Le couplage covalent de précurseurs moléculaires spécialement conçus, assisté par une surface métallique, a récemment émergé comme nouvelle voie pour la création de nouvelles architectures moléculaires prometteuses pour l’électronique moléculaire. Les phtalocyanines et leurs dérivés ont attiré beaucoup d’intérêt à cause de leurs propriétés chimiques et optoélectroniques. Dans cette thèse la synthèse de composés de phtalocyanine est présentée. Les composés sont obtenus par une réaction en surface entre précurseurs fonctionnalisés avec quatre groupements carbonitriles et des atomes métalliques. L’étude expérimentale est faite par microscopie à effet tunnel et spectroscopie de photoémission X. Les précurseurs moléculaires de TCN-DBTTF et de PPCN ont été étudiés. Les TCN-DBTTF ont été déposés avec les atomes de Mn, Fe ou Cu sur Ag(111) et Au(111). La réaction de cyclotetramerization a été activée par recuits. Dans le cas le plus favorable (TCN-DBTTF avec Fe sur Ag(111)), la réaction peut être activée à 200°C et permet la synthèse de phtalocyanines individuelles. Un recuit à plus haute température permet de continuer la réaction en 1D (250°C) et en 2D (275°C). Des résultats similaires ont été obtenus pour le dépôt de PPCN avec Mn ou Cu sur Au(111). L’évolution des spectres des niveaux de coeur permet d’obtenir une preuve de la réaction. Les différents facteurs qui influencent la cyclotetramerisation ont été étudiés.L'étude démontre la versatilité de la méthode: la synthèse en surface permet la création de polymères 2D originaux connectés par des macrocycles de phtalocyanine susceptibles d’être étendus à un grand nombre de précurseurs et d’atomes métalliques. / Surface-assisted covalent coupling of suitably designed molecular precursors on metal surfaces has recently emerged as a new route towards the design of novel molecular architectures promising for future applications. Phthalocyanines and their derivatives have been widely studied for their chemical and optoelectronic properties. In this thesis the synthesis of phthalocyanine compounds is presented. The compounds are obtained through an on-surface reaction between tetracarbonitrile-functionalized precursors and metals. The experimental investigation is carried out by means of scanning tunnelling microscopy and X-Ray photoemission spectroscopy. Two molecular precursors, TCN-DBTTF and PPCN, are studied. TCN-DBTTF molecules are deposited with metal atoms (Mn, Fe, or Cu) on Ag(111) and Au(111). Annealing is used to activate the reaction of cyclotetramerization between precursors and metals. In the most favourable case (TCN-DBTTF with Fe on Ag(111)) the reaction can be activated at 200°C and leads to the synthesis of individual phthalocyanines. Increasing the temperature allows the synthesis of polymeric lines, at 250°C, and small 2D domains, at 275°C. Similar results are obtained for PPCN deposition with Mn or Cu on Au(111). In this latter case, the evolution of core level spectra allows a chemical proof of the on-surface reaction. The factors affecting on-surface cyclotetramerization have also been studied. This study demonstrates the versatility of the method: on-surface cyclotetramerization allows creating original 2D polymers connected by phthalocyanine macrocycles, and may work with a wide range of tetracarbonitrile-functionalized precursors and metallic atoms.

Organic molecules adsorbed on inorganic substrates are the topics of interest in this thesis. Interfaces of this kind are found in dye sensitized solar cells that convert solar energy to electricity, a promising environmentally friendly energy source which might provide a route to replace fossil fuels. Another field where these interfaces play a role is in molecular electronics, an approach to solve the down scaling in the ever increasing hunt for miniaturized electronic devices. The motivation for this work lies among other in these applications and surface science is a suitable approach to investigate the electronic and morphologic properties of the interfaces as it provides detailed knowledge on an atomic level. Phthalocyanines are the organic molecules investigated and the inorganic substrates range from wide band gap via narrow band gap semiconductors to metals. Photoelectron and X-ray spectroscopy experiments are performed to shed light on the electronic properties of the adsorbed molecules and the substrate, as well as the chemical interaction between adsorbate and substrate at the interface. The ordering of the adsorbate at the interface is important as ordered molecular thin films may have other properties than amorphous films due to the anisotropic electronic properties of the organic molecules; this is investigated using scanning tunneling microscopy. We find that the phthalocyanines are affected by adsorption when the substrate is TiO2 or Ag, where charge transfer from the molecule occurs or an interface state is formed respectively. The molecules are adsorbed flat on these surfaces giving a large contact area and a relatively strong bond. On Ag, ordered structures appear with different symmetry depending on initial coverage. The reactivity of the TiO2 surface is not ideal in the solar cell application and by modifying the surface with a thin organic layer, the negative influence on the adsorbed phthalocyanine is reduced. ZnO is not as reactive as TiO2, thanks maybe to the upright adsorption mode of the phthalocyanines. The semiconductor InSb is less reactive leading to self-assembled molecular structures on the (001) surface, either homogenously distributed in a one monolayer thick film or in strands along the reconstruction rows. InAs on the other hand has a larger influence on the adsorbed molecules resulting in a metallic film upon thermal treatment. / QC 20100812

Organic solar cells (OSC) are interesting as low cost alternative to conventional solar cells. Unsubstituted Metal-phthalocyanines (Pc) are excellent electron donating molecules for heterojunction OSC. Usually organic solar cells with Pcs are produced by vapor deposition, although solution based deposition (like spin casting) is cheaper and offers more possibilities to control the structure of the film. With solution based deposition several parameters (like temperature, solvent and etc.) affect the self-organized structure formation via nucleation and growth. The reason why vapor deposition is typically used is the poor solubility of the metal-phthalocyanines in most common solvents. Furthermore the process of nucleation and growth of Pc aggregates from solution is not well understood. For preparation of Pc films from solution, it is necessary to find the appropriate solvents, assess the solution deposition techniques, such as dip coating, and spin casting. It is necessary to understand the nucleation and growth process for aggregation/precipitation and to use this knowledge to produce nanostructures appropriate for OSC. This is important because the nanostructure of the films determines their performance. In this thesis, optical absorption and the stability of 8 different unsubstituted metal Pc’s were studied quantitatively in 28 different solvents. Among the several solution based deposited thin films produced based on this study, copper phthalocyanine (CuPc) dissolved in trifluoroacetic acid (TFA) is chosen as a model system for an in-depth study. CuPc has sufficient solubility and stability in TFA and upon solution processing forms appropriate structures for OSCs. CuPc molecules aggregate into layers of nanoribbons with a thickness of ~ 1 nm and an adjustable width and length. The morphology and the number of deposited layers in the thin films are controlled by different parameters, like temperature and solution concentration. Material properties of CuPc deposited from TFA are studied in detail via x-ray diffraction, UV-Vis and FT-IR spectroscopy. Atomic force microscopy was used to study the morphology of the dried film. The mechanism of the formation of CuPc nanoribbons from spin casted CuPc/TFA solution in ambient temperature is investigated and explained. The parameters (e.g. solution concentration profile) governing nucleation and growth are calculated based on the spin casting theory of a binary mixture of a nonvolatile solute and evaporative solvent. Based on this and intermolecular interactions between CuPc and substrate a nucleation and growth model is developed explaining the aggregation of CuPc in a supersaturated TFA solution. Finally, a solution processed thin film of CuPc is applied as a donor layer in a functioning bilayer heterojunction OSC and the influence of the structure on OSC performance is studied. / In den vergangenen Jahren wurden kosteneffiziente nasschemische Beschichtungsverfahren für die Herstellung organischer Dünnfilme für verschiedene opto-elektronische Anwendungen entdeckt und weiterentwickelt. Unter anderem wurden Phthalocyanin-Moleküle in photoaktiven Schichten für die Herstellung von Solarzellen intensiv erforscht. Aufgrund der kleinen bzw. unbekannten Löslichkeit wurden Phthalocyanin-Schichten durch Aufdampfverfahren im Vakuum hergestellt. Des Weiteren wurde die Löslichkeit durch chemische Synthese erhöht, was aber die Eigenschaften von Pc beeinträchtigte. In dieser Arbeit wurde die Löslichkeit, optische Absorption und Stabilität von 8 verschiedenen unsubstituierten Metall-Phthalocyaninen in 28 verschiedenen Lösungsmitteln quantitativ gemessen. Wegen ausreichender Löslichkeit, Stabilität und Anwendbarkeit in organischen Solarzellen wurde Kupferphthalocyanin (CuPc) in Trifluoressigsäure (TFA) für weitere Untersuchungen ausgewählt. Durch die Rotationsbeschichtung von CuPc aus TFA Lösung wurde ein dünner Film aus der verdampfenden Lösung auf dem Substrat platziert. Nach dem Verdampfen des Lösungsmittels, die Nanobändern aus CuPc bedecken das Substrat. Die Nanobänder haben eine Dicke von etwa ~ 1 nm (typische Dimension eines CuPc-Molekül) und variierender Breite und Länge, je nach Menge des Materials. Solche Nanobändern können durch Rotationsbeschichtung oder auch durch andere Nassbeschichtungsverfahren, wie Tauchbeschichtung, erzeugt werden. Ähnliche Fibrillen-Strukturen entstehen durch Nassbeschichtung von anderen Metall-Phthalocyaninen, wie Eisen- und Magnesium-Phthalocyanin, aus TFA-Lösung sowie auf anderen Substraten, wie Glas oder Indium Zinnoxid. Materialeigenschaften von aufgebrachten CuPc aus TFA Lösung und CuPc in der Lösung wurden ausführlich mit Röntgenbeugung, Spektroskopie- und Mikroskopie Methoden untersucht. Es wird gezeigt, dass die Nanobänder nicht in der Lösung, sondern durch Verdampfen des Lösungsmittels und der Übersättigung der Lösung entstehen. Die Rasterkraftmikroskopie wurde dazu verwendet, um die Morphologie des getrockneten Films bei unterschiedlicher Konzentration zu studieren. Der Mechanismus der Entstehung der Nanobändern wurde im Detail studiert. Gemäß der Keimbildung und Wachstumstheorie wurde die Entstehung der CuPc Nanobänder aus einer übersättigt Lösung diskutiert. Die Form der Nanobändern wurde unter Berücksichtigung der Wechselwirkung zwischen den Molekülen und dem Substrat diskutiert. Die nassverarbeitete CuPc-Dünnschicht wurde als Donorschicht in organischen Doppelschicht Solarzellen mit C60-Molekül, als Akzeptor eingesetzt. Die Effizienz der Energieumwandlung einer solchen Zelle wurde entsprechend den Schichtdicken der CuPc Schicht untersucht.

Diese Dissertation unter dem Titel Experimentelle Bestimmung der elektronischen Eigenschaften anwendungsrelevanter Grenzflächen organischer Halbleiter mittels Photoelektronenspektroskopie wurde am Leibniz Institut für Festkürper- und Werkstoffforschung (IFW) Dresden am Institut für Festkörperforschung (IFF) unter der Betreuung von Prof. Dr. B. Büchner angefertigt. Zur wissenschaftlichen Untersuchung kamen hierbei zwei Typen anwendungsrelevanter Grenzflächen. Zum einem wurde der Einfluss einer Elektrodenpräparation unter Normalbedingungen mittels ex-situ Reinigungsverfahren im Vergleich zu insitu präparierten Kontakten auf das elektronische Verhalten des organischen Halbleiters Sexithiophen an Grenzflächen zu metallischen Substraten studiert. Als Substratmaterialien kamen hierbei die Metalle Silber, Palladium, Gold und Platin zum Einsatz. In einer zweiten Studie wurden die Grenzflächen der organischen Halbleiter Sexithiophen und Kupfer(II)- Phthalocyanin in Kontakt zu dünnen Filmen des Übergangsmetalloxides La0.7Sr0.3MnO3 untersucht. Auch hier wurde eine vergleichende Untersuchung für ex-situ und in-situ gereinigte La0.7Sr0.3MnO3-Kontakte durchgeführt. Die hierzu verwendeten Filme wurden im IFW Dresden am Institut für Metallische Werkstoffe (IMW) hergestellt. Auch im Rahmen dieser Untersuchungen stand der Einfluss von Sauerstoff auf das elektronische und chemische Verhalten an den Grenzflächen im Vordergrund.

Die vorliegende Arbeit beschreibt die experimentelle Untersuchung molekularer organischer Adsorbate mit Hilfe der Raster-Tunnel-Mikroskopie und -Spektroskopie im Ultrahochvakuum (UHV). Als Modellsubstanzen dienen Coronen, verschiedene Phthalo-cyanin-farbstoffe sowie je ein nematischer und ein discotischer Flüssigkristall. Mono- und Submonolagen dieser Substanzen werden hinsichtlich ihrer Adsorbatstruktur auf kristallographisch definierten Festkörper-oberflächen untersucht. Die dabei gewonnenen STM-Bilder zeigen die molekular und submolekular aufgelöste Struktur der Adsorbate. Die Untersuchung von Submonolagen zweier Metall-Phthalocyanine bei tiefen Temperaturen zeigt eine Bildung molekularer Ketten. Zur Ermittlung der elektronischen Eigenschaften der Moleküle werden molekulare Mono- und Submonolagen mit Hilfe der Raster-Tunnel-Spektroskopie (STS) bei Raumtemperatur und bei tiefen Temperaturen untersucht. Einige der Substanzen ermöglichen die Messung sehr stabiler lokaler Tunnelstromkennlinien. Die Ergebnisse der STS-Experimente an Coronen werden mit Resultaten von ab-initio-Rechnungen der Molekül-orbitalstruktur verglichen. / The work describes experimental investigations of molecular organic adsorbates in ultra high vacuum (UHV) by scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). Coronene, several phthalocyanine dyes, and both a nematic and a discotic liquid crystal are chosen as model substances. Mono- and submonolayers of these substances adsorbed onto crystallographically well-defined surfaces are observed by STM with regard to their adsorbate structure. The STM images reveal the molecular and intramolecular structure of the adsorbates. Submonolayers of two metal phthalocyanines, observed at low temperatures, reveal the formation of molecular chains. With special regard to the electronic properties, such ultra thin films are investigated by scanning tunneling spectroscopy (STS), both at room temperature and at helium-cooled low temperatures. Some of the substances allow the collection of very stable local STS curves. The STS data coincide very well with the results of ab-initio calculations of their molecular orbital structure.

No description available.

This work focuses on the solar cell based on the heterostructure formed between Copper Phthalocyanine (CuPc) and Cadmium Sulfide (CdS). Two different fabrication techniques were used for depositing the organic and inorganic layers of CuPc and CdS layers respectively. CuPc was deposited by electrodeposition while CdS was deposited by chemical bath deposition. Hybrid CdS/CuPc thin films were obtained from CdS films grown on Glass/ITO by chemical bath deposition followed by electrodeposition of CuPc onto these films and annealing at 250˚C after the deposition of each layer. The maximum open circuit voltage (Voc) and the short circuit current density (Jsc) obtained for this heterojunction solar cell are 0.59v and 0.7mA/cm2 respectively and these are the highest values achieved in literature till date. The materials characteristics and electrical performances of the device were analyzed. The effect of increasing the thickness of CuPc and CdS on the short circuit current density and open circuit voltage were also investigated.

Orientador: Prof. Dr. Wendel Andrade Alves / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2016. / Estudou-se a conjugação de micro/nanotubos de L,L-difenilalanina (MNTs-FF) com dois tipos de fluoróforo: hipericina (Hyp) e ftalocianinas de zinco (ZnPc), visando aplicação na terapia fotodinâmica. Foram feitas investigações sobre conjugados contendo hipericina organizados em diferentes arranjos cristalinos, uma fase hexagonal (P61) e outra ortorrômbica (P22121). Os resultados obtidos evidenciam uma maior eficiência na geração de espécies reativas de oxigênio (ROS) quando a hipericina está conjugada com MNTs-FF, sendo essa eficácia observada em ambas as fases, porém com melhor resultado para a fase hexagonal. Como mecanismo, foi proposto que a organização induzida pelas estruturas peptídicas e a disponibilidade de um ambiente hidrofóbico na interface de Hyp/peptídeo são fundamentais para incrementar a geração de ROS. Para os conjugados MNTs-FF com ftalocianinas de zinco, foram analisadas as propriedades morfológicas e estruturais. Com a variação dos grupos protetores dos derivados do glicerol presentes nas regiões periféricas das ZnPcs, a morfologia tubular usualmente observada em MNTs-FF muda drasticamente e passa a ser caracterizada por hastes micrométricas. Analisando sua superfície em estudos de alta resolução por AFM, foi perceptível a formação de camadas de fotossensibilizadores e um incremento substancial de rugosidade. Mesmo com a mudança na morfologia do material, a simetria cristalográfica P61, tradicionalmente encontrada em MNTs-FF não-conjugados, é mantida. Ensaios de toxicidade foram realizados em células tumorais mamárias (MCF-7), revelando que a morte celular é maior quando as ZnPcs estão conjugadas com MNTs-FF. Estudos de citometria identificaram que a principal via de morte celular é necrose, com eficiência de cerca 80% para os conjugados MNTs-FF/ZnPc. Esses achados mostram que essa conjugação aumenta a eficiência na geração de ROS dos fotossensibilizadores (Fs) utilizados nesse trabalho, indicando potencial aplicação desses materiais na terapia fotodinâmica. / It was studied the conjugation of L,L-diphenylalanine micro/nanotubes (MNTs-FF) with two types of fluorophore: hypericin (Hyp) and zinc phthalocyanines (ZnPc), order application in photodynamic therapy. It was made investigations on conjugates containing hypericin organized into different crystalline symmetries, a hexagonal phase (P61) and an orthorhombic phase (P22121). The results obtained here are evidence for higher efficiency in the generation of reactive oxygen species (ROS) when hypericin appears conjugated to MNTs-FF. This improvement is observed for MNT-FFs organized into both phases; however, efficiency is still higher for self-assemblies exhibiting hexagonal symmetry. As a mechanism, it was proposed that organization induced by peptide structures and availability of a hydrophobic environment in the vicinities of Hyp/peptide interfaces are crucial for boosting the generation of ROS. In conjugates formed between MNTs-FF and ZcPcs, structural and morphological properties were analyzed in detail. It was found that, by varying glycerol moieties in the periphery of ZnPcs, the tubular morphology usually observed in MNTs-FF changes dramatically and is then characterized by micrometer-long sticks with faceted surfaces. High-resolution AFM imaging showed the formation of layers of photosensitizers and substantial increment on the surface roughness. In despite these drastic morphological and surface changes, the crystalline arrangement of peptides within the complexes remained into the hexagonal P61 phase usually found in bare MNTs-FF. Cytotoxocity assays performed on tumoral mammary cells (MCF-7) indicated that cell death upon light irradiation is higher when ZnpCs is conjugated to MNTs-FF. Cytometry assays identified that the main mechanism leading to cell death is necrosis, with effectiveness of about 80% for MNTs-FF/ZnPc. These findings show that this conjugation enhances efficiency in ROS generation by the photosinthesizers used in this work, indicating the potential of these materials for photodynamic therapy.

Orientador: Prof. Dr. Anderson Orzari Ribeiro / Tese (doutorado) - Universidade Federal do ABC. Programa de Pós-Graduação em Ciência e Tecnologia/Química, 2016. / Considerando o histórico de fármacos enantiomericamente puros e suas interações específicas com células alvos, nesse trabalho foram sintetizadas e caracterizadas quinze ftalocianinas com substituintes opticamente ativos e analisada suas propriedades fotoquímicas para possível aplicação como fármaco fotossensibilizador. Todas as ftalocianinas foram caracterizadas por RMN 1H, espectroscopia de massas, absorção na região do UV-vis, rendimentos quânticos de fluorescência e geração de espécies reativas de oxigênio sob irradiação. Resultados evidenciam que os diferentes grupos inseridos na periferia do anel ftalocianínico influenciam na solubilidade e na agregação do macrociclo, porém não influenciam significativamente nos rendimentos quânticos de geração de espécies reativas nas condições empregadas. Em relação a atividade óptica dos grupos e seus pares enantioméricos, pode-se concluir que não há relação direta entre configuração espacial e características fotoquímicas e fotofísicas, visto que não houve nenhuma relação que possa ser estabelecida como "regra" para esses compostos. Posteriores testes biológicos devem ser realizados par determinar interação entre células e as diferentes ftalocianinas sintetizadas. / Considering the history of enantiomerically pure drugs and their specific interaction with target cells, in this study were synthesized and characterized fifteen phthalocyanines with optically active substituents to be applied as photosensitizers in photodynamic therapy.. All phthalocyanines were characterized by 1H NMR, mass spectrometry, absorption and fluorescence emission, quantum yields of fluorescence and the quantum yield of generation of oxygen reactive species under irradiation. Results show that the different groups inserted on the phthalocyanine peripheral ring have influence on the solubility and the aggregation of the macrocycle in solution. With respect to optical characteristics, analyzing the groups and their enantiomeric pairs, it can be concluded that there is no direct link between configuration and photochemical and photophysical characteristics, as no relationship could be established as "rule" for these compounds. Further analyses should be taken to understand the influence of chiral ligands in the interaction of these phthalocyanines with target cells.

This paper describes the development of an electrochemical sensor glassy carbon modified with gold nanoparticles and a film of multiâwalled carbon nanotube and cobalt phthalocyanine (CoPc-fMWCNTs/AuNp/GCE) for the determination of diethylstilbestrol hormone (DES) in water samples and meat, using a square wave technique voltammetry. (SWV). The electrolyte used was Britton-Robinson buffer (BR) 0.04 mol L-1 pH 10.0. Initially it was studied the electrode configuration to be used for the development work, after the optimization of solution pH, study scan speed to evaluate the charge transfer kinetics in the redox process of the DES, the optimized parameters for SWV, the analytical curve, and finally, applying the methodology developed. The optimized parameters for SWV were f = 5 sâ1, a = 50 mV and ΔEs=1 mV. The CoPc-fMWCNTs/AuNp/GCE was ready to be used for the application since all conditions were optimized. Analytical curves were obtained in the concentration ranged from 7.9365 à 10−7 â 5.6604 à 10−6 mol Lâ1 (R = 0.9996) and there were obtained limits of detection (LOD) and quantification (LOQ) of 1.9910 x 10â7 mol Lâ1and 6.6367 x 10â7 mol Lâ1, respectively, being comparable to those reported in the literature. The repeatability and reproducibility of the proposed procedure were evaluated. The relative standard deviation (RSD) were 4.33% and 3.49%, respectively, indicating the precision of the assay. The recovery percentage was 98.56% for the water sample and 94.05% for beef sample (RSD of 0.40 and 1.55% respectively). The modified electrode has developed sensitivity, reproducibility and repeatability appropriate and consistent LOD and LOQ values with those reported in the literature. Moreover, the results obtained by the use of CoPc-fMWCNTs/AuNp/GCE proved very efficient as the detection and DES recovery, being thus a promising device in the detection and quantification of DES in water samples and food. / O presente trabalho descreve o desenvolvimento de um sensor eletroquÃmico de carbono vÃtreo modificado com nanopartÃculas de ouro, nanotubos de carbono de paredes mÃltiplas funcionalizados e ftalocianina de cobalto (CV/NpAu/NTCPMf-FcCo) para a determinaÃÃo do hormÃnio dietilestilbestrol (DES) em amostras de Ãgua e carne, utilizando a tÃcnica de voltametria de onda quadrada (VOQ). O eletrÃlito empregado foi tampÃo BrittonâRobinson (BR) 0,04 mol Lâ1 pH 10,0. Inicialmente estudou-se a configuraÃÃo do eletrodo a ser utilizado para o desenvolvimento do trabalho, depois a otimizaÃÃo do pH do meio, estudo da velocidade de varredura para avaliar a cinÃtica de transferÃncia de carga no processo redox do DES, otimizaÃÃo dos parÃmetros da VOQ, construÃÃo da curva analÃtica e por fim, a aplicaÃÃo da metodologia desenvolvida. Os parÃmetros otimizados para a VOQ foram: f = 5 sâ1, a = 50 mV e ΔEs = 1 mV. De posse de todas as condiÃÃes otimizadas para aplicaÃÃo do CV/NpAu/NTCPMf-FcCo, curvas analÃticas foram obtidas no intervalo de concentraÃÃo de 7,9365 à 10−7 â 5,6604 à 10−6 mol Lâ1 (R = 0,9996) e os limites de detecÃÃo (LD) e de quantificaÃÃo (LQ) calculados foram 1,9910 x 10â7 mol Lâ1 e 6,6367 x 10â7 mol Lâ1, respectivamente, sendo comparÃveis aos citados na literatura. A repetibilidade e a reprodutibilidade do procedimento proposto foram avaliadas. Os valores de desvio padrÃo relativo (DPR) obtidos foram 4,33% e 3,49%, respectivamente, evidenciando a precisÃo da metodologia. O percentual de recuperaÃÃo foi de 98,56% para amostra de Ãgua e 94,05% para amostra de carne bovina (DPR de 0,40 e 1,55% respectivamente). O eletrodo modificado desenvolvido apresentou sensibilidade, reprodutibilidade e repetibilidade adequados, bem como valores de LD e LQ concordantes com os relatados na literatura. Os resultados obtidos pelo emprego do CV/NpAu/NTCPMf-FcCo se mostraram muito eficientes quanto à detecÃÃo e recuperaÃÃo de DES, mostrando-se, desse modo, um dispositivo promissor na detecÃÃo e na quantificaÃÃo de DES em amostras de Ãgua e alimentos.