Synthesis and application of molecularly imprinted polymers using sol–gel matrix imprinting technology for the efficient solid-phase extraction of BPA from water

Bisphenol A (BPA) is a synthetic organic compound widely used as a starting material in plastics synthesis. Highly selective BPA imprinted sol–gel silica-based hybrid inorganic-organic polymeric sorbent (sol–gel MIP) was synthesized via matrix imprinting approach for the extraction of BPA in water samples. Two functional sol–gel precursors, phenyl triethoxysilane (PheTES) and 3-aminopropyl triethoxysilane (3-APTES) were used to enhance functional selectivity. The application of tetraethyl orthosilicate (TEOS) as the cross-linking reagent ensures an open, sponge-like architecture facilitates the rapid removal of the template molecules and rapid analyte mass transfer during extraction. The inherent cage-like structure of the sol–gel MIP facilitates rapid extraction with relatively high imprinting factor. The extraction protocol was optimized using Central Composite Design (CCD) coupled to Response Surface Methodology (RSM). The optimum conditions require the use of 2 mL acetonitrile (ACN) and 15 min sample holding time. The cross-reactivity tests proved that the sol–gel MIP possesses higher specific retention and enrichment capacity for BPA compared to its non-imprinted analogue. The imprinting factor (IF) was equal to 6.58±0.23 (n=3) and the sol–gel MIP was adequately selective for BPA providing high absorption capacity. The molecularly imprinted solid-phase extraction combined with high pressure liquid chromatography photodiode array analysis method (MISPE-HPLC-PDA) was validated and demonstrated excellent linearity (0.995), high recovery (RE: 93.4 with RSD, n = 5), satisfying repeatability and precision over the range 90.7-96.1 ng μL−1 and 85.4-92.3 ng μL−1, respectively as well as adequately low detection and quantification limit for BPA (LOD: 0.015 ng μL−1, LOQ: 0.045 ng μL−1).