Development and Validation of flow methods with electrochemical detection for application in studies of interactions of Hg (II), As (III) and Se (IV) with naturally occurring heterogeneous ligands

• Grant number: 12/08065-1
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): July 01, 2012
• Effective date (End): June 30, 2016
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal researcher: Jorge Cesar Masini
• Grantee: Fernando Henrique Do Nascimento
• Home Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This project proposes the development and validation of flow methodologies with electrochemical detection (stripping chronopotentiometry or stripping voltammetry) for the determination of Hg(II), As(III) and Se(IV). These methods will be used in studies of interactions of these species with heterogeneous naturally occurring ligands and microalgae, in addition to assessing how these interactions are affected by the chemical composition of the solution, especially under different conditions of pH and ionic strength. For this study we intend to explore the use of screen printed sensors with gold working electrode (modified or not with sulfhydryl compounds) in automated sequential injection or flow injection systems. The analysis of speciation is important to assess chemical reactivity of the species of interest, allowing one to estimate the bioavailability and toxicity. We expect to contribute with more sensitive, selective and robust methodologies involving portable equipment for the determination of Hg(II), As(III) and Se(IV) as well as to contribute to a better understanding of the role of heterogeneous naturally occurring ligands and of microalgae in the mobility of these species in the environment.For the development and validation of methods, parameters such as accuracy, precision, selectivity, linearity, limits of detection and quantitation and robustness will be evaluated. Adsorption isotherms of Hg(II), As (III) and Se (IV) will be constructed in the presence of suspensions of naturally occurring ligands, as well as in ternary and / or quaternary systems containing the mixture of the ion and of different ligands that we intend to study, trying to mimic environmental conditions. The data of the isotherms will be treated by the Langmuir and Freundlich equation and distribution functions of equilibrium constants, which allow one to evaluate the stability of the binding as a function of the degree of occupation of the adsorption sites / complexation. These computations will allow one to quantify the interaction energy (and thus their physical or chemical nature), the adsorption capacity and the degree of heterogeneity of the adsorption sites.

Scientific publications

(5)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DO NASCIMENTO, FERNANDO H.; MASINI, JORGE CESAR. An electrochemical sequential injection method to investigate the adsorption of selenite on Fe(III) polyhydroxy cations intercalated vermiculite. WATER SCIENCE AND TECHNOLOGY, n. 1, p. 134-143, APR 2018. Web of Science Citations: 2.

DO NASCIMENTO, FERNANDO H.; RIGOBELLO-MASINI, MARILDA; DOMINGOS, RUTE F.; PINHEIRO, JOSE P.; MASINI, JORGE C. Dynamic interactions of Hg(II) with the surface of green microalgae Chlamydomonas reinhardtii studied by stripping chronopotentiometry. ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS, v. 24, n. A, p. 347-353, JUN 2017. Web of Science Citations: 1.

DO NASCIMENTO, FERNANDO HENRIQUE; DE SOUZA COSTA, DIEGO MIRANDA; MASINI, JORGE CESAR. Evaluation of thiol-modified vermiculite for removal of Hg(II) from aqueous solutions. APPLIED CLAY SCIENCE, v. 124, p. 227-235, MAY 2016. Web of Science Citations: 13.

DO NASCIMENTO, FERNANDO HENRIQUE; MASINI, JORGE CESAR. Sequential Injection Assisted Stripping Chronopotentiometry at Screen Printed Gold Electrodes for Determination of Hg(II) in Adsorption Studies. Analytical Letters, v. 49, n. 5, SI, p. 699-710, MAR 23 2016. Web of Science Citations: 5.

DO NASCIMENTO, FERNANDO HENRIQUE; MASINI, JORGE CESAR. Influence of humic acid on adsorption of Hg(II) by vermiculite. Journal of Environmental Management, v. 143, p. 1-7, OCT 1 2014. Web of Science Citations: 19.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

NASCIMENTO, Fernando Henrique Do. Development of methods of sequential injection analysis with electrochemical detection for application in interaction studies of Hg(II), As(III) and Se(IV) with heterogeneous naturally occurring ligands. 2016. Doctoral Thesis - Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) São Paulo.