Graphene grafted magnetic microspheres for solid phase extraction of bisphenol A and triclosan from water samples followed by gas chromatography-mass spectrometric analysis

Graphene grafted magnetic microspheres were prepared and used as the adsorbent for magnetic solid phase extraction (MSPE) of bisphenol A and triclosan from water samples prior to their determination by gas chromatography-mass spectrometric (GC-MS) detection. A new customized ground-glass stoppered conical flask with a side tube was used for MSPE operations to simplify the separation of the magnetic adsorbent from the sample solution. The main experimental factors affecting the extraction recoveries of the analytes including the amount of adsorbent, pH of the sample solution, extraction time, salt concentration, desorption conditions, and derivatization conditions were investigated. Under the optimal conditions, a linear response was observed in the concentration range of 0.05-2.50 mu g L-1 for bisphenol A and 0.10-5.00 mu g L-1 for triclosan. The limits of detection (S/N = 3) were 10.0 ng L-1 for bisphenol A and 20.0 ng L-1 for triclosan. The established method was applied to the determination of bisphenol A and triclosan residues in environmental water samples with satisfactory results. The recoveries of the analytes using this method from lake, river, bottled and tap water samples were in the range from 93.9% to 104.3% (intra-day), and from 93.5% to 99.5% (inter-day) with the relative standard deviations varying from 2.1% to 5.8% (intra-day), and from 3.1% to 5.7% (inter-day).