Mixed matrix membranes (MMMs) were prepared by incorporating organic surfactant-free hydrothermally synthesised ETS-10 and 1-ethyl-3-methylimidazolium acetate ionic liquid (IL) to chitosan (CS) polymer matrix. The membrane material characteristics and permselectivity performance of the two-component membranes were compared with the three-component membrane and the pure CS membrane. The addition of IL increased CO₂ solubility of the polymer, and, thus, the CO₂ affinity was maintained for the MMMs, which can be correlated with the crystallinity, measured by FT-IR, and void fraction calculations from differences between theoretical and experimental densities. The mechanical resistance was enhanced by the ETS-10 nanoparticles, and flexibility decreased in the two-component ETS-10/CS MMMs, but the flexibility imparted by the IL remained in three-component ETS-10/IL/CS MMMs. The results of this work provide insight into another way of facing the adhesion challenge in MMMs and obtain CO₂ selective MMMs from renewable or green chemistry materials.

There are only a few analytical techniques available that have sufficient sensitivity and selectivity for the determination and speciation of chromium in environmental waters. In this work, a non-chromatographic system is developed for the simultaneous determination of chromium(III) and chromium(VI) by solid phase extraction and inductively coupled plasma mass spectrometry (ICP-MS). The system is based on the use of three minicolumns packed, respectively, with chelating and anionic ion exchange resins, which were placed in the injection valve of a simple flow manifold. By using this device, diverse advantages are attained: speciation and simultaneous determination of Cr(III) and Cr(VI) as well as increase of the sensitivity and reduction of the interferences by the preconcentration. The effects of chemicals and flow variables were investigated. Detection limits (2 min sample loading time) were 0.009 μg L⁻¹ for Cr(VI) and 0.03 μg L⁻¹ for Cr(III). The relative standard deviations (n = 10) for 0.3 μg L⁻¹ of Cr(VI) and Cr(III) were 3.2% and 2.6%, respectively, demonstrating a good precision for the analysis. The accuracy of the proposed method was checked with certified reference materials. Values obtained were in accordance with those reported for the certified materials. The method was applied to the determination of chromium species in different seawater samples.