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A new sensitive and selective disposable potentiometric sensor based on polypyrrole (PPy) films for determination of sildenafil citrate (SC) was proposed. The pyrrole polymerization was performed in presence of citrate ions under galvanostatic conditions which resulted in a membrane of PPy doped with citrate anion at graphite pencil electrode surface. Experimental conditions (e.g., pH and conditioning time) and instrumental parameters (e.g., current density and electrical charge) were evaluated in order to reach the best potentiometric response for the proposed sensor. Under optimized conditions, the device presented a linear dynamic range (LDR) for citrate ions concentrations varying from 0.034 to 1.7 mmol L 21 with a Nernstian slope of 57.2 mV dec 21 and a limit of detection (LOD) of 30 mmol L 21 . The developed potentiometric sensor was applied for sildenafil citrate (SC) determination (pharmaceutical formulations) and results compared with an official spectrophotometric method indicating a good agreement for a confidence level of 95%. Effect of concomitants species on the potentiometric response of the proposed device and morphologic characterization using microscopy of atomic force (AFM) were realized. The surface roughness of PPy films (synthesized in citrate solution and chloride) showed poorly affected by changing the doping anion, probably because the polypyrrole nodules grow three-dimensionally simultaneously. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43762.

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In this study, the cold plasma technique was used to produce nanometric titanium films with hydrophobic and anti-fouling properties. The films where deposited on porcelain electrical insulators surfaces to minimize the effects of leakage current. The magnetron sputtering technique was used with a target of pure titanium sheet, and argon as the ionization gas. The deposited films present an average thickness of 58 to 350 nm. After coating the insulators, the assays performed indicated a greater degree of hydrophobicity and maintenance of leakage current after exposure to salt spray. Lower leakage current values were observed in both natural and saline environments compared with the uncoated device.