Electrochemical deposition of highly porous nanostructured copperoxide foam fiber as a novel sorbent for solid phase microextraction method

the past two decades, the determination of different compounds such as BTEXs in different environmental samples has received great attention because of their toxicity for human and the environment. Direct analysis of the pollutants is not possible because of low concentration of these compounds in environmental samples. So separation and pre-concentration steps are required prior to final analysis. Solid phase microextraction (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 have been focused on obviating the disadvantages of SPME. Nevertheless, the synthesis procedures are relatively complex, time consuming and difficult. Herein, a new headspace solid phase microextraction technique based on using a copper oxide foam nanostructure substrate followed by gas chromatography-flame ionization detection was developed for the determination of BTEXs in water and wastewater samples. The copper foam with highly porous nanostructured walls was fabricated on the surface of a copper wire by a rapid and facile electrochemical process during 3 seconds. Then the prepared copper foam was converted to copper hydroxide by hydrothermal method and finally changed to copper oxide foam by the thermal process. Finally, the fiber used for the microextraction of benzene, toluene, ethylbenzene and xylenes. The experimental parameters such as desorption temperature, desorption time, salt concentration, sample temperature, equilibrium time and extraction time, were investigated and optimized by experimental design method. The fiber-to-fiber reproducibility for three fibers prepared under the same condition was 5.6-8.4%.