A silica fiber coated with a ZnO-graphene oxide nanocomposite with high specific surface for use in solid phase microextraction of the antiepileptic drugs diazepam and oxazepam
1.Department of Chemistry, Faculty of Science,University of Qom,Qom,Iran;2.Department of Analytical Chemistry, Faculty of Chemistry,K.N. Toosi University of Technology,Tehran,Iran
Abstract:
A novel ZnO-graphene oxide nanocomposite was prepared and is shown to be a viable coating on fused silica fibers for use in solid phase microextraction (SPME) of diazepam and oxazepam from urine, this followed by thermal desorption and gas chromatographic quantitation using a flame ionization detector. A central composite design was used to optimize extraction time, salt percentage, sample pH and desorption time. Limits of detection are 0.5 μg·L?1 for diazepam and 1.0 μg·L?1 for oxazepam. Repeatability and reproducibility for one fiber (n?=?4), expressed as the relative standard deviation at a concentration of 50 μg·L?1, are 8.3 and 11.3% for diazepam, and 6.7 and 10.1% for oxazepam. The fiber-to-fiber reproducibility is <17.6%. The calibration plots are linear in the 5.0–1000 μg·L?1 diazepam concentration range, and from 1.0–1000 μg·L?1 in case of oxazepam. The fiber for SPME has high chemical and thermal stability (even at 280 °C) after 50 extractions, and does not suffer from a reduction in the sorption capacity.
Graphical abstract A hydrothermal method was introduced for preparation of ZnO- GO nano composite on a fused silica fiber as solid phase microextraction with high mechanical, chemical stability and long service life
