Dithizone functionalized carbon nanofibers as novel nanomaterial for microextraction and determination of mercury in non-alcoholic beverages

In this work, a new nanomaterial obtained by surface functionalization of carbon nanofibers with dithizone (CNF@DTZ) was implemented as adsorbent in the dispersive micro-solid phase extraction technique. Preconcentration and determination of Hg in non-alcoholic beverage samples including fruit juices and drinking water were performed with the proposed method. Important parameters of the extraction and back-extraction steps were optimized. Using 3 mg CNF@DTZ only, an extraction efficiency of 98.0 % was achieved for 30 mL of sample. Quantitative back-extraction was achieved with 600 µL of 12 mol/L HCl. A sensitivity enhancement factor of 50 was obtained. The calibration curve was linear in the range from 0.23 to 4.0 µg/L, the LOD was 0.07 µg/L and the RSD% was 3.5 % (2 µg/L Hg, n = 10). This methodology was successfully applied on spiked samples with recoveries from 96.0 to 100 %. This work reports the first application of CNF@DTZ in the dispersive microsolid phase extraction technique for trace Hg determination in non-alcoholic beverages.Fil: Carrizo, Brian Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentina. Universidad Nacional de San Juan; ArgentinaFil: Fiorentini Chirino, Emiliano Franco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Wuilloud, Rodolfo German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; ArgentinaFil: Escudero, Leticia Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; 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