Philosophiae Doctor - PhD / The thesis presents a simple, sensitive, low cost and a novel graphenated polyaniline doped tungsten trioxide nanocomposite, as an electrochemical sensor for the detection and quantitative and determination of PAHs, which are ubiquitous, toxic, as well as dangerous organic pollutant compounds in the environment. The selected PAHs (anthracene, phenanthrene and pyrene) in wastewater were given priority as a result of their threat to human nature and that of the environment. In order for a healthy, non-polluted and well sustainable environment, there is need for an instrument that is capable of detecting and quantifying these organic pollutants onsite and also for constant monitoring. The nanocomposites were developed by chemical and electrochemical methods of preparations, exploiting the intrinsic properties of polyaniline, graphene and tungsten trioxide semiconducting materials. Chemically, graphene-polyaniline (GR-PANI) nanocomposite was synthesised by in situ polymerisation method, then casted on a surface of glassy carbon electrode to form GR-PANI modified electrode. The properties of the prepared electrode were investigated through morphological and spectroscopic techniques, which confirmed the formation of the composite. The electroactivity of the prepared modified electrode revealed great improvement in cyclic and square wave voltammetric response on anthracene. A dynamic range of 2.0 × 10-5 to 1.0 × 10-3 M and detection limit of 4.39 x 10-7 M was established.

This paper describes the development of simple and efficient electrochemical sensors, based on multi-walled carbon nanotubes (MWNCT) chemically modified with nitroanilines (NA), and electroreduced products. These sensors were developed for the simultaneous determination of uric acid (UA), ascorbic acid (AA) and dopamine (DO). NAs, on the MWCNT-modified glassy carbon, suffer reduction, where the nitro group is reduced irreversibly generating the redox couple hydroxylamine/nitroso, originating the chemically modified electrode (CME). The techniques employed for this work were cyclic voltammetry and chronoamperometry, which were used to study the electrochemical behavior of the modified electrode, for detection of analytes in biological samples, obtaining the kinetic parameters and analytical characterization of the platform. In order to assess the effect of the nitro group position in the series of nitroanilines, the isomers ortho-nitroaniline (oNA) and meta-nitroaniline (mNA) were evaluated for sensitivity and response toward AA and UA detection, following the same procedure applied for para-nitroaniline (pNA), which showed the highest current variation, indicating greater effectiveness. The chronoamperometric studies were used, in order to obtain more information about the redox process between AA and the functionalized platforms, since this proved to be a catalytic process. Thus, by means of graphs and Cottrell equation, it was possible to obtain values for the apparent diffusion coefficient (DAA) and the catalytic constant (kcat) for the reaction with AA. The values of kcat and DAA determined for AA were 3.83 x 10-6 cm-2 s-1 and 1.879 x 106 M-1 s-1, respectively. The amperometric sensor allowed the determination of AA, DO and UA. The following figures of merit were obtained: for AA: linear range 5 to 80 M and detection limit of 9.84 M; for DO, linear range of 5 to 80 M and detection limit of 2.13 M and, for UA, linear range of 5 to 80 M and detection limit of 2.30 M. From the obtained performance, the use of nanostructured platform composed of MWNCT and activated pNA is justified, mainly for the simultaneous determination of AA, DO and UA. The comparative study of the isomers showed that the pNA and mNA chemically modified sensors showed increased sensitivity toward the analytes AA and UA, compared to oNA. The study with diazonium salts showed that para-nitroaniline adheres to the surface of the electrode by grafting. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho é descrito o desenvolvimento de um sensor eletroquímico simples e eficiente à base de nanotubos de carbono de paredes múltiplas (do inglês MWNCT) e quimicamente modificado com nitroanilinas polimerizadas e seus produtos de redução, no intuito de desenvolver um sensor para determinar simultaneamente ácido úrico (AU), ácido ascórbico (AA) e dopamina (DO). As nitroanilinas sobre o MWNCT depositado em carbono vítreo, são reduzidas, gerando o par redox hidroxilamina/nitroso, originando o eletrodo quimicamente modificado (EQM). As técnicas empregadas para a realização deste trabalho foram voltametria cíclica e cronoamperometria, as quais foram utilizadas para estudar o comportamento eletroquímico dos eletrodos modificados, detecção dos analitos em amostras biológicas, obtenção dos parâmetros cinéticos e caracterização analítica da plataforma. Com o intuito de verificar a influência da posição do grupo nitro na série das nitroanilinas, os isômeros orto-nitroanilina (oNA) e meta-nitroanilina (mNA) foram avaliados em relação à sensibilidade e resposta para a detecção de AA e AU, seguindo a mesma metodologia de modificação e ativação do sensor modificado com para-nitroanilina (pNA), que apresentou maior variação de corrente, indicativa de maior sensibilidade. Os estudos cronoamperométricos foram realizados com o objetivo de obter maiores informações acerca dos processos redox entre AA e a plataforma funcionalizada, uma vez que este demonstrou ser um processo catalítico. Assim, por meio de gráficos e equações de Cottrell, foi possível obter os valores aparentes para o coeficiente de difusão (DAA) e a constante catalítica (kcat) da reação para o AA. Os valores do DAA e de kcat, determinados para AA, foram de 3,83 x 10-6 cm-2 s-1 e 1,88 x 106 M-1 s-1, respectivamente. O sensor amperométrico apresentou como figuras de mérito relativas à determinação de AA, DO e AU, os seguintes valores: em relação ao AA apresentou faixa linear de 5 a 80 M e limite de detecção 9,84 M; para DO, faixa linear de 5 a 80 M e limite de detecção de 2,13 M e, em relação a AU, faixa linear de 5 a 80 M, e limite de detecção de 2,30 M. A partir do desempenho obtido, justifica-se a utilização da plataforma nanoestruturada fundamentada em MWNCT e pNA ativado como sensor principalmente para a determinação simultânea de AA, DO e AU. O estudo comparativo entre os isômeros evidenciou que os sensores formados por pNA e mNA mostraram maior sensibilidade frente aos analitos AA e AU quando comparados com a plataforma formada por oNA. O estudo com os sais de diazônio, utilizando os mesmos parâmetros da oxidação e ativação, mostrou que a para-nitroanilina adere a superfície do eletrodo por grafitagem.

Les besoins d’outils d’analyse et de contrôle de plus en plus performants en termes de spécificité et sensibilité favorisent le développement des capteurs chimiques et des biocapteurs. Ce travail, s’inscrivant dans ce contexte, a conduit au développement d’un capteur électrochimique à base de polymères conducteurs dédiés à la détection de molécules de faible poids moléculaire. Celui-ci repose sur l’association entre les propriétés de reconnaissance des polymères à empreintes moléculaires et celles de conduction des polymères conducteurs obtenant ainsi un capteur à base de polymères conjugués à mémoires de forme le SMP. Le polymère est obtenu en deux étapes i) une électropolymérisation sur une électrode de platine de l’EDOT avec le pré-complexé formé par l’acide thiophène-3-acétique avec atrazine via des liaisons hydrogène ii) l’extraction de l’atrazine créant des sites à mémoire de forme. Le SMP développé présente une gamme de concentration de 2,5.10-6 M à 5.10-3 M avec un seuil de détection de l’ordre du µM et une sélectivité vis-à-vis de la famille des triazines. Afin d’améliorer les performances de ce capteur et d’élargir le choix de cibles à détecter la synthèse de terthyènyle constitués de l’EDOT de part et d’autre d’un thiophène central fonctionnalisé en β a été réalisé. Ces trimères présentant des pics d’oxydation vers les 0,7 V / Ag/AgNO3 permettent d’envisager le développement de nouvelles fonctionnalités avant ou post-polymérisation tout en ayant un contrôle de la stœchiométrie et de la répartition des groupements fonctionnels. / A rapidly increasing interest is actually devoted in the literature to the design of new analytical and control devices able to form efficient chemical sensors. Thus the aim of our work was the design and the development of an electrochemical sensor based on intrinsically molecularly imprinted conducting polymer for the selective and sensitive detection of small target molecules. This goal will be achieved by the used of the recognition properties of moleculary imprinted polymer, together with the electrical conduction of conducting polymer. An original electrochemical sensor based on shape memory polymer has been constructed. This sensor has been realized following two steps: (i) a frst electropolymerisation on a platinum electrode of two co-monomers Thiophene acetic acid TAA already associated through H bonding to the atrazine target and EDOT which is intinded to play the role of conjugated link between the TAA moieties and (ii) removal of atrazine from the resulting conjugated polymer, leaving recognition sites with shape memory. The obtained sensor shows remarkable properties: a high selectivity towards the triazinic family, a large detection dynamic (2.5x10−6 to 5x10−3 M) and a low detection threshold (10−6 M). In order to increase the efficiency of this sensor and to allow the detection of a wide range molecular targets, a terthienyl, i.e. two EDOT units on both sides of the -functionalized thiophene units has been syntesized. These trimers possess an oxydation peak at about +0.7 V/ Ag/AgNO3, allowing the potential development of new pre or post polymerisation functionalities, still controling of the stoechiometry and the distributuion of functional groups.

Para o desenvolvimento dos sensores aqui descritos foram utilizados materiais inovadores considerando relatos atuais da literatura, materiais estes: óxido de grafeno, óxido de grafeno reduzido, nanocompósitos de grafeno e nanopartículas (ródio, antimônio e sílica mesoporosa desordenada), materiais híbridos a base de grafeno e quantum dots de CdTe, além de biossensores incorporando a enzima lacase. Estes materiais foram sintetizados utilizando metodologias específicas e caracterizados por diversas técnicas analíticas como microscopia eletrônica de transmissão de alta resolução, microscopia de força atômica, espectroscopia Raman, difração de raios-X, espectroscopias de UV-Vis e fotoluminescência, e técnicas eletroquímicas. Posteriormente, os materiais foram utilizados para modificação em eletrodos de carbono vítreo e utilizados na determinação de interferentes endócrinos (os hormônios estriol e 17β-estradiol) como sensores eletroquímicos em amostras ambientais e clínicas. Em essência, os eletrodos desenvolvidos apresentaram importantes vantagens, tais como alta sensibilidade, boa reprodutibilidade, simples instrumentação, fácil preparação e procedimentos analíticos rápidos, apresentando baixos limites de detecção, na ordem de picomolar e nanomolar, com baixa taxa de interferência de outras espécies na mesma matriz da amostra. Concluindo assim que as técnicas eletroquímicas podem ser facilmente aplicadas na determinação de interferentes endócrinos em amostras reais. / For the development of the sensors described here innovators materials were used considering current literature reports, these materials: Graphene oxide, reduced graphene oxide, nanocomposites graphene and nanoparticles (rhodium and antimony), hybrid materials of graphene and CdTe quantum dots, and biosensors incorporating the laccase enzyme. These materials were synthesized using specific methodologies and characterized by several analytical techniques such as transmission electron microscopy, high resolution transmission electron microscopy, atomic force microscopy, Raman spectroscopy, X-ray diffraction, UV-Vis and photoluminescence spectroscopy and electrochemical techniques. Subsequently, the materials were used for modification of glassy carbon electrodes to the determination of endocrine disruptors (estriol and 17β-estradiol hormone) as electrochemical sensors for environmental and clinical samples. In essence, developed electrodes showed important advantages such as high sensitivity, good reproducibility, simple instrumentation, easy preparation and quick analytical procedures, with low detection limits in the range of picomolar and nanomolar, low interference rate of other species in same matrix sample. Finally, electrochemical techniques can be easily applied in the determination of endocrine disruptors in real samples.

Made available in DSpace on 2016-08-19T12:56:40Z (GMT). No. of bitstreams: 1 DISSERTACAO ANA PAULA03072012.pdf: 1293829 bytes, checksum: 334feb3233e863de1a2f3bf991a6af4b (MD5) Previous issue date: 2012-07-03 / Lipoic acid, also known as thioctic acid is a compound organosulfur derived from octanoic acid, which is a saturated fatty acid. It is an antioxidant that has the property of suppressing free radicals in both aqueous and lipid environment, which differs from other antioxidants. Nowadays, various techniques are employed for determining the lipoic acid such as capillary electrophoresis, chromatography, high performance liquid chromatography efficiency. However, the electrochemical detection is a promising method, because since it is less labor intensive and can distinguish between the oxidized and reduced form of lipoic acid. A growing number of studies has shown the need for a rapid procedure for evaluating the content of lipoic acid and electrochemical techniques were employed successfully. This study aimed to develop a pyrolytic graphite electrode modified with cobalt metallophthalocyanines for the determination of lipoic acid. The oxidation of lipoic acid has a peak located at approximately 0.8 V vs SCE, being close to the peak potential presented in the literature. The cyclic voltammograms reported in the presence of 1 x 10-3 mol L-1 of lipoic acid in phosphate buffer 0.1 mol L-1 (pH 7.0) to a potential scan rate 25 mV s-1 showed that the electrode modified with 1 x 10-4 mol L-1 CoPc, showed better profiles in relation to the voltammetric electrode unmodified or modified with other metallophthalocyanine. Is then optimized the parameters for the cyclic voltammetry, chronoamperometry and differential pulse. Was then constructed curves for analytical techniques mentioned. For the cyclic voltammetry technique limits of detection and quantification are 8.7 × 10-8 mol L-1 and 2.9 x10-7 mol L-1 for the technique of chronoamperometry 9.8 x 10-8 mol L-1 and 3.2 x 10-7 mol L-1 and differential pulse voltammetry are 3.4 x 10-9 mol L-1 and 1.2 x 10-8 mol L-1 respectively. / O ácido lipóico, também conhecido como ácido tióctico, é um composto organosulfurado derivado do ácido octanóico, que é um ácido graxo saturado. É um antioxidante que apresenta a propriedade de reprimir radicais livres tanto em meio lipídico quanto aquoso, o que o diferencia dos demais antioxidantes. Atualmente, diferentes técnicas são empregadas para a determinação do ácido lipóico tais como eletroforese capilar, cromatografia gasosa, cromatografia liquida de alta eficiência. Contudo a detecção eletroquímica é um método promissor, pois uma vez que é menos trabalhosa e pode distinguir entre o oxidado e a forma reduzida de ácido lipóico. Um número crescente de estudos vem mostrando a necessidade de um procedimento rápido para a avaliação do teor de ácido lipóico e técnicas eletroquímicas foram empregadas com sucesso. Este trabalho teve por objetivo desenvolver um eletrodo de grafite pirolítico modificado com metaloftalocianinas de cobalto para a determinação de ácido lipóico. A oxidação do ácido lipóico apresenta um pico localizado em torno de 0,8V vs ECS, estando próximo dos potenciais de pico apresentado na literatura. Os voltamogramas cíclicos registrados na presença de 1 x 10-3 mol L-1 de ácido lipóico em solução tampão fosfato 0,1 mol L-1 (pH 7,0), para uma velocidade de varredura do potencial de 25 mV s-1, mostraram que o eletrodo modificado com 1 x 10-4 mol L-1 CoPc , apresentou perfis voltamétricos melhores em relação ao eletrodo não modificado ou modificado com outras metaloftalocianinas. Aperfeiçoou-se então os parâmetros para as técnicas de voltametria cíclica, pulso diferencial e cronoamperometria. Construíram-se então as curvas analíticas para as técnicas citadas. Para a técnica de voltametria cíclica os limites de detecção e de quantificação são 8,7x10-8 mol L-1 e 2,9x10-7 mol L-1 para a técnica de cronoamperometria 9,8 x 10-8 mol L-1 e 3,2x 10-7 mol L-1 e para voltametria pulso diferencial são 3,4 x 10-9 mol L-1 e 1,2 x 10-8 mol L-1 respectivamente.

Carbon nanotubes (CNTs) and gold nanoparticles (AuNPs) are widely used for sensing applications due to their distinctive electrical and optical properties, and we have explored the development of methods that enable the incorporation of these nanomaterials into new and improved sensing devices. As a means for fabricating simple, low-cost and fast detection platforms for various applications, we have developed paper-based electrochemical detection platforms based on CNTs or platinum nanoparticle (PtNP)-CNT composite materials. We describe the use of a paper-based, low density, a three-dimensional thin film of interconnected CNTs as an electrode material. We studied the electrochemical properties of these paper-based CNT electrodes and demonstrated their use as an electrochemical sensor for the sensitive detection of guanine-based nucleotides. We further describe the functionalization of this paper-based electrode by fabricating a PtNP-SWCNT hybrid film via a vacuum filtration-based method. The interconnected PtNP structure formed on top of the CNT-coated paper was directly used as an electrocatalyst for methanol oxidation. Compared to paper-based PtNP-SWCNT hybrid films formed by electrochemical deposition, hybrid films formed by vacuum filtration showed a higher electrochemical surface area and enhanced electrocatalytic response to methanol oxidation. We have also developed methods based around DNA-modified AuNPs, which offer an excellent colorimetric platform for target detection. The DNA density on the surface of modified AuNPs affects enzymatic activity, colloidal stability of AuNPs, the orientation of the probe DNA and its hybridization efficiency. The combination of all these factors ultimately dictates the reaction time and sensitivity of colorimetric assays. We demonstrate the use of DTT as a modulator to control DNA surface coverage on the surface of AuNPs. Using this DTT treatment and a novel probe for exonuclease III activity, we have developed a colorimetric assay based on DTT-treated, DNA-modified AuNPs that can achieve more sensitive and rapid detection of DNA and enzymes relative to existing sensor platforms.

The research on electrochemical sensor applications in combination with application-defined electronic circuits is a very fast developing field of modern sensorics. Device designing of unique integrated systems with specific properties and parameters is now becoming the everyday practice for producers of devices based on the latest technology progress in microelectronics. In the process of realization of a new device type, the main objective consists in increasing the possibility of detecting very low concentrations of heavy metals in the given chemical solution, extending the signal-to-noise ratio, and measuring the potential of a sensor. The general aim of this Master’s thesis is to design the topology of a sensor based on the thick film technology, to materialize the sensor, and to make experimental measurement using the sensor prototype. The practical reason for basing the measurement on the application of this thick film sensor is to find out whether the operational integration of the sensor and the circuit has been achieved according to the original hypothesis. Importantly, it is also necessary to determine whether the reproducibility of measured results has been reached. The innovative aspect of the created device consists in the improvement of output characteristics given by the integration of ASIC (IMAM CHIP). The integration of ASIC on the surface of the sensor eliminates the huge parasitic influence that affects the accuracy of measurement.

In recent years (Of late year)microelectronic technology significantly affected in the field of sensor technology, especially in the field of electrochemical sensors. This thesis deals with design and construction of thick-film voltammetric sensors array. The reason for proposal of voltammetric sensors array is to increase of speed, increase the accuracy and extension possibilities measurement compared with common systems.By reason of increase of sensitivity of these sensors it is efficient use the potentiostat chip for measurement output signal. Created sensors must fulfill the specified parameters and also requirements of thick-film technology. Next step is design the basic blocks of electronic circuit used to evaluate the measured values.

O lactato é um metabólito chave formado pelo metabolismo anaeróbico da glicose nos músculos, e tem se tornado um biomarcador importante no âmbito clínico e esportivo. Atualmente, existem biossensores eletroquímicos portáteis que são capazes de determinar os níveis de lactato no organismo em tempo real. No entanto, tal método é invasivo uma vez que requer amostras de sangue. O presente projeto tem como objetivo desenvolver um biossensor eletroquímico descartável para detecção de lactato no suor. Para isto a configuração do dispositivo foi feita utilizando a celulose bacteriana como substrato para obtenção de um dispositivo que seja resistente à deformação mecânica, especialmente quando molhado e, também, permeável ao suor. A impressão dos eletrodos de carbono neste substrato foi efetuada utilizando o processo de serigrafia. Com os dispositivos produzidos foram realizados experimentos de voltametria cíclica e espectroscopia de impedância eletroquímica, a fim de caracterizar o sensor desenvolvido e investigar a influência do pré-tratamento eletroquímico na sua performance analítica. A partir da modificação da superfície eletródica com nanocubos de Azul da Prússia foi possível desenvolver um sensor eletroquímico para detecção de peróxido de hidrogênio. A cronoamperometria foi utilizada para a determinação da curva analítica para o peróxido de hidrogênio. Com todos os parâmetros da cronoamperometria otimizados, uma dependência linear da corrente catódica com a concentração de peróxido de hidrogênio foi obtida, com a equação: Ip = 0,1 + 4,30 [H2O2], com r2 = 0,999 (n = 3). Esta curva analítica mostrou que a metodologia apresenta um Limite de Detecção e de Quantificação de mol L-1 e mol L-1, respectivamente. Para a configuração do biossensor eletroquímico a enzima lactato oxidase foi incorporada à superfície do papel pelo método de ligação covalente. Adotando esta metodologia foi verificado um aumento da área eletroativa que possibilitou uma melhora significativa no desempenho do sensor desenvolvido. No qual se obteve uma região linear de 1-24,0 mmol L-1 em suor sintético, obtendo-se Limites de detecção e Quantificação de e mol L-1. Tais parâmetros se mostraram adequados já que o suor pode apresentar níveis de aproximadamente 25 mmol L-1 de lactato. De modo geral, foi possível desenvolver uma plataforma eletroquímica no substrato de celulose bacteriana para a detecção de lactato em amostras de suor sintético. O dispositivo desenvolvido apresentou uma boa durabilidade e resistência ao se executarem sucessivas medidas corroborando a viabilidade deste substrato na projeção de sensores vestíveis para a aplicação direta na pele e monitoramento dos níveis de lactato em tempo real. / Lactate is a key metabolite formed in the anaerobic metabolism of glucose in the muscles. It has become an important biomarker in the clinical and sport scopes. Currently, there are portable biosensors that are able to determine lactate levels in real time. However, these methods are invasive since they require blood samples. Herein, we aim to develop a disposable wearable electrochemical biosensor for detection of lactate in sweat. For this purpose the configuration of the device was made with bacterial cellulose substrate in order to be permeable to sweat and resistant to mechanical deformation, especially when wet. The fabrication of the electrodes was made through screen printing technique. Electrochemical impedance spectroscopy and cyclic voltammetry were used to characterize the sensor developed in order to investigate the influence of the electrochemical pre-treatment in the analytical performance of the electrodes. To develop an electrochemical sensor for the detection of hydrogen peroxide the screen printed electrode was modified with Prussian blue nanocubes. Chronoamperometry experiments were used to detect of hydrogen peroxide. From optimized chronoamperometry parameters, a linear dependence of the cathodic current with the hydrogen peroxide concentration was obtained with the equation: Ip = 0.1 + 4.30 [H2O2], with r2 = 0.999 (n = 3). The limit of detection (LOD) and the limit of quantification (LOQ) were mol L-1 e mol L-1, respectively. For the configuration of the electrochemical biosensor the lactate oxidase enzyme was immobilized on the paper surface by the covalent bonding method. Adopting this methodology was verified an increase of the electroactive area that allowed a significant improvement in the performance of the developed sensor. In which a linear concentration range of 1-24.0 mmol L-1 was obtained in the synthetic sweat, obtaining LOD and LOQ of mol L-1 e mol L-1, respectively. Such parameters were adequate since sweat may have lactate levels of approximately 25 mmol L-1. Finally, it was possible to develop an electrochemical platform using the bacterial cellulose substrate for the detection of lactate in samples of synthetic sweat. The developed device presented a good durability and resistance when performing electrochemical measurements assuring the feasibility of this substrate in the projection of wearable sensors for the direct application to skin and monitoring of lactate levels in real time.

Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-04-12T15:30:06Z No. of bitstreams: 1 Juliana Santos Farias.pdf: 1234303 bytes, checksum: 420e49b91acb05fb1346e95075411509 (MD5) / Made available in DSpace on 2017-04-12T15:30:06Z (GMT). No. of bitstreams: 1 Juliana Santos Farias.pdf: 1234303 bytes, checksum: 420e49b91acb05fb1346e95075411509 (MD5) Previous issue date: 2017-03-06 / CAPES, FAPEMA,CNPQ / This paper describes the development of a simple and new sensor electrochemical determination of flutamide in voltamétrica formulations pharmaceutical and artificial urine specimens using a carbon electrode vitreous (ECV) modified with oxidized carbon nanotubes and graphene oxide (NCO-OG), which was named ECV/NCO-OG. Electronic microscopy techniques scanning (SEM) and Raman Spectroscopy were used for the characterization of carbon based materials. The electrochemical response of the analyte front of the ECV/NCO-OG was investigated by cyclic voltammetry techniques (VC) and square wave voltammetry (VOQ). The sensor exhibited a high activity eletrocatalítica for the reduction of flutamide in 0.05 V vs. Ag/AgCl. The parameters experimental influence the response of the electrode was investigated and the optimum conditions were found for the electrode modified with NCO-OG, in Britton-Robinson buffer solution-BR on concentration of 0.1 mol L-1 (pH 5). The proposed sensor presented a wide range of linear response of concentration for the flutamide of 0.1 to 1000 µmol L-1 (or µ g L-1 27.6 to 0.27 g L-1) for n = 15 (R2 = 0.997), limit of detection (LOD), limit of quantification (LOQ), and sensitivity of 0.03 µmol L-1, 0.1 µmol L-1, and 0.30 µmol µA -1 L, respectively. The ECV/NCO-OG was successfully applied to the determination of flutamide in pharmaceutical formulations used in the treatment of prostate cancer and artificial urine samples. The results obtained with the proposed sensor were compared with the method described in the literature and showed a level of 95% confidence, demonstrating that there is no statistical difference between the method of reference and the method proposed. The addition and recovery studies show that the proposed method presents a satisfactory accuracy with average value of 101% recovery ( 1)%. for the fortified samples. / Este trabalho descreve o desenvolvimento de um simples e novo sensor eletroquímico para determinação voltamétrica de flutamida em formulações farmacêuticas e amostras de urina artificial empregando um eletrodo de carbono vítreo (ECV) modificado com nanotubos de carbono oxidado e óxido de grafeno (NCO-OG), o qual foi denominado ECV/NCO-OG. As técnicas microscopia eletrônica de varredura (MEV) e a Espectroscopia Raman foram utilizadas para a caracterização dos materiais à base de carbono. A resposta eletroquímica do analito frente ao ECV/NCO-OG foi investigada através das técnicas de voltametria cíclica (VC) e voltametria de onda quadrada (VOQ). O sensor exibiu uma alta atividade eletrocatalítica para a redução da flutamida em 0,05 V vs Ag/AgCl. Os parâmetros experimentais que influenciam a resposta do eletrodo foram investigados e as condições ótimas foram encontradas para o eletrodo modificado com NCO-OG, em solução tampão Britton-Robinson-BR na concentração de 0,1 mol L-1 (pH 5). O sensor proposto apresentou uma ampla faixa de resposta linear de concentração para a flutamida de 0,1 a 1000 µmol L-1 (ou 27,6 µg L-1 a 0,27 g L-1) para n=15 (R2=0,997), com limite de detecção (LOD), limite de quantificação (LOQ), e sensibilidade de 0,03 µmol L-1, 0,1 µmol L-1, e 0,30 µA µmol-1 L, respectivamente. O ECV/NCO-OG foi aplicado com sucesso para a determinação de flutamida em formulações farmacêuticas utilizadas no tratamento de câncer de próstata e amostras de urina artificial. Os resultados obtidos com o sensor proposto foram comparados com o método descrito na literatura e observou-se um nível de confiança de 95%, demonstrando que não há diferença estatística entre o método de referência e o método proposto. Os estudos de adição e recuperação mostram que o método proposto apresenta uma exatidão satisfatória com valor médio de recuperação de 101% ( 1) %. para as amostras fortificadas.