Dicyclohexano 18 crown 6 dch18c6

Tricaprylammonium chloride (Aliquat® 336, [A336][Cl], 88.2–90.6%), dicyclohexano-18-crown-6 (DCH18C6, ≥98%), LiCl (99%) and HNO₃ (≥65%) were purchased from Sigma-Aldrich (Diegem, Belgium). SmCl₃·6H₂O (99.9%) and Eu(NO₃)₃·6H₂O (99.9%) were purchased from Strem Chemicals, Inc. (Newburyport, USA). Sm(NO₃)₃·6H₂O (99.9%) and LiNO₃ (anhydrous, 99%) were purchased from Alfa Aesar (Karlsruhe, Germany). EuCl₃·6H₂O (99.9%), Sr(NO₃)₂ (99.9%) and granular zinc (30 mesh, ≥99.7%) were purchased from Acros Organics (Geel, Belgium). SrCl₂·6H₂O (≥99%), NH₄Cl (≥99.8%), Na₂SO₄ (≥99%) and acetonitrile (≥99.5%) were purchased from Chem-Lab (Zedelgem, Belgium), as well as the Sm, Eu, Zn and Cu standard solutions (≥99.99%, 1000 μg mL⁻¹, 2–5% HNO₃, Plasma HIQU). NH₄NO₃ (≥99%) was purchased from Merck Millipore (Darmstadt, Germany). All products were used as received, without any further purification steps. Aqueous samples were prepared with Milli-Q water (18.2 MΩ cm at 25 °C).