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Pilot monitoring study of ibuprofen in surface waters of north of Portugal
Paíga, Paula; Santos, Lúcia; Amorim, Célia G.; Araújo, Alberto N.; Montenegro, M. Conceição B. S. M.; Pena, Angelina; Delerue-Matos, CristinaIbuprofen is amongst the most worldwide consumed pharmaceuticals. The present work presents the first data in the occurrence of ibuprofen in Portuguese surface waters, focusing in the north area of the country, which is one of the most densely populated areas of Portugal. Analysis of ibuprofen is based on pre-concentration of the analyte with solid phase extraction and subsequent determination with liquid chrom...
Development of a simple analytical method for the simultaneous determination of...
Santos, Lúcia H. M. L. M.; Paíga, Paula; Araújo, Alberto N.; Pena, Angelina; Delerue-Matos, Cristina; Montenegro, M. Conceição B. S. M.Paracetamol is among the most worldwide consumed pharmaceuticals. Although its occurrence in the environment is well documented, data about the presence of its metabolites and transformation products is very scarce. The present work describes the development of an analytical method for the simultaneous determination of paracetamol, its principal metabolite (paracetamol-glucuronide) and its main transformation p...
Gran method for end point anticipation in monosegmented flow titration
Aquino,Emerson V; Pasquini,Celio; Rohwedder,Jarbas J. R; Raimundo Jr,Ivo M; Montenegro,M. Conceição B. S. M; Araújo,Alberto NAn automatic potentiometric monosegmented flow titration procedure based on Gran linearisation approach has been developed. The controlling program can estimate the end point of the titration after the addition of three or four aliquots of titrant. Alternatively, the end point can be determined by the second derivative procedure. In this case, additional volumes of titrant are added until the vicinity of the en...
Determination of gibberellic acid by sequential injection analysis using a pote...
Santos,Emília M. G.; Couto,Cristina M. C. M.; Araújo,Alberto N.; Montenegro,M. Conceição B. S. M.; Reis,Boaventura F.This work describes the determination of gibberellic acid in growth promoters formulations used in agriculture by sequential injection analysis and potentiometric detection. The potentiometric detectors with improved characteristics used a PVC membrane prepared with Mn(III)tetraphenylporphyrin-Cl as electroactive specie. Different membranes formulated with several ionic additives were compared in order to selec...
Monosegemented flow potentiometric titration for the determination of chloride ...
Vieira,Jonas A.; Raimundo Jr.,Ivo M.; Reis,Boaventura F.; Montenegro,M. Conceição B.S.M.; Araújo,Alberto N.An automated flow potentiometric titration procedure for the determination of chloride in milk and wine exploiting the monosegmented flow approach is described. The flow network was designed based on a six-way solenoid valve, controlled by a microcomputer running software written in VisualBasic 3.0, allowing selection of the titration conditions. An Ag2S tubular electrode selective for Cl- and a conventional Ag...
Detectores potenciométricos para sistemas de análise por injecção em fluxo, evo...
Couto,Cristina M. C. M.; Montenegro,M. Conceição B. S. M.The field of flow injection potentiometry (FIP) is reviewed and its current status assessed. The research development and application of electrodes in flow injection systems are presented and discussed.
Complexação da tetraciclina, da oxitetraciclina e da clortetraciclina com o cat...
Couto,Cristina M. C. M.; Montenegro,M. Conceição B. S. M.; Reis,SaletteStability constants of complexes formed by copper (II) with three different tetracyclines (tetracycline, oxytetracycline and chlortetracycline) have been determined potentiometrically with an automatic system in aqueous medium at 25,0 ± 0,2 ºC and I = 0,1 mol L-1 NaNO3. The protonation constants of the three tetracyclines were also determined under the same conditions. The distribution of the complexes was then...
Construction and use of a tubular picrate ion-selective electrode for reducing ...
Lopes, Teresa I. M. S.; Rangel, António O. S. S.; Lima, José L. F. C.; Montenegro, M. Conceição B. S. M.A picrate ion-selective electrode without inner reference solution and based on bis(triphenylphosphoranylidene)ammonium picrate dissolved in 2-nitrophenyloctyl ether was constructed and its characteristics assessed. With respect to reducing sugar determination in Port wine, a tubular electrode based on the same sensor system was developed and incorporated into a flow-injection manifold devised for this determin...
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