Síntese e controle de qualidade da ureia enriquecida em 13C para diagnóstico da Helicobacterpylori (HP)

The aim of the study was to synthesize the urea (13CO(NH2)2), with 99% 13C atoms, and to perform a quality analysis for the diagnosis (breath test) of Helicobacter pylori. Furthermore, the process was submitted to economic analysis. The reaction was performed in a stainless steel reactor, lined with polytetrafluoroethylene, under low pressure and temperature. The synthesis method was shown to be appropriate (2.35 g; 81.9% yield), evidenced by physico-chemical and microbiological results, according to Brazilian legislation. The production and diagnosis costs were competitive compared with national and international market values, rendering this a valuable tool in clinical medicine.

Application of cloud point preconcentration and flame atomic absorption spectrometry for the determination of cadmium and zinc ions in urine, blood serum and water samples

A simple, sensitive and selective cloud point extraction procedure is described for the preconcentration and atomic absorption spectrometric determination of Zn2+ and Cd2+ ions in water and biological samples, after complexation with 3,3',3",3'"-tetraindolyl (terephthaloyl) dimethane (TTDM) in basic medium, using Triton X-114 as nonionic surfactant. Detection limits of 3.0 and 2.0 µg L-1 and quantification limits 10.0 and 7.0 µg L-1were obtained for Zn2+ and Cd2+ ions, respectively. Relative standard deviation was 2.9 and 3.3, and enrichment factors 23.9 and 25.6, for Zn2+ and Cd2+ ions, respectively. The method enabled determination of low levels of Zn2+ and Cd2+ ions in urine, blood serum and water samples.

Sodium dodecyl sulfate coated γ-alumina support modified by a new Schiff base for solid phase extraction and flame-AAS determination of lead and copper ions

A simple and fast approach for solid phase extraction is herein described, and used to determine trace amounts of Pb2+ and Cu2+ metal ions. The solid phase support is sodium dodecyl sulfate (SDS)-coated γ-alumina modified with bis(2-hydroxy acetophenone)-1,6-hexanediimine (BHAH) ligand. The adsorbed ions were stripped from the solid phase by 6 mL of 4 M nitric acid as eluent. The eluting solution was analyzed by flame atomic absorption spectrometry (FAAS). The sorption recovery of metal ions was investigated with regard to the effects of pH, amount of ligand, γ-alumina and surfactant and the amount and type of eluent. Complexation of BHAH with Pb2+ or Cu2+ ions was examined via spectrophotometry using the HypSpec program. The detection limit for Cu2+ was 7.9 µg L-1 with a relative standard deviation of 1.67%, while that for Pb2+ was 6.4 µg L-1 with a relative standard deviation of 1.64%. A preconcentration factor of 100 was achieved for these ions. The method was successfully applied to determine analyte concentrations in samples of liver, parsley, cabbage, and water.

Influência das substâncias húmicas de sedimentos na biodisponibilidade de metais para o sistema aquático

In rivers, sediments act as sinks for retaining contaminants. This study evaluated the influence of sediment humic substances (HS) on the bioavailability of metals. The levels of metals in sediments and HS indicated that most are complexed with HS. Characterization of HS showed a high degree of humification. The complexation capacity of HS for metals established the affinity order:Pb2+complexation capacity of metals.

Vanadato de bismuto sintetizado por combustão em solução na presença de diferentes combustíveis: síntese, caracterização e estudo da atividade fotocatalítica

In this manuscript, a BiVO4 semiconductor was synthesized by solution combustion synthesis using different fuels (Alanine, Glycine and Urea). Also, the Tween® 80 surfactant was added during synthesis. BiVO4 was characterized by XRD, SEM and diffuse reflectance spectroscopy. Photocatalytic activity was evaluated by the discoloration of methylene blue at 664 nm under UV-visible light irradiation. According to XRD, the monoclinic phase of BiVO4 was obtained for the samples. The smallest particle size and highest k obs value were observed for the BiVO4/alanine sample, which promoted greater demethylation of methylene blue.

Separação e determinação quantitativa dos alcanos lineares e dos cíclicos/ramificados em petróleos brasileiros por aduto de ureia e cromatografia gasosa: um estudo de caso revisitado

A complete analysis of oils and their fractions allows correlations to be defined between their composition and derivatives or related geological materials. This work focused on optimization and implementation of a method for separation and quantification of n-alkanes in Brazilian oil samples by urea adduction and GC-FID techniques. Ten samples with different ºAPI were analyzed in triplicate to quantify individual n-alkanes and cyclic/branched alkane fraction. For individual quantification of n-alkanes, internal standardization with deuterated n-tetracosane was used. The use of urea adduction for the separation and quantification of n-alkanes was highly effective, with recovery values of above 80%.

APPLICATION OF SULFONIC ACID FUNCTIONALIZED NANOPOROUS SILICA (SBA-Pr-SO3H) FOR THE PREPARATION OF 4,6-DIARYLPYRIMIDIN-2(1H)-ONES

In this work, we report the Biginelli-type reaction between various aldehydes, acetophenones and urea systems in the presence of sulfonic acid functionalized silica (SBA-Pr-SO3H) under solvent-free conditions, which led to 4,6-diarylpyrimidin-2(1H)-ones derivatives. SBA-Pr-SO3H with a pore size of 6 nm was found to be an efficient heterogeneous solid acid catalyst for this reaction which led to high product yields, was environmentally benign with short reaction times and easy handling.

OBTENÇÃO E CARACTERIZAÇÃO DE MATERIAL HÍBRIDO ENTRE SÍLICA E CICLODEXTRINAS

The obtention of silica and cyclodextrin hybrid materials was accomplished by refluxing them in xylol using citric acid as a binding agent. The materials were characterized by infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and elemental analysis. Evidence for the docking of cyclodextrins α and γ was substantiated based on the variation in band intensity for groups such as ≡Si-OH. Additional docking evidence includes the displacement of some of the bands that are related to cyclodextrin such as the deformation of the C-H axial bond. The α and γ-CDSi materials were characterized as amorphous compounds. The products obtained in the synthesis showed changes in the decomposition temperatures of their isolated constituents, in which the mass of α and γ-CD docked to the silica surface gave the estimated values of 41% and 47%, respectively. The elemental constituents were shown to be consistent and close to their relative theoretical values. ​Thermogravimetric analysis showed that a reduction in the percentage of the hybrids was proportional to the amount of lost mass. This new material is an improvement over synthesized organosilane materials because the operator and the environment benefit from a less toxic methodology. In addition, the material has several potential applications in complexation systems with cyclodextrin.

Lability of Cd, Cr, Cu, Mn and Pb complexed by aquatic humic substances

The lability of Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) complexed by humic substances (HSs) was investigated by means of ion exchange on cellulose modified with p-aminobenzoic groups (Cell-PAB), using a batch procedure. The HSs were extracted from water samples using adsorption in a column packed with XAD 8 resin. The metal-HS complexes were prepared by adding solutions containing all the aforementioned metal ions ( Cd(II), Cr(III), Cu(II), Mn(II) and Pb(II) ). The results indicated that the distribution coefficients (Kd) of Cell-PAB decreased with the presence of HSs, and that the lability of metal fractions complexed by HSs decreases in pH values > 4.0, complexation time > 10 h and HS concentration > 500 mg L-1. The metal exchange between HSs and Cell-PAB exhibited the following order of metal ion lability: Cd < Pb < Mn @ Cr < Cu.

Spectrophotometric determination of methyldopa in pharmaceutical formulations

A new, simple, precise, rapid and low-cost spectrophotometric method for methyldopa determination in pharmaceutical preparations is described. This method is based on the complexation reaction of methyldopa with molybdate. Absorbance of the resulting yellow coloured product is measured at 410 nm. Beer's Law is obeyed in a concentration range of 50 - 200 µg ml-1 methyldopa with an excellent correlation coefficient (r = 0.9999). No interference was observed from common excipients in formulations. The results show a simple, accurate, fast and readily applied method to the determination of methyldopa in pharmaceutical products. The analytical results obtained for these products by the proposed method are in agreement with those of the Brazilian Pharmacopoeia procedure at 95% confidence level.

Spectrophotometric study of iron oxidation in the iron(II)/thiocyanate/acetone system and some analytical applications

The possibility of using thiocyanate to determine iron(II) and/or iron(III) in water-acetone mixture has been re-examined as part of a systematic and comparative study involving metallic complexes of pseudohalide ligands. Some parameters that affect the complete oxidation of the ferrous cations, their subsequent complexation and the system stability have been studied to optimize the experimental conditions. Our results show the viability and potentiality of this simply methodology as an alternative analytical procedure to determine iron cations with high sensitivity, precision and accuracy. Studies on the calibration, stability, precision, and effect of various different ions have been carried out by using absorbance values measured at 480 nm. The analytical curve for the total iron determination obeys Beer's law (r = 0.9993), showing a higher sensitivity (molar absorptivity of 2.10x10(4) L cm-1 mol-1) when compared with other traditional systems (ligands) or even with the "similar" azide ion [1.53x10(4) L cm-1 mol-1, for iron-III/azide complexes, in 70% (v/v) tetrahydrofuran/water, at 396 nm]. Under such optimized experimental conditions, it is possible to determine iron in the concentration range from 0.5 to 2 ppm (15-65% T for older equipments, quartz cells of 1.00 cm). Analytical applications have been tested for some different materials (iron ores), also including pharmaceutical products for anemia, and results were compared with atomic absorption determinations. Very good agreement was obtained with these two different techniques, showing the potential of the present experimental conditions for the total iron spectrophotometric determinations (errors < 5%). The possibility of iron speciation was made evident by using another specific and auxiliary method for iron(II) or (III).

Interaction study of moxifloxacin with Cu(II) ion using square-wave voltammetry and its application in the determination in tablets

This work presents an electroanalytical method for the determination of moxifloxacin (MOXI) in tablets by its interaction with Cu(II) ion and subsequent electrochemical reduction at hanging mercury drop electrode (HMDE). A well-defined reduction peak at -0.21 V vs. Ag/AgCl in Phosphate buffer 0.04 mol L-1 pH 8.0 was observed for the complex reduction MOXI-Cu(II), using square-wave voltammetry (SWV). Using a 10 s of accumulation time at -0.40 V was found a limit detection of 3.60x10-8 mol l-1. The obtained results have shown good agreement with those obtained by spectrophotometric method.

Spectrophotometric determination of arsenic in soil samples using 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol (Br-PADAP)

In this paper, a new, simple and sensitive method for arsenic determination in soil is proposed. This is based on the reduction of silver (I) and iron (III) ions by arsine followed by a complexation reaction of iron (II) with the spectrophotometric reagent Br-PADAP 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol. Arsenic determination with a Sandell's sensitivity of 3.1 10-4 cm-2, linear range from 0.1 µg ml-1 to 2.0 µg ml-1 (r560 = 0.9995), molar absorptivity of 2.45 10(5) l mol-1 cm-1 and a concentration detection limit of 1.4 ng ml-1 (3s) were obtained using a 10 ml sample volume. Selectivity was increased with the use of EDTA as a masking agent. The proposed method was applied for arsenic determination in the presence of several ions amounts in digested soil samples. The results revealed that antimony (III), mercury (II), germanium (IV), platinum (IV) interferes at all analyzed proportions. The interferences can be easily removed by the use of EDTA. Precision and accuracy obtained were satisfactory with a R.S.D. < 5 %. Recovery of arsenic in soil samples varied from 95.55 to 102.70 % with a mean of 99.63 %. These results demonstrated that the proposed method is applicable for arsenic analysis in different soil samples.

Evolución el añublo del arroz en dos condiciones de fertilidad nitrogenada

Con el objetivo de evaluar la evolución de la infección producida por Pyricularia oryzae (cooke) Sacc, en la hoja y en la panícula, fueron seleccionados tres genotipos de arroz (Oryza sativa). Los genotipos: El Paso 144 (EP), Don Ignacio (DI) y H 316-1-2-1-1 (H 316) fueron sembrados en condiciones de campo, en la Estación Experimental La Plata, y en dos condiciones de disponibilidad de nitrógeno (testigo o sin nitrógeno y 150 kg N ha-1 en forma de urea). El hongo fue inoculado en la tercera hoja, con una mezcla de razas, a una concentración de 1,2 x 10(5) fragmentos de hifa/ml, incubándose durante 48 horas en cámara húmeda. Fueron evaluados la severidad y tipo de mancha en la hoja y la severidad e incidencia en la panícula. Se realizó el ANOVA, y las diferencias estadísticas fueron analizadas a través del test Tukey (p<0,05). Fueron aplicados modelos Log-lineares para datos no paramétricos. No se observó interacción entre genotipo y fertilización, en las hojas, en los estadios de primer perfilo (M) y diferenciación (D). La fertilización aumentó la severidad en las hojas. El coeficiente de correlación entre el tipo de mancha y el porcentaje de severidad en la hoja fue elevado. Fue observada interacción entre genotipo y fertilización en los valores de severidad en la panícula, los mismos que disminuyeron con la fertilización en los genotipos EP y DI, pero no presentaron diferencias en H 316.

Processo de interação ensino, serviço e comunidade: a experiência de um PET-Saúde

Este relato apresenta a experiência de um grupo PET-Saúde da Universidade Estadual de Feira de Santana (Uefs), na Bahia, Brasil, em Unidades de Saúde, em uma perspectiva crítico-reflexiva da interação ensino-serviço-comunidade. Participaram do projeto acadêmicos dos cursos de Ciências Farmacêuticas, Educação Física, Enfermagem, Medicina e Odontologia. A avaliação do processo incluiu reuniões de acompanhamento, bem como o uso do portfólio. A experiência dos diferentes atores no grupo caracterizou-se como uma vivência inovadora, desafiadora e complexa, uma vez que exigiu articulação entre instituição de ensino, serviços de saúde, profissionais e comunidade.