Efficient solid phase extraction of α-tocopherol and ß-sitosterol from sunflower oil waste by improving the mesoporosity of the zeolitic adsorbent.

The recovery of α-tocopherol and ß-sitosterol from the deodorizer distillate of sunflower oil using solid phase extraction is reported. Performance of the silicon-rich and inexpensive zeolite, ZSM-5, and its modified versions were compared as adsorbents. Modifications of the zeolite frame were performed under both acidic and basic conditions to desilicate and dealuminate the parent ZSM-5. Base treatment resulted in hierarchical porosity and increased mesoporosity in the structure, which made the desilicated material as the best adsorbent of the study. Optimization of the solid phase extraction conditions was also studied and high recoveries of α-tocopherol and ß-sitosterol, up to 99.20% and 97.32%, respectively, were achieved. The preparation and characterisation of the reported sorbents, as high-performance adsorbents, were not only proved to be economically promising, due to recycling of nutritious products, but also improves the ecological credentials of the process through reduction in waste.

A New Dispersive Liquid-Liquid Microextraction Method for Preconcentration and Determination of Aluminum, Iron, Copper, and Lead in Real Water Samples by HPLC.

In this study, dispersive liquid-liquid microextraction coupled with HPLC with variable-wavelength detection was applied for the simultaneous determination of Al, Fe, Cu, and Pb in various water samples at trace levels. In the proposed method, all the system parameters in both the extraction and separation/determination steps, such as extraction and disperser solvent type and their volumes, complexing reagent concentration, salt addition, extraction and centrifugation times, and pH, were optimized to get not only high extraction efficiency but also lower LODs for the analytes. Hematoxylin was used as a complexing reagent, and carbon tetrachloride and methanol were chosen as the extraction and disperser solvents, respectively. Metal complexes were separated with a reversed-phase C18 column by isocratic elution, with methanol-tetrahydrofuran-water (20 + 12 + 68, v/v/v) as the mobile phase at a flow rate of 1.0 mL/min and detection at 575 nm. The accuracy of the method was checked by a Standard Reference Material of water (SRM 1643e), and the recovery values for the analytes were found in the range of 95.6-101.3%. Under the optimum conditions, the developed method was applied to tap water, bottled mineral water, lake water, and seawater for the accurate and sensitive determination of the analytes of interest.