Scielo RSS <![CDATA[Journal of the Chilean Chemical Society]]> http://www.scielo.cl/rss.php?pid=0717-970720120002&lang=es vol. 57 num. 2 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<b>VOLATILE TERPENOID COMPOSITION OF <i>ROSMARINUS OFFICINALIS,</i> "CIM-HARIYALI"</b>: <b>VARIABILITY</b> <b>IN NORTH INDIA DURING ANNUAL GROWTH</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200001&lng=es&nrm=iso&tlng=es To investigate the seasonal influence on essential oil content and composition of rosemary (Rosmarinus of ficinalis) cultivar 'CIM-Hariyali' a study was conducted in Kumaon region of western Himalaya. Essential oil content was found to vary from 1.0% to 1.14% during the year. GC and GC-MS analyses enabled to identify thirty components representing 95.33% - 97.03% of the total oil composition. Main components of the oils were 1,8-cineole (22.61% - 23.85%), camphor (24.40% - 25.85%), α-pinene (10.74% - 12.59%), verbenone (4.90% - 5.77%), camphene (5.46% - 6.16%), β-pinene (3.28% - 4.02%), limonene (2.86% - 3.39%) and ,S-myrcene (1.89% - 1.95%). The study clearly showed that there were no drastic changes in the essential oil content and composition of rosemary due to season. Therefore, the crop may be harvested in any season to get good quality oil in hilly region of north India. <![CDATA[DEVELOPMENT OF SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF PERINDOPRIL ERBUMINE IN PHARMACEUTICAL FORMULATIONS USING 2, 4 DINITROFLUOROBENZENE]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200002&lng=es&nrm=iso&tlng=es A simple, rapid and sensitive spectrophotometric method was developed for the determination of perindopril in pharmaceutical formulations. The proposed method is based on the reaction of amine group of drug with 2, 4 dinitrofluorobenzene in dimthylsulfoxide (DMSO) to form yellow colored product, which absorbs maximally at 410 nm. Beer's law was obeyed in the concentration range 2.5 - 25 ìg/mL with molar absorptivity 6.71 x10³ L/mol/cm. The limits of detection and quantitation of the proposed method were 0.17 and 0.52 ìg/mL, respectively. The optimum experimental condition for the proposed procedure was investigated. The results of the proposed method were compared with those of Abdellatefs spectrophotometric method, which indicated excellent agreement with acceptable true bias of all samples within ±2.0%. <![CDATA[<b>TEMPORAL AND SPATIAL TRENDS OF TOTAL ALIPHATIC HYDROCARBONS OF DIESEL RANGE AND TRACE ELEMENTS IN SEDIMENTS AND MUSSELS OF THE CORRAL BAY AREA, VALDIVIA, SOUTH CENTRAL CHILE</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200003&lng=es&nrm=iso&tlng=es Sediments and mussel specimens of Mytilus chilensis were analyzed for organic pollutant fingerprints and heavy metals in the Corral Bay area of Valdivia, South Central Chile during the period 2003-2004. GC-MS analysis show hydrocarbon fingerprints corresponding mainly to mixed inputs of aliphatic hydrocarbons of the TPH-diesel fraction and biogenic hydrocarbons, indicating low to medium contamination by petroleum hydrocarbons with high biodegradation of petroleum in sediments at Las Coloradas, La Escuela and Corral Bay (C17/Pri < 1 and C18/Phy < 1). Mussel TPH fingerprints show weathered hydrocarbons resulting in a zone of increased concentration of cyclic respect to acyclic aliphatic components (UCM), indicating the presence of petroleum hydrocarbons. No temporal variation the in concentration of TPH-diesel found in sediments as well as mussels were observed except for samples collected during January 2004. TPH concentration levels in the sediments varied from 0.4 μgg-1 to 33.8 μgg-1 d.w. whereas in mussels varied between 61 μg g-1 and 287 μgg-1 d.w. Heavy metals were also analyzed by atomic absorption spectrometry and low concentration as well as no seasonal variations of concentration were found in mussels at each sampling point and a relatively even distribution of metals among stations was observed. Maximum concentrations in all sampling points of sediments were found for Fe (24128-43791 μgg-1) and Mn (181-388 μgg-1) while the minimum concentration was found for Pb (nd-12 μgg-1). According to the Sediment Quality Guidelines (SQGs-NOAA), the concentration levels of Cu and As in all sediment sampling points are above the "Effects Range-Low" (ERL), indicating that there may be a probable toxicity effect over the biota and attention must be paid on a moderate range of priority. <![CDATA[EFFECT OF THE MEMBRANE CHARACTERISTICS AND OPERATION MODES, IN THE FOULING OF ULTRAFILTRATION MEMBRANES BY NATURAL ORGANIC MATTER (NOM)]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200004&lng=es&nrm=iso&tlng=es Membrane fouling by natural organic matter (NOM) is a major problem in ultrafiltration (UF) water treatment. The objective of this study was to evaluate the effects of operations modes on natural organic matter fouling, rejection and flux decline during UF. A comparison of constant pressure and constant flux tests confirmed that modest constant flux provided the most beneficial conditions. As general observation hydrophilic membranes were less prone to NOM fouling. <![CDATA[SORPTION OF POLYBROMINATED DIPHENYL ETHERS IN BIOSOLID MODEL SAMPLES]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200005&lng=es&nrm=iso&tlng=es Biosolid model samples (BMSs) were developed to study the capacity of various matrixes to adsorb polybrominated diphenyl ethers (PBDEs) as a function of their composition. A commercial standard reference samples for biosolids containing a certified amount of PBDEs is currently not available for extraction evaluation. Therefore, this study will allow for the selection of an appropriate concentration of PBDEs to produce a reference material for analytes associated with the matrix. The sorption of PBDEs increased clearly concomitantly with the amount of organic matter present in the model, revealing that organic matter rather than the inorganic fraction is mainly responsible for the analyte-matrix interaction. Hydrophobic interactions are predominant in the retention of PBDEs in the biosolid matrix because more hydrophobic congeners are generally sorbed to a higher extent than those that are less hydrophobic. In order to know the probable PBDE sorption mechanism on the model sample of biosolid, the Gibbs free energies were calculated using the Freundlich model, giving values between -8 and -10 kJ/mol. These results suggest that the sorption mechanism of the PBDEs is through physiosorption. Therefore, the Freundlich model should be satisfactory for describing the analyte behavior. <![CDATA[ADSORPTION OF FUNGICIDES IN CHILEAN SOILS INCUBATED WITH BIOSOLIDS]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200006&lng=es&nrm=iso&tlng=es The efficiency of the adsorption process of the fungicides Captan and Thiram was studied in four Chilean soils from the VI [O'Higgins, (HGS)], VII [Talcarehue, (THL)], VIII [Diguillin, (DIG)] and Metropolitan [Maipo, (MAO)] regions of Chile. Changes in the efficiency of adsorption when the natural soils were incubated with biosolids were analyzed. The values of parameters Kf and n from the Freundlich equation indicated an increase in the adsorption of fungicides incubated with biosolids (1% and 10%) with respect to natural soil. A high Kf value (12.1) for DIG-Thiram and a lower Kf value (4.3) for MAO-Captan interaction were observed for natural soils, while in soils incubated with biosolids (10%) the greatest value was (20.3) for DIG-Thiram and the lowest Kf value (10.2) for MAO-Captan. In general the high Kf values for Captan and Thiram were correlated with organic carbon content in the natural and incubated soils, except for the interaction THL-Thiram, in which inorganic compounds of soils (clay) were dominant. The distribution constant between solid-liquid phases (Kd) increased in soils incubated with biosolids; the magnitude of this constant was more significant with Thiram. The same behavior was observed for the constant related to organic carbon constants (Koc). The results of this work confirm that amending soils with biosolids is beneficial for immobilizing fungicides and helps prevent the percolation of Captan and Thiram through the soil profile and into groundwater. <![CDATA[EFFECT OF ENVIRONMENTAL FACTORS IN THE DECOLORIZATION OF REMAZOL BRILLIANT BLUE R BY <i>POLYPORUS</i> SP. S133]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200007&lng=es&nrm=iso&tlng=es The effects of environmental conditions such as pH, agitation, carbon and nitrogen sources, metal ion, salinity and phenolic compound on the decolorization of the anthraquinone type textile dyestuff Remazol Brilliant Blue R by white rot fungi, Polyporus sp. S133 were investigated. After extensive testing, the best performance took place at pH 4 and decolorization of the dye in liquid effluents was significantly increased by agitation. Compared to other carbon and nitrogen sources tested, glucose and ammonium tartrate gave rise to better decolorization performances. Decolorization of RBBR occurred in the presence of metal ions which are typically found in textile industry effluents. Of all the metal ions tested, Fe++ was the most inhibiting of the decolorization. The effect of culture salinity on decolorization was also investigated. Under high-salt conditions, RBBR was also decolorized completely in 6 d. The presence of phenolic compounds inhibited the decolorization at a concentration of 1 mM, but protocatechuic acid showed no inhibition. The results indicate that possibly anthraquinone type dyes such as RBBR act as enzyme substrates that are directly oxidized by laccase. <![CDATA[EFFICIENT ONE-POT SYNTHESIS OF BENZOXAZOLE DERIVATIVES CATALYZED BY NICKEL SUPPORTED SILICA]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200008&lng=es&nrm=iso&tlng=es A simple and efficient method has been developed for the synthesis of benzoxazoles from 2-aminophenol and substituted aldehydes in the presence of a catalytic amount of nickel supported silica at room temperature. <![CDATA[<b>METHOXYCARBONYLATION OF STYRENE BY PALLADIUM(II) COMPLEX CONTAINING THE DIPHENYLPHOSPHINOCYRHETRENE LIGAND</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200009&lng=es&nrm=iso&tlng=es The palladium-catalyzed methoxycarbonylation of vinylarenes has been investigated for the first time using phosphinocyrhetrene [(Ti5-C5H4PPh2)Re(CO)3] a non-metallocenic organometallic ligand. The catalytic system trans-[(T5-C5H4PPh2)Re(CO)3]PdCl2(NCMe)/PPh3 (1:2 ratio), carbon monoxide and methanol, in the presence of HCl as acidic promoter, showed good catalytic activity, excellent regioselectivity to the branched products and chemoselectivity up to 94%. <![CDATA[EXTRACTIVE SPECTROPHOTOMETRIC DETERMINATION OF KETOCONAZOLE, CLOTRIMAZOLE AND FLUCONAZOLE BY ION-PAIR COMPLEX FORMATION WITH BROMOTHYMOL BLUE AND PICRIC ACID]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200010&lng=es&nrm=iso&tlng=es The reactions of picric acid and bromothymol blue with three important antifungal drugs containing an imidazole ring ketoconazole (KC) and clotrimazole (CT) and fluconazole (FC) have been studied for the development of simple, rapid, sensitive an extractive-spectrophotometric method for determining the concentration of these drugs. This method is based on the formation of yellow ion-pair complexes between the basic nitrogen of the drug and sulphonphthalein acid dyes, namely; bromothymol blue (BTB) in phosphate buffer of pH =3 and picric acid (PA) in citrate buffer of pH=2.5. The formed complexes were extracted with chloroform and measured at 410 and 415nm for KC, at 410 and 413nm for CT and at 373 and 415nm for FC using PA and BTB, respectively. The analytical parameters and their effects on the reported systems are investigated. Beer's law was obeyed in the range 1-60 , 1-58 and 3-60 ìg/ mL with PA and 3-55, 2-50 and 5-55 ìg/ mL with BTB for CT, KC and FC, respectively. The composition of the ion pairs was found 1:1 by mole ratio and job0 s method in all cases. The proposed methods have been applied successfully for the analysis of the studied drugs in pure forms and pharmaceutical formulations.The results are in good agreement with those obtained by official methods. <![CDATA[ONE-POT SYNTHESIS OF HIGHLY LUMINESCENT CdTe QUANTUM DOTS USING SODIUM TELLURITE AS TELLURIUM SOURCE IN AQUEOUS SOLUTION]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200011&lng=es&nrm=iso&tlng=es A novel technology has been developed for the synthesis of thioglycolic acid (TGA)-capped CdTe quantum dots (QDs) in aqueous medium. The reaction was carried out in air atmosphere with one-pot by using Na2TeO3 to replace Te or Al2Te3. The mechanism for the formation of CdTe QDs is elucidated. The influences of various experimental variables, including refluxing time, pH value, Cd/Te and Cd/TGA molar ratios, on the luminescent properties of the obtained CdTe QDs have been systematically investigated. Furthermore, the obtained QDs were characterized by fourier transform infrared spectra (FTIR), X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), respectively. The results demonstrate that, under the optimized experimental conditions, the obtained CdTe QDs exhibited a narrow photoluminescence band (fwhm33-45 nm) with reproducible room-temperature quantum yields as high as 28 %, the emission color is tunable from green to orange with increasing diameter of QDs. <![CDATA[KRAFT PULPING OF <i>EUCALYPTUS GLOBULUS</i> AS A PRETREATMENT FOR BIOETHANOL PRODUCTION BY SIMULTANEOUS SACCHARIFICATION AND FERMENTATION]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200012&lng=es&nrm=iso&tlng=es The kraft pulping process was evaluated in this study as a pretreatment of Eucalyptus globulus for bioethanol production. Wood chips were pretreated under different pulping conditions (155°C and 165°C; 15 and 20 % alkali active AA, 15-60 min). A total of 12 pulps were obtained, with pulp yields ranging from 49 to 57%. Glucan remained in pulps were from 77% and 90%, while 50% of the hemicelluloses were solubilized. Lignin removal increased with increased severity of cooking (high active alkali charge, pretreatment time and temperature) reaching delignification over 78%. The enzymatic hydrolysis of kraft pulps with cellulase presented a rapid glucan conversion rate to glucose with values over 90%. Lignin, hemicellulose removal, as well as, cellulose polymerization degree showed an effect on the increment of enzymatic hydrolysis. The degree of crystallinity increased slightly between 1-5%, having no effect on the enzymatic hydrolysis. The simultaneous saccharification and fermentation was performed (SFS) at 10% substrate consistency with a production at 30-38 g ethanol/L. The maximum amount of ethanol that could be produced from E. globulus is 258 g ethanol/kg wood, assuming total glucose conversion into ethanol. The amounts of ethanol obtained from the different pulps varied between 168-202 g ethanol/kg wood. The ethanol yields obtained from kraft pulps varied between 65 and 78% (wood basis). The maximum ethanol yield was 78% at 155°C, 15% AA and 60 min reaction, while the yield was 74% at 165°C, 15% AA and 30 min of reaction time. Results showed that an efficient enzymatic hydrolysis at low enzyme loads could be obtained from kraft pulps employing less severe conditions than those used to produce bleachable -grade pulps. <![CDATA[NEW APPROACHES FOR THE SYNTHESIS OF HYDRAZONE DERIVATIVES AND THEIR ANTITUMOR EVALUATION]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200013&lng=es&nrm=iso&tlng=es The hydrazide-hydrazone 3 reacted with benzenediazonium chloride to give the phenylhydrazone derivative 5. The latter underwent a series of hetero-cyclization reactions to give pyridazine, 1,2,3-triazole and pyrazole derivatives. The antitumor evaluation of the newly synthesized products against the three cancer cells lines namely breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and CNS cancer (SF-268) showed that some of them have higher inhibitory effects towards the three cell lines compared to the standard. <![CDATA[TRIMETHYLSILYL CHLORIDE CATALYZED SYNTHESIS OF SUBSTITUTED BENZIMIDAZOLES USING TWO PHASE SYSTEM UNDER MICROWAVE CONDITIONS, AND THEIR ANTIMICROBIAL STUDIES]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200014&lng=es&nrm=iso&tlng=es A convenient method using TMSCl (20 mol %) and microwave-induced technique for the synthesis of various benzimidazole is described. This has reduced the reaction time drastically as well as improved the yield when compared to conventional heating. The synthesized compounds were evaluated for their in vitro antibacterial and antifungal activities against four strains each. Preliminary results indicated that, compounds 3e, 3f, 3g, 3k, 3m, 3n and 3o demonstrated very good antimicrobial activity, comparable to the first line standard drugs. The most effective compounds have exhibited activity at MIC of 6.25 μg/mL. <![CDATA[<b>BIOLOGICAL ACTIVITIES AND CORRELATIONS TENDENCY OF ELECTROCHEMICAL PROPERTIES OF SOME INDOLIZINO[1,2-B]QUINOLINE DERIVATIVES</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200015&lng=es&nrm=iso&tlng=es We report the preparation of a series of indolylquinone and pyridine derivatives in order to evaluate structure-activity relationships in human gastric (AGS), lung (SK-MES-1), bladder (J82) cancer cell lines and human normal lung fibroblasts (MCR-5). Two correlations tendency between half-wave redox potentials against their antineoplasic activity were found making it possible to establish that for epithelial human gastric cancer (AGS) cell lines and human normal lung fibroblasts (MCR-5). The quinone bioreduction should correspond to a one electron process under normomix conditions, whilst for all other lines this process should correspond to a two electron attachment via a hypoxic process. <![CDATA[KINETIC STUDY OF CHARGE TRANSFER COMPLEXES OF IODINE WITH SOME CROWN ETHERS IN NONAQUEOUS SOLVENTS]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200016&lng=es&nrm=iso&tlng=es Charge-transfer complexation of iodine with 15-crown-5(15C5), dicyclohexyl-18-crown-6 (DC18C6), benzo-18-crown-6 (B18C6) and dibenzo-24-crown-8 (DB24C8) has been studied in chloroform (CHCl3), Dichloromethane (DCM) and 1,2-dichloroethane (1,2-DCE) solutions at different time. The results indicated immediate formation of an electron donor-electron acceptor complex; which is followed by two relatively slow consecutive reactions. The pseudo-first-order rate constants for the formation of the ionic intermediate and the final product have been evaluated at 25 °C. The rate of formation of product has been measured as a function of time in different halocarbone solvents. The pseudo first order rate constants were evaluated from the absorbance- time data and found to vary in the order of 1,2-DCE >DCM >CHCl3. <![CDATA[<b>USING AN INDOL DERIVATIVE AS COMPLEXING AGENT FOR CLOUD POINT PRECONCENTRATION AND DETERMINATION OF MAGNESIUM AND SILVER IONS IN VARIOUS SAMPLES BY FAAS</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200017&lng=es&nrm=iso&tlng=es A very simple cloud point extraction (CPE) methodology for the preconcentration of trace amounts of silver and magnesium as a prior step for their determination by flame atomic absorption spectrometry (FAAS) has been developed. The method is based on the extraction of silver and magnesium at pH 10 by using non-ionic surfactant Triton X-114 and 4 methyl-3-((1-H-Indol-3-iyl) (phenyl) methyl)) -1-H-Indol (MPBIM) as a complexing agent. Several important variables that affect the CPE efficiency and FAAS signal were investigated and optimized. The calibration curves, using the preconcentration system, were linear in the range of 0.007-0.200 μg mL-1 with a correlation coefficient of 0.999. The lower limits of detection (3s) obtained in the optimal conditions were 1.47 ng mL-1 and 3.00 ng mL-1 for Mg²+ and Ag+ ions, respectively. The relative standard deviation for five replicate determinations of magnesium and silver at 0.133 μg mL-1 concentration level, were 1.17 and 0.97, respectively. The proposed method was successfully applied to the ultra-trace determination of silver and magnesium in various water samples, blood serum, urine, and radiology film samples. <![CDATA[ELECTROCHEMICAL SENSORS FOR DIRECT DETERMINATION OF SIMVASTATIN IN PHARMACEUTICAL FORMULATIONS AND BIOLOGICAL FLUIDS]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200018&lng=es&nrm=iso&tlng=es The construction and performance characteristics of simvastatin (SIM) selective electrodes were developed. Three types of electrodes: plastic membrane I, coated wire II, and coated graphite rod III were constructed based on the incorporation of simvastatin with phosphotungstic (PTA) or phosphomolybdic (PMA) acids and mixed ion pair (PTA/PMA) for the three electrodes, respectively. The influence of membrane composition, kind of plasticizer, type of ion-pair, pH of the test solution, soaking time, and foreign ions on the electrodes was investigated. The electrodes showed a Nernstain response with a mean calibration graph slope of 56.24±0.43, 55.44±0.14 and 58.93±0.34 mV decade-1 at 25°C over simvastatin concentration range from 1.0 x 10-6-5.0 x 10-2, 9.0 x 10-6-5.0 x 10-3 and 9.0 x 10-7-1.0 x 10-2 mol L-1, with detection limit of 5.0 x 10-7, 3.9 x 10-6 and 3.2 x 10-7 mol L-1 for electrode I, II and III, respectively. The pH range for the proposed electrodes was 4-7. The influence of possible interfering species such as common inorganic cations, many sugars, amino acids and a pharmacologically related drug 'ezetimibe' was studied. Statistical student's t-test and F test showed insignificant systematic error between proposed and official methods. <![CDATA[ELECTROCHEMICAL COPOLYMERIZATION OF CROSS-LINKABLE POLYTHIOPHENE AND CARBAZOLE]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200019&lng=es&nrm=iso&tlng=es The copolymerization of carbazole(C) and poly3-ethyl-3-({[6-(3-thienyl)hexyl]oxy}-methyl)oxetane(PTO) was successfully achieved electrochemically in CH2Cl2 containing 25% boron trifluoride diethyl etherate BFEE(by volume) as supporting electrolyte by direct anodic oxidation of the monomer mixtures on platinum or an optically transparent ITO electrode. As-formed copolymer own the advantages of PTO, such as good electrochemical behaviors, excellent ambient stability. The structure of the copolymer were investigated by UV-vis, fluorescence spectra and thermal analysis, respectively. The fluorescence spectra indicate that PPTOC films are yellow-light emitters. Thermal analysis studies confirmed PPTOC has a good thermal stability. <![CDATA[<b>PREPARATION AND CHARACTERIZATION OF BONDED-PHASES OF CALIXARENE-SULFONYL-CARBOXAMIDES IN PARTIAL-CONE CONFORMATION FOR DETERMINATION OF SALBUTAMOL IN LIVESTOCK BY NANO-MEDIATED BONDED-PHASES</b>: <b>NANO-BASKETS OF CALIXARENE IN PARTIAL-CONE CONFORMATION</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200020&lng=es&nrm=iso&tlng=es A new sensitive method for determination of salbutamol, as a nutrient repartitioning agent, in livestock is presented to protect the consumers. Eight nano-baskets of p-tert-calix[4]arene bearing di-[N-(X)sulfonyl carboxamide] and di-(1-propoxy) in partial-cone conformation were synthesized and were used to prepare bended phases of HPLC-UV. The new synthesized bonded-phases were characterized and optimized, the bonding interactions of solute and stationary phases were examined and the main interactions were reported. The results revealed that for the best bonded-phase, the LOD and LOQ were 0.02 and 0.06 μg/mL, respectively. <![CDATA[SOL-GEL INCORPORATION OF ORGANOMETALLIC COMPOUNDS INTO SILICA: USEFUL PRECURSORS TO METALLIC NANOSTRUCTURED MATERIALS]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200021&lng=es&nrm=iso&tlng=es Inclusion of the organometallic MLn = [HOC5H4N-Cp2TiCl][PF6] (1), HOC5H4N-W(CO)5 (2), HOC5H4N-Mo(CO)5 (3), [HOC6H4CH2CN-Cp2TiCl][PF6] (4), HOC6H4CH2CN-W(CO)5 (5) and HOC6H4CH2CN-Mo(CO)5 (6) into amorphous silica using the gelator precursor TEOS and N3P3{NH[CH2]3Si[OEt]3}6 afford the gels (MLn)(SiO2)n. The inorganic-organic hybrid nanocomposites were pyrolyzed under air at 800°C to give nanostructured metal oxides and/or metal pyrophosphates (phosphates) included in the silica matrices. The morphology of the monolithic nanocomposites exhibited a strong dependence on the gel precursor used being mainly laminar for those prepared using N3P3{NH[CH2]3Si[OEt]3} as gelator. TEM images show different shape and size such as circular nanoparticles, nanocables and agglomerates in some cases with sizes of 20 nm for the circular nanostructures, and diameter about 25 nm for the nanocables. <![CDATA[PVC/COPPER OXIDE COMPOSITES AND THEIR EFFECT ON BACTERIAL ADHERENCE]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200022&lng=es&nrm=iso&tlng=es In this work, PVC/CuO and PVC/Cu2O composites were prepared by melt-blending method. The results of scanning electron microscopy (SEM) - X ray energy dispersive spectroscopy (EDS) Cu-mapping showed that the composites are a hybrid of the polymer and the copper oxide particles, and these particles were distributed uniformly in the polymer matrix. The adherence of Escherichia coli ATCC 25922 on the surface of composite materials was assessed through the inventory of adhered viable cells and SEM analysis. In PVC/copper oxide composite, the number of adhered bacterial cells was reduced by almost 2 units log10 with regard to those adhere to the pure PVC polymer. SEM images of composite materials showed a significant decrease in bacterial adherence when compared to the pure polymer. It was also found through transmission electron microscopy (TEM) images to that E. coli incubated in the presence of cuprous oxide (Cu2O) and cupric oxide (CuO) microparticles go through structural and morphological changes at the membrane level. Bacterial cells incubated in the presence of Cu2O were bacillary with blunt ends, and their size was reduced by 30% when compared to those incubated in the absence of copper oxides. The results obtained indicate that the PVC/copper oxide composites inhibit the adhesion of E. coli to their surface. <![CDATA[SILICON-CONTAINING AROMATIC POLY(ESTERS) DERIVED FROM BIS(4-CARBOXYPHENYL)METHYL-R-SILANE AND BIS(4-(HYDROXYMETHYL) PHENYL)METHYL-R-SILANE: SYNTHESIS, CHARACTERIZATION AND THERMAL STUDIES]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200023&lng=es&nrm=iso&tlng=es This work describes the synthesis, characterization and thermal studies of poly(esters) (PEs) containing two Si atoms in the main chain, derived from aromatic diacids and aliphatic dialcohols in which the Si atom is bonded to methyl and/or ethyl groups. PEs were characterized by FT-IR and ¹H, 13C and 29Si spectroscopy and the results were in agreement with the proposed structures. Poly(esters) were soluble in polar aprotic solvents, such as DMSO and DMF, and acetone, and partially soluble in ethanol. The inherent viscosity and glass transition and thermal decomposition temperatures, h inh, Tg and TDT respectively, were determined. These results showed that PE-2 and PE-4, derived from the dialcohol with the -Si(CH3)(CH2CH3)- moiety as central element, had the larger values of h inh, Tg, TDT and the residual weight after heating at 900 °C, indicating that the specific structure of aliphatic dialcohols control the reaction. <![CDATA[COMPARISON THE DYE REMOVAL ACTIVITY OF SYSTEMS CONTAINED SURFACTANTS AND FUNGUS]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200024&lng=es&nrm=iso&tlng=es Dye decolorization ability of the systems contained only R. arrhizus, only cationic surfactants and both of them were studied. The optimal pH (3-7), initial dye (50-800 mg/L) and surfactant concentration (0.5 and 1 mM) for Alkythrimethyl ammonium bromide (CTAB) was determined in three days incubation period and the difference of Remazol Blue dye removal activity between Dodecylthrimethyl ammonium bromide (DTAB), Hegzadecylthrimethyl ammonium bromide (HTAB) and CTAB was identified. In the surfactant effect experiments it was observed that maximum dye removal activity occured in the system contained both fungus and 0.5 mM CTAB as, 77.52%, while the dye removal activity of only fungus and only CTAB were 21.2% and 71.2% in 100 mg/L dye concentration. The optimal conditions for dye removal were pH 5, low initial dye concentratios such as 100 mg/L and 1 mM CTAB concentration at the end of three days incubation period and the 95.4% dye removed by the sytem contained both fungus and CTAB. The dye removal activiy of the system contained fungus and cationic surfactants (DTAB, CTAB and HTAB) was compaired in the same optimal conditions and observed that maximum dye removal occured in the system that contained fungus and 1 mM HTAB, as 98.4%. The systems that contained surfactant and fungus are new approcahes for effective dye removal from textile effluents. According to this study, the CMC of surfactant is an important issue to increase dye removal efficiency. <![CDATA[A THEORETICAL STUDY ON THE MECHANISM OF THE ADDITION REACTION BETWEEN CYCLOPROPENYLIDENE AND ETHYLENE]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200025&lng=es&nrm=iso&tlng=es The reaction mechanism between cyclopropenylidene and ethylene has been systematically investigated employing the MP2/6-311+G* level of theory to better understand the cyclopropenylidene reactivity with unsaturated hydrocarbons. Geometry optimization, vibrational analysis, and energy property for the involved stationary points on the potential energy surface have been calculated. Energies of all the species are also further refined by the CCSD(T)/6-311+G* single-point calculations. Firstly, one important reaction intermediate (INTa) has been located via a transition state (TSa). After that, the common intermediate (INTb) for the two pathways (1) and (2) has been formed via TSb. At last, two different products possessing three- and four-membered ring characters have been obtained through two reaction pathways. In the reaction pathway (1), a three-membered ring alkyne compound has been obtained. As for the reaction pathway (2), a four-membered ring conjugated diene compound has been formed, which is the most favorable reaction to occur from the kinetic and thermodynamic viewpoints. <![CDATA[DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR THE ESTIMATION OF TRIFLUSAL IN BULK AND IN CAPSULE FORMULATION]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200026&lng=es&nrm=iso&tlng=es A simple, rapid, selective and sensitive RP-HPLC method was developed and validated for the estimation of triflusal. The method was carried out using 5-j1m particle size, C18-bonded silica column, quaternary pump and acetonitrile: 1 mM potassium dihydrogen phosphate (65:35 v/v) pH 3 as the mobile phase with UV detection at 226 nm. The proposed method is advantageous as it follows isocratic elution in short run time (10 min). The result obtained shown that the method best fits for estimation of drug in capsule formulation and thus can be used for its routine analysis. The newly developed method was validated according to the ICH guidelines with respect to specificity, linearity, accuracy, precision and robustness. <![CDATA[TOTAL AND MAIN As SPECIES PRESENT IN CARDIOVASCULAR TISSUES OF PEOPLE LIVINGIN As CONTAMINATED AREAS]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200027&lng=es&nrm=iso&tlng=es The concentration levels of As in the Chilean II Region of Antofagasta produces non cancer health outcomes such as cardiovascular diseases and in last term heart attack. On this study, the determination of total As content and main inorganic and organoarsenic species found in three heart tissues (auricle, mammary artery and fat) and the saphene vein of people living in the Chilean II Region, suffering coronary thrombosis has been carried out. Comparison with similar tissues of patients from other non-contaminated areas has been undertaken. The extraction of As species occurred in methanol: water (1:1) and As species determination have been used the tandem HPLC-ICP-MS using the Hamilton PRP X100 anion column. For total As determination has been performed by HG-AAS and ICP-MS. The auricle and in less extend the saphene support the higher As concentration (mean values of 7.7 and 2.5 μg g-1, respectively), being As(III) the predominant species. Methylarsonate (MA) and dimethylarsinate (DMA) is not a favoured mechanism. The presence of high total As and high As(III) species content in the auricle and saphene of more contaminated people, the damage found in the saphene tissue and the global characteristics of the people under study in which the As stigmas are present in all of them, suggests that As could be involved in the cardiovascular diseases. <![CDATA[SIMULTANEOUS DETERMINATION OF PIPERACILLIN AND TAZOBACTAM IN THE PHARMACEUTICAL FORMULATION TAZONAM® BY DERIVATIVE SPECTROPHOTOMETRY]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200028&lng=es&nrm=iso&tlng=es In this paper, a simple and rapid method was developed for the simultaneous determination of Piperacillin (PIP) and Tazobactam (TAZ) by second-order derivative spectrophotometry. Water was selected as a solvent for extraction and determination of both analytes. Further studies of photo-stability and forced degradation for both drugs were also performed. The spectral variables were optimized, a smoothing factor of 8·10³ and a scaling factor of 1·10(4) were selected and the analytical signals were evaluated at 296.3 nm and 233.3 nm for PIP and TAZ, respectively. The detection and quantification limits for PIP and TAZ were: 3.2•10-7 to 9.5•10-7 and 2.7•10-7 to 8.9•10-7 mol/L, respectively. The levels of repeatability (RSD) were 1.5% and 2.4% for PIP and TAZ respectively. The method was applied to the pharmaceutical formulation TAZONAM NF® Wyeth. USA, with a nominal content of 4.0 g of PIP, 0.5 g of TAZ, 0.139 g of citric acid and 1 mg of EDTA. A study of excipients was carried out and it was found that they do not interfere with quantification. By applying this method, a content of 3.96 ± 0.04 g and 0.57 ± 0.01 g was found of PIP and TAZ, respectively. <![CDATA[HYDROGENATION OF NITROBENZENE ON Au/ZrO<sub>2</sub> CATALYSTS]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072012000200029&lng=es&nrm=iso&tlng=es The hydrogenation of nitrobenzene at 298K and pressure of 40 bar of H2 over zirconia supported Au catalysts has been studied. Three different procedures were used to prepare 1wt% of Au/ZrO2 catalysts: i) An impregnation method using HAuCl4 as gold precursor ii)Depositation precipitation of Au nanoparticles generated in the presence of urea and iii) Deposition of Gold nanoparticles generated in presence of cetryltrimethylammonium bromide (CTMABR) as surfactant. The catalysts were characterized by nitrogen adsorption-desorption isotherms at 77 K, XRD, TEM and XPS techniques. The reactions were carried out in a stainless steel batch reactor using ethanol as solvent. The catalysts exhibits a higher selectivity to aniline, with low accumulation of intermediate products. The kinetic study displayed orders 1 respect to hydrogen pressure and to the substrate concentration (nitrobenzene), and the activation energy was 67.2 KJ/mol.