Herce-Sesa Belén, López-López José A, Moreno Carlos
Department of Analytical Chemistry, Faculty of Marine and Environmental Sciences, Institute of Marine Research (INMAR), University of Cádiz, 11510, Puerto Real, Cádiz, Spain.
Anal Bioanal Chem. 2025 Mar;417(7):1369-1379. doi: 10.1007/s00216-024-05655-5. Epub 2024 Nov 28.
In this work, we explore a new dispersive liquid-liquid microextraction (DLLME) method to selectively separate chemical species of Cd and Zn in saline waters. It is based on the use of the magnetic ionic liquid (MIL) methyltrioctylammonium tetrachloroferrate ([N][FeCl]), which allows an efficient and environmentally friendly extraction of the target species. In addition, the paramagnetic component in the MIL simplifies the separation step required in DLLME, allowing for fast separation and recovery of the extracted species with a magnet, without a centrifugation step. The optimum conditions for the separation by MIL-DLLME were 3.3 mg mL MIL, sample pH = 8, and an extraction time of 30 min. Under these conditions, metal chlorocomplexes (99.7% and 81.0% of total metal concentration for Cd and Zn, respectively) were quantitatively separated, remaining the free cations in the aqueous samples. In a second step, the extracted metal species were back-extracted with 1 mol L HNO and a re-extraction time of 15 min. For cadmium, this acidic solution separated the neutral complex CdCl (60.5%), while CdCl (21.5%) and CdCl (18.1%) remained in the organic phase. For Zn, the anionic complex ZnCl (17.3%) was retained by the organic reagent, while ZnCl (45.7%) and ZnCl (37.0%) were re-extracted by the nitric acid solution. The separation of the chemical species of metals along the three liquid phases used allowed their quantification in several samples of real seawater and a certified reference material.
在本研究中，我们探索了一种新的分散液液微萃取（DLLME）方法，用于选择性分离盐水中的镉和锌化学物种。该方法基于使用磁性离子液体（MIL）四氯铁酸甲基三辛基铵（[N][FeCl]），它能高效且环保地萃取目标物种。此外，MIL中的顺磁性成分简化了DLLME所需的分离步骤，无需离心步骤，用磁铁即可快速分离并回收萃取的物种。MIL-DLLME分离的最佳条件为3.3 mg mL MIL、样品pH = 8以及萃取时间30分钟。在此条件下，金属氯配合物（镉和锌分别占总金属浓度的99.7%和81.0%）被定量分离，水样中的游离阳离子得以保留。第二步，用1 mol L HNO反萃取萃取的金属物种，反萃取时间为15分钟。对于镉，该酸性溶液分离出中性配合物CdCl（60.5%），而CdCl（21.5%）和CdCl（18.1%）保留在有机相中。对于锌，有机试剂保留了阴离子配合物ZnCl（17.3%），而ZnCl（45.7%）和ZnCl（37.0%）被硝酸溶液反萃取。沿着所使用的三个液相分离金属化学物种，使得它们能够在多个实际海水样品和一种有证标准物质中进行定量分析。
