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Quantification of TiO <sub/>2</sub> and ZnO nanoparticles in wastewater using inductively coupled plasma optical emission spectrometry
摘要： The applicability of inductively coupled plasma optical emission spectrometry has been examined for determination titanium dioxide and zinc oxide nanoparticles in industrial wastewater samples. The extraction and preconcentration of the nanoparticles were achieved using ligandless ultrasound-assisted surfactant-based dispersive liquid–liquid microextraction. Under optimized conditions, the developed method had limits of detection (LOD) of 2.7 ng L?1 for Ti and 3.6 ng L?1 for Zn resulting from dissolved TiO2 and ZnO nanoparticles. The relative standard deviation values for intraday precision were 2.5% and 3.1% for TiO2 and ZnO, while the interday precision was 4.5% and 5.0%. Percentage recoveries ranging from 98% to 100% were obtained. Finally, the applicability of the method was examined by analyzing spiked samples and wastewater samples collected from textile, cosmetic and paint industries.
关键词： Surfactant-based dispersive liquid–liquid microextraction,emerging contaminant,desirability function,engineered nanoparticles,wastewater
更新于2025-09-11 14:15:04
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DLLME-GC/ECD Method for the Residual Analysis of Parathion-Methyl and its Application in the Study of the UV-Photodegradation Process
摘要： A new method has been developed to determine trace levels of organophosphorus pesticide parathion-methyl in water samples by using dispersive liquid-liquid microextraction (DLLME), followed by gas chromatograph coupled with electron capture detector (GC/ECD) analysis. The optimized and validated method showed high extraction recovery (101.1%), high enrichment factor (57.3), low limits of detection and quantification, 0.083 and 0.250 μg L-1, respectively. The established DLLME-GC/ECD method has been successfully applied for the evaluation of the photodegradation of the parathion-methyl by UV254nm radiation in different conditions of pH and temperature. The parathion-methyl photodegradation at pH 3 and 35 °C achieved > 99.5% after 120 min of exposition. For this condition, it was observed the kinetic rate of 0.0515 min-1, the quantum yield of 1.22 × 10-5 mol Einstein-1 and a half-life time of 13.46 min. All experimental conditions tested proved to be strongly influenced by pH and temperature. The application of the optimized process in distilled and drinking water spiked with parathion-methyl provided residues of this pesticide at levels below the maximum permitted by Brazilian legislation, which is 9.0 μg L-1.
关键词： UV radiation,degradation,gas chromatography,pesticide,dispersive liquid-liquid microextraction
更新于2025-09-11 14:15:04