A new approach for the determination of As, Cu, and Pb in seawater samples using manganese oxide octahedral molecular sieve as a sorbent for dispersive solid-phase microextraction

Marina Araujo J Lopes da Costa; Mariana F Costa; Rayane Sorrentino; Nakédia M F Carvalho; Jefferson S de Gois

doi:10.1016/j.talanta.2023.125320

A new approach for the determination of As, Cu, and Pb in seawater samples using manganese oxide octahedral molecular sieve as a sorbent for dispersive solid-phase microextraction

Talanta. 2024 Feb 1;268(Pt 1):125320. doi: 10.1016/j.talanta.2023.125320. Epub 2023 Oct 21.

Authors

Marina Araujo J Lopes da Costa¹, Mariana F Costa², Rayane Sorrentino³, Nakédia M F Carvalho⁴, Jefferson S de Gois⁵

Affiliations

¹ Rio de Janeiro State University, Graduate Program in Chemical Engineering, Rua Sāo Francisco Xavier 524 - Maracanā, Rio de Janeiro, RJ, 20550-013, Brazil.
² Rio de Janeiro State University, Department of Analytical Chemistry, Rua São Francisco Xavier 524, Maracanã, Rio de Janeiro, RJ, 20550-013, Brazil.
³ Federal University of Bahia, Interdisciplinary Center of Energy and Environment, Barão de Jeremoabo S/N - Campus de Ondina, Salvador, BA, 40170-115, Brazil.
⁴ Rio de Janeiro State University, Department of General and Inorganic Chemistry, Rua São Francisco Xavier 524, Maracanã, Rio de Janeiro, RJ, 20550-013, Brazil.
⁵ Rio de Janeiro State University, Graduate Program in Chemical Engineering, Rua Sāo Francisco Xavier 524 - Maracanā, Rio de Janeiro, RJ, 20550-013, Brazil; Rio de Janeiro State University, Department of Analytical Chemistry, Rua São Francisco Xavier 524, Maracanã, Rio de Janeiro, RJ, 20550-013, Brazil. Electronic address: jefferson.gois@uerj.br.

PMID: 37890371
DOI: 10.1016/j.talanta.2023.125320

Abstract

This study introduces a novel method for preconcentrating As, Cu, and Pb from seawater samples using manganese oxide octahedral molecular sieve (OMS-2), as a sorbent, and the analysis by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The OMS-2 nanomaterial was synthesized and characterized using X-ray diffraction and scanning electron microscopy, revealing a crystallite size of 20.9 nm and a typical needle-like morphology of cryptomelane structure. To optimize the ICP-OES operating conditions and the preconcentration process, a central composite design was used. The optimal conditions for ICP-OES analyses were 1200 W and 0.7 L min^-1 for the levels of the radio frequency potential (RF) and nebulization gas flow rate, respectively. The optimal conditions for the adsorption process were achieved at a pH of 6.5, 30 mg of OMS-2, and 35 min of stirring time, in the presence of the sample matrix. The enrichment factors obtained were 66, 45, and 21, and a limit of detection of 0.3, 0.1, and 2.1 μg L^-1 for As, Cu, and Pb, respectively. The recovery tests ranged from 80 % to 120 %. The method was successfully applied to determine As, Cu, and Pb in seawater samples.

Keywords: DMSPE; ICP-OES; Molecular sieve; OMS-2; Preconcentration; α-MnO(2).