Noteworthy Method for Direct Determination of Sb III and Total Inorganic Antimony in Natural Waters

A procedure was developed for the direct determination of Sb III and total inorganic Sb in water samples by hydride generation atomic absorption spectrometry (HG AAS), without prereduction of Sb V . The NaBH 4 concentration was maintained at 0.4% (m/v) to perform the selective generation of stibine from Sb III and online stibine generation was carried out with 5.0% (m/v) NaBH 4 to obtain the total antimony concentration. Sb V was calculated as the difference between the values obtained for total Sb and Sb III . In both cases, the procedure did not appear to be adversely affected by potential interferents such as Sb Sb III and 0.4% for 10.0 µg L -1 total Sb. A sampling rate of approximately 30 determinations per hour was achieved, requiring 300 mL of NaBH 4 , and the amount of waste generated was in order of 960 mL, indicating that this analytical procedure can be considered as green. The method was shown to be satisfactory for the determination of trace levels of antimony in water samples. The result obtained for the assaying of certified drinking water samples was 9.7 ± 0.1 µg L -1 (certified value 10.0 ± 0.5 µg L -1 )

Numerical simulation of the liquid phase in SnO(2) thin film deposition by sol-gel-dip-coating

The fluid flow of the liquid phase in the sol-gel-dip-coating process for SnO(2) thin film deposition is numerically simulated. This calculation yields useful information on the velocity distribution close to the substrate, where the film is deposited. The fluid modeling is done by assuming Newtonian behavior, since the linear relation between shear stress and velocity gradient is observed. Besides, very low viscosities are used. The fluid governing equations are the Navier-Stokes in the two dimensional form, discretized by the finite difference technique. Results of optical transmittance and X-ray diffraction on films obtained from colloidal suspensions with regular viscosity, confirm the substrate base as the thickest part of the film, as inferred from the numerical simulation. In addition, as the viscosity increases, the fluid acquires more uniform velocity distribution close to the substrate, leading to more homogenous and uniform films.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPESConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPqFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESPINCT-MACCINCT-MAC