Scielo RSS <![CDATA[Química Nova]]> http://www.scielo.br/rss.php?pid=0100-404220120006&lang=es vol. 35 num. 6 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.br/img/en/fbpelogp.gif http://www.scielo.br <![CDATA[<b>Diálogos da sociedade sobre a biodiversidade brasileira na Rio+20</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600001&lng=es&nrm=iso&tlng=es <![CDATA[<b>Chemical composition of wet precipitation at metropolitan Porto Alegre, Brazil, 2005-2007</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600002&lng=es&nrm=iso&tlng=es This work aims to quantify the wet precipitation the Metropolitan Area of Porto Alegre (MAPA), in southern Brazil, through the analysis of major ions (by ion chromatography) and metallic elements (ICP/AES). By principal components analysis and cluster analysis was possible to identify the influence of natural and anthropic sources in wet precipitation. The results indicated of the higher contribution to the ions NH4+, SO4(2-) and Ca2+. Thus it was possible to identify the contribution of anthropogenic sources in wet precipitation in the study area, such as power plants, oil refineries, steel and vehicle emissions. <![CDATA[<b>Preparation, characterization and biodegradation studies on blends based on PDLLA and PVP</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600003&lng=es&nrm=iso&tlng=es Poly(D,L-lactide), PDLLA, is a polymer with potential applications in medical, environmental, and pharmaceutical areas. Despite its versatility, the hydrophobicity limits its applications. To overcome this problem, one strategy is the preparation of blends with hydrophilic polymers such as poly(vinylpyrrolidone), PVP. In this study, we report the preparation and characterization of blends based on PDLLA and PVP and the biodegradation studies by the Sturm test. It was observed that the components of the blends PDLLA/PVP are thermodynamically immiscible, however the biodegradation is faster than that of pure PDLLA. <![CDATA[<b>Biodegradation of paclobutrazol in saturated soil systems by <i>Pseudomonas spp</i>.</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600004&lng=es&nrm=iso&tlng=es Paclobutrazol is growth regulator of plants that has low mobility in soil and therefore has accumulated. The objective of this study was to investigate the paclobutrazol biodegradation in two soils from the São Francisco River Valley. The biodegradation experiments were conducted in batch using paclobutrazol and paclobutrazol added glycerol. The experiments were performed in sterile and nonsterile conditions using a mixed culture of Pseudomonas. The concentration of paclobutrazol was determined by high performance liquid chromatography. The biodegradation reached 43% in 14 days of experiments with only paclobutrazol and 70% in 28 days of experiments that contained glycerol and paclobutrazol. <![CDATA[<b>Rotenoids from <em>Tephrosia toxicaria</em> with larvicidal activity against <i>Aedes aegypti</i>, the main vector of dengue fever</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600005&lng=es&nrm=iso&tlng=es In the search for new larvicides from plants, we have investigated the potential activity of the rotenoids deguelin (1), 12a-hydroxy-α-toxicarol (2) and tephrosin (3), isolated from the bioactive ethanol extract of roots of Tephrosia toxicaria Pers., against Aedes aegypti, the main vector of dengue. The absolute configuration of these compounds was determined by circular dichroism (CD) spectra. The LC50 values of the compounds evaluated justify the potential of T. toxicaria as a new natural larvicide. <![CDATA[<b>Actividad catalítica de metales de transición en la descomposición de peróxido de hidrógeno</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600006&lng=es&nrm=iso&tlng=es This paper compares the catalytic activities of some transition metal ions (Fe3+, Co2+, Cu2+, Ni2+, Zn2+) in the H2O2 decomposition in homogenous and heterogeneous processes, including solid mixed systems (Fe-Cu-Co/Al2O3, Fe-Cu/Al2O3, Fe-Co/Al2O3 and Co-Cu/Al2O3). The solids were characterised by X-ray diffraction to explore evolution of phases or possible changes. Different trends of the catalytic activity were observed: in homogeneous medium the most active species was Fe3+, whereas in heterogeneous one the higher activities were shown for Co/Al2O3 and Co-Cu/Al2O3. A strong cooperative effect for the Co-Cu/Al2O3 system was observed, which can be considered as a new catalyst of interest for this type of reactions. <![CDATA[<b>Use of additives in the wood biodegradation by the fungus <i>Ceriporiopsis subvermispora</i></b>: <b>effect in the manganese peroxidase-dependent lipid peroxidation</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600007&lng=es&nrm=iso&tlng=es Ceriporiopsis subvermispora is a selective fungus in the wood delignification and the most promising in biopulping. Through the lipid peroxidation initiated by manganese peroxidase (MnP), free radicals can be generated, which can act in the degradation of lignin nonphenolic structures. This work evaluated the prooxidant activity (based in lipid peroxidation) of enzymatic extracts from wood biodegradation by this fungus in cultures containing exogenous calcium, oxalic acid or soybean oil. It was observed that MnP significant activity is required to promote lipid peroxidation and wood delignification. Positive correlation between prooxidant activity x MnP was observed up to 300 IU kg-1 of wood. <![CDATA[<b>Structural comparison between samples of hydrotalcite-like materials obtained from different synthesis route</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600008&lng=es&nrm=iso&tlng=es Three samples of hydrotalcite-like materials (HTC) were synthesized and their structural characteristics were compared with two HTCs obtained commercially. Thermal analyses, FT-IR, PXRD and textural analyses were used to investigate the structural differences between commercial and synthetic samples. Particularly, the memory effect was observed at temperature higher than 600 ºC. The Rietveld refinements were obtained with expressive accuracy and the statistical parameters of goodness of fit are quite satisfactory. In conclusion, the procedures adopted in synthesis of HTC produced crystalline materials with high surface area materials. <![CDATA[<b>Palladium-supported catalysts in methane combustion</b>: <b>comparison of alumina and zirconia supports</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600009&lng=es&nrm=iso&tlng=es Palladium catalysts supported on alumina and zirconia were prepared by the impregnation method and calcined at 600 and 1000 ºC. Catalysts were characterized by BET measurements, XRD, XPS, O2-TPD and tested in methane combustion through temperature programmed surface reaction. Alumina supported catalysts were slightly more active than zirconia supported catalysts, but after initial heat treatment at 1000 ºC, zirconia supported palladium catalyst showed better performance above 500 ºC A pattern between temperature interval stability of PdOx species and activity was observed, where better PdOx stability was associated with more active catalysts. <![CDATA[<b>Flavonoids and a neolignan glucoside from <i>Guarea macrophylla</i> (Meliaceae)</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600010&lng=es&nrm=iso&tlng=es This work describes the phytochemical study of the methanol extract obtained from leaves of Guarea macrophylla, leading to the isolation and identification of three flavonoid glycosides (quercetin 3-O-β-D-glucopyranoside, quercetin 3-O-b-D-galactopyranoside, kaempferol 7-O-β-D-glucopyranoside) and a neolignan glucoside, dehydrodiconiferyl alcohol-4-β-D-glucoside. All compounds were identified by a combination of spectroscopic methods (¹H, 1D, 2D NMR, 13C and UV), ESI-MS and comparison with the literature data. This is the first report of flavonoids in the genus Guarea and of a neolignan glucoside in the Meliaceae family. <![CDATA[<b>Evaluation of chitosan microparticles containing curcumin and crosslinked with sodium tripolyphosphate produced by spray drying</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600011&lng=es&nrm=iso&tlng=es The aim of this study was to encapsulate curcumin into chitosan, using sodium tripolyphosphate (TPP) as an ionic crosslinker by the spray drying method. The influence of TPP on the properties of the final product, such as solubility, morphology, loading efficiency, thermal behavior, swelling degree and release profiles, was evaluated. The microparticles had a spherical morphology (0.5-20 µm) with no apparent porosity or cracks. Results indicated the formation of a polymeric network, which ensures effective protection for curcumin. Controlled-release studies were carried out at pH 1.2 and 6.8, to observe the influence of pH on curcumin release while the mechanism was analyzed using the Korsmeyer-Peppas equation. <![CDATA[<b>Determination of Mn and Zn in rice by energy dispersive x-ray fluorescence spectrometry</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600012&lng=es&nrm=iso&tlng=es A simple, fast and inexpensive method was developed to determine essential elements in pellets of rice samples using energy dispersive X-ray fluorescence spectrometry (EDXRF). The accuracy and precision were evaluated using Standard Reference Material (rice flour NIST 1568a), and yielding relative standard deviation below 5%. The paired t-test showed good agreement within 95% confidence values. The detection limits (3σ) of Mn and Zn were 5.1 and 2.2 mg kg-1, respectively. The proposed method proved to be effective when used to determine Mn and Zn in commercial samples of rice without go by stage of decomposition. <![CDATA[<b>Flavonoids and other bioactive phenolics isolated from <i>Cenostigma macrophyllum </i>(Leguminosae)</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600013&lng=es&nrm=iso&tlng=es This work describes the phytochemical study of stem bark and leaves of Cenostigma macrophyllum Tul. (Leguminosae). Through usual chromatographic techniques were isolated bergenin as the primary compound of the stem bark of and from the leaves gallic acid, methyl gallate, ellagic acid, quercetin, quercetin-3-O-β-D-glucopyranoside, quercetin-3-O-(6"-O-galloyl)-β-D-glucopyranoside (tellimoside), quercetin-3-O-(6"-O-E-p-coumaroyl)-β-D-glucopyranoside (helichrysroside), agathisflavone and vitexin were obtained. The isolates were identified by spectroscopic data analysis, and bergenin showed dose-related antinociception when assessed in acetic acid-induced writhing in mice. <![CDATA[<b>Nuclear magnetic resonance characterization of apple juice containing enzyme preparations</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600014&lng=es&nrm=iso&tlng=es In this work, ¹H Nuclear Magnetic Resonance (¹H NMR) was employed to evaluate changes in apple juice in response to the addition of Panzym® Yieldmash and Ultrazym® AFP-L enzymatic complexes and compare it with premium apple juice. The juice was processed at different temperatures and concentrations of enzymatic complexes. The differences in the results were attributed mainly to the enzyme concentrations, since temperature did not cause any variation. A quantitative analysis indicated that the concentration of fructose increased while the concentrations of sucrose and glucose decreased in response to increasing concentrations of the enzymatic complexes. <![CDATA[<b>Ternary nanocomposites of thermoplastic starch and maleated polybutadiene</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600015&lng=es&nrm=iso&tlng=es Liquid polybutadiene (PBLH) was modified with maleic anhydride (MA). The material (PBLHM) was characterized and used to prepare hybrid materials by blending with glycerol-plasticized cassava starch (TPS) and an organophilic clay at 5 wt% content. Processing was performed by extrusion under mild conditions and led to TPS/PBLHM/clay hybrids, at 95/5 to 85/15 TPS/PBLHM compositions, which were characterized by contact angle measurements, X-ray diffraction and mechanical analysis. The results revealed a reduction in the hydrophilicity and the reinforcement of the hybrid materials. Biodegradability tests showed that the addition of clay and of PBLHM led to materials with high biodegradability. <![CDATA[<b>Lead removal from battery solutions using kaolinite modified with manganese oxide</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600016&lng=es&nrm=iso&tlng=es Nine absorbents were prepared using a mixture of Amazonian kaolinite and MnO2 at three temperatures (600, 700 and 900 ºC) in order to retain Pb2+ ions contained in the battery solutions. The batch experiments carried out with the batteries used water for 3 h and the kinetic isotherm was fitted with the pseudo-second order Lagergren equation. Findings show that synthesized adsorbents AD4, AD5 and AD7 performed well in reducing the Pb2+ ion content from 0.36 to 0.00 mg g-1. The better performance for removing the Pb2+ ions occurred for adsorbents synthesized in the temperature range from 600 to 700 ºC. <![CDATA[<b>Chemical drawings correlate to biological properties</b>: <b>MIA-QSAR</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600017&lng=es&nrm=iso&tlng=es Descriptors in multivariate image analysis applied to quantitative structure-activity relationship (MIA-QSAR) are pixels of bidimensional images of chemical structures (drawings), which were used to model the trichomonicidal activities of a series of benzimidazole derivatives. The MIA-QSAR model showed good predictive ability, with r², q² and r val. ext.² of 0.853, 0.519 and 0.778, respectively, which are comparable to the best values obtained by CoMFA e CoMSIA for the same series. A MIA-based analysis was also performed by using images of alphabetic letters with the corresponding numeric ordering as dependent variables, but no correlation was found, supporting that MIA-QSAR is not arbitrary. <![CDATA[<b>Mid-infrared spectroscopy and sensory analysis applied to detection of adulteration in roasted coffee by addition of coffee husks</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600018&lng=es&nrm=iso&tlng=es Mid-infrared spectroscopy and chemometrics were used to identify adulteration in roasted and ground coffee by addition of coffee husks. Consumers' sensory perception of the adulteration was evaluated by a triangular test of the coffee beverages. Samples containing above 0.5% of coffee husks from pure coffees were discriminated by principal component analysis of the infrared spectra. A partial least-squares regression estimated the husk content in samples and presented a root-mean-square error for prediction of 2.0%. The triangular test indicated that were than 10% of coffee husks are required to cause alterations in consumer perception about adulterated beverages. <![CDATA[<b>Phenolic derivatives and other chemical compounds from <i>Cochlospermum regium</i></b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600019&lng=es&nrm=iso&tlng=es This study describes the chemical investigation of the ethyl acetate fraction obtained from the hydroethanolic extract of the xylopodium of Cochlospermum regium (Mart. & Schr.) Pilger, which has been associated with antimicrobial activity. Phytochemical investigation produced seven phenol derivatives: ellagic acid, gallic acid, dihydrokaempferol, dihydrokaempferol-3-O-β-glucopyranoside, dihydrokaempferol-3-O-β-(6"-galloyl)-glucopyranoside, pinoresinol, and excelsin. It also contained two triacylbenzenes, known as cochlospermines A and B. The hydroethanolic extract and its fractions exhibited antimicrobial activity (0.1 mg/mL) against Staphylococcus aureus and Pseudomonas aeruginosa. Gallic acid showed activity against S. aureus. Dihydrokaempferol-3-O-β-(6"-galloyl)-glucopyranoside is reported here for the first time in the literature. <![CDATA[<b>Biochemical characterisation of lipase from a new strain of <i>Bacillus</i> sp. </b><b>ITP-001</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600020&lng=es&nrm=iso&tlng=es Lipases are characterised mainly by catalytic versatility and application in different industrial segments. The aim of this study was to biochemically characterise a lipase from a new strain of Bacillus sp. ITP-001. The isoelectric point and molecular mass were 3.12 and 54 kDa, respectively. The optima lipase activity was 276 U g-1 at pH 7.0 and a temperature of 80 ºC, showing greater stability at pH 5.0 and 37 ºC. Enzymatic activity was stimulated by various ions and pyridine, and inhibited by Cu+ and ethanol. The values of Km and v max were 105.26 mmol and 0.116 mmol min-1 g-1, respectively determined by the Eadie-Scatchard method. <![CDATA[<b>Licanol, a new flavanol, and other constituents from the <i>Licania macrophylla </i>Benth</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600021&lng=es&nrm=iso&tlng=es The phytochemical investigation of L. macrophylla Benth led to the isolation of a new flavanol named licanol: (-)-4'-O-methyl-epigallocatechin-3'-O-α-L-rhamnoside, along with nine known compounds, identified as: (-)-4'-O-methyl-epigallocatechin, pheophytin A, 13²-hydroxy-(13²-S)-pheophytin A, pheophytin B, sitosterol, stigmasterol, sitosterol-β-O-glucoside, betulinic alcohol and oleanolic acid. The structures were established based on IR, HR-ESI-MS, and NMR spectrometric data analysis with the aid of 2D techniques. The methanolic extracts of leaves and stem bark as well as the compounds licanol, 13²-hidroxi-(13²-S)-feofitina A, and betulinic alcohol demonstrated antimicrobial activity against several bacterial strains. <![CDATA[<b>Bioactive triterpenes and phenolics of leaves of<i> Eugenia brasiliensis</i></b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600022&lng=es&nrm=iso&tlng=es A chemical investigation of Eugenia brasiliensis Lam. (Myrtaceae) leaves led to the isolation of α-amyrin and β-amyrin (in a mixture), betulin, 29-hydroxy-oleanolic acid, quercetin, catechin and gallocatechin. Herein, the identification of 29-hydroxy-oleanolic acid is reported for the first time in the Myrtaceae family. Moreover, in this study, the extract, fractions and six of the seven compounds were monitored for toxicity toward Artemia salina, antibacterial and acetylcholinesterase inhibitory activity. The crude ethanol extract of the leaves and fractions were found be active on A. salina toxicity bioassay. <![CDATA[<b>Antiparasitic bromotyrosine derivatives from the Caribbean marine sponge <i>Aiolochroia crassa</i></b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600023&lng=es&nrm=iso&tlng=es Six bromotyrosine-derived compounds were isolated from the Caribbean marine sponge Aiolochroia crassa: 3-bromo-5-hydroxy-O-methyltyrosine (1), 3-bromo-N,N,N-trimethyltyrosinium (2), 3-bromo-N,N,N,O-tetramethyltyrosinium (3), 3,5-dibromo-N,N,N-trimethyltyrosinium (4), 3,5-dibromo-N,N,N,O-tetramethyltyrosinium (5), and aeroplysinin-1 (6). Structural determination was performed using NMR, MS and comparison with literature data. All isolated compounds were screened for their in vitro activity against Leishmania panamensis, Plasmodium falciparum and Trypanosoma cruzi. Compound 4 showed selective antiparasitic activity against Leishmania and Plasmodium parasites. This is the first report of compounds 1, 4 and 5 in the sponge A. crassa and the first biological activity reports for compounds 2-4. This work shows that bromotyrosines are potential antiparasitic agents. <![CDATA[<b>Estudio del coeficiente de reparto de ácidos carboxílicos grasos en sistemas modificados heptano/agua</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600024&lng=es&nrm=iso&tlng=es The use of fatty acids (FAs) as amphiphiles is very important because they have a behaving similar to surfactants. The formulation for the preferential partition of these species was studied by varying the amount of salt at constant acid concentration. As the salt concentration increases, a Winsor I→III→II transition is observed for all the systems studied. Furthermore, the electrolyte concentration required to obtain the optimum formulation varies inversely with the chain length of the acid. The partition coefficient of the surfactant allows one to obtain thermodynamic information on the acid transfer process between the phases of the system. <![CDATA[<b>Evaporative light-scattering detector for analysis of natural products</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600025&lng=es&nrm=iso&tlng=es The interest in the use of evaporative light scattering detector (ELSD) for the analysis of different classes of natural products has grown over the years. This is because this detector has become an excellent alternative compared to other types of detectors, such as the refractive index detector and the ultraviolet (UV) detector. This review describes the basic principles of ELSD functioning and discusses the advantages and disadvantages in using an ELSD for the analysis of organic compounds. Additionaly, an overview, covering the last 23 years, of ELSD applications in natural products analysis (saponins, terpenes, carbohydrates, glycosides, alkaloids, steroids, flavonoids, peptides, polyketides, coumarins and iridoids) is presented and discussed. <![CDATA[<b>Nuclear test fallout signatures in sediments on the Brazilian coast (<sup>240+239</sup>Pu and <sup>137</sup>Cs)</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600026&lng=es&nrm=iso&tlng=es The aim of this review is to take a look at Cold War era nuclear tests signatures found in Brazilian coastal sediments. Both137Cs and 240+239Pu signatures have been documented in mangrove, coastal mudflats and continental shelf sediments, associated with above ground nuclear tests beginning in the 1950's. The dates associated to the anthropogenic radionuclide signatures 137Cs and 240+239Pu along sediment columns are confirmed by 210Pb geochronology in many of the studies highlighted in this review. The results outlined in this review characterize the extent to which nuclear fallout products reach the Brazilian coast in quantities sufficient for detection, allowing the use of these radioisotopes as geochronometers. <![CDATA[<b>Considerations about the preparation of samples containing estrogenic micropollutants</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600027&lng=es&nrm=iso&tlng=es In this work, the materials used in the recovery of estrogens from aqueous matrices by filtration and solid phase extraction were evaluated. The results showed that glass-fiber filters allow a recovery and repeatability compatible with this type of analysis, whereas cellulose esters lead to significant losses of the analytes, mainly due to adsorption processes. On the other hand, the transferring of the sample to the extraction cartridges should be carried out with glass or Teflon tubing, since the adsorption observed with other polymeric materials (eg. silicone, Tygon, polyethylene and PVC) dramatically reduces the recovery and repeatability of the extraction process. <![CDATA[<b>Stability indicating HPLC method for simultaneous determination of moxifloxacin hydrochloride and ketorolac tromethamine in pharmaceutical formulations</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600028&lng=es&nrm=iso&tlng=es A simple, RP-HPLC method was established for determining moxifloxacin and ketorolac in pharmaceutical formulations. Moxifloxacin, ketorolac and their degradation products were separated using C8 column with methanol and phosphate buffer pH 3.0 (55:45 v/v) as the mobile phase. Detection was performed at 243 nm using a diode array detector. The method was validated using ICH guidelines and was linear in the range 20-140 µg mL-1 for both analytes. Good separation of both the analytes and their degradation products was achieved using this method. The developed method can be applied successfully for the determination of moxifloxacin and ketorolac. <![CDATA[<b>Fast determination of basic drugs in plasma by gas chromatography with nitrogen phosphorus detector</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600029&lng=es&nrm=iso&tlng=es A simple and fast method for determination of 40 basic drugs in human plasma employing gas-chromatography with nitrogen-phosphorus detection was developed and validated. Drugs were extracted from 800 µL of plasma with 250 µL of butyl acetate at basic pH. Aliquots of the organic extract were directly injected on a column with methylsilicone stationary phase. Total chromatographic run time was 25 min. All compounds were detected in concentrations ranging from therapeutic to toxic levels, with intermediate precision CV% below 11.2 and accuracy in the range of 92-114%. <![CDATA[<b>Development and validation of analytical method for determination of glycyrrhizic acid, salicylic acid, and caffeine in chitosan-alginate nanoparticles</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600030&lng=es&nrm=iso&tlng=es The present work consists of the development and validation of analytical method for evaluation of glycyrrhizic acid, salicylic acid, and caffeine in chitosan-alginate nanoparticles by high performance liquid chromatography. Method validation investigated parameters such as linearity, precision, accuracy, robustness and specificity, which gave results within the acceptable range. The methods were applied to nanoparticles suspensions containing the drugs and were able to determine the entrapment efficiency successfully. The best entrapment efficiency was achieved with the glycyrrhizic acid (95.4%). <![CDATA[<b>Simvastatin assay and dissolution studies by feasible RP-HPLC in tablets</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600031&lng=es&nrm=iso&tlng=es Commonly used HPLC acetonitrile solvent has been through a worldwide shortage with a cost increase in 2008 and 2009. In order to get around this situation, a method by RP-HPLC employing methanol and aqueous acid mobile phase was developed and validated to evaluate simvastatin. The quality control assay and dissolution studies of this lipid-lowering drug were performed in diluents methanol and 0.01 M phosphate buffer with 0.5% SDS, pH 7, respectively. Dissolution test aliquots did not go through sample treatment, as described in USP SIM tablets monograph by ultraviolet spectrophotometry. The proposed method is fast, simple, feasible and robust. <![CDATA[<b>Development and validation of a High Performance Liquid Chromatographic method for determination of etoposide in biodegradable polymeric implants</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600032&lng=es&nrm=iso&tlng=es A method using HPLC-UV was developed and validated for the determination of etoposide incorporated into polycaprolactone implants. The method was carried out in isocratic mode using a C18 column (250 x 4.6 mm; 5 µm), at 25 ºC, with acetonitrile and acetic acid 4% (70:30) as mobile phase, a flow rate of 2 mL/min, and UV detection at 285 nm. The method was linear (r² &gt; 0.99) over the range of 5 to 65 µg/mL, precise (RSD < 5%), accurate (recovery of 98.7%), robust, selective regarding excipient of the sample, and had a quantitation limit equal to 1.76 µg/mL. The validated method can be successfully employed for routine quality control analyses. <![CDATA[<b>Determination of deoxynivalenol and zearalenone in natural and parboiled rice and their fractions using quEChERS and HPLC/UV-FL</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600033&lng=es&nrm=iso&tlng=es The QuEChERS extraction method followed by quantification using HPLC/UV-FL was evaluated for deoxynivalenol (DON) and zearalenone (ZEA) determination in natural and parboiled rice and their fractions (bran and husk). The comparison between QuEChERS and partition with acetonitrile extraction showed that the first one was better. It presented higher recovery (91% for DON, 105% for ZEA) wih precision ranging from 1.5 to 18.6%. The limits of quantification were 22.2 µg kg-1 for DON and 4.3 µg kg-1 for ZEA. DON and ZEA showed higher levels in endosperm of parboiled rice (8 e 111.7 µg kg-1, respectively) when compared to natural rice. <![CDATA[<b>From the first to the second twelve principles of Green Chemistry</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600034&lng=es&nrm=iso&tlng=es The second 12 principles of Green Chemistry (Winterton, 2001) are presented and discussed to show how they press academic chemists to focus the invention of synthetic pathways more directly on industrial process development, allowing a quicker progress along the greenness chain and a softer implementation of Green Chemistry in the industrial practice of chemistry. The relationships between the two sets of principles are tentatively established and discussed to make easier their joint use. The net of connections shows the systemic nature of Green Chemistry. <![CDATA[<b>Synthesis of Epoxone from D-fructose</b>: <b>a didactic experiment for organic chemistry laboratory courses focusing on green chemistry principles</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600035&lng=es&nrm=iso&tlng=es In recent years, the introduction of the Green Chemistry concepts in undergraduate chemistry classes has been intensively pursued. In this regard, the two-step preparation of Epoxone (an organocatalyst developed by Shi & col.) from commercial D-fructose, through ketalization of vicinal diols followed by oxidation of a sterically congested secondary alcohol, involves important topics in Organic Chemistry and employs inexpensive and nontoxic reagents. The reactions are easy to perform and the products from both steps are readily obtained as crystalline solids after simple procedures, thus facilitating their chemical characterization. <![CDATA[<b>Vibrational analysis of coordination compounds of nickel (II)</b>: <b>an approach to the teaching of point groups</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600036&lng=es&nrm=iso&tlng=es This paper presents an IR and Raman experiment executed during the teaching of the course "Chemical Bonds" for undergraduated students of Science and Technology and Chemistry at the Federal University of ABC, in order to facilitate and encourage the teaching and learning of group theory. Some key aspects of this theory are also outlined. We believe that student learning was more significant with the introduction of this experiment, because there was an increase in the discussions level and in the performance during evaluations. This work also proposes a multidisciplinary approach to include the use of quantum chemistry tools. <![CDATA[<b>Processing of ink-jet printer cartridges</b>: <b>an example of management of a post-consumption product</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600037&lng=es&nrm=iso&tlng=es This work presents a route for processing spent ink-jet cartridges in an experimental course. The disassembly of the cartridges requires several steps and the recognition of their different components is essential to define the best final destination (recycling, co-processing). The plastic strips were chemically processed so as to recover gold and copper. The students recognized the difficulty of processing multicomponent wastes and the importance of the chemical work under the best safety conditions; they also experienced many laboratory techniques and recognized the value of the selective collection and the reverse logistics to reach a viable commercial scale recycling. <![CDATA[<b>Implantation and implementation of standards of good laboratory practice (GLP) at the laboratory for residue analysis of the State University of Campinas</b>]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422012000600038&lng=es&nrm=iso&tlng=es In the context of quality and good laboratory practices, the article recovers some historical data. From a specific Institutional situation (CPQBA/UNICAMP), is presented an experience of establishing and implementing a standard (NIT-DICLA-035) for good laboratory practice according to definitions of the Brazilian authority (INMETRO) responsible for regulating, monitoring, supervising and recognition in this area. The issue aims to focus on studies of pesticide residues in GLP parameters.