Characterization of Italian honeys (Marche Region) on the basis of their mineral content and some typical quality parameters

<p>Abstract</p> <p>Background</p> <p>The characterization of three types of Marche (Italy) honeys (Acacia, Multifloral, Honeydew) was carried out on the basis of the their quality parameters (pH, sugar content, humidity) and mineral content (Na, K, Ca, Mg, Cu, Fe, and Mn). Pattern recognition methods such as principal components analysis (PCA) and linear discriminant analysis (LDA) were performed in order to classify honey samples whose botanical origins were different, and identify the most discriminant parameters. Lastly, using ANOVA and correlations for all parameters, significant differences between diverse types of honey were examined.</p> <p>Results</p> <p>Most of the samples' water content showed good maturity (98%) whilst pH values were in the range 3.50 – 4.21 confirming the good quality of the honeys analysed. Potassium was quantitatively the most relevant mineral (mean = 643 ppm), accounting for 79% of the total mineral content. The Ca, Na and Mg contents account for 14, 3 and 3% of the total mineral content respectively, while other minerals (Cu, Mn, Fe) were present at very low levels. PCA explained 75% or more of the variance with the first two PC variables. The variables with higher discrimination power according to the multivariate statistical procedure were Mg and pH. On the other hand, all samples of acacia and honeydew, and more than 90% of samples of multifloral type have been correctly classified using the LDA. ANOVA shows significant differences between diverse floral origins for all variables except sugar, moisture and Fe.</p> <p>Conclusion</p> <p>In general, the analytical results obtained for the Marche honeys indicate the products' high quality. The determination of physicochemical parameters and mineral content in combination with modern statistical techniques can be a useful tool for honey classification.</p

Optimización de la producción de átomos de selenio en espectroscopías atómicas : aplicaciones a su especiación y cuantificación en matices ambientales

El objetivo de este trabajo es el estudio y la optimización de mecanismos deproducción de átomos de selenio en diferentes celdas de atomización: hornos de grafitoy tubos de cuarzo. Los resultados obtenidos han sido aplicados en el desarrollo desistemas de inyección en flujo acoplados a detectores atómicos que permitieran ladeterminación de selenio total en matrices biológicas y ambientales y la especiación de Se(IV) y Se(VI) en aguas de hemodiálisis y de consumo. En el capítulo l se presenta la optimización de la determinación optimizada deselenio total por espectrometría de absorción atómica con horno de grafito. Se evalúa laaptitud de diferentes modificadores de matriz (sales de níquel, cobre y paladio) paraaumentar la estabilidad térmica de formas inorgánicas (Se(IV)) y orgánicas (selenometionina) de selenio. Tras la selección del modificador más apto, se presenta elestudio de las interacciones selenio/modificador con el fin de interpretar losmecanismos de estabilización térmica y optimizar los programas de calentamiento delhorno. En el Capítulo de 2 se presenta un sistema automático de pre-concentración parala cuantificación de ultravestigios de Se(IV) y Se(VI) basado en el acoplamiento de unsistema en flujo al horno de grafito. Se utilizan resinas aniónicas fuertes para laretención de las dos formas inorgánicas, las que son eluidas selectivamente consoluciones de ácido clorhídrico de distinta concentración. Se utiliza un modificador “permanente” que consiste en depositar iridio en la superficie del horno previo a lassecuencias de calentamiento, con el objetivo de favorecer la automatización del métodoy prevenir el efecto de interferencias que modifiquen la señal. En el capítulo 3 se presenta un método alternativo para la especiación de seleniobasado en el acoplamiento de un sistema de flujo a un generador de hidruros. Dado queel Se(IV) es la única especie formadora de hidruros y que el Se(VI) necesita entoncesser prerreducido, se muestra un estudio de la cinética de reducción de Se(VI) a Se(IV) yde los factores que la afectan, con el objetivo de encontrar las condiciones de trabajo quepermitan realizar la conversión Se(VI)/Se(IV) en tiempos compatibles con la operación “en línea”. Teniendo en cuenta que la sensibilidad de la técnica se afecta por un grannúmero de variables y que algunas de ellas son interdependientes, se ha optimizado elmétodo a través del empleo de diseño factorial y construcción de las superficies derespuesta. Dado que las interferencias inorgánicas (particularmente el cobre y el hierro)reducen la eficiencia de generación de hidruros se desarrolló una estrategia paraeliminarlas en linea utilizando resinas de intercambio aniónico para retener las especiescloruradas de los metales. En el capitulo 4 se aborda la discusión del concepto de trazabilidad en quimicaanalítica, presentándose las distintas estrategias para la validación de los métodosexpuestos en los capítulos anteriores. El capitulo 5 presenta los métodos y materiales utilizados y el capítulo 6 señalalas más relevantes conclusiones del trabajo.This work is dedicated to the study and Optimization of the mechanisms ofproduction of selenium atoms in graphite furnaces and quartz atomization cells. Theoptimized conditions have been applied to flow injection systems coupled to atomicdetectors which allowed the determination of total selenium in biological andenvironmental samples and the speciation of Se(IV) and Se(VI) in hemodyalisis and tapwaters. In chapter 1, the improved determination of total selenium via graphite furnaceatomic spectrometry is presented. The aptitude of different matrix modifiers (nickel,copper and palladium salts) for increasing the thermal stability of inorganic and organicforms (selenomethionine) of selenium is assessed. After the selection of the modifier, anstudy involving the different interactions between the analyte and the modifier ispresented. In this way it was possible to advance on the knowledge of the stabilizationmechanisms of selenium inside the tube and to optimize the heating programs as well. In chapter 2, a fully automatic system for the preconcentration and quantitationof ultratraces of Se(IV) and Se(VI) is shown. The system involves a coupling between aflow injection system and the graphite furnace. Strong anionic resins are employed forthe retention of both inorganic forms of selenium which are eluted in a selective waywith hydrochloric acid solutions of different concentration. A "permanent" modifierobtained by depositing iridium on the graphite furnace surface is employed. In this waythe method optimization is favored and the influence of interferences is prevented. Along chapter 3, an alternative methodology for selenium speciation ispresented. The method is based on the coupling of a flow system to a hydride generator. Considering that only Se(IV) is reduced to H2Se by sodium borohydride and in order toperform this convertion "on-line", the kinetics of reduction Se(VI)/Se(IV) was fullystudied. Results allowed to manage short reduction times which are compatible with "on-line" operation. Taking into account that the sensitivity of this technique is affected by aconsiderable number of variables and that some of them are inter-dependent, the bestconditions were selected through factorial design and the subsequent building ofresponse surfaces. Regarding chemical interferences (mainly copper and iron), ion-exchangers havebeen employed for the on-line elimination. Chapter 4 discusses the concept of traceability and shows different strategies forthe validation of the new methodologies presented in the previous chapters. Chapter 5 shows the employed materials and methods and chapter 6 details themore relevant conclusions of the work.Fil: Stripeikis, Jorge Daniel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Baseline trace metals in gastropod mollusks from the Beagle Channel, Tierra del Fuego (Patagonia, Argentina)

With the aim to evaluate the mollusk Nacella (P)magellanica as biomonitor of elemental pollution in seawater of the Beagle Channel, more than one hundred individuals of the gastropod were sampled, separated in viscera and muscle, and then examined with respect to the accumulation of Cd, Cr, Cu, Ni, Pb and Zn. Collection was performed in seven strategic locations along 170 km of the coastal area of the Beagle Channel (Tierra del Fuego, Argentina) in two campaigns during 2005 and 2007. Samples of surrounding seawater in the different sites were obtained and tested for the same metals as well. The accumulation capacity of Nacella (P)magellanica and thus its aptitude as biomonitor, was evaluated through the calculus of the preconcentration factors of the metals assayed. A discussion involving the comparison with other mollusks previously tested will be given. Several statistical approaches able to analyze data with environmental purposes were applied. Non parametric univariate tests such as Kruskal-Wallis and Mann-Whitney were carried out to assess the changes of the metal concentrations with time (2005 and 2007) in each location. Multivariate methods (linear discriminant analysis on PCA factors) were also applied to obtain a more reliable site classification. Johnson's probabilistic method was carried out for comparison between different geographical areas. The possibility of employing these results as heavy metals0 background levels of seawater from the Beagle Channel will be debated. © Springer Science+Business Media, LLC 2012.Fil: Conti, Marcelo Enrique. Università di Roma; Italia. International Academy of Environmental Sciences; ItaliaFil: Stripeikis, Jorge Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Finoia, Maria Grazia. Istituto Superiore per la Protezione e la Ricerca Ambientale; ItaliaFil: Tudino, Mabel Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentin

Flow injection solid phase extraction electrothermal atomic absorption spectrometry for the determination of Cr(VI) by selective separation and preconcentration on a lab-made hybrid mesoporous solid microcolumn

A lab-made hybrid mesoporous solid was employed in a flow injection solid phase extraction electrothermal atomic absorption spectrometric (FI-SPE-ETAAS) system for the selective retention of Cr(VI). The solid was prepared by co-condensation of sodium tetraethylortosilicate and 3-aminopropyltriethoxysilane by sol-gel methodology and one-pot synthesis and characterized by Fourier transform infrared spectroscopy, X ray diffraction spectroscopy, and scanning electronic microscopy. Adsorption capacities at different pH values of both, Cr(VI) and Cr(III), were also measured in order to obtain the optimum retention for Cr(VI) with no interference of Cr(III). The maximum capacity of adsorption (4.35 mmol g- 1) was observed for pH values between 2-3, whilst Cr(III) was found to remain in solution (adsorption capacity = 0.007 mmol g- 1). Then, a microcolumn (bed volume: 7.9 μL) was filled with the solid and inserted in the FI-ETAAS system for analytical purposes. Since the analyte was strongly retained by the filling in the anionic form, 0.1 mol L- 1 hydroxylammonium chloride in 1 mol L- 1 hydrochloric acid was selected as eluent due to its redox characteristics. In this way, the sorbed Cr(VI) was easily released in the cationic form. The enrichment factor (EF) was found as a compromise between sensitivity and sample throughput and a value of 27 was obtained under optimized conditions: pH 2, sample loading 2 mL min- 1 (60 s), elution flow rate 0.5 ml min- 1 (eluent volume: 75 μL). Under optimized conditions the limit of detection for Cr(VI) was 1.2 ng L- 1, the precision, expressed as RSD was 2.5%, the sample throughput 21/h, and the microcolumn lifetime was over 300 adsorption/desorption cycles. Cr(III) determination was also performed by simply measuring its concentration at the end of the column and after Cr(VI) retention by the mesoporous solid. Applications of the methodology to the determination of Cr(VI) in deionized, osmosis, mineral, effluent and river waters showed very good results. Validation was performed by means of recovery studies as no certified materials were available for Cr(VI). Total chromium determinations, obtained by the sum of Cr(III) and Cr(VI) concentrations, were validated using NIST, SRM 1643e certificate reference material (Trace Element in Natural Water).Fil: Kim, Manuela Leticia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Stripeikis, Jorge Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; ArgentinaFil: Tudino, Mabel Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentin

Towards broadening thermospray flame furnace atomic absorption spectrometry: Influence of organic solvents on the analytical signal of magnesium

This study demonstrates the influence of the solvent when thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) is employed for the determination of elements of low volatility, taking magnesium (Mg) as leading case. Several organic solvents/water solutions of different characteristics (density, surface tension, viscosity, etc.) and proportions were employed for the TS-FF-AAS analytical determination. To this end, solutions containing methanol, ethanol and isopropanol in water were assayed. Measurements were performed at different acetylene/air ratios of the combustion flame and then, the corresponding response surfaces were obtained. Methanol/water 75% v/v as carrier and a fuel rich flame were found as the most sensitive alternative.In the light of these findings and in order to explain the changes on the analytical signal, the influence of the solvent characteristics, the sample droplet size and the redox environment was studied. An estimation of the temperature of different zones of the heated flame furnace based on a modified signal ratio pyrometry method was analyzed for comparative purposes. A full discussion is provided throughout the paper.Once obtained the best conditions for analysis, Mg was determined in samples of effervescent vitamin tablets comparing two different solvents. The tablets were dissolved in methanol/water 75% v/v and ethanol/water 75% v/v and then, directly introduced in the TS device. The methanol/water 75% v/v dissolution yielded a slightly higher sensitivity when compared to ethanol/water and thus, the latter was selected due to its lower toxicity. The obtained figures of merit are: LOD (3σb): 0.021mgL-1; LOQ (10σb): 0.068mgL-1, sensitivity: 0.086Lmg-1; RSD%: 3.55, dynamic linear range 0.068-5mgL-1. Comparison of the results was performed by flame atomic absorption spectrometry (FAAS), showing a good agreement (95% confidence level, n=5). Whilst the FAAS approach needed sample mineralization as no complete solubility was attained with both alcohol/water solvents, TS allowed direct introduction of the sample with an excellent recovery of the analyte after spiking. The whole TS procedure was more economic (lower amount of reagents and wastings, lower time of operation) and faster (60h-1 sampling throughput) than FAAS.Nonetheless, the main objective of this work is to show that an analytical signal different from zero can be obtained for Mg via TS by simply choosing the adequate operational variables that allow an optimization of the mass transfer of the analyte into the atomizer and a favorable dynamics of desolvation/atomization.This approach could broad TS analytical capabilities to other elements of lower volatility as it is shown here for the case of Mg.Fil: Morzan, Ezequiel Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Stripeikis, Jorge Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina. Instituto Tecnológico de Buenos Aires. Departamento de Ingeniería Química; ArgentinaFil: Tudino, Mabel Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentin

Composite materials based on hybrid mesoporous solids for flow-through determination of ultratrace levels of Cd(ii)

In this work we present a solid phase extraction (SPE) flow-through system coupled to graphite furnace atomic absorption spectrometry (GFAAS) for the determination of Cd(ii) at ultratrace levels. The flow system holds a minicolumn which was filled, one at a time, with three different lab-made materials: (a) mesoporous silica functionalized with 3-aminopropyl groups from 3-aminopropyl triethoxysilane (HMS); (b) HMS with a resin, Amberlite IR120; and (c) HMS-Amberlite IR120 and polyvinyl alcohol (PVA). All the solids were characterized by FTIR and SEM. Batch experiments were performed in order to study the optimum adsorption pH, the adsorption kinetics and the maximum adsorption capacity. The materials were compared in terms of their aptitude for the pre-concentration of the analyte under dynamic conditions. Microvolumes of HCl were employed for the release of cadmium and its introduction into the electrothermal atomizer. The operational variables of the flow system were also tested and optimized. A comparison of the figures of merit revealed that HMS-A-PVA was the best option from an analytical point of view: limit of detection = 4.7 ng L-1, limit of quantification = 16 ng L-1, RSD% = 4 (n = 6, 100 ng L-1), linear range: from LOQ up to 200 ng L-1 and a lifetime of over 600 cycles with no obstructions to the free movement of fluids, material bleeding or changes in the analytical sensitivity. The proposed method was shown to be tolerant to several ions typically present in natural waters and was successfully applied to the determination of traces of Cd(ii) in real samples. A full discussion of the main findings with emphasis on the metal ion/filling interaction is provided.Fil: Minaberry, Yanina Susana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Stripeikis, Jorge Daniel. Instituto Tecnológico de Buenos Aires. Departamento de Ingeniería Química; ArgentinaFil: Tudino, Mabel Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Inorgánica, Analítica y Química Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentin

Heavy metal accumulation in the Lichen Evernia prunastri transplanted at urban, rural and industrial sites in Central Italy

The lichen Evernia prunastri has been employed for biomonitoring the atmospheric deposition of heavy metals at urban, rural and industrial sites in Central Italy. Lichen samples have been collected in a control site 1500 m a. s. l. (Parco Nazionale d’Abruzzo, Central Italy) and subsequently transplanted at urban site (Cassino city center), at rural location 7 km away from Cassino (S. Elia Fiumerapido) and at industrial location (Piedimonte S. Germano) surrounding an automobile factory. Once defined the surface of impact relevant to this work, the lichen samples were transplanted at the four cardinal points of each site. Studies of bioaccumulation of Pb, Cd, Cr, Cu and Zn in lichen samples were performed five times at regular intervals between November 2000–December 2001. Microwave digestion of the samples and graphite furnace atomic absorption spectrometry were employed for the heavy metal determinations. Suitable certified reference materials (CRM) were used for validation of the analytical methodology. Results showed the ability of Evernia prunastri to accumulate the heavy metals under study. As expected, the area chosen as control site showed significantly (Friedman test, cluster analysis) lower impact in comparison to the other sites and the rural site showed smaller impact than the urban and the industrial sites

Baseline trace metals in bivalve molluscs from the Beagle Channel, Patagonia (Argentina)

In order to test the aptitude of individuals of Mytilus chilensis as biomonitors of heavy metals pollution in seawater, several samples of this mollusk together with surrounding seawater samples were collected along 170 km of the coastal area of the Beagle Channel (Tierra del Fuego, Argentina) in 2005 and 2007. The study, performed in seven locations strategically selected, involved the determination of Cd, Cr, Cu, Ni, Pb and Zn in seawaters and mollusks by atomic absorption spectrometry (AAS) and the calculation of the respective concentration factors (CFs). Obtained data were standardized and analyzed by multivariate techniques in order to establish differences between sampling sites and periods. Obtained results will be shown and the bioaccumulation ability of M. chilensis will be evaluated by comparison with results obtained for Mytilus species in different geographical marine areas. A fully discussion on the possibility of employing the results as background levels for comparative purposes in other marine waters of the world will be provided. The possible harm derived from human consumption of these mollusks will be also assessed. © 2011 Springer Science+Business Media, LLC.Fil: Conti, Marcelo Enrique. Università di Roma; Italia. International Academy of Environmental Sciences; ItaliaFil: Stripeikis, Jorge Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Finoia, Maria Grazia. Università di Roma; ItaliaFil: Tudino, Mabel Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentin

Trace metals intake of Nacella (P) magellanica from the Beagle Channel, Tierra del Fuego (Patagonia, Argentina)

Nacella species and Mytilus species constitute a popular food in the Beagle Channel zone as both of them are well distributed in the area. With the aim to infer the daily intake of heavy metals through the consumption of these gastropod molluscs in the diet, more than one hundred individuals of Nacella (P) magellanica were sampled, separated in viscera and muscle, and then examined with respect to the accumulation of different transition metals. Collection was performed in seven strategic locations along 170 km of the coastal area of the Beagle Channel (Tierra del Fuego, Argentina) in two campaigns during 2005 and 2007. In this study, the intake of the trace metals Cd, Cr, Cu, Ni, Pb and Zn by molluscs was calculated and evaluated in terms of the potential risks to human health derived from their consumption. Particularly, cadmium and lead presented more interest as they are nonessential and very well known toxic metals. Generally, the integrated evaluation of the results evidence that risks for humans seem unlikely for the regular consumption in the area. Further discussion will be provided on this issue. Copyright © 2012 Inderscience Enterprises Ltd

Surface studies on graphite furnace platforms covered with Pd, Rh and Ir as modifiers in graphite furnace atomic absorption spectrometry of tellurium

The main objective of this work is the study of correlations between the efficiency of the distribution of the permanent platinumgroup modifiers Pd, Rh and Ir over the graphite surfacewith the aimof improving analytical signal of tellurium. Modifier solution was deposited onto the platform and pyrolysed after drying. In the case of Pd, the physical vaporization/deposition technique was also tested. In order to analyze the differences amongst coverings (morphology, topology and distribution), the graphite surfaces were studied with scanning electron microscopy and energy dispersive X-ray microscopy. Micrographs for physical vaporization and pyrolytic deposition of Pd were also analyzed in order to explain the lack of signal obtained for tellurium with the first alternative. Similar micrographs were obtained for pyrolytic deposition of Ir and Rh and then, compared to those of Pd. Ir showed the most homogeneous distribution on the graphite surface and the tallest and sharpest transient. With the aimof improving the analytical signal of tellurium, the correlation between the surface studies and the tellurium transient signal (height, area and shape) is discussed.Fil: Pedro, J.. Universidad Nacional del Litoral. Facultad de Ingeniería Química; ArgentinaFil: Stripeikis, Jorge Daniel. Universidad de Buenos Aires; ArgentinaFil: Bonivardi, Adrian Lionel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Tudino, Mabel Beatriz. Universidad de Buenos Aires; Argentin