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

On-line analysis of NH3, CO2, and SO2 diffusion through microporous Teflon

Dynamic responses of self-made potentiometric NH3, CO2, and SO2 sensitive gas sensors are followed in the 10-5-5×10-3 M concentration range. By least squares fitting of potential versus time curves, Dk product values at the diffusion of NH3, CO2, and SO2 through microporous Teflon are calculated. The obtained results are fairly reflected by the behavior of the sensor. Measurements of potential versus time in mixed solutions of CO2 and SO2 with the CO2 sensitive sensor indicate the presence of the interferent.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Cytotoxic Effect of Chitosan-Gold Nanoparticles on Two Cell Lines in Culture

Among metallic nanoparticles gold possess several unique properties. It has been argued that AuNPs have significant toxicity both in vitro and in vivo but that coating may partially prevent harmful effects. Chitosan is a natural polysaccharide derivative of chitin known to have immunoenhancing effects, antitumor, antifungal and antimicrobial activities. The aim of this study was to investigate the cytotoxic effect of chitosan-AuNPs on C26 (murine colon carcinoma) and HeLa (human cervix carcinoma) cell lines. C26 and HeLa cells were exposed to 10 and 60 nm sized chitosan-AuNPs at five different concentrations (5, 10, 25, 50 and 100 μg/ml). After 24 h of incubation, cytotoxicity was assessed by the MTT colorimetric method and IC50 values were calculated. In C26 cells 60 nm particles were more toxic than 10 nm particles. On the other hand in HeLa cells the situation was reversed and 10 nm particles had the most harmful effect at a concentration 2.5 times smaller than that of 60 nm particles. Our results could suggest that chitosan-AuNPs have an antiproliferative effect on C26 and HeLa cell lines but that this depends on cell type and is influenced by particle size and concentration

Free Base Porphyrins as Ionophores for Heavy Metal Sensors

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