Improved selective extraction of 3,3′-dichlorobenzidine by molecularly imprinted polysiloxane microspheres

This report shows an improved selective extraction of the 3,3′-dichlorobenzidine pollutant using molecularly imprinted polysiloxane microspheres (MIPS). 3,3′-Dichlorobenzidine and degradation products are of environmental concern due to their carcinogenic nature. Environmental samples containing 3,3′-dichlorobenzidine are very complex, and the concentration of 3,3′-dichlorobenzidine is usually very low. Current analysis of 3,3′-dichlorobenzidine in environmental matrices often requires cleanup and preconcentration steps that are complex and time-consuming. Therefore, we designed an improved analytical technique. MIPS were synthesized by covalent imprinting. MIPS were characterized by Fourier-transform infrared spectroscopy, nuclear magnetic resonance and transmission electron microscopy. MIPS size ranges from 150 to 250 nm. Adsorption capacity and recognition selectivity toward 3,3′-dichlorobenzidine were studied using ultraviolet spectroscopy and high-performance liquid chromatography. Compared with non-imprinted polysiloxane microspheres, results show that the amount of 3,3′-dichlorobenzidine adsorbed by MIPS is greater by a factor of ten. The binding capacity of MIPS for 3,3′-dichlorobenzidine is seven times larger than diphenylamine. MIPS exhibits high affinity to 3,3′-dichlorobenzidine and can be used for the selective extraction of 3,3′-dichlorobenzidine.