays) were fabricated on a glass substrate of 20 × 30 mm in size. The individual Au/Cr (1.0/0.1 μm thickness) electrodes had widths of 50 μm and an inter-electrode interval of 100 μm. The fabricated source-drain electrodes were further coated with an insulation layer comprising a porous SiO2 particle modified amino-group to adsorb the chelate molecules. The electrode chip was equipped with a handy-type sensor signal analyzer that was mounted on an amplifier circuit using a MinishipTM or a system in a packaged LSI device. For electrode surfaces containing different adsorbed chelate molecules an increase in the sensor voltage depended on a combination of host-guest reactions and generally decreased in the following order: 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)-21H,23H-porphine, tetrakis(p-toluenesulfonate) (TMPyP) as a Cu2+ chelator and Cu2+ > 2-nitroso-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (nitroso-PSAP) as an Fe2+ chelator and Fe2+ > 4,7-diphenyl-1,10-phenanthrolinedisulfonic acid, disodium salt (BPDSA) as an Fe2+ chelator and Fe2+ > 3-[3-(2,4-dimethylphenylcarbamoyl)-2-hydroxynaphthalene-1-yl-azo]-4-hydroxybenzenesulfonic acid, sodium salt (XB-1) as a Mg2+ chelator and Mg2+ > 2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolinedisulfonic acid, disodium salt (BCIDSA) as a Cu2+ chelator and Cu2+, respectively. In contrast, for the electrode surfaces with adsorbed O,O'-bis(2-aminoethyl)ethyleneglycol-N,N,N',N'-tetraacetic acid (GEDTA) or O,O'-bis(2-aminophenyl)ethyleneglycol-N,N,N',N'-tetraacetic acid, tetrapotassium salt, hydrate (BAPTA) as a Ca2+ chelator no increase in the detection voltage was found for all the electrode tests conducted in the presence of Ca2+. To determine the differences in electrode detection, molecular orbital (MO) calculations of the chelate molecules and surface molecular modeling of the adsorbents were carried out. In accordance with frontier orbital theory, the lowest unoccupied MO (LUMO) of the chelate molecules can accept two lone pair electrons at the highest occupied MO (HOMO) of the amino group on the model surface structure of the SiO2 particle. As a result, a good correlation was obtained between the LUMO-HOMO difference and the ion response of all the electrodes tested. Based on the results obtained, the order of adsorbed chelate molecules on adsorption particles reflects the different metal ion detection abilities of the electrode chips. Full article
(This article belongs to the Special Issue Selective Chelating Agents)
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