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

Determination of carbamate pesticides using micellar liquid chromatography

1417-1422Carbaryl, methiocarb and propoxur, have been rapidly determined by micellar liquid chromatography, using a C18 (250×4.0 mm) column, UV-detection (230 nm) and direct injection of the samples. Sodium dodecyl sulphate (SOS), due to its shorter retention times compared to that of Brij-35, and pentanol have been chosen as surfactant and organic modifier respectively in the optimisation procedure. An interpretative optimization strategy has been used to select the optimum mobile phase, SDS 150 mM-6% (v/v) pentanol-pH 3. The analysis time is lower than 10 min. Intra and inter-day precisions are lower than 1.9% in terms of relative standard deviation. Limits of detection (3s criterion) are 0.1 ng mL-1 for carbaryl and 0.6 ng/mL for methiocarb and propoxur. Calibration is linear between the LOD and 100μg mL-1. The developed method has been applied to the determination of carbamates in spiked water samples (domestic tap, agricultural and waste water) at 50 ng mL-1 concentration levels. The results are similar to those obtained by the Environmental Protection Agency (EPA) reference method

Determination of drugs in pharmaceuticals and pesticides by micellar liquid chromatography

1973-1982Micellar liquid chromatography (MLC) is a reversed-phase liquid chromatography technique that uses surfactants as components in the mobile phase at a concentration higher than the critical micellar concentration. Chromatographic procedures using micellar mobile phases have been reported for the analysis of pharmaceutical formulations commercialised as tablets, pills, capsules, drops, solutions, syrups, gels, suspension s, enemas, sprays, oily injections, ointment and creams. The compounds studied in this work include benzodiazepines, phenethylamines, antihistamines, vitamins, and corticosteroids formulations, and carbamates pesticides. These compounds are usually determined by reversed-phase liquid chromatography (RPLC) with aqueous-organic mobile phases. MLC has the advantages of avoiding sample pretreatment, analysis time, accuracy, reproducibility, toxicity, environmental impact and low cost of the procedures respect to the classical RPLC. Some features of the analytical procedures arc examined including modelling of the retention behaviour of solutes, selection of column, surfactant and alcohol, study of hydrophobicity, and screening analysis. Usually, optimum pH is fixed at 7, but pH 3 is used in the case of the most hydrophilic analytes. C18 columns are often used, but C8 columns allow the obtention of rapid procedures with the lowest analysis time. Pentanol, butanol or propanol are used in function of the hydrophobicity of the substrate. Finally, optimised procedures have been applied for the determination of the substances in pharmaceuticals and in biological samples, including serum and urine

Development of novel SOlid Materials for high power Li polymer BATteries (SOMABAT). Recyclability of components.

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