A chromium(III) oxide-coated steel wire prepared by arc ion plating for use in solid-phase microextraction of aromatic hydrocarbons

摘要

The authors introduce an arc ion plating method for the deposition of chromium oxide (Cr2O3) on a steel wire substrate, and its use as a coating for solid phase microextraction. The coating has a micro-and nano-scaled structure after annealing at 700 degrees C. It is found that Cr2O3 exhibits a good extraction capability for the aromatic hydrocarbons naphthalene, anthracene, fluorene, fluoranthene, and biphenyl. Following desorption by high temperature at 300 degrees C, the analytes were quantified by gas chromatography (GC). The limits of detection are in the range between 20 and 200 ng.L-1, and calibration plots are linear within a wide range (0.2 to 400 mu g.L-1). The coating has excellent mechanical properties, with a hardness is as high as 31.7 GPa, and the adhesion strength between coating and substrate reaches 20.1 N (corresponding to the critical Hertzian contact stress of 10 GPa). This, along with the chemical and thermal stability of the Cr2O3 coating, endows the wire with a long operational life. It was used for at least 100 times without any obvious decline of extraction capability.