Solid phase extraction of arsenic on modified MWCNT/Fe3O4 magnetic hybrid nanoparticles from copper ores samples with ETAAS determination

A simple procedure for the synthesis of magnetic hybrid nanoparticles (MHNP) was developed by combining multi-walled carbon nanotubes modified by microwave energy and magnetic iron oxide nanoparticles. MHNP were introduced as sorbents in a magnetic solid phase extraction methodology for the total Arsenic determination in copper ore samples. Arsenic is penalized contaminant element in copper ores. Arsenic was determined by electrothermal atomic absorption spectrometry with a reduced temperature program. Arsenic adsorption corresponded to 96 - 104%, at ug g−1 levels. After a variable screening stage using a Placket-Burman (PBD) experimental design, the developed methodology was optimized using a Box-Behnken experimental design. Based on the optimal working parameters, a detection limit of 30 ng L−1 was reached, with a relative standard deviation of 7.1% and a preconcentration factor (PF) of 50. The Certified Geochem Base Metal Reference Material Product Code GBM900-10 was analyzed for the validation stage.Fil: Villafañe Salinas, Manuel Gastón. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; ArgentinaFil: Bazán, Vanesa. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; ArgentinaFil: Brandaleze, Elena. Universidad Tecnológica Nacional; ArgentinaFil: López, Ayelén. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; ArgentinaFil: Pacheco, Pablo Hugo. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Maratta Martínez, Sergio Ariel. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentin

Photocatalytic preconcentration of Bi on TiO2 nanoparticles

Titanium dioxide nanoparticles (NP-TiO2) are implemented for the dispersive micro-solid phase extraction of Bi by photocatalytic adsorption by UVA irradiation (365 nm) in the presence of ethanol as a sacrificial agent. The determination of bismuth was carried out by electrothermal atomic absorption spectrometry. The optimization stage was performed using the response surface method, implementing a Box-Behnken design. The proposed methodology does not require pH conditioning of the sample for Bi adsorption on NP-TiO2. The procedure reached limits of detection and quantification of 0.5 and 1.6 ng L−1 respectively. The relative standard deviation was 8.3% for a Bi solution of 50 ng L−1, with a preconcentration factor of 20 when 20 mL of sample were treated with 30 mg of NP-TiO2 and eluted with 1 mL of HNO3. The method was applied to the determination of Bi in digested copper ore samples, obtaining quantitative recoveries.Fil: Maratta Martínez, Sergio Ariel. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Villafañe Salinas, Manuel Gastón. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Brandaleze, Elena. Universidad Tecnológica Nacional; ArgentinaFil: Pacheco, Pablo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Bazán, Vanesa. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; Argentin

Antimony speciation analysis by hydride trapping on hybrid nanoparticles packed in a needle trap device with electro-thermal atomic absorption spectrometry determination

Oxidized multiwall carbon nanotubes (oxMWCNTs) were combined with TiO2 nanoparticles to obtain hybrid nanoparticles (HNPs). A miniaturized flow injection (FI) system was introduced for antimony speciation and a headspace vial was used for hydride generation. HNPs were introduced into a needle trap device (NTD) as a sorbent for antimony hydride preconcentration in gas phase trapping. Antimony hydrides were adsorbed on HNPs. Electrothermal Atomic Absorption Spectrometry (ETAAS) was used for determination. The synergistic effect of HNPs improves Sb adsorption compared to oxMWCNTs reaching the quantitative preconcentration of the analyte in 1 minute. However, NaBH4 concentration, HCl concentration and the elution volume were selected as variables for optimization. A Box-Behnken design indicated that the optimal response is achieved using 0.5% NaBH4 (m v-1), 1.5 mol L-1 HCl and 40 μL volume of elution. After optimization a retention efficiency of 99.8% was achieved with a preconcentration factor of 100. The limits of detection (LOD) and quantification (LOQ) were 0.4 and 1.2 ng L-1. The relative standard deviation was 7.9% (n = 10). The time of analysis was 14 minutes. The developed technique was successfully applied to the analysis of river water samples.Fil: Maratta Martínez, Sergio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Carrizo, Brian Gabriel. Universidad Nacional de San Juan. Facultad de Filosofía, Humanidades y Artes. Instituto de Ciencias Básicas; ArgentinaFil: Bazan Brizuela, Vanesa Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; ArgentinaFil: Villafañe Salinas, Manuel Gastón. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Investigaciones Mineras; ArgentinaFil: Martinez, Luis Dante. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Pacheco, Pablo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentin