Determination of cadmium in commercial tobacco by EMFAAS

In this work we present the use of EMFAAS (Electrothermal Metallic Furnace Atomic Absorption Spectroscopy) for the determination of Cd in the tobacco cigarettes of five commercial brands. Optimization of the experimental conditions was done by controlling the sample flow rate and the temperature of both the injection capillary and the atomization cell. The determination was made in the whole cigarettes, filters and ashes of the cigarettes once consumed, cases in which the Cd concentration is much lower and its quantification is more difficult. For the validation of the results, the ICP-OES technique was used, obtaining good agreement within the experimental error. The results show that EMFAAS is a promising tool for the determination of volatile analytes.Fil: Carrone, Guillermo Alejandro. 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: 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: 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; ArgentinaFil: Etchenique, Roberto Argentino. 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

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

Non-chromatographic determination of ultratraces of V(V) and V(IV) based on a double column solid phase extraction flow injection system coupled to electrothermal atomic absorption spectrometry

In this work, a non-chromatographic procedure for the on-line determination of ultratraces of V(V) and V(IV) is presented. The method involves a solid phase extraction-flow injection system coupled to electrothermal atomic absorption spectrometry (SPE-FI-ETAAS). The system holds two microcolumns (MC) set in parallel and filled with lab-made mesoporous silica functionalized with 3-aminopropyltriethoxy silane (APS) and mesoporous silica MCM-41, respectively. The pre-concentration of V(V) is performed by sorption onto the first MC (C1) filled with APS at pH 3, whilst that of V(IV) is performed by sorption onto the second column (C2) filled with mesoporous silica MCM-41 at pH 5. Aqueous samples containing both analytes are loaded and, after pre-concentration (pre-concentration factor PCF = 10, sorption flow rate = 1 mL min-1, sorption time = 10 min), they are eluted in separate vessels with hydroxylammonium chloride (HC) 0.1 mol L-1 in HCl 0.5 mol L-1 (elution volume = 1 mL, elution flow rate = 0.5 mL min-1). Afterwards, both analytes are determined through ETAAS with graphite furnace. Under optimized conditions, the main analytical figures of merit for V(V) and V(IV) are, respectively: detection limits (3 s): 0.5 and 0.6 μg L-1, linear range: 2-100 μg L-1 (both analytes), sensitivity: 0.015 and 0.013 μg-1 L and sample throughput: 6 h-1 (both analytes). Recoveries of both species were assayed in different water samples. Validation was performed through certified reference materials for ultratraces of total vanadium in river water.Fil: Kim, Manuela Leticia. 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: 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

Patagonia. Bio-monitoring the environment.

In the picturesque lands of Patagonia in the southern tip of South America, two research groups from Sapienza, Rome, Italy and from Buenos Aires University have been breaking new ground in analyzing mollusks to evaluate the baseline metal contamination in marine ecosystems. The famous Beagle Channel can be considered, apart from cadmium, a reference ecosystem for marine areas around the world

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

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

Determination of As(III) in nonacidified groundwater samples for inorganic speciation analysis using flow injection hydride generation atomic absorption spectrometry

A flow injection system coupled to hydride generation atomic absorption spectrometry with heated quartz tube atomizer was employed for the selective determination of As(III) in real groundwater samples under nonacidic conditions. The use of low-acidity conditions was carefully evaluated in order to minimize the interconversion of redox arsenic species. The As(III) hydride was generated using 0.1 mol L-1 HCl as carrier solution and 0.2% (m/v) NaBH4 in 0.025% NaOH as the reductant. A coil reaction larger than the used one for higher acidity conditions (480 mm instead of 115 mm) was selected. The generated hydride was transported to the atomizer by a nitrogen flow of 75 ml min-1. The main parameters that influenced the signal intensity and shape were studied. Under the best found experimental conditions, a detection limit (3σ) of 1.0 μgL-1 As(III) was obtained for a 500 μl sample volume. The analytical recovery ranged between 90% and 98%. In addition, the total inorganic arsenic concentration in the samples was determined on sample aliquots acidified with concentrated HCl and prereduced with 5% (m/v) KI-5% (m/v) C6H8O6 solution. HCl 1.2 mol L-1 as carrier solution, NaBH4 0.2% (m/v) as reductant, and a nitrogen flow rate of 75 ml min-1 were used in this case. The concentration of As(V) was calculated by difference between the total inorganic arsenic and As(III) concentrations. © Taylor & Francis Group, LLC.Fil: Sigrist, Mirna Edit. Universidad Nacional del Litoral. Facultad de Ingeniería Química; ArgentinaFil: Beldomenico, Horacio Ramon. Universidad Nacional del Litoral. Facultad 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