Potentiometric porphyrinic sensors

Based on the oxidation of AA by periodate. A new potentiometric periodate sensor is constructed to monitor this reaction. The selective membranes are of PVC with porphyrin-based sensing systems and a lipophilic cation as additive... 

T. L. Blair, J. R. Allen, S. Daunert, and L. G. Bachas, Potentiometric and fiber optic sensors for pH based on an electtopolymerized cobalt porphyrin, Anal. Chem. 65, 2155-2158 (1993). 

Electrocatalytic groups such as porphyrins and phthalocyanines that act as supramolecular hosts for different metals and mimic the active sites of various proteins are commonly used in amperometric sensors [66,67]. A biomimetic sensor based on an artificial enzyme or synzyme has been demonstrated [68]. The artificial enzyme used in this study was a synthetic polymer (quaternised polyethyleneimine containing 10% primary amines) which decarboxylated oxaloacetate. The product carbon dioxide was detected potentiometrically via a gas membrane electrode. 

Porphyrins are often employed in sensors on account of their ability to act as cation hosts and, with a suitable metal ion coordinated, as redox catalysts. Electropolymerised poly(metalloporphyrin)s have been used as potentiometric anion-selective electrodes [131] and as amperometric electrocatalytic sensors for many species including phenols [132], nitrous oxide [133] and oxygen [134]. Panasyuk et al. [135] have electropolymerised [nickel-(protoporphyrin IX)dimethylester] (Fig. 18.10) on glassy carbon in the presence of nitrobenzene in an attempt to prepare a nitrobenzene-selective amperometric sensor. Following extraction of the nitrobenzene the electrode was exposed to different species and cyclic voltammetric measurements made. A response was observed at the reduction potential of nitrobenzene (the polyporphyrin film acts only to accumulate the analyte and not in a catalytic fashion). Selectivity for nitrobenzene compared with w-nitroaniline and o-nitroto-luene was enhanced compared with an untreated electrode, while a glassy carbon-... 

A. Preparation of Porphyrin-Based Potentiometric Sensors for Anions.252... 

A. PREPARATION OF PORPHYRIN-BASED POTENTIOMETRIC SENSORS FOR ANIONS... 

But the most smdied electropolymerizable porphyrins are the tetra-amino-and tetrahydroxyphenyl-substituted ones. Indeed, both of them were developed to elaborate electrodes having potentiometric responses to several kinds of anions, such as iodide for example . Co(II) tetrakis(p-hydroxyphenyl)porphyrin 53-based films were used for the elaboration of potentiometric and fibre optic pH sensors with minimal interferences from anions. Zn(II)-53-based films were also used and characterized for kinetics studies of hydrogen evolution at their surface . Zn(II)-53 as well as Pd(II)-53 and free base tetra(4-methyl pyridinium) porphyrin (H2-54) were electropolymerized on indium tin oxide substrates, leading thus to starting materials for the making of donor/acceptor... 

Bruti, E.M., M. Giannetto, G. Mori, and R. Seeber (1999). Electropolymerization of tetrakis(o-aminophenyl)porphyrin and relevant transition metal complexes from aqueous solution. The resulting modified electrodes as potentiometric sensors. Electroanalysis 11(8), 565-572. 

D. Vlascici, S. Pruneanu, L. Olenic, F. Pogacean, V Ostafe, V. Chiriac, E.M. Pica, E. Fagadar-Cosma, Manganese(III) porphyrin-based potentiometric sensors for diclofenac assay in pharmaceutical preparations. Sensors, 10 (10), 8850-8864,2010. 

Amini, M.K., Shahrokhian, S. and Tangestaninejad, S. (1999) Porphyrins as carriers in poly(vinyl chloride)-based membrane potentiometric sensors for histamine. Analyst, 124, 1319-1322. 

Electrodes modified only with porphyrins or porphyrins associated with other species were explored as potentiometric detectors for different applications. A manganese(lll) porphyrin was utilized as the main component of recovered glassy carbon electrodes used as potentiometric detector of thiocyanate in urine. This sensor was coupled to a FIA system to optimize parameters such as membrane composition, pH, and flow injection parameters. Under the best conditions, a Nemstian response with 58.0 mV per decade of thiocyanate concentration was recorded. The new sensor presented a linear response in the 4.2 x to... 

Sulfadimethoxine (SMD) is a dmg frequently used to prevent the spreading of diseases in freshwater fish aquaculture, but its control is important to avoid environmental contamination. A potentiometric sensor selective to SMD was built inside a micropipette tip [211] by immersing a PVC membrane loaded with 1 % of meTO-tetra(phenyl)porphyrinate manganese(lll) chloride in a reference solution. This electrode gave near Nemstian response (54.1 mV/decade) and excellent detection limit (2.4 x 10 mol L ) was attained. For the quantification of SO2, a selective electrode was prepared by incorporation of Cio-(tetraphenyl)porphyr-inate zinc(ll) in a PVC membrane plasticized with 2-nitrophenyl-phenylether [212]. The new electrode presented a selective response to sulphite, with good linearity in an interval larger than four decades of concentration and slope of -59.5 mV per decade, and detection limit of 3.7 x 10 mol L . This sensor presented high... 

The multitransduction of signals was explored for the quantification of metals in solution. A polymeric membrane sensor was developed by incorporation of 5,10,15,20-tetra(ferrocenyl)porphyrin [248]. Simultaneous optical and potentiometric measurements made possible the detection of lead in the 2.7 x 10 to... 

Beheshti SS, Sohbat F, Amini MK (2010) A manganese porphyrin-based sensor for flow-injection potentiometric determination of thiocyanate. J Porph5uins Phthalocyanines 14 (02) 158-165... 

Gupta VK, Jain AK, Singh LP, Khurana U (1997) Porphyrins as carrier in PVC based membrane potentiometric sensors for nickel(II). Anal Chim Acta 355 33-41 12. Morales-Bahnik A, Czolk R, Reichert J, Ache HJ (1993) An optochemical sensor for Cd(II) and Hg(ll) based on a porphyrin immobilized on Nafion membranes. Sensors Actuat B Chem 13 424 26... 

The principles of chemical recognition have been widely used in analytical chemistry for the development of selective sensing devices. The recognition properties of several ionophores have been exploited to enable the design of advanced materials suitable for the preparation of fiber optic and potentiometric sensors. Specifically, sensors were prepaid by electrochemically growing poly[Co(II)tetra(oamino-phenyl)porphyrin] and poly[Co(II)tetra(p-hydroxyphenyl)porphyrin] on glassy carbon electrodes and indium(tin) oxide (TTO) sUdes. 

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