Dummy template based molecularly imprinted solid-phase microextraction coating for analysis of plasticizers in food samples

Abstract

Abstract A series of molecularly imprinted polymers (MIPs) were prepared on the surface of microspheres(CG161M) and applied as adsorbent for the rapid and selective detection of phthalates compounds, including diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP). Surface deposition and layer by layer self-assembling method were also utilized in the preparetion of molecularly imprinted polymers. The synthesized composites were characterized by Fourier transform infrared spectrometer, scanning electron microscope, thermo gravimetric analysis and Nitrogen adsorption analysis. The maximum adsorption capacities of the MIPs for DEP, DBP and DOP were 0.006, 0.008 and 0.007 mg g− 1, respectively. The adsorption of phthalates reached equilibrium within 260 min and complied well with pseudo-second-order kinetic model and Langmuir model. Dioctyl phthalate(DOP) was used as a dummy template for diethyl phthalate(DEP) and dibutyl phthalate(DEP), allowing selective and specific identification of DEP and DBP and did not affect the accuracy of the analysis even if the leakage of template occured. Moreover, MIPs-based hollow fiber stir bar sorptive extraction followed by gas chromatography-mass spectrometry was applied to the detection of DEP, DBP and DOP in several food samples. Under the optimum conditions, the limits of detection (LODs) for DEP, DBP and DOP were 0.0047, 0.0054 and 0.0031 mg L− 1, with spiked recoveries of 73.06–106.02% and relative standard deviations (RSDs) of 3.91–6.89%, exhibiting high adsorption capacity, good selectivity and fast kinetic towards DEP, DBP and DOP. Since the template of surface molecularly imprinted polymers could be changed with the analytes, MIPs-based molecularly imprinted polymers combining with hollow fiber stirring bar sorptive extraction can be a promising and selective method for separation and extraction of series analytes with similar structure in complicated samples without sample clean-up.