Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Waehringer Strasse 42, 1090 Vienna, Austria.
Department of Analytical Chemistry, Faculty of Marine and Environmental Sciences, Instituto de Investigación Marina (INMAR), University of Cádiz, 11510 Puerto Real, Spain.
Molecules. 2018 Nov 17;23(11):3011. doi: 10.3390/molecules23113011.
Developments in the liquid micro-extraction of trace metals from aqueous phases have proven to be limited when extended from pure water to more complex and demanding matrices such as sea water or wastewater treatment effluents. To establish a system that works under such matrices, we successfully tested three task-specific ionic liquids, namely trihexyltetradecyl- phosphonium-, methyltrioctylphosphonium- and methyltrioctylammonium 3-hydroxy-2-naphthoate in two-phase solvent bar micro-extraction (SBME) experiments. We describe the influence of pH, organic additives, time, stirring rate and volume of ionic liquid for multi-elemental micro-extraction of Cu, Ag, Cd and Pb from various synthetic and natural aqueous feed solutions. Highest extraction for all metals was achieved at pH 8.0. Minimal leaching of the ionic liquids into the aqueous phase was demonstrated, with values < 30 mg L DOC in all cases. Sample salinities of up to 60 g L NaCl had a positive effect on the extraction of Cd, possibly due to an efficient extraction mechanism of the present chlorido complexes. In metal-spiked natural feed solutions, the selected SBME setups showed unchanged stability under all conditions tested. We could efficiently (≥85%) extract Cu and Ag from drinking water and achieved high efficacies for Ag and Cd from natural sea water and hypersaline water, respectively. The method presented here proves to be a useful tool for an efficient SBME of heavy metals from natural waters without the need to pretreat or modify the sample.
从纯水扩展到更复杂和苛刻的基质，如海水或废水处理厂的出水，证明痕量金属的液相微萃取技术的发展受到限制。为了在这种基质下建立一个可行的系统，我们成功地测试了三种任务特定的离子液体，即三己基十四烷基膦、甲基三辛基膦和甲基三辛基铵 3-羟基-2-萘酸酯，用于两相溶剂棒微萃取（SBME）实验。我们描述了 pH 值、有机添加剂、时间、搅拌速度和离子液体体积对从各种合成和天然水进料溶液中多元素 Cu、Ag、Cd 和 Pb 的微萃取的影响。所有金属的最高萃取都在 pH 值为 8.0 时达到。证明了离子液体最小程度地浸出到水相中，所有情况下均<30mg L DOC。高达 60g L NaCl 的样品盐度对 Cd 的萃取有积极影响，这可能是由于当前氯络合物的有效萃取机制。在金属掺杂的天然进料溶液中，所选的 SBME 装置在所有测试条件下均表现出不变的稳定性。我们能够从饮用水中高效（≥85%）提取 Cu 和 Ag，并分别从天然海水和高盐水体中高效提取 Ag 和 Cd。这里提出的方法被证明是一种从天然水中高效萃取重金属而无需预处理或修饰样品的有用工具。
