Examinando por Materia "Tartrazine"
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- PublicaciónSólo datosA New Electrochemical Method to Detect Sunset Yellow, Tartrazine and Thiomersal in a Pharmaceutical Dose Using a Carbon Paste Electrode Decorated with Molybdenum Oxide(Electroanalysis, 2020-07-09) Penagos‐Llanos, Johisner; García‐Beltrán, Olimpo; Nagles, Edgar; Hurtado, John J.His report allowed the detection of three substances using a carbon paste decorated with MoO2 (MoO/CPE). Tartrazine (TZ), sunset yellow (SY) and thiomersal (TMS) were analyzed for adsorptive voltammetry. The electrode was characterized by scanning electron microscopy, energy dispersive spectroscopy and cyclic voltammetry. TZ, SY and TMS were observed at 1.07, 0.80 and 0.95 V respectively. The detection limits (3*σ/m) for TZ, SY and TMS were 0.04, 0.06 and 0.10 μmol/L, respectively. The new analytical method was applied using pharmaceutical samples.
- PublicaciónSólo datosAdsorptive Stripping Voltammetric Determination of Amaranth and Tartrazine in Drinks and Gelatins Using a Screen-Printed Carbon Electrode(Sensors, 2017-11-15) Perdomo, Yeny; Arancibia, Verónica; García-Beltrán, Olimpo; Nagles, EdgarA fast, sensitive, and selective method for the simultaneous determination of one pair of synthetic colorants commonly found mixed in food products, Amaranth (AM) and Tartrazine (TZ), based on their adsorption and oxidation on a screen-printed electrode (SPE) is presented. The variation of peak current with pH, supporting electrolyte, adsorption time, and adsorption potential were optimized using square wave adsorptive voltammetry. The optimal conditions were found to be: pH 3.2 (PBS), Eads 0.00 V, and tads 30 s. Under these conditions, the AM and TZ signals were observed at 0.56 and 0.74 V, respectively. A linear response were found over the 0.15 to 1.20 µmol L−1 and 0.15 to 0.80 µmol L−1 concentrations, with detection limits (3σ/slope) of 26 and 70 nmol L−1 for AM and TZ, respectively. Reproducibility for 17.7 µmol L–1 AM and TZ solutions were 2.5 and 3.0% (n = 7), respectively, using three different electrodes. The method was validated by determining AM and TZ in spiked tap water and unflavored gelatin spiked with AM and TZ. Because a beverage containing both AM and TZ was not found, the method was applied to the determination of AM in a kola soft drink and TZ in an orange jelly and a soft drink powder.
- PublicaciónSólo datosDevelopment of a Novel Electrochemical Sensor Based on a Carbon Paste Electrode Decorated with Nd2O3 for the Simultaneous Detection of Tartrazine and Sunset Yellow(Electroanalysis, 2018-09-21) Marquez‐Mariño, Karen; Penagos-Llanos, Johisner; García-Beltrán, Olimpo; Nagles, Edgar; Hurtado, JohnThe simultaneous detection of tartrazine (TZ) and sunset yellow (SY) using a carbon paste‐decorated neodymium (III) oxide electrode (NdOx/CPE) is reported for the first time in this work. The surface properties of the NdOx/CPE were studied by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. The anodic peak currents for TZ and SY increased by more than 60 %, and the anodic peak potentials for TZ and SY were observed at potential values less positive than those of the carbon paste without NdOX. Under the optimal parameters (pH 3.0; accumulation time tACC 30 s; and accumulation potential EACC 0.10 V), the detection limits for TZ and SY observation were 0.02 μmol L−1 (10.6 μg L−1) and 0.09 μmol L−1 (40.6 μg L−1), respectively. The new sensor was sensitive, stable, easily manufactured, and very convenient for the detection of TZ and SY in food samples and pharmaceutical materials and provided consistent results.
- PublicaciónSólo datosVoltammetric determination of amaranth and tartrazine with a new double-stranded copper(I) helicate-single-walled carbon nanotube modified screen printed electrode(Journal of Electroanalytical Chemistry, 2018-05-26) Nuñez-Dallos, Nelson; Macías, Mario; García-Beltrán, Olimpo; Calderón, Jorge A.; Nagles, Edgar; Hurtado, JohnIn this work, we report the synthesis of a new double-stranded copper(I) helicate (H) and its use for the first time in a single-walled carbon nanotube-modified screen printed electrode (SWCNT/SPCE) for the voltammetric determination of amaranth (AM) and tartrazine (TZ). H was synthesized through a self-assembly process between Cu(I) iodide and 1,3-bis(1H-benzotriazol-1-ylcarbonyl)benzene (L). The compound was structurally characterized by infrared, photoluminescence spectroscopy, elemental and thermogravimetric analyses as well as single-crystal and powder X-ray diffraction. The SWCNT/SPCE was coated with H by simple drop casting, and the surface (H-SWCNT/SPCE) was characterized using cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and Raman spectroscopy. The presence of H on the surface of the modified electrode reduces the charge transfer resistance of the redox couple and improves the sensitivity toward the oxidation of AM and TZ with oxidation current increases of almost 80% and 60%, respectively, thus allowing their determination using square-wave adsorptive stripping voltammetry (SWAdSV). The detection limits (3σ/b) were 30.0 and 60.0 nmol L−1 for AM and TZ, respectively. The relative standard derivation was 3.5% (n = 7) with three different electrodes. Furthermore, the new sensor was applied in the detection of these dyes in commercial samples such as synthetic orange juice and a soft drink.