Hybrid nanocomposites based on Fe₃O₄ magnetic nanoparticles (MNPs) coated with different types of carbon nanotubes (CNTs) have been studied for the first time as sorbent materials for magnetic solid phase extraction (MSPE) for mercury speciation analysis. Monomethylmercury (MMHg) was the target mercury species in water samples and the adsorption and desorption processes were optimized based on this species. Single-walled CNT-MNP showed higher adsorption capacity than double-walled or multi-walled CNTs. Then, the magnetic sorbent was retrieved with an external magnet and MMHg was selectively desorbed from it with dichloromethane (DCM) in two steps with vortex agitation. Inorganic mercury was removed during the desorption stage. The rapid adsorption and desorption equilibrium, the magnetic separation of the sorbent, and the simple and fast synthesis of CNT-MNPs without any additional modification of the CNTs simplified and shortened the extraction procedure. The extract was submitted to derivatization of the mercury species by ethylation (with an optional nitrogen stream evaporation of the organic phase) and injection into a gas chromatograph coupled to an atomic fluorescence detector (GC-pyro-AFS). The overall procedure provides the preconcentration of MMHg up to 150 times and the removal of inorganic mercury at the same time. The procedural limits of detection (LOD) and quantification (LOQ) were 5.4 and 17.9 pg mL⁻¹, respectively. Moreover, magnetic nanocomposites can be reused at least 7 times without losing their efficiency. The methodology was validated in tap, dam and river water samples to evaluate the performance under real conditions with recoveries from 79% to 97% of spiked MMHg.

基于Fe ₃ O _4的杂化纳米复合材料首次研究了涂覆有不同类型碳纳米管（CNTs）的磁性纳米颗粒（MNP）作为吸附剂材料，用于磁性固相萃取（MSPE）进行汞形态分析。单甲基汞（MMHg）是水样品中的目标汞种类，并基于该种类优化了吸附和解吸过程。单壁CNT-MNP显示出比双壁或多壁CNT更高的吸附能力。然后，用外部磁体回收磁性吸附剂，并在两个步骤中通过涡旋搅拌选择性地用二氯甲烷（DCM）从中解吸MMHg。在解吸阶段去除了无机汞。快速的吸附和解吸平衡，吸附剂的磁分离，CNT-MNP的简单快速合成，无需对CNT进行任何其他修饰，简化并缩短了提取过程。提取物通过乙基化（​​可选的有机相氮气流蒸发）进行汞物种衍生化，然后注入与原子荧光检测器（GC-pyro-AFS）连接的气相色谱仪中。整个程序可对MMHg进行多达150次的预浓缩，并同时去除无机汞。检出限（LOD）和定量限（LOQ）分别为5.4和17.9 pg / mL 提取物通过乙基化（​​可选的有机相氮气流蒸发）进行汞物种衍生化，然后注入与原子荧光检测器（GC-pyro-AFS）连接的气相色谱仪中。整个程序可对MMHg进行多达150次的预浓缩，并同时去除无机汞。检出限（LOD）和定量限（LOQ）分别为5.4和17.9 pg / mL 提取物通过乙基化（​​可选的有机相氮气流蒸发）进行汞物种衍生化，然后注入与原子荧光检测器（GC-pyro-AFS）连接的气相色谱仪中。整个程序可对MMHg进行多达150次的预浓缩，并同时去除无机汞。检出限（LOD）和定量限（LOQ）分别为5.4和17.9 pg / mL^-1。此外，磁性纳米复合材料可重复使用至少7次，而不会损失其效率。该方法已在自来水，大坝和河水样本中进行了验证，以评估实际条件下的性能，其加标MMHg的回收率为79％至97％。