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Um método eletroanalítico original e rápido para a determinação de naproxeno em formulações farmacêuticas usando análise por injeção em batelada (BIA) com detecção amperométrica pulsada é descrito. Eletrodo de carbono vítreo foi usado como eletrodo de trabalho e solução tampão fosfato 0,05 mol L -1 como eletrólito suporte. O método amperométrico envolveu a aplicação contínua de dois pulsos de potencial ao eletrodo de trabalho com intuito de detectar naproxeno pela sua oxidação eletroquímica (+1,5 V por 200 ms) e de limpar a superfície do eletrodo de produtos de adsorção (+1,0 V por 100 ms), evitando contaminação do eletrodo. O método proposto possui várias vantagens para análises de rotina, incluindo: baixo desvio padrão relativo (3,0%, n = 10), elevada frequência analítica (90 h -1 ), exatidão satisfatória (baseado em determinações comparativas por espectrofluorimetria) e baixo limite de detecção (0,3 µmol L -1 ).A novel and fast electroanalytical method for naproxen determination in pharmaceutical formulations using batch injection analysis (BIA) with pulsed amperometric detection is described. Bare glassy carbon electrode was used as working electrode and 0.05 mol L -1 phosphate buffer solution as supporting electrolyte. The amperometric method involved the continuous application of two sequential potential pulses to the working electrode in order to detect naproxen by its electrochemical oxidation (+1.5 V for 200 ms) and to clean the electrode surface from adsorption products (+1.0 V for 100 ms), avoiding electrode contamination. The proposed method has several advantages for routine analysis, including: a low relative standard deviation between injections (3.0%, n = 10), high analytical frequency (90 h -1 ), satisfactory accuracy (based on comparative determinations by spectrofluorimetry) and low limit of detection (0.3 µmol L -1 ).Keywords: batch injection analysis, multiple-pulse amperometry, non-steroidal antiinflammatory drug IntroductionNaproxen, 2-(6-methoxynaphthalen-2-yl) propanoic acid, is a non-steroidal anti-inflammatory drug (NSAID) derived from propionic acid and has been widely used as an over-the-counter analgesic, anti-inflammatory and antipyretic agent. It is also commonly used for the reduction of stiffness caused by conditions including kidney stones, rheumatoid arthritis and other inflammatory rheumatic diseases. 1,2 NSAIDs have been associated with the increasing number of potentially cardiovascular events. However, a recent study classified naproxen as the least harmful NSAID in cardiovascular terms. 3 Different analytical methods have been proposed for the determination of naproxen in pharmaceutical formulations including spectrophotometry (UV region), 4,5 spectrofluorimetry, 6-8 capillary isotachophoresis 9 and high-performance liquid-chromatography (HPLC) coupled with spectrophotometric, 10 amperometric 11 and mass spectrometric detectors. 1 Nevertheless, these analytical methods require expensive equipment and reagents, are time-consuming and often necessitate laborious pre-and pos...

3D printing technologies have been considered an important technology due to the ease manufacturing of objects, freedom of design, waste minimization, and fast prototyping. In chemistry, this technology potentializes the fabrication of conductive electrodes in large scale for sensing applications. Herein, we reported the modification of a 3D printed graphene electrode with Prussian blue. The modified electrode (3DGrE/PB) was characterized by microscopy (SEM and AFM) and spectroscopic techniques, and its electrochemical properties were compared to the traditional electrodes: glassy carbon, gold, and platinum. The 3DGrE/PB was used in the sensing of hydrogen peroxide in real-world samples of milk and mouthwash, and the results obtained according to the technique of batch-injection analysis were satisfactory for the concentration range typically found in such samples. Thus, 3DGrE/PB can be used as a new platform for sensing of molecular targets.

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