Efeitos de reguladores vegetais na propagação vegetativa do porta-enxerto de videira '43-43' (Vitis vinifera x V. rotundifolia)

Este trabalho teve como objetivo desenvolver uma metodologia para a propagação vegetativa do porta-enxerto de videira '43-43'. Estacas lenhosas retiradas em agosto, herbáceas retiradas em janeiro e semilenhosas retiradas em março foram imersas, por 10 segundos, em soluções contendo diferentes doses dos fitorreguladores paclobutrazol (0; 100 e 200 mg.L-1) e ácido indolilbutírico (0; 500 e 1.000 mg.L-1), combinados ou não, totalizando nove tratamentos para cada tipo de estaca. Após 60 dias do plantio das estacas, foram avaliadas as variáveis porcentagem de estacas enraizadas, número de raízes, massa fresca de raízes e porcentagem de estacas com brotações. Estacas lenhosas apresentaram 100% de brotação das gemas, mas não foi constatado enraizamento, independentemente da utilização de reguladores vegetais. Estacas herbáceas que não foram tratadas com reguladores vegetais apresentaram 92,0% de enraizamento e 84,0% de brotação. Para este tipo de estaca, o AIB a 1.000 mg.L-1 aumentou o número de raízes. Estacas semilenhosas apresentaram a maior porcentagem de enraizamento (23,5%) quando se utilizou AIB a 1.000 mg.L-1. Este tratamento também propiciou maior massa e número de raízes; no entanto, estes valores foram inferiores àqueles verificados para estacas herbáceas.

Estaquia do porta-enxerto de videira '43-43' (V. vinifera x V. rotundifolia) resistente à Eurhizococchus brasiliensis

O experimento foi realizado com o objetivo de avaliar a propagação vegetativa por estaquia do porta-enxerto de videira '43-43'. Ramos herbáceos coletados em janeiro e semilenhosos em março que foram separados em dois lotes: um de estacas retiradas do ápice e outro da base dos ramos. As estacas foram então imersas por 10 segundos em soluções contendo diferentes concentrações de ácido indolilbutírico (0; 1.000; 1.500; 2.000; 2.500 ou 3.000 mg.L-1), totalizando 12 tratamentos para cada época de enraizamento. Posteriormente, as estacas foram plantadas em vasos de polipropileno com areia e mantidas em casa de vegetação sob sistema de nebulização. Sessenta dias após o plantio das estacas, para cada época, foram avaliadas as seguintes variáveis: porcentagem de estacas enraizadas, comprimento médio de raízes, massa fresca de raízes e porcentagem de estacas brotadas. Estacas herbáceas e semilenhosas apresentaram alta porcentagem de enraizamento (66,0% e 68,0%, respectivamente) mesmo quando não tratadas com o fitorregulador. Estacas apicais apresentaram maior comprimento e massa fresca de raízes. A aplicação de AIB reduziu a porcentagem de enraizamento e de brotação de estacas herbáceas e semilenhosas. Estacas semilenhosas, quando tratadas com o AIB a 1.000 mgL-1, apresentaram maior comprimento e massa fresca de raízes.

Influência do agente precipitante na preparação do óxido de nióbio (V) hidratado pelo método da precipitação em solução homogênea

This work reports the preparation, characterization and study of the ion exchange behavior of hydrous niobium oxide prepared by a homogeneous precipitation method. The precipitating agent was obtained in aqueous solution by thermal decomposition of urea or ammonium carbonate. The compounds were chemically and physically characterized by X-ray diffractometry, thermal analysis (TG/DTG), surface area measurements and ion exchange behavior with sodium. The materials prepared with ammonium carbonate presented a higher degree of crystallinity and better ion exchange capacity with sodium than materials prepared with urea. In the homogeneous precipitation method, materials were obtained with specific surface area of 123 - 224 m² g-1. A variation of the preparation process produced hydrous niobium oxide with a different degree of hydration and specific surface area. This provided materials with different physico-chemical properties.

Identificação de substâncias em análise toxicológica sistemática utilizando um sistema informatizado para cálculo de parâmetros cromatográficos e busca em bases de dados

In spite of the availability of large databases of chromatographic data on several standardized systems, one major task in systematic toxicological analysis remains, namely how to handle the experimental data and retrieve data from the large available databases in a meaningful and productive way. To achieve this purpose, our group proposed an Internet-based tool using previously published STA databases, which interlaboratorial reproducibility tests have already evaluated. The developed software has the capability to calculate corrected chromatographic parameters, after the input of data obtained with standard mixtures of calibrators, and search the databases, currently incorporating TLC, color reactions, GC and HPLC data. At the end of the process, a list with candidate substances and their similarity indexes is presented.

Adsorção de arsênio(V) pela quitosana ferro - III reticulada

The removal of As(V) by a crosslinked iron(III)-chitosan adsorbent was evaluated under various conditions. The adsorption capacity of CH-FeCL was around 54 mg/g of As(V). The kinetics of adsorption obeys a pseudo-first-order model with rate constants equal to 0.022, 0.028, and 0.033 min-1 at 15, 25 and 35 ºC respectively. Adsorption data were well described by the Langmuir model, although they could be modeled also by the Langmuir-Freundlich equation. The maximum adsorption capacity, calculated with the Langmuir model, was 127 mg g-1 of As(V). The inhibition by competing anions is dependant on their kind and valence.

Determinação simultânea de creatinina e indicadores biológicos de exposição ao tolueno, estireno e xilenos em urina por cromatografia líquida de alta eficiência

A simple liquid chromatographic method for the simultaneous determination of creatinine, hippuric acid, mandelic acid, phenylglyoxylic acid and o, m and p-methylhippuric acids was developed and validated. Sample preparation was only dilution with water (1:10), followed by centrifugation. Analysis was performed in a reversed phase column (Lichrospher RP 8ec), 250 x 4.0 mm, with isocratic elution with phosphate buffer pH 2.3 and acetonitrile (90:10, v/v). The method presents adequate linearity, precision and accuracy and allows the simultaneous determination of the biomarkers of exposure to toluene, xylene and styrene together with creatinine, reducing cost and laboratory time.

Determinação de metil-etil-cetona em amostras de urina com amostragem por micro extração em fase sólida (MEFS) em headspace associada à cromatografia gasosa com detector de ionização de chama (CG-DIC)

Methyl ethyl ketone (MEK) is a solvent commonly used in chemical, paint and shoe industry. The aim of this study was to develop and validate a method for urinary quantification of MEK, employing headspace solid phase micro extraction sampling (SPME) coupled to gas chromatography with flame ionization detection (GC-FID). The calibration curve (y=4.6851x-0.0011) presented good linearity with r²=0.9993. Accuracy (94-109%), intra-assay precision (4.07-5.91%) and inter-assay precision (3.03-5.62%) were acceptable. The quantification limit was 0.19 mg/L. This low cost method can be used routinely in the biological monitoring of occupational exposure to MEK, according to the requirements of the Brazilian legislation.

Determinação de ácido valpróico em soro por cromatografia líquida de alta eficiência com detector de arranjo de diodos (CLAE-DAD), após derivatização com brometo de fenacila

Valproic acid (VA) is a drug used to control seizures in several epileptic conditions. In VA pharmacotherapy, therapeutic drug monitoring is recommended to obtain adequate seizure control and avoid toxicity. The aim of this study was to validate a method for the determination of valproic acid in serum, employing high performance liquid chromatography with diode array detection (HPLC-DAD), after derivatization with phenacyl bromide. The calibration curve (y=0.0133x-0.0025) presented good linearity with r²=0.9999. Accuracy (101-115%), intra-assay precision (4.53-8.15%) and inter-assay precision (3.15-6.77%) were acceptable. The quantification limit was 2.0 µg/mL. The method presented similar results to enzyme immunoassay.

Determinação de etanol e voláteis relacionados em sangue e fluido oral por microextração em fase sólida em headspace associada à cromatografia gasosa com detector de ionização em chama

The aim of this study was to validate a method for the determination of acethaldehyde, methanol, ethanol, acetone and isopropanol employing solid-phase microextraction associated to gas chromatography with flame ionization detection. The operational conditions of SPME were optimized by response surface analysis. The calibration curves for all compounds were linear with r² > 0.9973. Accuracy (89.1-109.0%), intra-assay precision (1.8-8.5%) and inter-assay precision (2.2-8.2%) were acceptable. The quantification limit was 50 µg/mL. The method was applied to the meaurement of ethanol in blood and oral fluid of a group of volunteers. Oral fluid ethanol concentrations were not directly correlated with blood concentrations.

Daño oxidativo en la microalga Pseudokirchneriella subcapitata expuesta a aguas receptoras de un efluente minero en del Río Blanco (V Región, Chile)

In this investigation antioxidant response and toxicity of metals in receiving water effluent miner in the Blanco river in Pseudokirchneriella subcapitata was assessed. The catalase activity, lipid damage through Tbars, the growth rate of was determined. The result showed an inhibition of the growth rate of P. subcapitata which correlated with increased catalase activity and the lipid liperoxidation. These responses were correlated with the concentrations of copper and iron.

Determinação de citrato de sildenafila e de tadalafila por cromatografia líquida de ultraeficiência com detecção por arranjo de diodos (CLUE-DAD)

A simple ultra-performance liquid chromatographic method for the simultaneous determination of sildenafil citrate and tadalafil was developed and validated. Sample preparation was dissolution in methanol, followed by centrifugation and dilution (1:10) with methanol. Analysis was performed in an Acquity® UPLC system with Acquity® BEH C18 column (2.1 x 50 mm, with 1.7 μm particles). The elution was isocratic with phosphate buffer pH 2.3 and acetonitrile (65:35, v/v) at a flow rate of 0.7 mL/min. The method presented adequate specificity, linearity, precision and accuracy and allowed the determination of the drugs in seized forensic samples.

Adsorção de chumbo, cádmio e prata em óxido de nióbio (V) hidratado preparado pelo método da precipitação em solução homogênea

This paper describes the adsorption of heavy metals ions from aqueous solution by hydrous niobium oxide. Three heavy metals were selected for this study: cadmium, lead and silver. Adsorption isotherms were well fitted by Langmuir model. Maximum adsorption capacity (Q0) for Pb2 +, Ag+ and Cd2 + was found to be 452.5, 188.68 and 8.85 mg g-1, respectively.

Determinação de 2,5-hexanodiona em urina empregando cromatografia líquida de alta eficiência, após derivatização com 2,4-dinitrofenil-hidrazina

A method for quantifying urinary 2,5-hexanedione was optimized and validated. Urine samples were hydrolyzed and derivatized with 2,4-dinitrophenylhydrazine. The analyte was separated in a high performance liquid chromatography system with a diode array detector, using a C18 column (150 x 4.6 mm, p.d. 5 µm) and a mobile phase composed of phosphate buffer pH 2.3:acetonitrile (40:60, v/v), at a flow rate of 1 mL/min. The chromatograms were monitored at 334 nm. Retention time was 7.3 minutes. Main validation parameters were: coefficient of determination: 0.9994, accuracy: 96 to 107%; intra-assay precision (RSD): 3.08 to 6.72%; inter-assay precision (RSD): 2.54 to 8.17% and limit of quantitation of 0.19 µg/mL.

Adsorção de arsênio(V) pelo compósito magnético hidrotalcita: óxido de ferro

In this work, hydrotalcite, a layered double hydroxide, had its adsorption and ion exchange properties combined with the magnetic properties of iron oxide to produce a magnetic adsorbent, HT-Fe. The removal of As(V) by a HT-Fe adsorbent was evaluated under various conditions. The Kinetic process was well described by a pseudo-second order rate model. The maximum adsorption capacity, calculated with the Langmuir model showed to be dependent on pH, reaching values of 24.09, 10.19 and 7.44 mg g-1, respectively, for pH values of 4.0, 7.0 and 9.0. The inhibition by competition of anions is dependent on the type of ionic species.

Determinación simultánea de Cr, Ni y V en orina mediante et aas

A procedure for the simultaneous determination of Cr, Ni, and V in urine by electrothermal atomic absorption spectrometry (ET AAS) was optimized by factorial design, and performed at a pyrolysis and atomization temperatures of 1300 and 2500 ºC, respectively, using 15 µg de Mg(NO3)2 as chemical modifier. Characteristics mass of 14, 6 and 220 ρg and detection limits of the method of 0.07, 0.38 and 0.75 µg L-1 were obtained for Cr, Ni and V respectively. The methodology was validated using a Liphochek Urine Metals Control sample (Bio-Rad) (P=0.05). The methodology was applied to samples of voluntary Venezuelan people, not environmentally exposed to specific emissions, and results ranging from < LOD-1.1 and 1.3-3.3 µg L-1 was observed for Cr and V, respectively, and not detectable levels for Ni.