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

• Published in: Talanta (Oxford) 2024-02, Vol.268, p.125320-125320, Article 125320
• Main Authors: Lopes da Costa, Marina Araujo J., Costa, Mariana F., Sorrentino, Rayane, Carvalho, Nakédia M.F., de Gois, Jefferson S.
• Format: Article
• Language: English
• Subjects: adsorption; atomization; crystallites; detection limit; DMSPE; electron microscopy; ICP-OES; manganese monoxide; Molecular sieve; nanomaterials; OMS-2; Preconcentration; radio waves; seawater; solid phase microextraction; sorbents; spectroscopy; X-ray diffraction; α-MnO2
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2023.125320

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. [Display omitted] •A new material was applied for the determination of As, Cu, and Pb.•The factors affecting the separation were optimized using chemometrics.•Very sensitive method was achieved for As, Cu, and Pb determination.