Surface plasmon resonance in a D-shaped plastic optical fibre: Influence of gold layer thickness in monitoring molecularly imprinted polymers

For the detection of chemical agents in different environments, the combination of a D-shaped plastic optical fibre (POF) and a molecularly imprinted polymer (MIP) layer resulted as an effective way to obtain a low cost, highly selective and sensitive surface plasmon resonance (SPR) optical platform. In this work a deeper investigation on the dependence of performance of this optical platform on the gold film thickness is reported, aiming to the improvement of the signal to noise ratio. Preliminary results have been obtained on a specially developed SPR optical platform with a 30 nm gold layer and a new molecularly imprinted polymer as a receptor for the selective detection of dibenzyl disulfide (DBDS) in transformer oil. The experimental measurements confirm that a good compromise between high signal to noise ratio and high sensitivity of the developed optical chemical platform can be obtained by decreasing the gold layer thickness down to 30 nm.