Residual biomass of coffee as a binding agent in diffusive gradients in thin-films technique for Cd, Cu, Ni, Pb and Zn measurement in waters

Lauren N M Yabuki; Amauri A Menegário; Hendryk Gemeiner; Ana Marta C M Rolisola; Didier Gastmans; Paul N Williams

doi:10.1016/j.talanta.2019.120148

Residual biomass of coffee as a binding agent in diffusive gradients in thin-films technique for Cd, Cu, Ni, Pb and Zn measurement in waters

Talanta. 2019 Dec 1:205:120148. doi: 10.1016/j.talanta.2019.120148. Epub 2019 Jul 17.

Authors

Lauren N M Yabuki¹, Amauri A Menegário², Hendryk Gemeiner³, Ana Marta C M Rolisola³, Didier Gastmans³, Paul N Williams⁴

Affiliations

¹ Universidade Estadual Paulista (Unesp), Instituto de Geociências e Ciências Exatas, Rio Claro, Av. 24 A, 1515, 13506-900, São Paulo, Brazil.
² Universidade Estadual Paulista (Unesp), Centro de Estudos Ambientais, Rio Claro, Av. 24 A, 1515, 13506-900, São Paulo, Brazil. Electronic address: amauri.antonio-menegario@unesp.br.
³ Universidade Estadual Paulista (Unesp), Centro de Estudos Ambientais, Rio Claro, Av. 24 A, 1515, 13506-900, São Paulo, Brazil.
⁴ Queen's University Belfast, Institute for Global Food Security, School of Biological Sciences, Belfast, BT9 5BN, United Kingdom.

PMID: 31450468
DOI: 10.1016/j.talanta.2019.120148

Abstract

Spent coffee grounds (SCG) immobilized in agarose gel are proposed as a novel binding agent for application in the Diffusive Gradients in Thin films (DGT) technique for the determination of Cd, Cu, Ni, Pb and Zn in waters. The SCG-agarose gel was characterized by Scanning Electron Microscopy, Energy Dispersive X-ray Spectrometry and Porosimetry by nitrogen adsorption. Elution of analytes from the binding agent was effectively performed with 2 mol L^-1 HCl. The effects of key DGT parameters (e.g. immersion time, ionic strength and pH) were evaluated with a deployment of DGT devices (DGT-SCG) in synthetic solutions with ionic strengths between 0.005 mol L^-1 and 0.1 mol L^-1 and within a pH range of 3.5-8.0. The results were in excellent agreement with the predicted theoretical curve for mass uptake. Consistent results were found for solutions with ionic strengths between 0.005 mol L^-1 and 0.1 mol L^-1 and within a pH range of 3.5-8.0. The DGT-SCG performance was also evaluated in two spiked river water samples (Corumbataí and Piracicaba river) with satisfactory uptake values (C_DGT-SCG/C_sol) between 0.74 and 1.53. The proposed DGT-SCG opens opportunities for using residual biomass as binding phase in the DGT technique, showing low costs in production and complying with "green" technology approaches.

Keywords: Labile species; Macro-DGT; Metal; River water; Spent coffee grounds.