Manganese(III) Porphyrin-based Potentiometric Sensors for Diclofenac Assay in Pharmaceutical Preparations

Two manganese(III) porphyrins: manganese(III) tetraphenylporphyrin chloride and manganese(III)-tetrakis(3-hydroxyphenyl)porphyrin chloride were tested as ionophores for the construction of new diclofenac–selective electrodes. The electroactive material was incorporated either in PVC or a sol–gel matrix. The effect of different plasticizers and additives (anionic and cationic) on the potentiometric response was studied. The best results were obtained for the PVC membrane plasticized with dioctylphtalate and having sodium tetraphenylborate as a lipophilic anionic additive incorporated. The sensor response was linear in the concentration range 3 × 10−6 – 1 × 10−2 M with a slope of −59.7 mV/dec diclofenac, a detection limit of 1.5 × 10−6 M and very good selectivity coefficients. It was used for the determination of diclofenac in pharmaceutical preparations, by direct potentiometry. The results were compared with those obtained by the HPLC reference method and a good agreement was found between the two methods

A novel sensor for monitoring of iron (III) ions based on porphyrins

[EN] Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl- and dimethoxysubstituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 ¿ 10¿7¿1 ¿ 10¿1 M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples.The research leading to these results has received funding from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 266090 (SOMABAT), Romanian PNCDI2 Program-Module III-EU 128/2011 and is a result of collaboration between the coauthors within the project POSDRU/21/1.5/G/38347.Vlascici, D.; Fagadar-Cosma, E.; Popa, I.; Chiriac, V.; Gil Agustí, MT. (2012). A novel sensor for monitoring of iron (III) ions based on porphyrins. Sensors. 12(6):8193-8203. https://doi.org/10.3390/s120608193S8193820312

A New Composition for Co(II)-porphyrin-based Membranes Used in Thiocyanate-selective Electrodes

In the present paper, the potentiometric response characteristics of ametalloporphyrin-based electrode in o-nitrophenyloctylether (o-NPOE) plasticizedpolyvinyl chloride (PVC) membrane are presented for a set of monovalent anions. Asmembrane ionophore, 5,10,15,20-tetrakis-(4-methoxyphenyl)-porphyrin-Co(II)(CoTMeOPP) was used. To establish the optimum composition of the membrane, differentmolar percents of cationic derivative (mol.% relative to ionophore) were used. Electrodesformulated with membranes containing 1 wt.% ionophore, 66 wt.% o-NPOE, 33 wt.% PVC(plasticizer: PVC = 2:1) and the lipophilic cationic derivative (35 mol%) are shown toexhibit high selectivity for thiocyanate with a near-Nernstian slope in the workingconcentration range of 1.0×10−1–1.0×10−5 M, with a good stability in time

Synthesis, characterization and correlative biological effects in wheat of a benzoxaza- and a diaza-phosphorus(V) heterocycles

Dichloro-p-tolylphosphine, involved in a Mannich type reaction, together with o-aminophenol or 1,2- diaminopropane and acetone generated two phosphorin-2-oxide ring compounds, namely: hexahydro-3,3,5-trimethyl-2-p-tolyl-1,4,2-diazaphosphorine-2-oxide and 3,4-dihydro-3,3-dimethyl-2-p-tolyl-2H-1,4,2-benzoxaza-phosphorine-2-oxide. The two compounds were fully characterized by MS, IR, UV, 1H-NMR, and gas chromatography. Anothermain objective of the present study was to examine to what extent the treatments with different concentrations of the above-mentioned diaza- and benzoxaza-compounds affected the content of leaf chlorophyll of a monocotyledonous plant (wheat), in correlation with all the other changes concerning the general development of the tested plants

Optical Detection of Bromide Ions Using Pt(II)-5,10,15,20-Tetra-(4-methoxy-phenyl)-porphyrin

Bromide ions are present in many environments, such as sedative drugs, methyl-bromide-treated vegetables and seawater. Excess bromide in humans interferes with iodide metabolism and is considered toxic. The need for fast and inexpensive methods for bromide detection is of interest. Spectrophotometric detection methods provide accurate and sensitive results. The well-known ability of metalloporphyrins to bind anionic ligands to the central metal ion has been exploited. The changes in the optical properties of Pt(II) 5,10,15,20-tetra(4-methoxy-phenyl)-porphyrin (PtTMeOPP) under the influence of bromide ions allowed us to achieve a fast, simple and reliable UV-vis spectrophotometric method of detection with a detection limit of 2.5 × 10−8 M and a good confidence coefficient: 99.05%. The potential interfering ions, such as Cl−, I−, NO2−, NO3−, SCN−, SO32−, SO42− and PO43− of 100-fold higher and Cl− and R-S− of 1000-fold higher concentrations in the mixture as compared to the determined concentration of bromide ions (c = 10−5 M), were tested and did not influence the results. The behavior of the sensitive porphyrin in various pH media was investigated in order to determine their influence upon the bromide detection capacity

Free Base Porphyrins as Ionophores for Heavy Metal Sensors

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