Molecularly imprinted polymer modified optical fiber sensor based on surface plasmon resonance spectroscopy for determination of atrazine

Abstract

A sensitive sensor device based on surface plasmon resonance (SPR) spectroscopy was developed on an optical fiber and made to be selective to atrazine by molecularly imprinted polymer. The SPR probe was fabricated by deposition of gold nanoparticles on the uncladed surface of an optical fiber by self-assembly method. The size and distribution of gold nanoparticle was optimized by varying the soaking time of the optical fiber. The surface was further modified for selective sensing of atrazine with the molecularly imprinted polymer (MIP). The MIP was synthesized via 2 methods, the first was thermal polymerization method, the MIP was then in-situ polymerized by dropping the pre-polymer solution on the surface of the SPR probe. The second method was atom-transfer radical polymerization or so calls ATRP. The MIP with ATRP was in-situ synthesized on the SPR probe by using thiol-gold bonding initiator of 4-bromo thiophenol. The polymer further grew by heating at 80°C for 1 hr in the oven. The ATRP showed that the amount of polymer could be controlled by incubation time, and showed the dip of resonance wavelength at 569.27 nm. The calibration of SPR probe modified with MIP via ATRP was established in the range of 0-30 ppm of atrazine for quantitative analysis. The % recoveries of spiked atrazine standard in real water sample were in the range of 88-104%. The limit of detection was 4.6 ppm.