Examinando por Autor "Ibarra, Laura"
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- PublicaciónSólo datosDevelopment of a novel electrochemical sensor based on cobalt(II) complex useful in the detection of dopamine in presence of ascorbic acid and uric acid(Journal of Electroanalytical Chemistry, 2017-02-01) Nagles, Edgar; Ibarra, Laura; Penagos-Llanos, Johisner; Hurtado, John; García-Beltrán, Olimpo[(Co(bdmpzm)2(NCS)2] (bdmpzm = bis(3,5-dimethylpyrazol-1-yl)methane) was synthesized and combined with single walled carbon nanotubes (SWCNT) and nafion on a screen printed carbon electrode (SPCE). The electrocatalytic activity of modified electrode (Nafion-SWCNT-[Co(bdmpzm)2(NCS)2]/SPCE) was evaluated for dopamine (DA) oxidation. Anodic and cathodic peak were seen to 0.42 V.and0.29 V respectively, showed a much more quasi-reversible process, (∆ V 0.128) compared with the electrode without cobalt complex. The detection limit (3σ/b) for dopamine was 0.095 μmol L− 1. The studies of reproducibility determined as relative standard deviation (RSD) was 2.5%.(n = 5) with four different electrodes. The repeatability were 1.5% (n = 5) The new sensor was used in the quantify DA in human urine with an average recovery between 83.0 and 93.0%.
- PublicaciónSólo datosElectrochemical sensors for dopamine using graphene-cobalt(II) complex modified glassy carbon electrode by adsorptive voltammetry(Analytical and Bioanalytical Electrochemistry, 2016-11-15) Cuadrado, Carol; Ibarra, Laura; Hurtado, John; García-Beltrán, Olimpo; Nagles, Edgar[Co(bdmpzm)2(NCS)2] (bdmpzm=bis(3,5-dimethylpyrazol-1-yl)methane) was dispersed in graphene oxide (GOx). Composite GOx-[Co(bdmpzm)2(NCS)2] was deposited on a glassy carbon electrode (GCE) and reduced at -1.0 by 60 s. The modified electrode rGOx-[Co(bdmpzm)2(NCS)2]/GCE allowed the oxidation for dopamine (DA) at 0.41 V Our results showed reversible and sensitive process, (∆V 0.09 V) compared with the electrode without modified in buffer phosphate solution pH 3.0. The detection limit (3σ/b) for dopamine was 0.11 µmol L-1 and the RSD was 3.0%. The presence of uric acid and ascorbic acid did not interfere with the signal for dopamine.
- PublicaciónSólo datosSynthesis, crystal structure, catalytic and anti-Trypanosoma cruzi activity of a new chromium(III) complex containing bis(3,5-dimethylpyrazol-1-yl)methane(Journal of Molecular Structure, 2017-06-01) Hurtado, John; Ibarra, Laura; Yepes, David; García-Huertas, Paola; Macías, Mario; Triana-Chavez, Omar; Nagles, Edgar; Suescun, Leopoldo; Muñoz-Castro, AlvaroThe reaction of CrCl36H2O with the ligand bis(3,5-dimethylpyrazol-1-yl)methane (L) yielded the cationic complex [(Cr(L)(H2O)2Cl2]+, which crystallized as the chloride trihydrate [(Cr(L)(H2O)2Cl2]Cl·3H2O. The chromium complex was characterized by elemental analysis, electrical conductivity, Infrared and Ultraviolet/Visible spectroscopy. The crystal structure determination using single-crystal X-ray diffraction showed a chromium center in a distorted octahedral coordination sphere. In the crystal, the packing was directed by OH⋯(O,Cl) hydrogen bonds and weak CH⋯O interactions to build a monoclinic P21/c supramolecular structure. The complex showed excellent properties as an initiator for the ring opening polymerization of є-caprolactone (CL) under solvent-free conditions. The obtained polymer showed high crystallinity (89.9%) and a decomposition temperature above 475 °C. In addition, the new complex was evaluated against epimastigotes from Trypanosoma cruzi (T. cruzi) strains. The results indicated that this complex has a high activity against this parasite with a minimum inhibitory concentration 50 (MIC50) of 1.08 μg/mL. Interestingly, this compound showed little effect on erythrocytes, indicating that it is not cytotoxic. These results provide interesting contributions to the design of metal complexes by using simple and accessible ligands with activity against T. cruzi and with potential applications in the polymerization of CL.
- PublicaciónSólo datosSynthesis, crystal structure, catalytic and anti-Trypanosoma cruzi activity of a new chromium(III) complex containing bis(3,5-dimethylpyrazol-1-yl)methane(Journal of Molecular Structure, 2017-06-01) Hurtado, John; Ibarra, Laura; Yepes, David; García-Huertas, Paola; Macías, Mario A.; Triana-Chavez, Omar; Nagles, Edgar; Suescun, Leopoldo; Muñoz-Castro, AlvaroThe reaction of CrCl36H2O with the ligand bis(3,5-dimethylpyrazol-1-yl)methane (L) yielded the cationic complex [(Cr(L)(H2O)2Cl2]+, which crystallized as the chloride trihydrate [(Cr(L)(H2O)2Cl2]Cl·3H2O. The chromium complex was characterized by elemental analysis, electrical conductivity, Infrared and Ultraviolet/Visible spectroscopy. The crystal structure determination using single-crystal X-ray diffraction showed a chromium center in a distorted octahedral coordination sphere. In the crystal, the packing was directed by Osingle bondH⋯(O,Cl) hydrogen bonds and weak Csingle bondH⋯O interactions to build a monoclinic P21/c supramolecular structure. The complex showed excellent properties as an initiator for the ring opening polymerization of є-caprolactone (CL) under solvent-free conditions. The obtained polymer showed high crystallinity (89.9%) and a decomposition temperature above 475 °C. In addition, the new complex was evaluated against epimastigotes from Trypanosoma cruzi (T. cruzi) strains. The results indicated that this complex has a high activity against this parasite with a minimum inhibitory concentration 50 (MIC50) of 1.08 μg/mL. Interestingly, this compound showed little effect on erythrocytes, indicating that it is not cytotoxic. These results provide interesting contributions to the design of metal complexes by using simple and accessible ligands with activity against T. cruzi and with potential applications in the polymerization of CL.