Solid/liquid phase microextraction of five bisphenol-type endocrine disrupting chemicals by using a hollow fiber reinforced with graphene oxide nanoribbons, and determination by HPLC-PDA

A novel solid/liquid phase microextraction (SLPME) technique was developed and applied to the simultaneous determination of five bisphenol-type endocrine disrupting chemicals (EDCs) including bisphenol A, bisphenol S, bisphenol F, bisphenol B and bisphenol AF. The method is based on the use of agraphene oxide nanoribbon-reinforced hollow fiber (GONRs-HF) and 1-octanol. GONRs were longitudinally unzipped from multiwalled carbon nanotubes (MWCNTs) by means of chemical oxidation and carefully characterized. GONRs were dispersed in ultrapure water with the assistance of surfactant and then immobilized into the wall pores of HF. Compared with CNTs, the hydrophilicity of GONRs was improved, and a uniform dispersion was formed. This simplifies the preparation process and reduces waste of materials. The pores and lumen of GONRs-HF were filled with 1-octanol, and then the whole assembly was used for the extraction of the analytes. In comparison with different extraction modes, GONRs-HF-SLPME exhibits a more effective extraction performance for five bisphenol-type EDCs. Response surface methodology was used to optimize experimental parameters affecting the extraction efficiency. The enrichment factors are in the range from 76 to 127 with good inter-fiber and batch-to-batch reproducibility. The method shows good linearity with determination coefficients (R-2) higher than 0.9985. The limits of detection are in the range of 0.1-0.4gL(-1). Recoveries from spiked real samples are between 83% and 114% with relative standard deviations between 1.6% and 7.8%.