Preparation of flowerlike metal/metal oxides nanostructures derived from layered double hydroxide on nanoporous anodic aluminum oxide/aluminum wire as solid-phase microextraction fiber

In this study, a hierarchical CoAl layered double hydroxide (CoAl-LDH) has been fabricated via the in situ crystallization technique on nonporous anodic aluminum oxide/aluminum wire (AAO/Al) as both the substrate and the aluminum source. Then hierarchical peony-like metal/metal oxides (Co/Al2O3 and Co3O4/Al2O3) composites assembled with uniform nanosheets were successfully synthesized using CoAl Layered double hydroxides as self-sacrificial templates. The prepared wire with high surface area and compact structure was used as solid phase microextraction (SPME) fiber for separation and determination of benzene, toluene, ethylbenzene and xylene (BTEX) from aqueous solutions in combination with gas chromatography-flame ionization detector (GC-FID). SPME is a solvent-free microextraction technique applicable for the extraction of analytes from various matrices. In spite of the great applicability of SPME method, it has some major difficulties such as low chemical and mechanical coating stability, memory effect, expensive fibers, limited selection of commercially available fibers, fragility and limited lifetime of the fiber, and easy swelling in organic solvents. Therefore, most attempts such as this study have been focused on obviating the disadvantages of SPME. An experimental design optimization strategy (CCD) was applied for optimizing the important extraction parameters such as extraction temperature, extraction time, ionic strength and desorption time and temperature.