Design and construction of ion-selective electrode based on a new Schiff base and its application in determination of copper(II) ions

51-56A copper(II) selective sensor has been made from polyvinyl chloride matrix membrane based on the carrier, 2-(5-bromo-2-hyroxybenzylidineamino) pyridine 3-ol as an ionophore, ortho-nitrophenyl octyl ether (o-NPOE) as mediator solvent and sodium tetraphenylborate (NaTPB) as additive. The best performance is presented by membrane of composition of ionophore (Schiff base):PVC:o-NPOE:NaTPB of 3:33:63:1 (by weight). The membrane potential response is linear in the concentration range of 1.0×10-7 to 1.0×10-2 M with the Nernstian slope of 29.5±0.5 mV per decade of Cu2+ and a detection limit of 7.4×10-8 M. The response time of the sensor is very short; less than 10 s, and it can be used for at least 8 weeks without any difference in potential. The proposed copper(II) selective electrode displays excellent selectivity towards alkali, alkaline earth and transition metal ions and can be used in the pH range of 4-7. It has been successfully used as an indicator electrode for the determination of Cu(II) in water samples. The electrode has also been employed as an indicator electrode in titration of Cu2+ with EDTA

FTIR analysis and quantification of phenols and flavonoids of five commercially available plants extracts used in wound healing

ABSTRACT Natural products are used in wound healing in order to prevent infection. Propolis is a well known antimicrobial with phenolic compounds and flavonoid content which vary according to the propolis origin. Besides propolis (from both Brazilian and UK sources), pomegranate, dragon's blood and sage are possible antimicrobials to be used in biomaterials. The goal of this work was to analyze the amount of phenols and flavonoid compounds in these natural products, their antioxidant activities and the bonds present by FTIR. The FTIR analysis revealed the presence of active compounds in all drug samples. The phenols quantification showed that Brazilian propolis was rich in phenols compared to the other drugs, followed by pomegranate and UK propolis. UK propolis was the most rich in flavonoids, which is expected on account of its origin. Pomegranate, UK propolis and Dragon's blood presented the highest antioxidant activity. All samples presented antioxidant activity > 82%