Graphene oxide/β-cyclodextrin composite as fiber coating for high efficiency headspace solid phase microextraction of organophosphate ester flame retardants in environmental water

A novel solid-phase microextraction fiber was prepared using graphene oxide/beta-cyclodextrin (GO/beta-CD) composite as a coating material immobilized on a stainless steel wire using sol-gel technique. The coating has large surface area with uniform porous structure, stable performance at high temperature, and good coating preparation reproducibility. The prepared GO/beta-CD sol-gel stainless steel fiber used as a headspace solid phase microextraction (HS-SPME) fiber was evaluated by the determination of organophosphate ester flame retardants (OPFRs) in water samples coupled to a gas chromatography/nitrogen phosphorus detector (GC/NPD). The studied OPFRs have a wide range of polarities and volatilities, and are not easily extracted by conventional commercial SPME fibers simultaneously. The prepared GO/beta-CD SPME fiber showed good extraction performance for all the studied OPFRs. The developed HS-SPME-GC/NPD method provided low limits of detection ranging between 1.1 and 60.4 ng L-1. Good intra- and inter-day precision expressed as relative standard deviations for a single fiber were in the range of 2.2-9.6% and 2.7-9.7%, respectively, and fiber-to-fiber reproducibility was in the range of 6.3-10.9%. The calibration curves were linear in the concentration range from 10 to 50 000 ng L-1 (R > 0.9955). The developed method was applied for the analysis of tap, lake and river water samples and the relative recoveries were found to be in the range from 82.1 to 116.9%. Based on these features, the proposed fiber has great potential for widespread use as an effective and useful extraction tool.