Sol-gel Coated Molecularly Imprinted Polymers As Novel Stationary Phase For Stir Bar Sorptive Extraction Of Bisphenol A

Bisphenol A (BPA), which is widely used in the production of plastic and epoxyresins, can disrupt endocrine system of human even at trace amount. Therefore, it isessential to monitor trace BPA in environment. In this work, we prepared a uniquestir bar coated with dummy molecularly imprinted polymers (DMIPs) of BPA bysol-gel method. A novel method for the determination of BPA by DMIPs-coated stirbar sorptive extraction coupled with high-performance liquid chromatography viafluorescence detection (HPLC-FLD) was developed and successfully employed todetect the trace amount of BPA in tap water.Stir bar sorptive extraction (SBSE), a simple and environmental friendly pretreatmenttechnique, has been widely used in trace analysis in environmental, foodand biomedical fields for its extraordinarily high sensitivity. In this study, we appliedsol-gel technique to prepare the stir bars coated with DMIPs for BPA. The scanningelectron microscopic image of the coating presented a homogeneous surface with athickness of about 57μm. Fourier transform infrared spectra of the coatingsconfirmed the incorporating of DMIPs with the sol-gel network.When used to extract BPA from aqueous solution containing BPA and its threeanalogues, the recoveries of BPA with DMIPs-coated stir bars were about 3~4 timesas much as those of 4, 4'-Dihydroxybiphenyl, 3~7 times those of 4-tert- Butylphenol,and 61~103 times those of 3, 3', 5, 5'-Tetrabromobisphenol A. Obviously, DMIPscoatedstir bars possessed high selective absorption for BPA. Moreover, the recoveriesof BPA with DMIPs-coated bars were stable even if the concentrations of each analogue increased, and this indicated the great anti-interferences ability of DMIPscoatedstir bars. Besides, DMIPs-coated stir bars showed larger extraction amountthan the bars coated with non-imprinted polymers (NIPs) or polydimethyl-siloxane(PDMS). The recoveries of BPA with DMIPs-coated bar were about 7 times as muchas those with NIPs-coated bar and 24 times with PDMS bar, respectively.The conditions of SBSE using DMIPs-coated stir bars were optimized and a newmethod to determine BPA in tap water was established by coupling DMIPs-SBSEwith HPLC-FLD. The method was validated with respect to linearity, range anddetection limit. The calibration curve showed good linearity with correlationcoefficient of 0.9994 in the concentration range of 0.0228?0.456 ng mL-1 of BPA.The limit of detection was about 5.70 pg mL-1 (S/N=3). Finally, the method built wasexploited to analyze BPA in tap water and showed good sensitivity. The spikedrecoveries of BPA were in the range of 81.7?98.2% with relative standard deviation10.2%.